Topology Optimization of Flexible Multibody Systems


The field of lightweight structural design has been the focus of many researches as the reduction of mass results in energy efficiency and cost reduction. It is specially important in design of active multibody dynamic systems where energy consumption is often a crucial parameter. However, reduction of mass in elastic multibody systems reduces the stiffness of flexible parts which increases undesired deformations in the dynamic system. These deformations are a point of concern specially in high speed and high precision machines. Therefore, it is necessary to use optimization methods to reduce the mass in a dynamic system without impairing its performance.

Topology optimization method is a powerful tool for designing lightweight structures. This method tries to find the best distribution of material in a fixed design space. Therewith, this method allows for any formation of material inside the specified domain. So far, it has been mostly applied for static applications. In dynamic application it has been mostly used to influence the structure's eigenfrequencies. In contrast, in this project, topology optimization problem for flexible multibody systems are developed. These are based on transient simulation of the flexible multibody systems [1]. The necessary steps in the topology optimization of flexible multibody systems are shown below.

  • Topology optimization procedure for flexible multibody systems

This topology optimization of flexible multibody systems is used for example to minimize end-effector tracking error in a flexible manipulator [2][3]. Other possible applications are the design of vehicle suspension parts or the piston rod. Investigation of different efficient methods in implementation of topology optimization in flexible multibody systems and enhancing the accuracy of optimization and multibody simulations are goals of this project.

  • Example of the topology optimization of a flexible piston rod.

    Selected publications

    1. Held, A. On structural optimization of flexible multibody systems. PhD Thesis, University of Stuttgart, Shaker Verlag, Aachen, 2014.
    2. Seifried, R.; Held, A.: Optimal Design of Lightweight Machines using Flexible Multibody System Dynamics. Proceedings of the ASME 2012 International Design Engineering Technical Conferences (IDETC/CIE 2012), August 12-15, 2012, Chicago, IL, USA, paper ID DETC2012-70972.
    3. Held, A.; Seifried, R.: Topology Optimization of Members of Elastic Multibody Systems. PAMM Proceedings in Applied Mathematics and Mechanics, Vol. 12, 2012, pp. 67-68, [DOI:10.1002/pamm.201210025].