Topology Optimization for Multi-Functional Components in Multibody Dynamics Systems.

Abstract

This research extends topology optimization techniques to consider multibody dynamics systems with a much more open design space, which can include passive, active, and reactive components, with a special application focus on a gunner restraint system (GRS) design problem. General representative models for the multi-functional components are established in a multibody dynamics system. The topology optimization process has been advanced for the optimization of geometrically nonlinear, time-dependent, and timing-dependent multibody dynamics systems undergoing large nonlinear displacements with nonlinear dynamics responses as design objectives. Three efficient sensitivity analysis methods have been proposed, which include the constant dynamic loading method, the time integration incorporated method based on the Generalized-Alpha algorithm and the iterative method. These new methods have made it possible to calculate the sensitivities in complicated multibody dynamic systems and provide users with choices to significantly reduce the computational costs, especially, in the topology optimization process, and to obtain desired accuracy in the sensitivity analysis. In addition to the sensitivity analysis methods, an efficient and reliable Kriging variable screening method based on the REML criterion has been developed to identify significant variables in the systems to determine the worst cases for various system uncertainty studies.

A specific application of the multi-functional components system optimization technology is the GRS design problem, in which both the vehicle and the gunner can undergo large relative and absolute motions under various driving or threat conditions. In meanwhile, the restraint components may need to allow amplitude-dependent, time-dependent, timing-dependent nonlinear response behaviors, such as those seeing in restraint belts, airbags, and retractors. The restraint system layout design needs to keep a wide open design space, thus to find the truly optimal design. The developed methodologies have been employed in the GRS design problems to demonstrate usage of the new methodologies.