University of Illinois, Urbana Champaign - ENGR 100Revisit-Worksheet12

Objectives: • Determine resultant forces for a three-dimensional loading scenario • Construct Mohr’s circle and determine principal stresses • Use the Tresca yield criterion to predict the failure stress Introduction: A lug wrench is firmly a!xed to a lug nut. A torque T is required to loosen the nut. You decide to step on the end of the wrench in order to turn it. Assume that the force provided by your foot can be modeled as a concentrated force with magnitude F. We also assume that the force vector lies within the vertically-oriented yz-plane and makes an angle with the y-axis. Note that the lug wrench’s coordinate system has its origin at the center of the wrench, the nut is located at position x = !L and the force is applied at position y = !L