Cut-out grooves optimization to improve crashworthiness of a gradual energy-absorbing structure for subway vehicles

• Proposes a new cut-out groove design to improve the crashworthiness of structures.
• The energy-absorbing structure FE model was created and validated by impact tests.
• An increase of cut-out groove dimensions leads to a decrease of the EA and IPCF.
• The longitudinal dimension affects the EA and the groove depth determines the IPCF.
• The IPCF can be improved greatly by using optimal algorithm with constraint of EA.

In this study, a new cut-out groove design is addressed, aiming to improve the crashworthiness of a gradual energy-absorbing structure for subway vehicles. First, the crashing characteristics of the gradual cut-out grooved energy-absorbing structure (GCGES) are studied and the finite element model (FEM) is validated by dynamic impact tests. Then, response surface (RS) models are established regarding the validated FEM. Based on RS models, the energy absorption (EA) and initial peak crushing force (IPCF) are formulated as functions of cut-out groove dimensions. In further, parametric studies are performed to evaluate the effects of design variables on collision responses. It is found that both EA and IPCF are negatively affected by the cut-out grooves. Particularly, the effect of design parameters on IPCF is obviously greater than that on EA capacity. To minimize the IPCF under the constraint of EA, optimization technology with adaptive simulated annealing (ASA) algorithm is adopted. The optimal results indicate that the IPCF decreases by 31.02% comparing with the initial designed GCGES and 63.60% comparing with the common flat surface energy-absorbing structure (FSES). From the vehicle safety view, the cut-out grooves are introduced successfully and the optimized GCGES is of considerable significance and advantages in crashworthiness application.

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