Structural Optimization and Energy Absorption Characteristics of Double-Layer Variable-Diameter Energy-Absorbing Components for Anti-Impact Brackets

In order to effectively mitigate the destructive effects of impact ground pressure on hydraulic supports, a double-layer variable-diameter energy-absorbing component with enhanced energy absorption was proposed based on previous research on single-layer variable-diameter structures. Using the energy method, the energy dissipation theory of the expansion and reduction deformation of tubular components with different cross-sections was analyzed, and the bearing capacity formulas for stable diameter reduction processes under various combinations of corrugated and circular tubes were derived. Through numerical simulations, the energy absorption curves, bearing capacity curves, and deformation patterns of eight types of energy-absorbing components were obtained. Comparative analysis revealed that the double-layer variable-diameter energy-absorbing component structure (SBY-type), consisting of an inner corrugated tube and an outer circular tube, exhibited superior energy absorption performance. The influence of key structural parameters on the energy absorption characteristics was further investigated. Among these, inner tube thickness, outer tube thickness, corrugation radius, and inner chamfer angle of the base were found to have the most significant effects. A Latin hypercube sampling scheme was designed, and the parameters were optimized using a Kriging surrogate model coupled with a multi-objective particle swarm optimization algorithm. The optimal parameter combination was determined as follows: inner tube thickness of 6.0 mm, outer tube thickness of 2.9 mm, corrugation radius of 6.9 mm, and base chamfer angle of 40°. Subsequently, axial quasi-static compression tests were conducted to verify the accuracy and effectiveness of the numerical and optimization results. The results indicate that, the total energy absorption of the double-layer variable-diameter energy-absorbing component increased by 54.2%, the specific energy absorption increased by 55.6%, the average bearing capacity increased by 43.2%, and the load standard deviation increased by 59.5%. These enhancements demonstrate that the optimized component exhibits superior and more stable energy absorption performance, thereby improving the reliability of the yielding anti-impact process. This study provides an important theoretical basis and design reference for developing energy-absorbing components in hydraulic supports for deep roadway reinforcement.