Stress constraint topology optimization of coupled thermo-mechanical problems using the temperature dependence of allowable stress

Abstract

Engine components in the aerospace industry are used in high-temperature environments to improve performance. The material strength of metals significantly reduces at high temperatures compared to room temperature. This phenomenon is important in design since the design allowance considers temperature dependence. This study proposed a new stress-constrained topology optimization methodology for coupled thermo-mechanical problems. As for stress constraints, global constraints are applied, which can reduce computational cost, and constraints are imposed on the maximum stress in the body. Assuming an actual design, the proposed methodology defines allowable stress as a function of temperature and considers temperature dependence of the allowable stress. The proposed methodology simplifies the optimization problem by allowing the user to constrain temperature and stress with a single constraint function. The temperature constraint is automatically determined based on the degree of stress generated, making it easier to obtain valid optimization conditions and optimize results for the design. Further, the analytical sensitivity needed to obtain an optimized structure is developed. Finally, numerical calculations are performed to show the effects of temperature dependence on the allowable stress.