Stress and Strain Essay Example

Stress and Strain Essay Several mechanical properties of materials that are important in design are ascertained by applying tension, compression or shear load on the material.     Of the three, the most common mechanical stress-strain tests are performed in tension (Callister, 1997).   When performing tensile tests, the load and elongation are measured in relation to the cross-sectional area or original length of the material (before the elongation).   These geometric factors are normalized to the respective parameters of engineering stress and engineering strain. When a specimen has an original cross-sectional area Ao and original length lo is subjected to a uniaxial force F, engineering stress ÏÆ' and engineering strain ÃŽ µ (which are subsequently referred to as just stress and strain) are defined as:   and where l is the instantaneous length of the specimen (Schaffer, et. al, 1999).   For some materials, especially for most metals, subjected to low levels of tensile load, stress and strain are linearly related.   The linear relationship is referred to as Hooke’s law. As the stress is increased however, Hooke’s law ceases to be applicable as the linear relationship between stress and strain results to a curve.   At this instant plastic deformation occurs, which means that the deformation becomes permanent and nonrecoverable (Callister, 1997).   When stress is increased further, it will reach a maximum before resulting to fracture (the separation of the material into two or more pieces).   The maximum stress on the stress-strain curve is referred to as tensile strength and is the maximum stress that can be sustained by a material in tension.   When this stress is maintained, fracture will result. We will write a custom essay sample on Stress and Strain specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Stress and Strain specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Stress and Strain specifically for you FOR ONLY $16.38 $13.9/page Hire Writer Compression tests are also done in almost the same manner as the tensile test except of course the force applied is compressive instead of tensile (Callister, 1997).   Compressive stress and strain are computed using the same formula presented above.   By convention, compressive force is taken to be negative which results to a negative stress.   In compression, since lo will be greater than l, the strain will likewise be negative.   And just like tensile strength, compressive strength is the maximum compressive stress applied to a material which when sustained results to the material being crushed.

Problem Solving Strategies

Problem Solving Strategies The type of problem solving strategy you use depends, in part, on the type of situation you are facing. For instance, finding the answer to a mathematical equation requires different skills than writing an essay on the differences between two philosophers views on religion. Problem solving is considered to be the process of finding solutions to difficult issues.  The type of  problem solving  strategy you use depends, in part, on the type of situation you are facing. For instance, finding the answer to a mathematical equation requires different skills than writing an essay on the differences between two philosophers views on religion. One has a fixed, set answer; the other is subject to interpretation. THE ART OF PROBLEM SOLVING Problem Solving Strategies Below are a few problem-solving strategies, how each works and when they are appropriate: ALGORITHMS. These types of problem-solving techniques rely on a set formula that allows you to arrive at one fixed answer. Good examples of algorithms are mathematical formula and computer programs. HEURISTIC. Heuristic problem-solving tactics are commonly referred to as rule of thumb strategies. These tactics are based on past experience and dont usually arrive at a single, fixed answer. Such problem-solving techniques are used when an exact answer isnt necessary when a range or an approximation is good enough. An example of using a heuristic problem-solving technique is estimating how long it will take you to drive home from campus. If, on previous trips, it has taken between 30 and 35 minutes, its likely that the next trip will take the same amount of time. However, unusually heavy traffic or construction could change this answer. CONSTRUCTIVE CONTROVERSY. This problem-solving technique, developed in the late 1970s, involves presenting your proposed solution to a group of other people, defending your idea, listening to their input and modifying your idea based on their feedback. This approach works well for team projects. INSIGHT. This technique is less structured, but often very effective. This is the let me sleep on it way of solving problems, such as when you awake with an answer to a problem or the answer comes to you in the shower or on the way to class. This technique relies on the subconscious using our past experiences to formulate an answer to a similar problem to those weve dealt with in the past. Since you have no way of knowing if youll arrive at an answer this way, this is obviously a poor technique to use for projects with a deadline. BRAINSTORMING. Brainstorming unleashes the talents of multiple team members on a single project. This technique involves throwing out tentative ideas, discussing each ideas merits and challenges and using the best of these possible solutions to solve the problem. DIVIDE AND CONQUER. Some projects, such as reading an entire text or writing a 5,000-word paper, can seem overwhelming. Dividing those huge projects into smaller, more manageable segments, such as reading a chapter a night or writing 500 words a week, often makes them easy to handle. RESEARCH. This problem-solving tactic makes use of other peoples past experience with similar problems to solve a current problem. As the name implies, this technique involves studying past performances and applying this acquired knowledge to the task at hand. Problem-solving strategies are a necessary part of college, the work environment, and everyday life. The better you become at the different types of strategies and at determining which type to use in which situation, the easier you will find not only your college studies but navigating the world at large. PROBLEM SOLVING SKILLS In case you are working on a problem solving assignment, and are having difficulties with it, would be happy to assist. Feel free to contact our writers and they will help you to work through the assignment. Our staff will assign writers with suitable backgrounds and adequate experience. This will result in a paper that is properly written and formatted, with thorough background research and a solid literature base. Feel free to contact us anytime  or place an order and we will gladly help you.