Design and analysis adaptivity in multi‐resolution topology optimization

Multiresolution topology optimization (MTO) methods involve decoupling of the design and analysis discretizations, such that a high‐resolution design can be obtained at relatively low analysis costs. Recent studies have shown that the MTO method can be approximately 3 and 30 times faster than the traditional topology optimization method for 2D and 3D problems, respectively. To further exploit the potential of decoupling analysis and design, we propose a dp‐adaptive MTO method, which involves locally increasing/decreasing the polynomial degree of the shape functions (p) and the design resolution (d). The adaptive refinement/coarsening is performed using a composite refinement indicator which includes criteria based on analysis error, presence of intermediate densities as well as the occurrence of design artefacts referred to as QR‐patterns. While standard MTO must rely on filtering to suppress QR‐patterns, the proposed adaptive method ensures efficiently that these artefacts are suppressed in the final design, without sacrificing the design resolution. The applicability of the dp‐adaptive MTO method is demonstrated on several 2D mechanical design problems. For all the cases, significant speed‐ups in computational time are obtained. In particular for design problems involving low material volume fractions, speed‐ups of up to a factor of 10 can be obtained over the conventional MTO method.