An empirical study on stress-based fail-safe topology optimization and multiple load path design

Abstract

Explicitly considering fail-safety within design optimization is computationally very expensive, since every possible failure has to be considered. This requires solving one finite element model per failure and iteration. In topology optimization, one cannot identify potentially failing structural members at the beginning of the optimization. Hence, a generic failure shape is applied to every possible location inside the design domain. In the current paper, the maximum stress is considered as optimization objective to be minimized, since failure is typically driven by the occurring stresses and thus of more practical relevance than the compliance. Due to the local nature of stresses, it is presumed that the optimization is more sensitive to the choice of the failure shape than compliance-based optimization. Therefore, various failure shapes, sizes and different numbers of failure cases are investigated and compared on the basis of a general load-path-based evaluation scheme. Instead of explicitly considering fail-safety, redundant structures are obtained at much less computational cost by controlling the maximum length scale. A common and easy to implement maximum length scale approach is employed and fail-safe properties are determined and compared against the explicit fail-safe approach.

Topology Optimization of Strength-Safe Continuum Structures Considering Random Damage

“…Hederberg et al [14] used moving morphable components (MMCs) to simulate structural damage and combined with density-based topology optimization method to obtain damage-safety design. Kranz et al [15] used the maximum length scale method to conduct a damage-safety topology optimization study with the goal of stress minimization. During the optimization process, they evaluated the failure scenarios according to the actual load path, and not only designed the damage-safety design with good performance, but also reduced the calculated cost.…”

Reliability index based strategy for the probability-damage approach in fail-safe design optimization (β-PDFSO)

“…It was concluded that the methodology was significantly more efficient than densitybased techniques, since the number of analyses required is proportional to the number of geometric components and independent from the mesh. Kranz et al [26] proposed load-path-based evaluation scheme for fail-safe topology optimization, where redundant structures are obtained at much less computational cost. Hederberg and Thore [23] combined density-based topology optimization with a moving morphable component representation of structural damage, obtaining more robust fail-safe designs.…”

Stress Topology Analysis for Porous Infill Optimization

“…It has also been applied to design porous shell structures (Träff et al, 2021). Other notable extensions include the design of porous structures with gradation in the porosity and pore size (Schmidt et al, 2019;Das and Sutradhar, 2020), use of multiple materials (Li et al, 2020;Zhao and Zhang, 2021), stress constraints (Kranz et al, 2021), as well as design of self-supporting infill (Liu et al, 2021) and fiber-reinforced structures (Li et al, 2021). Dou proposed a projection operator to implicitly incorporate local volume constraints (Dou, 2020).…”