泡沫铝基耗能装置在铁路桥墩防车撞中的应用研究

Application of Aluminum Foam-Based Energy Dissipation Devices in Railway Pier Protection Against Vehicle Collisions

随着公路、铁路、城市立交桥的大量建设,跨线桥数量剧增,桥墩被汽车撞击的可能性大大增加。因此,针对目前铁路桥墩防车撞防护装置的不足,提出了一款泡沫铝基组合耗能装置的结构型式。该研究结合了静力压缩试验、落锤冲击试验以及有限元数值模拟,研究了防撞装置缓冲材料的物理力学性能及车辆撞击防撞装置的冲击动力学响应。结果表明,泡沫铝-聚氨酯-泡沫铝三层组合结构型式中工况3~4吸能效果最佳,其吸能密度(EA)、比吸能(SEA)以及吸能效率(EEA)值分别为3×10^(3) kJ/m^(3)、12.21 kJ/kg、28.57%。在数值模拟中,无防撞装置工况下,车辆撞击力最大值为5 332.99 kN,桥墩吸收的能量为22.05 kJ,最大应力为124.46 MPa,墩身产生明显损伤;在有防撞装置工况下,车辆撞击力最大值为2 674.41 kN,降低了49.85%;桥墩最大应力为6.96 MPa,降低了94.41%。结果表明该防撞装置组合结构对桥墩起到了良好的防护效果。

With the large-scale construction of highways,railways and urban overpasses,the number of overpasses has increased sharply,significantly raising the risk of bridge piers being hit by vehicles.To address the shortcomings of current protective devices for railway bridge piers against vehicle collisions,a structural form of an aluminum foam-based energy dissipation device was proposed.This study combined static compression tests,drop hammer impact tests,and finite element numerical simulations to investigate the physical and mechanical properties of the buffer material in the anti-collision device and the dynamic impact response of the vehicle during collisions.The results showed that the three-layer aluminum foam-polyurethane-aluminum foam composite structure,under test conditions 3 and 4,achieved the best energy absorption performance.Its energy absorption density(EA),specific energy absorption(SEA),and energy absorption efficiency(EEA)values were 3×10^(3)kJ/m^(3),12.21kJ/kg,and 28.57%,respectively.In numerical simulations,without a protective device,the maximum vehicle impact force was 5332.99kN,the energy absorbed by the bridge pier was 22.05kJ,and the maximum stress was 124.46MPa,causing significant damage to the pier.With the protective device in place,the maximum vehicle impact force was 2674.41kN,a reduction of 49.85%;the maximum stress on the pier was 6.96MPa,a decrease of 94.41%.The results showed that this protective device provided excellent protection for bridge piers.