Solve the Problem
Pierce Pacific provided a set of load charts that depicted the maximum lifting capability of the boom at a range of locations. This chart was verified with Working Model®, a mechanical analysis program, and then used to calculate the forces on the pin in the joint. The result was a new load chart with all the forces, torques, and moments aligned to the axis of the main boom. These values allowed the joint to be evaluated at any point, without regard to the position of the other boom sections.
Pro/Engineer® is the parametric modeler that was used to create a 3D model of the casting. This program also will calculate the area moment of inertia of any cross section as well as determine the total weight. A set of equations was created in Engineering Equation Solver® to calculate the stress in the casting at several points, based on the load charts from Working Model® and the area moments of inertia from Pro/Engineer®. The design was optimized for minimum weight and acceptable stresses through several iterations.