Stochastic Sampling for Structural Topology Optimization with Many Load Cases: Density-Based and Ground Structure Approaches

TL;DR

This paper introduces a probabilistic, stochastic sampling method for topology optimization that significantly reduces computational costs when dealing with many load cases, maintaining similar accuracy to traditional methods.

Contribution

The authors develop a novel randomized optimization approach with a damping scheme, enabling efficient topology optimization with many load cases by solving fewer finite element problems per iteration.

Findings

Reduces computational cost by solving only a few finite element problems per step.

Achieves similar topology and compliance results as standard algorithms.

Damping scheme improves convergence speed and stability.

Abstract

We propose an efficient probabilistic method to solve a deterministic problem -- we present a randomized optimization approach that drastically reduces the enormous computational cost of optimizing designs under many load cases for both continuum and truss topology optimization. Practical structural designs by topology optimization typically involve many load cases, possibly hundreds or more. The optimal design minimizes a, possibly weighted, average of the compliance under each load case (or some other objective). This means that in each optimization step a large finite element problem must be solved for each load case, leading to an enormous computational effort. On the contrary, the proposed randomized optimization method with stochastic sampling requires the solution of only a few (e.g., 5 or 6) finite element problems (large linear systems) per optimization step. Based on simulated annealing, we introduce a damping scheme for the randomized approach. Through numerical examples in two and three dimensions, we demonstrate that the stochastic algorithm drastically reduces computational cost to obtain similar final topologies and results (e.g., compliance) compared with the standard algorithms. The results indicate that the damping scheme is effective and leads to rapid convergence of the proposed algorithm.