Structural optimization of multibody system components described using level set techniques

Abstract

The structural optimization of the components in multibody systems is performed using a fully coupled optimization method. The design's predicted response is obtained from a flexible multibody system simulation under various service conditions. In this way, the resulting optimization process enhances most existing studies which are limited to weakly coupled (quasi-) static or frequency domain loading conditions. A level set description of the component geometry is used to formulate a generalized shape optimization problem which is solved via efficient gradient-based optimization methods. Gradients of cost and constraint functions are obtained from a sensitivity analysis which is revisited in order to facilitate its implementation and retain its computational efficiency. The optimizations of a slidercrank mechanism and a 2-dof robot are provided to exemplify the procedure.

Kinematic-based structural optimization of robots

“…A graph theory-based approach has been used [4] to estimate the type synthesis while the best dimension parameters are calculated by the precision position method. On the dimensional level, shape optimization of the link of the robot using level set techniques have been dealt with in [5]. On the type level, the critical point in most works is the graph theory [6], where possible topologies are enumerated to get the best type.…”

Topology optimization of a flexible multibody system with variable-length bodies described by ALE–ANCF

“…1 The first stage deployment of a spinning solar sail [6] Topology optimization of an FMBS has called considerable attention in recent years to reduce the moving weight, improve the energy efficiency and enhance the dynamic performance. Since the pioneering work by Bendsøe and Kikuchi [13], several approaches [14] have been studied for the topology optimization of fluids, acoustics, electromagnetics and optics, as well as FMBS [15][16][17][18][19], but not yet for any FMBS with variable-length subject to both large overall motion and large deformation. This is probably due to the fact that the variable-length gives rise to three challenges for the topology optimization.…”

“…Consequently, the topology optimization can be performed using the method of the equivalent static loads (ESL) or directly from the dynamic simulation of an FMBS. The former is named the ESL method [15,18,[27][28][29][30][31], while the latter is called the integrated optimization method [16,32]. For an FMBS with variable-length bodies, the design domain varies over time.…”

On the equivalent static load method for flexible multibody systems described with a nonlinear finite element formalism

“…Several works were realized using this weakly coupled method, for example [7][8][9]. The weakly coupled method contrasts with the fully coupled method [10][11][12][13] wherein the optimization process considers the time response coming directly from the MBS simulation.In [6], the ESL derivation is carried out for MBS described with a floating frame of reference formulation. This formalism is suitable to define ESL because the flexibility of the components is introduced within a body-attached frame and that the component responses are described with respect to this frame.…”

“…Several works were realized using this weakly coupled method, for example [7][8][9]. The weakly coupled method contrasts with the fully coupled method [10][11][12][13] wherein the optimization process considers the time response coming directly from the MBS simulation.…”