Non-Linear Constraints and Stiffness Representations in Simple Flexible-Body Dynamic Beam Formulations
Abstract: A simple discrete four-degree-of-freedom (lumped parameter) model representing a flexible beam undergoing large overall planar prescribed motion has been developed. It serves as a simple tool to investigate two previously studied problems involving flexible-body beam dynamics, namely those involving bending and membrane stiffness dominated behavior. The tool is used to investigate the requirements to accurately solve these problems using non-linear constraints and a non-linear spring representation. The validity of this model is demonstrated by comparing results to those previously published for continuous flexible-body beam formulations. One of these continuous representations is modified to include a non-linear tether spring representation. This allows additional model verification as well as insight into the non-linear constraint and stiffness representations. Taken in its entirety, this investigation demonstrates the utility of these simple lumped parameter models, by showing their ability to provide rapid insight into the behavior of the more complicated continuous models, as well as the system in general.