Topology optimization design for strengthening locally damaged structures: A non-gradient directed evolution method

Existing non-gradient topology optimization algorithms require numerous objective function evaluations for reinforcement design of damaged structures, resulting in huge computational costs. In this study, a non-gradient directed evolution (NGDE) topology optimization method is proposed for strengthening locally damaged RC structures. First, a topology description strategy for reinforcement material (RM) component is developed to reduce the number of design variables. Then, a directed generation criterion of RM samples is given by locating the regions with the maximum concrete damage from the previous iteration step. Subsequently, the random disturbance operation, incorporating mutation, crossover, and selection, is employed to enhance the diversity of RM samples. On this basis, the element removal and size adjustment strategies of RM components are presented to overcome the numerical instability. Finally, the applicability and effectiveness of the proposed method is illustrated by the numerical examples. Results show that the proposed method can effectively generate a reasonable RM configuration for strengthening damaged RC structures without relying on design sensitivity.