Crashworthiness analysis and shape design optimization of corrugated tubes for railway application

Thin-walled tubes have been widely used as energy-absorbing devices since they are light and have high energy absorption efficiency. However, the downside is that conventional thin-walled tubes usually exhibit an excessive peak crushing force (PCF) and large fluctuations in the force-displacement curve. Corrugated tubes are introduced to reduce the PCF and to increase the stability of energy-absorbing devices. Since the performance of corrugated tubes is highly influenced by their geometry, design optimization methods can be utilized to optimize the performance of corrugated tubes. It is difficult to apply conventional gradient-based optimization methods in crashworthiness analysis because of the strong nonlinearity and large computational time. In this paper, we utilize shape design optimization based on an adaptive surrogate model. The EA is maximized in transition crushing mode (T-mode), which is the boundary between progressive crushing mode (P-mode) and simultaneous crushing mode (S-mode), while simultaneously optimizing the contact force efficiency (CFE).