DISCUSSION Base on our discussion after done performed torsion test, we know that we totally got 4 table result and 2 graphs for aluminum and the other 4 table and 2 graphs for mild steel. The experiment will start with the aluminum torsion test and then continue for mild steel torsion test. For the first table we key in the result after calibrate the mild steel and aluminum diameter and gage length, after done key in then we started the experiment.
At the end of the torsion test, we will get the final result that mild steel will break at the end of experiment but it is opposite for aluminum. If we compared mild steel and aluminum steel in the 2nd table, we can see that the changing of the aluminum angle is much faster than mild steel material. The is totally due to aluminum material is much soften than mild steel, then for both graphs, aluminum graph have a curve at the mid of the experiment if compared with mild steel.
In the table 3 we use the formula of Shear stress, Shear stress=Tc/J And Shear strain, Shear strain=? c/L? to calculate the shear stress and strain. Comparing the result of aluminum with mild steel, the result of mild steel is much higher than aluminum which is 107688. 926Mpa for shear stress and 2. 652539706 rad for shear strain. After put the value of both steel into the graphs, the result for the graphs is same as previous graph. At the end of the result the mild steel can be declare by torsion failures.