基于落锤冲击试验和数值模拟研究了侧向冲击下圆形双钢管混凝土(concrete-filled double-tube, CFDT)柱的损伤模式；以弯矩-转角关系作为评估指标，建立了圆形CFDT柱的冲击质量-冲击速度、冲击能量-冲击质量损伤评估模型；讨论了冲击位置、外钢管强度、内钢管径厚比和轴压比等参数对损伤评估模型的影响规律。结果表明：在冲击能量不变的情况下，圆形CFDT柱的损伤程度随冲击质量与冲击速度比值的增大而显著增加。圆形CFDT柱的临界冲击能量曲线随冲击质量的增大逐渐下降后趋于平缓，收敛于水平渐近线；不同损伤程度对应的临界冲击能量间存在显著差别。当冲击质量恒定时，增大内钢管径厚比、外钢管强度以及冲击点距自由端距离，可以提高圆形CFDT柱的临界冲击能量；增大轴压比则会使临界冲击能量呈先增加后下降的趋势。各参数对临界冲击质量的影响随着冲击速度的增大而减小，其中外钢管强度对损伤评估模型的影响最大，轴压比和冲击位置次之，内钢管径厚比的影响最小。

Damage modes of circular concrete-filled double-tube (CFDT) columns under lateral impact were studied by drop impact tests and numerical simulations.Using the moment-rotation relationship as the assessment indicator, the velocity-mass and mass-energy damage evaluation models for circular CFDT columns were established.The influences of the parameters including the impact position, external steel tube strength, diameter-thickness ratio of internal steel tube and axial compression ratio on the damage evaluation models were discussed.The results show that under constant impact energy, the damage degree of circular CFDT columns increases remarkably as the ratio of impact mass to impact velocity increases.The critical impact energies at different damage degrees are significantly different.As the impact mass remains constant, the critical impact energy of the circular CFDT column increases with the increase of the internal steel tube diameter-thickness ratio, external steel tube strength and distance from free-end to impact point, while it increases first and then reduces with increasing of the axial compression ratio.The influences of these parameters on critical impact mass decrease with the increase of impact velocity.Among them, the external steel tube strength has the greatest influence on the damage evaluation model, the axial compression ratio and the impact position take the second place, and the influence of the internal steel tube diameter-thickness ratio is the least.