Von Mises Stress

04/16/18

“How can we more accurately predict an object’s failure?”

 

One of the most important duties of a design engineer is to ensure that objects do not fail. However, classical failure theory does not always suffice. Instead, we must use more advanced concepts. One example of this is the Von Mises Stress, which is characterized by a superposition of all of the stresses on the object. If the Von Mises Stress is greater than the yield stress, then failure will occur. The formula for Von-Mises Stress is given by sigma_v = sqrt (sigma_1^2+sigma_2^2+sigma_3^2-sigma_1*sigma_2-sigma_2*sigma_3-sigma_1*sigma_3), where sigma_v is the Von Mises Stress and sigma_1,sigma_2, and sigma_3 are all stress superposition values. The Von Mises Stress can be visualized as an ellipse in 2 and 3 dimensions.