1. The problem statement, all variables and given/known data At a particular stage of the manufacturing process, a robotic arm has the position and loading shown in the figure; http://img246.imageshack.us/img246/5498/25481552jo0.th.png [Broken] Calculate the direct stresses due to bending and the shear stresses due to torsion. 2. Relevant equations M = r x F 3. The attempt at a solution First, I took the applied force and resolved the moments about point A as follows (assuming the applied force is travelling parallel to the z-axis); M = r x F = i(1-0) -j(2-0) = i - 2j I am fairly sure that the next step in the problem is resolving these moments about the x and y axes into a moment along the figure (a torsional moment) and a moment parallel to the BC section; please refer to the following diagram; http://img246.imageshack.us/img246/6007/72031118aw9.th.png [Broken] However I'm not exactly sure how to do this. A tutor told me it's ok to treat the moments as if they were forces but i can't get my head around the idea. Any advice or help would be appreciated.