横向冲击作用下预加荷载钢框架的动力响应分析

Analysis on dynamic response of pre-load steel frames under transverse impact loading

钢框架在冲击荷载作用下的冲击响应及损伤破坏是一个复杂的非线性过程。采用Johnson-Cook强度模型考虑钢材在冲击荷载下的动态力学行为,采取Johnson-Cook断裂准则作为冲击荷载下钢材损伤开始准则,并考虑钢材损伤演化。利用ABAQUS建立横向冲击下钢框架的三维模型,通过能量转换关系和沙漏能控制确保数值模拟方案的精确性与合理性。通过改变冲击动能、冲击位置和轴压力等参数,得到这些参数对横向冲击作用下预加荷载钢框架的冲击响应模式的影响,揭示冲击响应随参数变化规律。结果表明:在横向冲击荷载作用下预加荷载钢框架有3种冲击响应模式;冲击动能、冲击位置和轴压力的增加,会加剧框架的冲击响应;冲击动能是影响横向冲击作用下钢框架冲击响应的主要因素,钢框架在横向冲击作用下发生整体倒塌时存在临界冲击动能;整个横向冲击过程,损伤发生的区域主要在冲击体与钢框架接触区域。

The impact response and failure of steel frame subjected to impact are a complex nonlinear process. Johnson-Cook model is adopted to simulate dynamic behavior of the steel. The Johnson-Cook failure model is used to do the damage initiation criterion, and the damage evolution is also taken into account. A three-dimensional model of steel frame under transverse impact load is established using ABAQUS finite element analysis software. By investigating the conversion of the system energy and the proportion of the hourglass energy, the accuracy and rationality of the numerical simulation scheme are verified. By changing the impact energy, impact location and axial force, the effects of these parameters on the response mode of steel frames are investigated, and the distribution regularity of the structure response with different parameters is explained. The results show that: 3 kinds of impact response modes are obtained by parameter analysis; the increase of impact energy, impact position and axial pressure will intensify dynamic response of steel frame to some extent; the impact energy is a key parameter on the dynamic response of the pre-load steel frame subjected to a transverse impact load; the critical impact kinetic energy exists when the steel frame is collapsed under transverse impact loading; the critical impact kinetic energy is existed when steel frames collapse under lateral impact; the damage occurs mainly in the contact area between the impact body and the steel frame.