Learning Forum

[Rishis1096]

I am trying to account for the stress on a mechanism and have applied all the forces and accelerations, however I am unable to figure out how to determine the maximum shear stresses in specific directions (namely the x- y- and z-directions). I saw that this can be done using a normal stress, however the maximum shear stress value is the one I am looking for. Does anyone know how I can get this done?

[peteroznewman]

Rishis, you should review the material on Mohr's Circle. Maximum Shear Stress is calculated from the normal and shear stress in the xyz coordinate frame and exists in its calculated orientation in space; you don't get to choose a specific direction. This is the same for the Principal Stresses. In the 2D figure below, the stress in the xy coordinate system is shown in the lower left block. The Maximum Shear Stress is shown in the upper left, while the Principal Stresses are shown to the right of the xy coordinate stresses.