RPUF填充薄壁圆钢管短柱构件的轴压力学性能

Axial-crushing performance of RPUF-filled short circular thin-walled steel tube

摘要:

基于建筑工程领域存在的碰撞、冲击等工程背景,提出密度为300 kg/m³的硬质聚氨酯泡沫（RPUF, rigid polyurethane foam）填充建筑圆钢管短柱吸能构件,为获得该类构件在轴压荷载作用下的基本力学性能及吸能能力,开展了3组空钢管和3组RPUF填充圆钢管短柱构件的轴压试验.试验结果表明:轴压荷载作用下,填充RPUF能够有效改善建筑圆钢管在轴压荷载作用下的叠缩变形模式,使构件趋于对称叠缩变形；同时,RPUF填充圆钢管构件较空钢管的首个峰值荷载及各项吸能指标都有了较大幅度的提升,且壁厚越薄,提升幅度越大,体现了填充RPUF对建筑圆钢管的力学性能及吸能能力的提升.基于ABAQUS/Explicit求解器建立RPUF填充圆钢管短柱构件的轴压有限元模型,将仿真结果与试验结果对比,以验证有限元模型的准确性,随后开展参数分析,结果表明RPUF填充圆钢管耗能能力随壁厚和管径的增大而增大.在Alexander经典叠缩模型的基础上,推导了平均压缩力预测公式,与试验结果和数值模拟结果对比发现该公式能够有效预测RPUF填充圆钢管短柱构件在轴压荷载作用下的平均压缩力.

Abstract:

Circular steel tube filled with rigid polyurethane foam (RPUF) with density of 300 kg/m³ was proposed for energy absorbing components according to the requirement of civil engineering. Three groups of empty steel tubes and three groups of RPUF-filled short circular steel tubes were tested under axial compressive load to gain their mechanical properties and ability of energy absorbing. Experimental results show that filling RPUF could effectively transform the plastic bucking behavior of circular steel tube under axial compressive load from asymmetric mode towards symmetric mode. The first peak load and structural crashworthiness indicators of the RPUF-filled steel tube increased significantly. The thinner the wall thickness was, the greater the increased. Moreover, a finite element model of RPUF-filled short circular steel tube was built based on the ABAQUS/Explicit, and simulation results showed good agreement with experimental results, which confirmed the accuracy of the model. Parameters analysis was carried out subsequently, which showed that the energy absorbing ability of the RPUF-filled circular steel tube increased with its wall thickness and tube diameter increase. An effective prediction formula for mean crush load (MCL) was also deduced based on the classical progressive collapse model proposed by Alexander. After comparison with the experimental and simulation results, it is found that this formula can effectively predict the average compressive force of the RPUF-filled short circular steel tube.