Three-dimensional high resolution topology optimization considering additive manufacturing constraints

Abstract

This paper studies additive manufacturing oriented structural topology optimization with SIMP approach and aims at 3D high-resolution printable structural topology design with overhang and horizontal minimum length control for minimum compliance.To start with, we construct a hyperplane in ℝ4 by fitting a local element density distribution in the 18 Elements Scheme, use its gradient to estimate the overhang angle, the directional-dependent overhang angle and formulate the corresponding constraints. Next, we propose a Horizontal Square Scheme and four support sets around the concerned element. The horizontal minimum length is controlled by forbidding the concerned element’s density to be larger than the average density of the elements in one of the support sets. By combining these two constraints, the hanging feature is well suppressed.A new implementation scheme with an improved weight function is proposed to meet these element wise AM constraints well. To get high resolution structural boundaries with low computational efforts, this paper applies the multiresolution topology optimization (MTOP) method.The structural TO problem is solved by MMA. A number of numerical examples and AM experiments show the effectiveness of this method. The present approach works efficiently when the building direction is in slight misalignment with the vertical direction.