Explicit finite element analysis of a flexible multibody dynamic system with highly damped compliant fingers

Many industries require transferring objects from conveyors to a processing line at production rate. In food processing, grasping mechanisms with highly damped compliant fingers must be capable of accommodating a limited range of object shapes/sizes without causing damages on the products being handled. Most existing models, however, are inadequate to predict the dynamics of a compliant mechanism with large deformation, contact nonlinearity, and complex 3D geometries. This paper investigates the explicit finite-element (FE) method for industrial automation applications, where both geometric and operational parameters must be evaluated. Specifically, this paper discusses the effects of several key factors (that include material properties and element types as well as the numbers of nodes) on a FE computation. Along with an experiment /computation method (that relaxes limitations of a log-decrement method generally valid for systems with an oscillatory response), the procedure to account for the damping effect in simulating the dynamics of a compliant grasping system is numerically illustrated with experimental validation against published data.