Abstract:
This paper presents a novel approach to topology optimization in crashworthiness design, focusing on the redistribution of material to enhance energy absorption efficiency in structures subjected to impact loading. Traditional topology optimization techniques have been widely applied to linear elastic structures under static loads, typically using analytical or semi-analytical methods to perform sensitivity analysis. However, when dealing with contact-impact problems in explicit finite element simulations, obtaining sensitivity information is challenging. This study introduces an alternative formulation where element thickness is adjusted dynamically based on internal energy density (IED) distribution.
The proposed methodology optimizes structural performance by modifying finite element thickness according to energy absorption efficiency, allowing for the treatment of nonlinear effects such as plasticity and contact-impact. A key aspect of this approach is its ability to maintain load paths throughout the optimization process, ensuring that elements with reduced thickness can still contribute to the structure’s response. The study also considers multiple load cases by normalizing and summing IED values, enabling robust performance under various impact conditions.
Finite element models are developed using TrueGrid and analyzed with LS-DYNA, with post-processing handled through LS-PRE/POST and Perl scripts. The optimization process incorporates a volume constraint to prevent excessive mass growth and employs penalization techniques to regulate intermediate thickness values. The study explores key convergence factors, including target IED values, element modification range, and penalization parameters, which significantly impact optimization efficiency and accuracy.
Results demonstrate that the method effectively distributes material to create crashworthy structures with evenly distributed internal energy density. The optimized designs exhibit improved structural integrity while minimizing material usage. This study highlights the importance of integrating mesh analysis techniques and adaptive topology adjustments in crash simulations. Future research will focus on refining optimization parameters and expanding the methodology to complex three-dimensional crashworthiness applications.
