摘要:
H型钢柱在工业厂房、停车场等应用时容易遭受吊装荷载和车辆撞击作用。基于上述背景,本文在前期试验研究基础上,通过有限元开展H型钢柱撞击下及撞击后力学性能全过程分析。首先通过机理分析,获得不同轴压比影响下试件的变形特征、应力与耗能发展。结果表明,侧向撞击下H型钢柱以整体变形为主,上翼缘与腹板分别发生局部凹陷与平面外屈曲;撞击力时程曲线呈现明显的平台段,预加轴力明显削弱试件的抗撞能力。其次,建立108个参数分析模型,重点研究荷载参数(撞击质量m、撞击速度v与轴压比n)、材料参数(屈服强度fy)与几何参数(截面面积A与试件长度L)对撞击力、撞击变形和剩余承载力的影响规律。最后,基于响应面法提出了多因子交互影响的撞击下整体与局部变形及撞击后剩余承载力预测公式,可用于H型钢柱撞击全过程损伤评估与设计。
Abstract:
H-section steel columns have been widely employed in industrial buildings and parking lots, etc., which are vulnerable to crane-loading or vehicle collisions. Based on above background, the lateral impact model and residual load-carrying capacity model were established using Abaqus finite element software to analyze the performance of H-section steel columns during and after impact loading, following previous experimental studies. Firstly, the working mechanism, including the deformation characteristics, stress evolution and energy dissipation, was analyzed. Results indicated that under impact loading, the deformation pattern is mainly dominated by the global deformation, with the local deformation of the upper flange and out-of-plane buckling of web. The time history curve of impact force presents an obvious plateau phase, and the existence of the pre-axial loading obviously reduces the impact resistance of the specimens. In general, H-section steel columns exhibited favorable ductility performance during impact loading. Subsequently, a total of 108 parametric models were developed, and the influences of load parameters (impact mass, impact velocity and axial load ratio), material parameter (steel yield strength) and geometric parameters (sectional area and specimen length) on the impact force, deformation, and residual load-carrying capacity were emphatically studied. The results showed that as the impact mass, impact velocity, and pre-axial loading ratio increased, both the global and local deformations of H-section steel column increased, while the residual bearing capacity decreased. Finally, by considering the multi-factor interactions, the formulas for predicting global deformation and local deformation during impact and the residual load performance after impact were presented by using response surface method. Results showed that pre-axial loading was a key factor affecting global deformation, while the impact velocity affected local deformation. In addition, both the pre-axial loading and impact velocity significantly interact with other parameters. The proposed formulas can be employed for the damage evaluation and design of H-section steel columns during the whole impact process.