Analysis and Optimization of an Expansion Energy-Absorbing Anti-Crawler for Rail Vehicles

This paper describes the crashworthiness optimization of an intumescent energy-absorbing anti-crawler, which was applied to anti-crawling devices for rail vehicles. The energy absorption characteristics of the expansion-type energy-absorbing anti-crawler were studied experimentally, a finite element model (FEM) was established, and the finite element simulation results were verified with the experimental results. In this paper, the response of the expansion structure was predicted using a validated finite element model. Then, the effects of the variables (expansion tube thickness (T), friction coefficient (μ), and slope angle of conical mandrel (α)) on the response were sampled using the design-of-experiments (DOE) method, including a full factorial design and a central composite. Based on these samples, an alternative model was developed using the moving least-squares method (MLSM). Using the results from the full factorial design for main effects analysis, T was found to have the most significant effect on the average force (Favg), while α had the greatest effect on the specific energy absorption (SEA). The Favg, fracture strain, thickness, taper, and friction coefficient of the structure were used as constraints, and the multiobjective genetic algorithm (MOGA) method was used for parameter optimization to obtain a higher SEA. Finally, the best parameters (T = 5.76 mm, μ = 0.178, α = 25°) with an SEA value of 36.52 kJ/kg were obtained. The SEA value was increased by 31.70% compared to the initial results.