Multi-duration robust topology optimization of fiber-reinforced composite structures under dynamic loading

Abstract

In complex engineering environments, the duration of dynamic loads experienced by structures is highly variable. Traditional topology optimization approaches typically address only a single load duration, posing substantial safety risks. This study proposed a multi-duration robust topology optimization method for the design of fiber-reinforced composite structures (FRCS) subjected to dynamic loads with multiple potential durations. Operating under the assumption of linear elastic dynamics, the method employed time-averaged displacement fields to guide fiber orientation updates, effectively addressing the time-varying characteristics of principal stress directions during dynamic responses. To capture the morphological variability of structures under different load durations, a novel metric called the Morphological Dispersion Index (MDI) was introduced. Guided by the MDI, representative sub-durations were selected, and robust topology optimization was achieved by aggregating the objective functions and sensitivities of each sub-duration throughout the optimization process. Experimental validation of the numerical simulation framework was conducted using 3D printing and Digital Image Correlation (DIC). Benchmark cases demonstrated that variations in load duration significantly influenced the optimization outcomes. Compared to designs optimized for a single load duration, the proposed method reduced structural elastic strain energy by 29.98% to 75.80%, while maintaining stable and efficient structural configurations. The method exhibited strong adaptability across varying load durations, offering a new perspective for the robust design of FRCS under dynamic loading conditions.