4. PURPOSE STATEMENT The purpose of this presentation is to familiarize you as an up and, coming engineer, with the concept of creep deformation in engineering materials. Common creep testing machines
6. INTRODUCTION (1/3) Question: What is Creep Deformation? Answer: Creep deformation is a naturally occurring situation where a material becomes stretched, or deformed, by being subjected to constant forces at a given temperature. It is a function of changing strain over time. Guitar Strings Become Detuned after initially being strung because of creep deformation.
7. INTRODUCTION (2/3) First, lets define strain. Strain, in engineering, can be defined as the direct proportionality of the change in dimension and the inverse proportionality of its original dimension such that:
10. MATERIALS & METHODS (1/3) We conducted our own creep test. This is what we used to perform the experiment: Materials: 24-30in, 0.093 Gauge Solder Wire, 60% Tin-40% Lead (2) 1200g Weight (1) 1500g Weight (1) Wooden Dowel (1) Work Shop Tool Mounting Hooks (4) Workshop Tool Mounting Board (1) Yard Rulers (2)
11. MATERIALS & METHODS (2/3) -Experiment Setup- Mounting Hooks Wooden Dowel Solder Wire Gauge points at which to calculate change in length. Yard Ruler 1200g Weight 1500g Weight Mounting Board
12. MATERIALS & METHODS (3/3) We let the samples sit for a couple of weeks. The experiment took place indoors at room temperature. We took measurements by reading the measurement coinciding with the marks and subtracting the two to get our change in length. We repeated this process a few times during the day. After finishing, we plotted the data and determined the wires creep deformation graphically. We measured the time since the start of the experiment in cumulative minutes.
14. Analysis (1/3) After conducting the experiment we saw that our graph looked a lot like the graph at the beginning of the presentation. Look at the graph again.
16. Analysis (3/3) Our graph is missing stage 1 of the creep deformation. The reason for this is because this stage happens very rapidly, especially in a material like solder, and we were unable to record the early stage of creep.
18. CONCLUSION This presentation was created to provide other engineers with a familiarization of creep deformation. In the process of experimenting and recording data on the test samples, I believe we achieved that. Creep deformation is fundamentally important in the use and assignment of engineering materials to projects when time is important. Creep deformation can be defined by the deformation of a material at a constant temperature while under constant forces.
20. REFERENCES Buddinski, K., & Buddinski, M. (2010). Engineering Materials: Properties And Selection. Upper Saddle River: Pearson Education. Horton, H., Jones, F., Oberg, E., & Ryffel, H. (2008). Machinery's Handbook: 28th Ed. New York: Industrial Press. Kopeliovich, D. D. (2009, Febuary 3). Creep. Retrieved November 7, 2010, from substech.com: http://www.substech.com/dokuwiki/doku.php?id=creep Wikipedia.org. (2010, October 15). Creep (deformation). Retrieved November 7, 2010, from Wikipedia.org: http://en.wikipedia.org/wiki/Creep_(deformation)