Materials Testing
For this project, we received a 3.5 inch long rod of threaded aluminum. I used a metal lathe to widdle down a 1 inch section in the center of the rod so the center of the rod was only .125 inches in thickness. The rod had to be 3 inches in lenght to fit in the tester so it had to be shortened with a hand saw. The first few threads of the rod were rethreaded in order to ensure quality. After these steps, the rod was threaded into the tester.
Testing
After the tester pulled the dog bone in half and all of the data was recorded, I remeasured the dog bone. The lenght of the lathed part of the dog bone started out as 1 inch and was 1.103 inches after breaking and the diameter of it started out as 0.125 inches and ended up as 0.106 inches. The sample rod broke at 619 lbs.
Results
The rods total strain/deformation, which is the total amount of the elongation of the rod to rupture divided by the original length was 0.996.
etotal(strain)=stress/original length=0.996.
The rods ductility, which is the ability to be deformed plastically without breaking was 99.6%. Plastic elongation is the unrecoverable elongation beyond the elastic limit.
% of Elongation = etotal (100) = 99.6%
The rods reduction in area which can be found by subtracting the final area from the original area and dividing the difference by the original area multiplied by 100 was 0.004 inches.
Reduction in area = (A original – A final)/A original*100
Proportional Limit Stress = F/A = 45,528 PSI
Maximum Tensile Stress = F/A = 41,635 PSI
Ultimate/Tensile Stress = F/A = 38,618 PSI
Modulus of Elasticity = F/A = 31,111 PSI
etotal(strain)=stress/original length=0.996.
The rods ductility, which is the ability to be deformed plastically without breaking was 99.6%. Plastic elongation is the unrecoverable elongation beyond the elastic limit.
% of Elongation = etotal (100) = 99.6%
The rods reduction in area which can be found by subtracting the final area from the original area and dividing the difference by the original area multiplied by 100 was 0.004 inches.
Reduction in area = (A original – A final)/A original*100
Proportional Limit Stress = F/A = 45,528 PSI
Maximum Tensile Stress = F/A = 41,635 PSI
Ultimate/Tensile Stress = F/A = 38,618 PSI
Modulus of Elasticity = F/A = 31,111 PSI