Tensile strength testing
intro
In this unit we learned how to determine a material breaking point. To do this we used a uni-axial testing method, in other words a force was applied on one axis, or direction, of the object in question. In order to perform this test we had to have a dog-bone shaped material, such as the one shown below (my test piece).
Construction
![Picture](/uploads/1/3/7/6/13768163/6311013.jpg)
We were given a piece of aluminium all thread to create our test piece. We machined this down with a mini-lathe to the dog-bone shape with a cross section diameter of .125", that diameter extended 1 inch down the center of the all thread. After machining it, we cut/cleaned the threads with a die. For the most part, that encompasses the construction phase of this project. It was relatively simple.
testing
The testing phase was even simpler than the construction phase. We used the same stress tester that we used in our Truss project. The only difference being that it had a bracket that gripped one side of the material while a clamp pulled one the other side.
data collection
During the test, a computer logged every change in the material in correlation with the strain applied. I was able to collect and compile this into a Microsoft Excel spreadsheet and create a graph.
Based on this data my test piece had a tensile strength of 560 lbs/1/4 inch. At around 500 lbs it began "deformation," the material started to stretch around the future breaking point and "neck".
The calculations are as follows
Stress= Load/Area= 560lbs/.01227 in.squared= 45639.7718
Strain= Elongation/Orig. lenght= .036in/1in.=.036in
The calculations are as follows
Stress= Load/Area= 560lbs/.01227 in.squared= 45639.7718
Strain= Elongation/Orig. lenght= .036in/1in.=.036in