This week was our second and last week of tensile testing. This batch of plastics was our least rigid yet. Unfortunately this caused a great deal slippage within the vice grips of the machine. In order to minimize this factor, we added tape to the ends of the first few samples. This didn't seem to make a difference so in the end we removed the tape from the samples for all further testing. Because the slipping directly affects the recorded load values, this data set has inaccuracies.
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| Figure 9.a: Plastic sample with taped ends |
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| Figure 9.b: Tensile machine with taped sample |
Another issue we faced in this testing session was the fact that some of the samples did not break in the center. This means that most of the load weight was unevenly distributed across the sample. Because of this, the conclusions we can draw from the collected data have less validity. Ideally, the only section of the sample that should be strained (and therefore broken) should be the middle section. If the samples did not slip it's likely that the testing would have been more uniform and the samples would have compromised in the center.
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| Figure 9.c: Post-Test samples |
A big thanks to
Mr. Steve Pagano, Mr. Brian Wisner and Mr. Satish Rajaram for all their help in our research!
