Force Identification of Mechanical Systems by Using Particle Swarm Optimization

This paper presents an inverse procedure for the determination of external loads, given the dynamic responses of the loaded structure and its corresponding finite element model. The influence of the stress-stiffening effect on the dynamic characteristics of structural systems is used to establish a relation between the dynamical responses and the applied external loading. An optimization problem is formulated in which the objective function represents the difference between the measured modal characteristics of the loaded structure and their FE counterparts. The loading parameters (magnitude, position and direction), assumed as being unknown, are considered as design variables. The identification procedure is illustrated by means of numerical simulations, in which the identification problem is solved by using the heuristic named Particle Swarm Optmization together with the Lagrange-Newton SQP (Sequential Quadratic Programming) method.