Explain How to Plan Essay Example for Free

Explain How to Plan Essay Define the key concepts and principles of assessment Assessment is the way of finding and documenting that learning has taken place. It also enables you as the assessor to identify if the learner has achieved the required competencies, skill and knowledge needed at the given point of assessment towards their qualification. Assessment need to be a regular process built into the training program. The starting point of assessment is the pre-course information. It must be explained when assessment is taking place and what form the assessment will be in. Criteria for success must also be given. Explain the responsibilities of the assessor Attending meeting, exhibitions, award ceremonies, presentation events; Carrying out assessments in accordance with organisations requirements; Checking the authenticity of any whiteness testimonies; Completing and maintaining safe and secure records; Countersigning other assessor’s judgements; Dealing with any appeals made against your assessment decisions; Following organisational and regulatory body procedures; Identifying and dealing with and barriers to fair assessment; Implementing internal and external verifier’s action points; Liaising with others involved in the assessment process; Making judgements based on the assessment criteria; Maintaining occupational competencies; Negotiation and agreeing assessment types and methods; Making best use of different assessment types and methods; Providing statistics to managers; Reviewing learner’s progress; Standardising practices with other assessors; Supporting learners with special requirements; Working towards relevant qualification; Identify the regulations and requirements relevant to the assessment in your own area of practice The Health and Safety (First-Aid) Regulation 1981 Provide adequate first aid equipment, facilities and people. Health and Safety at Work (MHSW) Regulations 1999 Assess the risks on anyone who may be affected by their activities. The Safeguarding Vulnerable Groups Act 2006 Duty to register and undergo vetting process if working with vulnerable groups Equality Act 2010 Non-discrimination of age, disability, gender, race, religion/belief and sexual orientation. Q2 – Understand different types of assessment record Compare the strengths and limitations of a range of assessment methods with reference to the needs of individual learners ASSIGNMENT – Several activities or tasks, practical or theoretical, to assess various aspects of a qualification over a period of time. Strengths Challenges a learners potential Consolidate learning Several aspects of a qualification can be assessed Some assignment are set with clear criteria by awarding organisation Limitations Ensuring all aspects of the syllabus are covered Can be time consuming to prepare and assess Must be individually assessed with written feedback Assessor may be biased when marking CASE STUDY / SCENARIOS – Hypothetical situation, a description of an actual event or incomplete event, enabling learners to explore the situation. Strengths Can make topics more realistic enhancing motivation and interest Can be conducted individually or in a group Builds on current knowledge and experience Limitations If assessed in a group roles need to be individually assigned an personal contribution assessed Time should be allowed for a debrief Must have clear outcomes Can be time consuming to prepare and assess CHECKLISTS – A list of criteria that needs to be met to confirm that competence or achievement. Strengths Can form part of an ongoing record of achievement or profile Assessment can take place when the learner is ready Ensures all criteria are met and records are kept Limitations Learners may lose their copy and not remember what they’ve learnt ESSAYS – A formal piece of written text that has been produced by the learner for a specific topic Strengths Useful for academic subjects Can check your learners language and literacy skills at specific levels Limitations Not suitable for low level learners Marking can be time consuming Plagiarism can be an issue Doesn’t normally have right or wrong answer so can be difficult to grade Learners need good writing skills EXAMINATIONS – A formal test that should be conducted in certain conditions. Strengths Can be Open Book, enabling learners to have books and notes with them Some learners like the challenge of a formal examination and cope well Limitations Invigilation required Security arrangements before and after need to be in place for papers Learners may have been taught purely to pass the examination Learners may be anxious HOMEWORK – Activities carries out between sessions like answering questions on that day’s learning to confirm knowledge. Strengths Learners can complete at a time and pace that suits them Maintains an interest between sessions Encourages learners to stretch themselves Consolidates learning so far Limitations Clear time limits must be set Learners might not do it, or get someone else to do it for them Must be read/marked and individual feedback given OBSERVATIONS – Watching learners perform a skill. Strengths Enables skills to be seen in action Learners can make mistakes enabling them to realise what they’ve been doing wrong Can assess several aspects of a qualification at the same time Limitations Timing must be arranged No permanent record Questions still need to be asked to confirm understanding Assessor might not be objective with decision Q3 – Understand how to plan assessment Summarise key factors to consider when planning assessment Subjects can be either non-accredited (no formal certificate) or accredited (certificate issued) in which case delivery and assessments are monitored by awarding organisation to ensure guidelines are followed. Therefore before assessing:- You need to be fully aware of the program and the qualification that you are assessing You must confirm relevant policies, requirements and qualifications of the particular subject You must know when the learners are ready to be assessed Evaluate the benefits of using a holistic approach to assessment Explain how to plan a holistic approach to assessment Explain how to minimise risks through the planning process.

Distracted Driving Statistics

Distracted Driving Statistics Kaitlyn DAgati   According to the website, Distraction.gov, distracted driving is defined as any activity that could divert a persons attention away from the primary task of driving. In 2015, the State of Florida recorded a total of 45,740 traffic accidents that were a direct result of distracted driving. Of the total number of distracted driving accidents recorded, a total of 39,396 injuries were reported and, sadly, 214 people lost their lives as a result of distracted driving accidents. With astounding statistics as these, some would ask, is the State of Florida doing enough to prevent distracted driving? Given the statistics, the answer appears to be that the state is not doing enough to educate the public about the dangers of distracted driving although some may argue that it has. In order to make a proper determination, it is important to fully understand what distracted driving is, examine the statistics of distracted driving, and explore what more can be done in order to bring awareness to th e dangers of distracted driving. First, in order to properly discuss the topic of distracted driving, it is important to fully understand what distracted driving actually is. As defined earlier, distracted driving involves any activity that would cause the driver of vehicle to divert their attention (Distraction.gov). According the article entitled, Focus on Driving Florida distracted driving can be further broken down into three different categories: visual, manual, and cognitive (Focus on Driving Florida). Any activity that would require a driver to take their eyes off the road is would be a visual distraction. Manual distractions would require that the driver take their hands off the wheel; whereas, cognitive distractions involve the driver thinking about things other than driving (Focus on Driving Florida). Examples of distracted driving include: eating, grooming, unsecure pets, adjusting vehicle control. One of the most dangerous forms of distracted driving is texting because it involves all three categories of distraction: visual, manual, and cognitive. Next, in order to better grasp the growing problem of distracted driving, it is important to examine the statistics. In 2014, it was reported that 3,179 people were killed and another 431,000 people were injured in accidents that involved distracted drivers (distraction.gov). However, just the following year, the State of Florida reported that 214 people lost their lives in accidents due to distracted driving. When averaged out among the different states, the statistics provided in 2015 by the State of Florida appear to be an increase in the amount of injuries and fatalities caused by distracted driving. It is reported that in any given month, 169.3 billon text messages are sent across the US territories and approximately 660,000 drivers are using their cell phones or electronic devices at any given moment (distraction.gov). Additionally, it has been noted that the amount of drivers observed texting has increased from 1.7 percent in 2013 to 2.2 percent in 2014 (distraction.gov). Fina lly, and perhaps most scary of all, is that it only takes 5 seconds for a distracted driver going about 55 mph to cover approximately 100 yards, which equals the length of a football field (distraction.gov)! Finally, in order to begin to reverse the statistics discussed above, it is important to explore what more can be done in order to bring awareness to the dangers of distracted driving. In 2013, the State of Florida began issuing traffic citations for distracted driving and the number of citations issued since the start has steadily climbed. Currently, texting while driving is considered a secondary offense, which means an officer has to pull a driver over for another reason before the driver can be issued for texting while driving. The fine for the first offense for texting and driving is thirty dollars and isnt considered a moving violation. A second offense within a five-year period could result in a sixty dollar fine and would be considered a moving violation which would add points to the drivers license (Isger, S., 2013). At this time, drivers are allowed to use their phones while stopped at a light or stuck in traffic. In addition, drivers are allowed to speak on their phone whi le driving and can use their phone while driving to check maps, use voice commands, or for other programming (Isger, S., 2013). The State of Florida has attempted to bring awareness to the danger of distracted driving by releasing radio public service announcement ads and launching a social media campaign using the hashtag of FocusonDrivingFL on Twitter and Facebook (Focus on Driving FL). However, according to the article entitled, Brutally Honest: How to keep your teens from texting and driving that was published in August of 2016, 55% of young adult drivers believed that texting and driving was easy while 34% of teens admitted that they had texted while driving even though forty-four states passed laws making it illegal to text and drive (Wallace, 2016). Teens interviewed for the story admitted that they had seen their parents driving while they were distracted including texting while driving. With this knowledge, it soon becomes apparent that the State of Florida has failed to ad equately do enough to educate drivers both young and old so this begs the question, what more can the state do? First, it appears that the campaigns to bring awareness to this issue either need to be more consistent or need to reach a greater audience. The social media campaign stopped with just two platforms: Facebook and Twitter. Although more adults are on Facebook than ever before, most teens have fled that social networking site just for that reason. Instagram has quickly overtaken Twitter as the choice among many teens, yet the State hasnt attempted to launch campaigns on the social networking site. Additionally, tougher penalties need to be considered when a driver is caught texting and driving. In reality, most people will pay more for their designer coffee in a week than they will if they were ticketed for distracted driving! Finally, the state should consider more in-school campaigns, including those that have been injured or caused the injury of someone else because of di stracted driving. It seems as though these type of visual demonstrations have a major impact on teens. In conclusion, distracted driving is defined as any act that would require the driver to divert their attention from the task of driving. Distracted driving can fall into three different categories: visual, manual, and cognitive with some behaviors, such as texting falling into all three categories. The statistics have shown that the incidents of accidents, injuries, and deaths have continued to rise over the last couple of years. Given this information, it soon becomes apparent that the State of Florida has failed to do enough to educate drivers to the dangers of distracted driving. In order to begin to reverse these statistics, it is necessary for drivers, both young and older, to become more educated about the dangers of distracted driving. Works Cited Facts and Statistics. Distracted Driving : Facts And Statistics. N.p., n.d. Web. 11 Dec. 2016. . Florida Distracted Driving Awareness. Florida Highway Safety and Motor Vehicles. N.p., n.d. Web. 11 Dec. 2016. . Sonja Isger Palm Beach Post Staff Writers 10:18 P.m Monday, Sept. 30, 2013 Florida and Legislature News. Texting While Driving Illegal in Florida Starting Tuesday. Texting and Driving in Florida Illegal Tuesday. Palm Beach Post, 30 Sept. 2013. Web. 11 Dec. 2016. . Wallace, Kelly. Brutally Honest: How To Keep Your Teens From Texting and Driving. CNN. Cable News Network, 1 Aug. 2016. Web. 11 Dec. 2016. .

Pearl Harbor :: essays research papers

PEARL HARBOR AMERICA ENTERS THE WAR   Ã‚  Ã‚  Ã‚  Ã‚  December 7, 1941, â€Å"A date that will live in infamy,† was the name that our President gave the worst military attack ever on United States soil, Pearl Harbor. It all started in May 1940, when Japan sent Kiichi Gunji to the newest Pacific Battle Ship Port. We chose to read this book because we both are interested in Pearl Harbor and the new movie about it.   Ã‚  Ã‚  Ã‚  Ã‚  A major incident in the book Pearl Harbor was how the Japanese got all of the information it needed to attack the United States. They came over by a cruse ship from Japan to Hawaii and went around Hawaii like tourists. Yoshikawa and Mikami was the main spy who went around the island in a taxi with the driver named Kotoshirodo. They spied from several spots but liked the pier at Pearl City the best. He liked it so much because he could see the Pearl Harbor and the naval air strips on Ford Island from there. He went every so often so he did not make anyone too suspicious and also made sure he never went in the same clothing each time he went. He sent all the information he gathered and sent it back to Japan to be looked over. These spies where a major part of the story and the way the book ended. Another major event in this story is when the author talked about Yamamoto’s Operation Hawaii and all the problems with them. In February 1941, Commander Minoru Genda was assigned to Yamamoto’s Operation Hawaii. His comment was the plan was difficult but not impossible; but he turned down a lot of Yamamoto’s idea. Some ideas he didn’t keep were: the plans would take off from carriers about 500 miles from Hawaii. They would not have enough gas to make the trip there and back to the carrier ships, so Yamamoto’s plans to fly towards the carriers until their gas ran out and ditch in the Pacific, was scrapped. Genda wrote up a new plan that had the attack starts at dawn and should be a total surprise. Carriers would refuel at sea at Midway Island, and the planes would drop torpedo, dive, and high-level bombing on the United States ship and planes. Pearl Harbor :: essays research papers PEARL HARBOR AMERICA ENTERS THE WAR   Ã‚  Ã‚  Ã‚  Ã‚  December 7, 1941, â€Å"A date that will live in infamy,† was the name that our President gave the worst military attack ever on United States soil, Pearl Harbor. It all started in May 1940, when Japan sent Kiichi Gunji to the newest Pacific Battle Ship Port. We chose to read this book because we both are interested in Pearl Harbor and the new movie about it.   Ã‚  Ã‚  Ã‚  Ã‚  A major incident in the book Pearl Harbor was how the Japanese got all of the information it needed to attack the United States. They came over by a cruse ship from Japan to Hawaii and went around Hawaii like tourists. Yoshikawa and Mikami was the main spy who went around the island in a taxi with the driver named Kotoshirodo. They spied from several spots but liked the pier at Pearl City the best. He liked it so much because he could see the Pearl Harbor and the naval air strips on Ford Island from there. He went every so often so he did not make anyone too suspicious and also made sure he never went in the same clothing each time he went. He sent all the information he gathered and sent it back to Japan to be looked over. These spies where a major part of the story and the way the book ended. Another major event in this story is when the author talked about Yamamoto’s Operation Hawaii and all the problems with them. In February 1941, Commander Minoru Genda was assigned to Yamamoto’s Operation Hawaii. His comment was the plan was difficult but not impossible; but he turned down a lot of Yamamoto’s idea. Some ideas he didn’t keep were: the plans would take off from carriers about 500 miles from Hawaii. They would not have enough gas to make the trip there and back to the carrier ships, so Yamamoto’s plans to fly towards the carriers until their gas ran out and ditch in the Pacific, was scrapped. Genda wrote up a new plan that had the attack starts at dawn and should be a total surprise. Carriers would refuel at sea at Midway Island, and the planes would drop torpedo, dive, and high-level bombing on the United States ship and planes.

Essays --

Bearing in mind the aim of creating ranking criteria to support GPIC’s decision in choosing the most insurance company which it can rely on to pay its money back in case of a claim. Background research was initially performed to gain both knowledge and information regarding the Insurance industry in the Kingdom of Bahrain and worldwide. This knowledge in turn helped us to reach to our final deliverable. This criterion was based on a number of factors, to name them: †¢ Insurance company reputation both locally and worldwide †¢ Core business percentage & Insurance company area of specialty †¢ Nature of the insurance company, the question of is it a consolidated or non-consolidated company was the main concern. †¢ Insurance company performance based on specific ratios (detailed in the Financial analysis) †¢ Based communication networks so customers can reach them easily: available branches, online communications (website, e-mails), and clear communication lines including telephone numbers, faxes etc. Search Methodology and criteria formulation- Limitations and Difficulties: Before reaching t...

Technologies Impact on the Legal Profession Essay -- Law Lawyer Techno

Technologies Impact on the Legal Profession Law is a profession that has been important to the culture of our world since its beginning. Societies across the globe are each governed by a unique fabric of ethics and laws. Therefore, each culture has its own system formed to enforce those designated codes and standards. As early as 1792 B.C., the Babylonians had a written code of law. Known as the Hammurabi, this set of articles was designed to set up an orderly society. [1]Our government is formed by the Constitution laid out by our fore fathers in the early eighteenth century. This document lays out the form of our three branched government system, consisting of the legislative, executive, and judiciary braches. The judiciary branch is shaped as a system of courts to judge citizens that have broken the rules that are set by the legislative branch. In the majority of these courtroom scenarios, lawyers are used to argue for both the defense and the prosecution. The law professional, because of this, is one profession that has re mained interminable throughout history. Although law has always been with us, it does adapt to the present culture, and its effectiveness is based on the technologies of the day and the ability to best utilized them and grow with them. The men that formed the government of the United States realized that they had to form a system that would not only provide fairness and legal equality for its citizens, but also be able to adjust to the changing culture to endure that it remains fair for all generations. They understood that as society evolved over time, there would need to be new laws created to govern new crimes. In the years that our country was founded, modern technologies did not exist. Therefor... ...m a computer. These forms of research are important for business cases and can even be useful in the identity theft crimes that have become so widespread. There will of course have to be standards set regarding what information is allowable in the courtroom, and how far a lawyer may go to get the research. Technology however has opened many windows of possibility that at one time were not available. The legal profession may have been a profession practiced and embossed on our culture by our forefathers, but with today’s use of technology, it has evolved in many ways. It now utilizes forms of scientific research and the latest forms of researching tools, to help keep a society in order and to give peace to every citizen. A lawyer’s job is an important one, and the technological progressions in our culture have done much to advance its strength and effectiveness.

Comment Cuisiner Son Mari a L’africaine: How-to Manual or Cautionary Tale

De tous les arts, l'art culinaire est celui qui nourrit le mieux son homme. – Pierre Dac Calixthe Beyala was born in Cameroon in 1961. She was very disturbed by the extreme poverty of her surroundings. She went to school in Douala, and she excelled in Mathematics. Calixthe Beyala traveled widely in Africa and Europe before settling in Paris, where she now lives with her daughter. Beyala has published prolifically, and her most recent novel, which came out earlier this year, is called La Plantation.Beyala’s novel Comment cuisiner son mari a l'africaine appeared in the year 2000, published by Albin Michel. It is similar in structure to Laura Esquivel's Like Water for Chocolate, where the narrative is interrupted by the recipes which figure in the plot line. In her book, Beyala includes twenty-four of the recipes which her heroine Aissatou prepares to attract her neighbor and compatriot, Souleymane Bolobolo. In this way the book serves as a how-to manual, as its title sugg ests, on how to seduce, marry and keep a husband by cooking for him.The book begins with a prologue in the form of a legend where a woman arrives at the remote home of the recluse, Biloa. She announces that she has dreamed of him since she was a little girl, and that she has always known that they would marry. Biloa protests that he isn't the one she is seeking, repeating â€Å"Ce n'est pas moi†, but the woman tempts him with food so Biloa admits his identity, â€Å"C'est peut-etre moi,† and takes the woman and the basket of food into his house. This, according to the legend, is how Biloa came to be a member of the society of men.This prologue does, indeed, prefigure the struggles of Aissatou, our novel's heroine, who is a une dame-pipi28 caught between her identity as a Parisian and as an African. Fed up with romantic disappointments, she has chosen her neighbor Bolobolo to be her husband, though she hasn't really even met him. Aissatou, who habitually eats only three grated carrots for her dinner, and always takes her tea without sugar in order to maintain her slim figure goes to a marabout for advice on how to seduce Bolobolo, and is provoked by the other women that are also waiting there for advice.According to them, Aissatou's problem is that she is too skinny, and they lament the fact that â€Å"ces filles d'aujourd'hui ne savent meme pas cuisiner†¦.. et ca se veut des femmes. â€Å"29 Aissatou takes this all to heart and armed with the recipes she learned from her mother and grandmother, she attacks her neighbor on the culinary front. She begins by bringing â€Å"beignets aux haricots rouges† to Bolobolo's elderly mother who is suffering from a mental illness, and then continues tempting her neighbor with other exotic and spicy dishes.Aissatou is not unopposed, however, and deals with her rival, Bijou, by again eclipsing her performance in the kitchen. Eventually, Aissatou does seduce Bolobolo, and after his mother's death, t hey do marry. But the story doesn't end here. In an epilogue, the reader gets a glimpse of Aissatou and Bolobolo's marriage twenty years later. Aissatou admits that she cooks to save her marriage, which is constantly imperiled by her husband's infidelity.But, as her mother had told her, â€Å"There comes a time when one must prefer one's marriage to one's husband,† and so Aissatou sacrifices her pride and tends her relationship in the kitchen even though she realizes that her husband is an adulterous coward. The epilogue leaves a bitter taste at the end of such a delicious novel, but it keeps it honest, and doesn't allow it to seem like the simple re-telling of the legend of Biloa. Whereas the themes of food and cooking often serve as expressions of nostalgia in other novels, in Beyala's book, food is a language spoken by the different characters.Aissatou hears her mother's voice prescribing certain dishes to mend a broken heart and other dishes to soothe herself and her fami ly, for as she says, â€Å"Ventre plein n'a point de conscience. â€Å"30Her daughter, however, doesn't initially have the same reaction when feeling low and instead she makes herself a bowl of ‘veritable soupe chinoise en sachet. ‘ This means that prior to her decision to seduce Bolobolo by cooking for him, the only cooking that Aissatou undertakes is nothing more than adding water to a dried powder and heating it up.The fact that the dried powder is identified as ‘real’ and ‘Chinese’ point to the fact that it is really neither. Aissatou is not concerned with her food’s quality or ethnicity, and cares only about its convenience and calorie count. In the course of the novel, Aissatou will give up her proclivity for these ‘inauthentic’ foods and begin to enjoy the foods of West Africa prescribed by her mother and other African characters. In Beyala’s book, African food is imbued with nearly magical qualities. Yes, it does put meat on the bones of those who enjoy it, but it also excites the senses, and inflames the passions of those who eat it.Moreover, the true connoisseurs and sages of African food are all women. Even when Aissatou goes to consult a marabout about her love life, it is the women who actually reveal her ‘diagnosis. ’ Maimouna, who is known as ‘la cheftaine-reine des cuisines† amongst the women at the marabout’s apartment says that Aissatou’s problem is that she is too thin, and that a certain spicy shrimp dish will always attract a man. Once Aissatou decides to begin cooking African food in order to achieve her goal of seducing Bolobolo, she is also able to influence other situations through her cooking.She decides to provoke a macho response in her passive male best friend and prepares a jus de gingembre, a drink formulated to send him into a frenzy of desire, just to see what will happen. When confronted by her angry rival, mademoiselle Bi jou, she cooks a bouillie de mil for her to show that she is civilized and in control of the situation. Later, angered by Bijou's assessment of her relationship with Bolobolo, she also takes revenge on him by putting a laxative in a favorite dish of his. And of course, Aissatou's prime objective, clinched by her pepe-soupe aux poissons, is to arouse an appetite for passion within Bolobolo.Aissatou is speaking through her cooking, revealing her desires and fears, using food to express those things which she cannot explicitly state. In addition to its function as a way to provoke a physical response in the eater, food acts as an important cultural identifier in this novel. Through it we see the transformation of Aissatou from Parisian, back to African and from white, back to black. In other words, she effectuates a reverse migration, and food and cooking are the vehicle that she uses to bring herself back to her roots.Though this migration is easy to track, as she embraces her motherà ¢â‚¬â„¢s attitudes toward food, cooking and even marriage, it is more difficult to find Aissatou’s point of departure. In the beginning, Aissatou’s very racial and ethnic identity is called into question by Beyala’s own publisher’s blurb on the back of the novel itself. It describes her as  « une Parisienne pure black en proie au tourments de l’amour.  »31 But Aissatou claims that her self-imposed exile in France has made her forget the fact that she is black and that she doesn’t know when she became white.She admits that she has become white by imitating the thin, white Parisian women who are, as she is, completely caught up in the constant pursuit of beauty that is calculated to please men. She realizes that she has adopted a foreign mentality when it comes to her own body image and describes herself thus: â€Å"Moi, je suis une negresse blanche et la nourriture est un poison mortel pour la seduction. Je fais chanter mon corps en eplu chant mes fesses, en rapant mes seins, convaincue qu'en martyrisant mon estomac, les divinites de la sensualite s'echapperont de mes pores. 32It is interesting to note the use of the kitchen techniques, which indicate how previously her only cooking projects served to keep her thin. She combines these techniques where she literally scrapes her body until it is thin with words like martyr and divinity, playing into the idea that the denial of food in order to remain thin is a somehow sacred task. This is a long-standing dialectic, where women align divinity and asceticism when that same asceticism really represents a societal imperative to conform to ideals of beauty.This statement is a declaration of success; she has martyred her body in order to be desirable, and therefore white. Though Aissatou admits that she diets constantly and obsessively, like other Parisian women, she also lies about what she eats, just for the sake of being cruel. When asked about her diet by an apparently jealous overweight woman, Aissatou joyfully tells her that she has, since her birth, eaten, â€Å"le coq au vin, arrose d’un bon beaujolais nouveau; les epaules d’agneau aux champignon noirs, le ris de veau a la creme fraiche et le couscous mouton a la tunisienne. 33Of course, it is completely untrue that she ever indulges in such rich food, and certainly doubtful that she ate these traditional French dishes as a child in Cameroon. It is worth noting the inclusion of Tunisian couscous with the list of very traditional French food. Couscous has entered the repertory of French foods and is a common dish, despite its colonial origins. Though one may argue about the ‘authenticity’ of a Parisian â€Å"couscous a la Tunisienne† and how it plays on French ideas of exoticism, it is undeniably a part of French cuisine.This is in contrast to sub-Saharan African cuisine, which is much more difficult to find in the capital. Though you can eat couscous in every arrondissement, you would be hard pressed to find many restaurants that serve food from West Africa or the provisions necessary to make them at home. With this book, Beyala presents a fictionalized cookbook, and if the intrepid home cook should retrace the steps of the heroine, it could even serve as a guide for shopping for the ingredients in the recipes.As mentioned previously, this book’s structure is similar to other popular novels where recipes for the dishes prepared by characters are included, like Frances Mayes’, Under the Tuscan Sun, and Laura Esquivel’s, Like Water for Chocolate. But in these novels, the recipes are most often a part of the narration itself and sometimes are even recounted by one character to another, mimicking the traditional way that cooking recipes are transmitted, orally, from one cook to another, most often mother to daughter.In Beyala’s book, which features African characters who themselves benefited from the oral traditi on of passing down culinary knowledge, Beyala’s chooses to completely disconnect the recipes from the text, placing them on a separate page at the end of the chapter, and printing them like a traditional recipe that could be found in any cookbook or magazine article. Also, Beyala’s book differs from Mayes’ and Esquivel’s because their novels are both set in a time or place that is foreign to the reader.Esquivel’s novel is set during the Mexican revolution, and Mayes’ is set in Italy, and their settings automatically place them in a foreign and/or exotic locale. Despite this fact, the reader can easily recreate the recipes that their characters make, thereby exoticising themselves by their appropriation of the foreign meal. In contrast, Beyala’s book is both more accessible in its setting, and less accessible to the home cook. Comment cuisiner son mari a l’africaine is set in the present-day French capital and is completely reco gnizable in terms of its location and lifestyle.But re-creating the recipes that Aissatou makes is nearly impossible, because many of the ingredients listed in these recipes are not translated or even described. Though it would seem that this cookbook is intended for other immigrant women to use in re-creating dishes from West Africa, the lack of information about ingredients or possible substitutions runs counter to other cookbooks with similar propositions. Therefore, the status of the book as a manual is questionable, since it is not clear that one can even follow the recipes.Beyala’s book may just be using the recipes as other novels use illustrations. They are glimpses of a foreign culture provided by the author in order to pique the interest of the reader, just as an illustration does. Beyala’s location of the text in Paris is key in the novel, because it allows her to set up a cultural dialectic between France and Cameroon. Her heroine must navigate the multicul tural space of the post-colonial capital to assess the compromises and concessions that white and black women make.Aissatou is caught between her Parisian reality where sexual value is based on how thin a woman is, and her memories of her mother's advice which promoted the importance of domesticity and especially culinary satisfaction in the life of a couple. â€Å"Un homme qui vous fait ressentir de telles emotions†¦.. merite le paradis,†34 she would say as she seasoned a dish to please her man. Aissatou imagines the questions that her mother would have asked her if her daughter had come to her after a failed love affair.Her mother would have asked if first, she had satisfied him sexually, second, if she had kept the house well, and third if she had prepared nice dishes for him. As Aissatou begins cooking savory dishes for herself her thin figure fills in with more womanly curves, eliciting pitying looks from some who think that she has let herself go, and approval from others. Race, beauty, food and sex are all locked into an uneasy correlation that she cannot accept. She gives up on the idea of maintaining a French, i. e. thin, ideal of beauty and trades it for the African ideal of sensual pleasure of food as a means to attract men.Interestingly, she does not trade her French beauty regimen for an African one. She even cites the methods that she is unwilling to follow and decides that braiding her hair, massaging herself with shea butter and pretending to be fragile is not for her: â€Å"Rien qu’a y penser, je m’epuise comme si c’etait deja a l’ouvrage. †35 This return to her roots is unquestionably problematical for Aissatou. She is torn between the two worlds constantly. For example, when she sees Bolobolo leaving the apartment building, she is struck by her sudden ‘African’ reaction: â€Å"Si j'etais sa femme, je serais restee a la maison a l'attendre. But just as quickly she asks herself, â₠¬Å"Mais pourquoi dans le partage des roles les femmes doivent-elles garder le foyer, cuisiner, allumer les lampes†¦. jusqu'a ce que mort s'ensuive? †36This is the same reaction that she has when she asks herself if she is capable of using African methods of seduction. Aissatou’s onerous task is to reconcile her African mother’s advice on how to seduce and hold on to a man with her French post-feminist questions about that role. She knows that her mother is right, and that she will be able to seduce this African man by appealing to his sensual desires and African identity.So, she picks at Bolobolo's sensibilities as an African man and critiques him for doing the marketing himself, saying: â€Å"Vous vous etes finalement bien adapte a l'Occident qui voudrait que l'homme soit une femme et l'inverse. †37In this way, she calls attention to the cultural difference in the French and African views on the traditional division of labor and highlights the fact t hat she and Bolobolo share a common culture, though they may be forced to adapt to French practices.Aissatou also seeks to call attention to their shared culture when she uses Bolobolo's mother's condition as an excuse to get involved, which she does with ulterior motives: â€Å"J'ai l'impression que mon discours est en decalage, espace et temps. Je sais que j'ai eu une reaction africaine ou tout le monde se mele des casseroles etrangeres. â€Å"38 This statement is telling because it shows that Aissatou knows that she is acting in bad faith.She knows that she has rejected certain aspects of African seduction and that she is not being honest about her intentions, but she nevertheless goes forward with her culinary seduction of Bolobolo and his mother. When Aissatou brings the beignets to Bolobolo's mother he mentions that she mustn't have anything better to do if she is cooking for others, but Aissatou reminds him: â€Å"Oui, parce que dans ce pays il faut etre vieux ou au chomag e pour se rendre compte qu'il est important que l'on s'occupe des autres,† again setting herself apart from the French and reminding him that they are compatriots.She finally gains access to his house with this plate of food. Once inside, she professes that she loves to cook and he answers that he loves to do dishes, seeming indicating that they are ideally suited for each other, but also indicating that he may be an African man, but he has adapted to a non-African setting. And this is the prime reason that Aissatou cooks, and especially why she cooks African food, to spark Bolobolo's passion for her. Aissatou cooks constantly, and she cooks the most exotic dishes and uses ingredients that she must search for in all the African boutiques of the capital.Her apartment building is infused with the heady aromas of African cuisine, which causes different reactions among her French neighbors. The concierge battles the smells of cooking with the Airwick spray, but the old lady who li ves on the first floor creeps up the steps to hover on the landing while Aissatou is cooking. Aissatou’s cooking, because it is foreign and strange smelling, makes her black in the eyes of the racist concierge and Bolobolo’s metisse girlfriend, Bijou.Aissatou decides to invite Bolobolo and his mother to dinner at her apartment, where she intends to win him over with her prowess in the kitchen, but when she goes downstairs to invite him, another woman is in the apartment with him. Unfazed, she announces that she would be happy to bring dinner down to them to enjoy together. The dinner is a success with Bolobolo but his girlfriend, a lovely metissse named Bijou, doesn't enjoy herself at all: â€Å"Je n'ai jamais aime la cuisine africaine†¦Ã¢â‚¬ ¦ Parait qu'ils mangent des singes, ces Negres! † To which Aissatou responds: â€Å"Du serpent boa egalement†¦Ã¢â‚¬ ¦.C'est excellent, n'est-ce pas†39Again, the food has served to bring together the African s and place them in opposition to a separate group because they share a taste for a dish that others find objectionable. Aissatou even goes further in invoking their taste for boa constrictor, because she knows that Bijou will be disgusted by this prospect. Since Bijou is mulatto and not just French, Aissatou and Bolobolo’s shared food preference places emphasis on the fact that they are from the same country in Africa and therefore share a distinct culture, and should not be lumped in with other ‘people of color. But Aissatou's main goal for her fabulous dinner is achieved after Bijou's departure when Bolobolo starts kissing and caressing Aissatou while she is cleaning up the kitchen. This woman, who previously denied herself any sensual pleasure at all from food, is altered by her dinner with Bolobolo. With her seduction of Bolobolo she acquires a new language, where food metaphors dominate the description of sex and the body. Nicki Hitchcott sees the narrator’ s almost over the top references to food to be a demonstration of cliches on which Western advertising depends. 0But at the same time, this dinner is evocative of the traditional polygamous African family dynamic, where the wife who cooks for the husband is the one who sleeps with him that night. Although Aissatou must still deal with her more powerful rival, Bolobolo's mother, she is eventually successful in seducing and keeping him with her culinary talents. By the end of the novel, Aissatou's transformation is complete. She does experience uneasiness when it comes to her own motives and doubts regarding her role in what Hitchcott calls ‘postnational’ France, but Aissatou settles on using cooking in order to maintain her relationships.She has gone from being a self-described white woman who viewed food as a ‘fatal poison' in the matter of seduction, to using food as a tool to accomplish her goal of seducing Bolobolo. She now sees food as a positive, unifying for ce: â€Å"La nourriture est synonyme de la vie. Aujourd'hui elle constitue une unite plus homogene que la justice. Elle est peut-etre l'unique source de paix et de reconciliation entre les hommes.  »41And in this novel, cooking can also reflect passion, love, comfort, anger and civility.Food and Aissatou's deft manipulation of people through her cooking give her power that she doesn't have otherwise in French society. As Bolobolo’s mother says in the novel, cooking is indeed becoming a rare skill especially in large capital cities like Paris because women are increasingly working outside the home, and don’t have the time or even talent to cook, since they never really learned the skills from their mothers. Even though France may be a center for haute cuisine technique, it suffers the same problems of all modern countries where there has been a redistribution of domestic tasks from inside to outside the home.Women don’t cook as much as they used to, and more a nd more people eat outside the home. Therefore, we must ask ourselves for whom the didactic element of this book is intended. As stated above, it is not descriptive enough to satisfy a food adventurer in search of the exotic and by virtue of the fact that it is written and published in France, it is clearly not intended to be used by African women. Perhaps the reader who would find Beyala’s recipes to be the most accessible are women like herself, immigrant women who might need to be tempted back to the kitchen.When this is considered along with Beyala’s problematical portrayal of marriage, the book appears as an invitation to take up cooking, not as a way to experience the exotic, but as a way to reject the Western ideal of beauty and to appropriate some power within the community. Aissatou returned to this aspect of her African heritage, because she had a specific goal in mind and felt that this would allow her to achieve it. She questions herself, her methods and he r motives all along the way, and ultimately accepts the limitations of â€Å"un bon pepe-soupe† and her husband’s monogamy.Just as she advises her neighbor whose husband has begun to stray from the conjugal bed, she doesn’t reproach Bolobolo and accepts his infidelity, knowing that eventually, he will return to her. She rejected the literal and figurative hunger that she experienced as a ‘negresse blanche† and chose the culinary tools that allow her to make her husband happy, even though she knows that he will sometimes hurt her. Beyala’s heroine fully understands the limitations that she faces in a Paris, and negotiates an identity through her cooking that she can live with.

Ansys Tutorial Release 12.1

 ® ANSYS Tutorial Release 12. 1 Structural & Thermal Analysis Using the ANSYS Release 12. 1 Environment Kent L. Lawrence Mechanical and Aerospace Engineering University of Texas at Arlington SDC PUBLICATIONS www. SDCpublications. com Schroff Development Corporation Visit the following websites to learn more about this book: ANSYS Tutorial 2-1 Lesson 2 Plane Stress Plane Strain 2-1 OVERVIEW Plane stress and plane strain problems are an important subclass of general threedimensional problems. The tutorials in this lesson demonstrate:  ¦Solving planar stress concentration problems. Evaluating potential inaccuracies in the solutions.  ¦Using the various ANSYS 2D element formulations. 2-2 INTRODUCTION It is possible for an object such as the one on the cover of this book to have six components of stress when subjected to arbitrary three-dimensional loadings. When referenced to a Cartesian coordinate system these components of stress are: Normal Stresses ?x, ? y, ? z Shear Stresses ? xy, ? yz, ? zx Figure 2-1 Stresses in 3 dimensions. In general, the analysis of such objects requires three-dimensional modeling as discussed in Lesson 4.However, two-dimensional models are often easier to develop, easier to solve and can be employed in many situations if they can accurately represent the behavior of the object under loading. 2-2 ANSYS Tutorial A state of Plane Stress exists in a thin object loaded in the plane of its largest dimensions. Let the X-Y plane be the plane of analysis. The non-zero stresses ? x, ? y, and ? xy lie in the X – Y plane and do not vary in the Z direction. Further, the other stresses (? z,? yz , and ? zx ) are all zero for this kind of geometry and loading.A thin beam loaded in its plane and a spur gear tooth are good examples of plane stress problems. ANSYS provides a 6-node planar triangular element along with 4-node and 8-node quadrilateral elements for use in the development of plane stress models. We will use both triangles and qua ds in solution of the example problems that follow. 2-3 PLATE WITH CENTRAL HOLE To start off, let’s solve a problem with a known solution so that we can check our computed results as well as our understanding of the FEM process. The problem is that of a tensile-loaded thin plate with a central hole as shown in Figure 2-2.Figure 2-2 Plate with central hole. The 1. 0 m x 0. 4 m plate has a thickness of 0. 01 m, and a central hole 0. 2 m in diameter. It is made of steel with material properties; elastic modulus, E = 2. 07 x 1011 N/m2 and Poisson’s ratio, ? = 0. 29. We apply a horizontal tensile loading in the form of a pressure p = -1. 0 N/m2 along the vertical edges of the plate. Because holes are necessary for fasteners such as bolts, rivets, etc, the need to know stresses and deformations near them occurs very often and has received a great deal of study.The results of these studies are widely published, and we can look up the stress concentration factor for the case s hown above. Before the advent of suitable computation methods, the effect of most complex stress concentration geometries had to be evaluated experimentally, and many available charts were developed from experimental results. The uniform, homogeneous plate above is symmetric about horizontal axes in both geometry and loading. This means that the state of stress and deformation below a Plane Stress / Plane Strain 2-3 orizontal centerline is a mirror image of that above the centerline, and likewise for a vertical centerline. We can take advantage of the symmetry and, by applying the correct boundary conditions, use only a quarter of the plate for the finite element model. For small problems using symmetry may not be too important; for large problems it can save modeling and solution efforts by eliminating one-half or a quarter or more of the work. Place the origin of X-Y coordinates at the center of the hole. If we pull on both ends of the plate, points on the centerlines will move al ong the centerlines but not perpendicular to them.This indicates the appropriate displacement conditions to use as shown below. Figure 2-3 Quadrant used for analysis. In Tutorial 2A we will use ANSYS to determine the maximum horizontal stress in the plate and compare the computed results with the maximum value that can be calculated using tabulated values for stress concentration factors. Interactive commands will be used to formulate and solve the problem. 2-4 TUTORIAL 2A – PLATE Objective: Find the maximum axial stress in the plate with a central hole and compare your result with a computation using published stress concentration factor data.PREPROCESSING 1. Start ANSYS, select the Working Directory where you will store the files associated with this problem. Also set the Jobname to Tutorial2A or something memorable and provide a Title. (If you want to make changes in the Jobname, working Directory, or Title after you’ve started ANSYS, use File > Change Jobname or Di rectory or Title. ) Select the six node triangular element to use for the solution of this problem. 2-4 ANSYS Tutorial Figure 2-4 Six-node triangle. The six-node triangle is a sub-element of the eight-node quadrilateral. 2.Main Menu > Preprocessor > Element Type > Add/Edit/Delete > Add > Structural Solid > Quad 8node 183 > OK Figure 2-5 Element selection. Select the triangle option and the option to define the plate thickness, otherwise a unit thickness is used. 3. Options (Element shape K1) > Triangle, Options (Element behavior K3) > Plane strs w/thk > OK > Close Plane Stress / Plane Strain 2-5 Figure 2-6 Element options. 4. Main Menu > Preprocessor > Real Constants > Add/Edit/Delete > Add > OK Figure 2-7 Real constants. Enter the plate thickness of 0. 01 m. ) >Enter 0. 01 > OK > Close Figure 2-8 Enter the plate thickness. 2-6 ANSYS Tutorial Enter the material properties. 5. Main Menu > Preprocessor > Material Props > Material Models Material Model Number 1, click Structural > Line ar > Elastic > Isotropic Enter EX = 2. 07E11 and PRXY = 0. 29 > OK (Close the Define Material Model Behavior window. ) Create the geometry for the upper right quadrant of the plate by subtracting a 0. 2 m diameter circle from a 0. 5 x 0. 2 m rectangle. Generate the rectangle first. . Main Menu > Preprocessor > Modeling > Create > Areas > Rectangle > By 2 Corners Enter (lower left corner) WP X = 0. 0, WP Y = 0. 0 and Width = 0. 5, Height = 0. 2 > OK 7. Main Menu > Preprocessor > Modeling > Create > Areas > Circle > Solid Circle Enter WP X = 0. 0, WP Y = 0. 0 and Radius = 0. 1 > OK Figure 2-9 Create areas. Plane Stress / Plane Strain 2-7 Figure 2-10 Rectangle and circle. Now subtract the circle from the rectangle. (Read the messages in the window at the bottom of the screen as necessary. ) 8.Main Menu > Preprocessor > Modeling > Operate > Booleans > Subtract > Areas > Pick the rectangle > OK, then pick the circle > OK (Use Raise Hidden and Reset Picking as necessary. ) Figure 2-11 Geo metry for quadrant of plate. Create a mesh of triangular elements over the quadrant area. 9. Main Menu > Preprocessor > Meshing > Mesh > Areas > Free Pick the quadrant > OK Figure 2-12 Triangular element mesh. Apply the displacement boundary conditions and loads to the geometry (lines) instead of the nodes as we did in the previous lesson.These conditions will be applied to the FEM model when the solution is performed. 10. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Displacement > On Lines Pick the left edge of the quadrant > OK > UX = 0. > OK 2-8 ANSYS Tutorial 11. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Displacement > On Lines Pick the bottom edge of the quadrant > OK > UY = 0. > OK Apply the loading. 12. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Pressure > On Lines.Pick the right edge of the quadrant > OK > Pressure = -1. 0 > OK (A positive pressure would be a compressive load, so we use a nega tive pressure. The pressure is shown by the two arrows. ) Figure 2-13 Model with loading and displacement boundary conditions. The model-building step is now complete, and we can proceed to the solution. First, to be safe, save the model. 13. Utility Menu > File > Save as Jobname. db (Or Save as †¦. ; use a new name) SOLUTION The interactive solution proceeds as illustrated in the tutorials of Lesson 1. 14. Main Menu > Solution > Solve > Current LS > OKThe /STATUS Command window displays the problem parameters and the Solve Current Load Step window is shown. Check the solution options in the /STATUS window and if all is OK, select File > Close In the Solve Current Load Step window, select OK, and when the solution is complete, Close the ‘Solution is Done! ’ window. POSTPROCESSING We can now plot the results of this analysis and also list the computed values. First examine the deformed shape. 15. Main Menu > General Postproc > Plot Results > Deformed Shape > Def. + Undef. > OK Plane Stress / Plane Strain 2-9 Figure 2-14 Plot of Deformed shape.The deformed shape looks correct. (The undeformed shape is indicated by the dashed lines. ) The right end moves to the right in response to the tensile load in the X direction, the circular hole ovals out, and the top moves down because of Poisson’s effect. Note that the element edges on the circular arc are represented by straight lines. This is an artifact of the plotting routine not the analysis. The six-node triangle has curved sides, and if you pick on a mid-side of one these elements, you will see that a node is placed on the curved edge. The maximum displacement is shown on the graph legend as 0. 2e-11 which seems reasonable. The units of displacement are meters because we employed meters and N/m2 in the problem formulation. Now plot the stress in the X direction. 16. Main Menu > General Postproc > Plot Results > Contour Plot > Element Solu > Stress > X-Component of stress > OK Use PlotCtrls > Symbols [/PSF] Surface Load Symbols (set to Pressures) and Show pre and convect as (set to Arrows) to display the pressure loads. Figure 2-15 Surface load symbols. Also select Display All Applied BCs 2-10 ANSYS Tutorial Figure 2-16 Element SX stresses.The minimum, SMN, and maximum, SMX, stresses as well as the color bar legend give an overall evaluation of the ? x (SX) stress state. We are interested in the maximum stress at the hole. Use the Zoom to focus on the area with highest stress. (Your meshes and results may differ a bit from those shown here. ) Figure 2-17 SX stress detail. Plane Stress / Plane Strain 2-11 Stress variations in the actual isotropic, homogeneous plate should be smooth and continuous across elements. The discontinuities in the SX stress contours above indicate that the number of elements used in this model is oo few to calculate with complete accuracy the stress values near the hole because of the stress gradients there. We will not accept this stress solu tion. More six-node elements are needed in the region near the hole to find accurate values of the stress. On the other hand, in the right half of the model, away from the stress riser, the calculated stress contours are smooth, and SX would seem to be accurately determined there. It is important to note that in the plotting we selected Element Solu (Element Solution) in order to look for stress contour discontinuities.If you pick Nodal Solu to plot instead, for problems like the one in this tutorial, the stress values will be averaged before plotting, and any contour discontinuities (and thus errors) will be hidden. If you plot nodal solution stresses you will always see smooth contours. A word about element accuracy: The FEM implementation of the truss element is taken directly from solid mechanics studies, and there is no approximation in the solutions for node-loaded truss structures formulated and solved in the ways discussed in Lesson 1.The continuum elements such as the ones for plane stress and plane strain, on the other hand, are normally developed using displacement functions of a polynomial type to represent the displacements within the element, and the higher the polynomial, the greater the accuracy. The ANSYS six-node triangle uses a quadratic polynomial and is capable of representing linear stress and strain variations within an element. Near stress concentrations the stress gradients vary quite sharply. To capture this variation, the number of elements near the stress concentrations must be increased proportionately.To obtain more elements in the model, return to the Preprocessor and refine the mesh, first remove the pressure. All elements are subdivided and the mesh below is created 17. Main Menu > Preprocessor > Loads > Define Loads > Delete > Structural > Pressure > On Lines. Pick the right edge of the quadrant. Main Menu > Preprocessor > Meshing > Modify Mesh > Refine At > All (Select Level of refinement 1. ) Figure 2-18 Global mesh refineme nt. 2-12 ANSYS Tutorial We will also refine the mesh selectively near the hole. 18.Main Menu > Preprocessor > Meshing > Modify Mesh > Refine At > Nodes. (Select the three nodes shown. ) > OK (Select the Level of refinement = 1) > OK Figure 2-19 Selective refinement at nodes. (Note: Alternatively you can use Preprocessor > Meshing > Clear > Areas to remove all elements and build a completely new mesh. Plot > Areas afterwards to view the area again. Note also that too much local refinement can create a mesh with too rapid a transition between fine and coarse mesh regions. ) Reapply the pressure loading, repeat the solution, and replot the stress SX. 9. Main Menu > Solution > Solve > Current LS > OK Save your work. 20. File > Save as Jobname. db Plot the stresses in the X direction. 21. Main Menu > General Postproc > Plot Results > Contour Plot > Element Solu > Stress > X-Component of stress > OK Plane Stress / Plane Strain 2-13 Figure 2-20 SX stress contour after mesh refinement. Figu re 2-21 SX stress detail contour after mesh refinement. The element solution stress contours are now smooth across element boundaries, and the stress legend shows a maximum value of 4. 386 Pa, a 4. percent change in the SX stress computed using the previous mesh. To check this result, find the stress concentration factor for this problem in a text or reference book or from a suitable web site. For the geometry of this example we find Kt = 2. 17. We can compute the maximum stress using (Kt)(load)/(net cross sectional area). Using the pressure p = 1. 0 Pa we obtain. ? x MAX = 2. 17 * p * (0. 4)(0. 01) /[(0. 4 ? 0. 2) * 0. 01] = 4. 34 Pa 2-14 ANSYS Tutorial The computed maximum value is 4. 39 Pa which is around one percent in error, assuming that the value of Kt is exact. -5 THE APPROXIMATE NATURE OF FEM As mentioned above, the stiffness matrix for the truss elements of Lesson 1 can be developed directly and simply from elementary solid mechanics principles. For continuum problems in t wo and three-dimensional stress, this is generally no longer possible, and the element stiffness matrices are usually developed by assuming something specific about the characteristics of the displacements that can occur within an element. Ordinarily this is done by specifying the highest degree of the polynomial that governs the displacement distribution within an element.For h-method elements, the polynomial degree depends upon the number of nodes used to describe the element, and the interpolation functions that relate displacements within the element to the displacements at the nodes are called shape functions. In ANSYS, 2-dimensional problems can be modeled with six-node triangles, four-node quadrilaterals or eight-node quadrilaterals. Figure 2-22 Triangular and quadrilateral elements. The greater the number of nodes, the higher the order of the polynomial and the greater the accuracy in describing displacements, stresses and strains within the element. If the stress is constan t throughout a region, a very imple model is sufficient to describe the stress state, perhaps only one or two elements. If there are gradients in the stress distributions within a region, high-degree displacement polynomials and/or many elements are required to accurately analyze the situation. These comments explain the variation in the accuracy of the results as different numbers of elements were used to solve the problem in the previous tutorial and why the engineer must carefully prepare a model, start with small models, grow the models as understanding of the problem develops and carefully interpret the calculated results.The ease with which models can be prepared and solved sometimes leads to careless evaluation of the computed results. Plane Stress / Plane Strain 2-15 2-6 ANSYS FILES The files created during the solution were saved in step 20 of Tutorial 2A. Look in the working directory and you see Tutorial2A files with extensions BCS, db, dbb, esav, full, mntr, rst, and sta t. However, the Tutorial 2A problem can be reloaded using only Tutorial2A. db, so if you want to save disk space, you can delete the others. 2-7 ANSYS GEOMETRY The finite element model consists of elements and nodes and is separate from the geometry on which it may be based.It is possible to build the finite element model without consideration of any underlying geometry as was done in the truss examples of Lesson 1, but in many cases, development of the geometry is the first task. Two-dimensional geometry in ANSYS is built from keypoints, lines (straight, arcs, splines), and areas. These geometric items are assigned numbers and can be listed, numbered, manipulated, and plotted. The keypoints (2,3,4,5,6), lines (2,3,5,9,10), and area (3) for Tutorial 2A are shown below. (Your numbering may differ. ) Figure 2-23 Keypoints, lines and areas.The finite element model developed previously for this part used the area A3 for development of the node/element FEM mesh. The loads, displacement b oundary conditions and pressures were applied to the geometry lines. When the solution step was executed, the loads were transferred from the lines to the FEM model nodes. Applying boundary conditions and loads to the geometry facilitates remeshing the problem. The geometry does not change, only the number and location of nodes and elements, and at solution time, the loads are transferred to the new mesh.Geometry can be created in ANSYS interactively (as was done in the previous tutorial) or it can be created by reading a text file. For example, the geometry of Tutorial 2A can be generated with the following text file using the File > Read Input from command sequence. (The keypoint, line, etc. numbers will be different from those shown above. ) 2-16 ANSYS Tutorial /FILNAM,Geom /title, Stress Concentration Geometry ! Example of creating geometry using keypoints, lines, arcs /prep7 ! Create geometry k, 1, 0. 0, 0. 0 ! Keypoint 1 is at 0. 0, 0. 0 k, 2, 0. 1, 0. 0 , 3, 0. 5, 0. 0 k, 4, 0. 5, 0. 2 k, 5, 0. 0, 0. 2 k, 6, 0. 0, 0. 1 L, L, L, L, 2, 3, 4, 5, 3 4 5 6 ! Line from keypoints 2 to 3 ! arc from keypoint 2 to 6, center kp 1, radius 0. 1 LARC, 2, 6, 1, 0. 1 AL, 1, 2, 3, 4, 5 ! Area defined by lines 1,2,3,4,5 Geometry for FEM analysis also can be created with solid modeling CAD or other software and imported into ANSYS. The IGES (Initial Graphics Exchange Specification) neutral file is a common format used to exchange geometry between computer programs. Tutorial 2B demonstrates this option for ANSYS geometry development. -8 TUTORIAL 2B – SEATBELT COMPONENT Objective: Determine the stresses and deformation of the prototype seatbelt component shown in the figure below if it is subjected to tensile load of 1000 lbf. Figure 2-24 Seatbelt component. The seatbelt component is made of steel, has an over all length of about 2. 5 inches and is 3/32 = 0. 09375 inches thick. A solid model of the part was developed in a CAD system and exported as an IGES file. The f ile is imported into ANSYS for analysis. For simplicity we will analyze only the right, or ‘tongue’ portion of the part in this tutorial.Plane Stress / Plane Strain 2-17 Figure 2-25 Seatbelt ‘tongue’. PREPROCESSING 1. Start ANSYS, Run Interactive, set jobname, and working directory. Create the top half of the geometry above. The latch retention slot is 0. 375 x 0. 8125 inches and is located 0. 375 inch from the right edge. If you are not using an IGES file to define the geometry for this exercise, you can create the geometry directly in ANSYS with key points, lines, and arcs by selecting File > Read Input from to read in the text file given below and by skipping the IGES import steps 2, 3, 4, and 10 below. FILNAM,Seatbelt /title, Seatbelt Geometry ! Example of creating geometry using keypoints, lines, arcs /prep7 ! Create geometry k, 1, 0. 0, 0. 0 ! Keypoint 1 is at 0. 0, 0. 0 k, 2, 0. 75, 0. 0 k, 3, 1. 125, 0. 0 k, 4, 1. 5, 0. 0 k, 5, 1. 5, 0. 5 k, 6, 1. 2 5, 0. 75 k, 7, 0. 0, 0. 75 k, 8, 1. 125, 0. 375 k, 9, 1. 09375, 0. 40625 k, 10, 0. 8125, 0. 40625 k, 11, 0. 75, 0. 34375 k, 12, 1. 25, 0. 5 k, 13, 1. 09375, 0. 375 k, 14, 0. 8125, 0. 34375 2-18 L, L, L, L, L, L, L, L, ANSYS Tutorial 1, 2 3, 4 4, 5 6, 7 7, 1 3, 8 9, 10 11, 2 ! arc LARC, LARC, LARC, Line from keypoints 1 to 2 from keypoint 5 to 6, center kp 12, radius 0. 25, etc. 5,6, 12, 0. 25 8, 9, 13, 0. 03125 10, 11, 14, 0. 0625 AL,all ! Use all lines to create the area. 2. Alternatively, use a solid modeler to create the top half of the component shown above in the X-Y plane and export an IGES file of the part. To import the IGES file 3. Utility Menu > File > Import > IGES Select the IGES file you created earlier. Accept the ANSYS import default settings. If you have trouble with the import, select the alternate options and try again.Defeaturing is an automatic process to remove inconsistencies that may exist in the IGES file, for example lines that, because of the modeling or th e file translation process, do not quite join to digital precision accuracy. Figure 2-26 IGES import. Turn the IGES solid model around if necessary so you can easily select the X-Y plane. Plane Stress / Plane Strain 2-19 4. Utility Menu > PlotCtrls > Pan, Zoom, Rotate > Back, or use the side-bar icon. Figure 2-27 Seatbelt solid, front and back. 5.Main Menu > Preprocessor > Element Type > Add/Edit/Delete > Add > Solid > Quad 8node 183 > OK (Use the 8-node quadrilateral element for this problem. ) 6. Options > Plane strs w/thk > OK > Close Enter the thickness 7. Main Menu > Preprocessor > Real Constants > Add/Edit/Delete > Add > (Type 1 Plane 183) > OK > Enter 0. 09375 > OK > Close Enter the material properties 8. Main Menu > Preprocessor > Material Props > Material Models Material Model Number 1, click Structural > Linear > Elastic > Isotropic Enter EX = 3. 0E7 and PRXY = 0. > OK (Close Define Material Model Behavior window. ) Now mesh the X-Y plane area. (Turn on area numbers if it helps. ) 9. Main Menu > Preprocessor > Meshing > Mesh > Areas > Free. Pick the X-Y planar area > OK IMPORTANT NOTE: The mesh below was developed from an IGES geometry file. Using the text file geometry definition, may produce a much different mesh. If so, use the Modify Mesh refinement tools to obtain a mesh density that produces results with accuracies comparable to those given below. Computed stress values can be surprisingly sensitive to mesh differences. -20 ANSYS Tutorial Figure 2-28 Quad 8 mesh. The IGES solid model is no longer needed, and since its lines and areas may interfere with subsequent modeling operations, we can delete it from the session. 10. Main Menu > Preprocessor > Modeling > Delete > Volume and Below (Don’t be surprised if everything disappears. Just Plot > Elements to see the mesh again. ) 11. Utility Menu > PlotCtrls > Pan, Zoom, Rotate > Front front side of mesh. ) (If necessary to see the Figure 2-29 . Mesh, front view. Now apply displacement and pr essure boundary conditions.Zero displacement UX along left edge and zero UY along bottom edge. 12. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Displacement > On Lines Pick the left edge > UX = 0. > OK 13. Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Displacement > On Lines Pick the lower edge > UY = 0. > OK The 1000 lbf load corresponds to a uniform pressure of about 14,000 psi along the ? inch vertical inside edge of the latch retention slot. [1000 lbf/(0. 09375 in. x 0. 75 in. )]. 14.Main Menu > Preprocessor > Loads > Define Loads > Apply > Structural > Pressure > On Lines Plane Stress / Plane Strain 2-21 Select the inside line and set pressure = 14000 > OK Figure 2-30 Applied displacement and pressure conditions. Solve the equations. SOLUTION 15. Main Menu > Solution > Solve > Current LS > OK POSTPROCESSING Comparing the von Mises stress with the material yield stress is an accepted way of evaluating static load yielding for du ctile metals in a combined stress state, so we enter the postprocessor and plot the element solution of von Mises stress, SEQV. 16.Main Menu > General Postproc > Plot Results > Contour Plot > Element Solu > Stress > (scroll down) von Mises > OK Zoom in on the small fillet where the maximum stresses occur. The element solution stress contours are reasonably smooth, and the maximum von Mises stress is around 118,000 psi. Further mesh refinement gives a stress value of approximately 140,000 psi. The small fillet radius of this geometry illustrates the challenges that can arise in creating accurate solutions, however you can easily come within a few percent of the most likely true result using the methods discussed thus far.Figure 2-31 Von Mises stresses. 2-22 ANSYS Tutorial Redesign to reduce the maximum stress requires an increase in the thickness or fillet radius. Look at charts of stress concentration factors, and you notice that the maximum stress increases as the radius of the str ess raiser decreases, approaching infinite values at zero radii. If your model has a zero radius notch, your finite-size elements will show a very high stress but not infinite stress. If you refine the mesh, the stress will increase but not reach infinity.The finite element technique necessarily describes finite quantities and cannot directly treat an infinite stress at a singular point, so don’t ‘chase a singularity’. If you do not care what happens at the notch (static load, ductile material, etc. ) do not worry about this location but examine the stresses and strains in other regions. If you really are concerned about the maximum stress in a particular location (fatigue loads or brittle material), then use the actual part notch radius however small (1/32 for this tutorial); do not use a zero radius.Also examine the stress gradient in the vicinity of the notch to make sure the mesh is sufficiently refined near the notch. If a crack tip is the object of the anal ysis, you should look at fracture mechanics approaches to the problem. (See ANSYS help topics on fracture mechanics. ) The engineer’s responsibility is not only to build useful models, but also to interpret the results of such models in intelligent and meaningful ways. This can often get overlooked in the rush to get answers. Continue with the evaluation and check the strains and deflections for this model as well. 7. Main Menu > General Postproc > Plot Results > Contour Plot > Element Solu > Strain-total > 1st prin > OK The maximum principal normal strain value is found to be approximately 0. 004 in/in. 18. Main Menu > General Postproc > Plot Results > Contour Plot > Nodal Solu > DOF Solution > X-Component of displacement > OK Figure 2-32 UX displacements. Plane Stress / Plane Strain 2-23 The maximum deflection in the X direction is about 0. 00145 inches and occurs as expected at the center of the right-hand edge of the latch retention slot. -9 MAPPED MESHING Quadrilateral m eshes can also be created by mapping a square with a regular array of cells onto a general quadrilateral or triangular region. To illustrate this, delete the last line, AL,all, from the text file above so that the area is not created (just the lines) and read it into ANSYS. Use PlotCtrls to turn Keypoint Numbering On. Then use 1. Main Menu > Preprocessor > Modeling > Create > Lines > Lines > Straight Line. Successively pick pairs of keypoints until the four interior lines shown below are created. Figure 2-33 Lines added to geometry. 2.Main Menu > Preprocessor > Modeling > Create > Areas > Arbitrary > By Lines Pick the three lines defining the lower left triangular area. > Apply > Repeat for the quadrilateral areas. > Apply > OK Figure 2-34 Quadrilateral/Triangular regions. 3. Main Menu > Preprocessor > Modeling > Operate > Booleans > Glue > Areas > Pick All 2-24 ANSYS Tutorial The glue operation preserves the boundaries between areas that we will need for mapped meshing. 4. Main Men u > Preprocessor > Meshing > Size Cntrls > ManualSize > Lines > All Lines Enter 4 for NDIV, No. lement divisions > OK All lines will be divided into four segments for mesh creation. Figure 2-35 Element size on picked lines. 5. Main Menu > Preprocessor > Element Type > Add/Edit/Delete > Add > Solid > Quad 8node 183 > OK (Use the 8-node quadrilateral element for the mesh. ) 6. Main Menu > Preprocessor > Meshing > Mesh > Areas > Mapped > 3 or 4 sided > Pick All The mesh below is created. Applying boundary and load conditions and solving gives the von Mises stress distribution shown.The stress contours are discontinuous because of the poor mesh quality. Notice the long and narrow quads near the point of maximum stress. We need more elements and they need to be better shaped with smaller aspect ratios to obtain satisfactory results. Plane Stress / Plane Strain 2-25 Figure 2-36 Mapped mesh and von Mises results. One can tailor the mapped mesh by specifying how many elements are to be plac ed along which lines. This allows much better control over the quality of the mesh, and an example of using this approach is described in Lesson 4. 2-10 CONVERGENCEThe goal of finite element analysis as discussed in this lesson is to arrive at computed estimates of deflection, strain and stress that converge to definite values as the number of elements in the mesh increases, just as a convergent series arrives at a definite value once enough terms are summed. For elements based on assumed displacement functions that produce continuum models, the computed displacements are smaller in theory than the true displacements because the assumed displacement functions place an artificial constraint on the deformations that can occur.These constraints are relaxed as the element polynomial is increased or as more elements are used. Thus your computed displacements usually converge smoothly from below to fixed values. Strains are the x and/or y derivatives of the displacements and thus depend o n the distribution of the displacements for any given mesh. The strains and stresses may change in an erratic way as the mesh is refined, first smaller than the final computed values, then larger, etc. Not all elements are developed using the ideas discussed above, and some will give displacements that converge from above. (See Lesson 6. In any case you should be alert to computed displacement and stress variations as you perform mesh refinement during the solution of a problem. 2-11 TWO-DIMENSIONAL ELEMENT OPTIONS The analysis options for two-dimensional elements are: Plane Stress, Axisymmetric, Plane Strain, Plane Stress with Thickness and Generalized Plane Strain. The two examples thus far in this lesson were of the third type, namely problems of plane stress in which we provided the thickness of the part. 2-26 ANSYS Tutorial The first analysis option, Plane Stress, is the ANSYS default and provides an analysis for a part with unit thickness.If you are working on a design problem in which the thickness is not yet known, you may wish to use this option and then select the thickness based upon the stress, strain, and deflection distributions found for a unit thickness. The second option, Axisymmetric analysis is covered in detail in Lesson 3. Plane Strain occurs in a problem such as a cylindrical roller bearing caged against axial motion and uniformly loaded in a direction normal to the cylindrical surface. Because there is no axial motion, there is no axial strain.Each slice through the cylinder behaves like every other and the problem can be conveniently analyzed with a planar model. Another plane strain example is that of a long retaining wall, restrained at each end and loaded uniformly by soil pressure on one or both faces. The Generalized Plane Strain feature assumes a finite deformation domain length in the Z direction, as opposed to the infinite value assumed for standard plane strain. 2-12 SUMMARY Problems of stress concentration in plates subject to in-plane loadings were used to illustrate ANSYS analysis of plane stress problems.Free triangular and quadrilateral element meshes were developed and analyzed. Mapped meshing with quads was also presented. Similar methods are used for solving problems involving plane strain; one only has to choose the appropriate option during element selection. The approach is also applicable to axisymmetric geometries as discussed in the next lesson. 2-13 PROBLEMS In the problems below, use triangular and/or quadrilateral elements as desired. Triangles may produce more regular shaped element meshes with free meshing.The six-node triangles and eight-node quads can approximate curved surface geometries and, when stress gradients are present, give much better results than the four-node quad elements. 2-1 Find the maximum stress in the aluminum plate shown below. Use tabulated stress concentration factors to independently calculate the maximum stress. Compare the two results by determining the percen t difference in the two answers. Convert the 12 kN concentrated force into an equivalent pressure applied to the edge. Plane Stress / Plane Strain 2-27 Figure P2-1 -2 Find the maximum stress for the plate from 2-1 if the hole is located halfway between the centerline and top edge as shown. You will now need to model half of the plate instead of just one quarter and properly restrain vertical rigid body motion. One way to do this is to fix one keypoint along the centerline from UY displacement. Figure P2-2 2-28 ANSYS Tutorial 2-3 An aluminum square 10 inches on a side has a 5-inch diameter hole at the center. The object is in a state of plane strain with an internal pressure of 1500 psi. Determine the magnitude and location of the maximum principal stress, the maximum rincipal strain, and the maximum von Mises stress. Note that no thickness need be supplied for plane strain analysis. Figure P2-3 2-4 Repeat 2-3 for a steel plate one inch thick in a state of plane stress. 2-5 See if yo u can reduce the maximum stress for the plate of problem 2-1 by adding holes as shown below. Select a hole size and location that you think will smooth out the ‘stress flow’ caused by the load transmission through the plate. Figure P2-5 2-6 Repeat 2-1 but the object is now a plate with notches or with a step in the geometry. (See the next figure. ) Select your own dimensions, materials, and loads.Use published stress concentration factor data to compare to your results. The published results are for plates that are relatively long so that there is a uniform state of axial stress at either end relatively far from notch or hole. Create your geometry accordingly. Plane Stress / Plane Strain 2-29 Figure P2-6 2-7 Solve the seatbelt component problem of Tutorial 2B again using six node triangular elements instead of the quadrilaterals. Experiment with mesh refinement. Turn on Smart Sizing using size controls to examine the effect on the solution. See if you can compute a maxi mum von Mises stress of around 140 kpsi. -8 Determine the stresses and deflections in an object ‘at hand’ (such as a seatbelt tongue or retaining wall) whose geometry and loading make it suitable for plane stress or plane strain analysis. Do all the necessary modeling of geometry (use a CAD system if you wish), materials and loadings. 2-9 A cantilever beam with a unit width rectangular cross section is loaded with a uniform pressure along its upper surface. Model the beam as a problem in plane stress. Compute the end deflection and the maximum stress at the cantilever support. Compare your results to those you would find using elementary beam theory.Figure P2-8 Restrain UX along the cantilever support line, but restrain UY at only one keypoint along this line. Otherwise, the strain in the Y direction due to the Poisson effect is prevented here, and the root stresses are different from elementary beam theory because of the singularity created. (Try fixing all node points in UX and UY and see what happens. ) Select your own dimensions, materials, and pressure. Try a beam that’s long and slender and one that’s short and thick. The effect of shear loading becomes more important in the deflection analysis as the slenderness decreases.