Weight Reliability-Based Optimization of Framed Vehicles

The motion of vehicles over rough pavement induces random variable stresses in their structures, that may cause fail by fatigue. Fatigue lifetime estimation is a phenomena with great levels of variability, and it may adequately treated through reliability methods, in terms of fail probability or reliability indexes. In this work, a procedure for optimization considering discrete design variables is applied in weight optimization of a mini baja structure, with reliability-based design constrain. The lifetime estimation is based in time-domain approach, using “stress levels vs. Number of cycles” curves, the Palmgreen-Miner Rule to compute the cumulative damage and the Rainflow Method for cycles counting. First Order Reliability Method (FORM) and Monte Carlo Simulation with Importance and Adaptive Sampling are used to evaluate the reliability index.