冲击荷载作用下热轧H型钢梁数值模拟研究

为了研究热轧H型钢梁在冲击荷载作用下的力学性能与破坏形式,对H型钢梁的冲击试验建立精细化有限元模型,再与试验结果进行对比,验证有限元模型的准确性。基于有限元模型分析冲击荷载作用下钢梁的荷载重分布和内力变化。之后开展拓展参数分析,研究钢材强度、锤头几何形状、有无局部加固、冲击位置、边界条件对钢梁抗冲击性能的影响。结果表明:冲击荷载作用下,钢梁出现局部屈曲,并在响应结束阶段承受不对称剪力,其主要破坏形式为局部屈曲和扭转变形; 提高钢材强度,相应钢梁整体抗冲击性能得到增强; 改变锤头几何形状,导致接触刚度改变,冲击力时程曲线出现变化; 在冲击区设有局部加固可以提高冲击区的刚度以及稳定性,钢梁抗冲击能力得到提升; 当冲击位置靠近支座时,冲击力出现至支座反力出现的时间间隔缩短,钢梁能更好地抵抗冲击荷载造成的破坏; 当钢梁边界条件由铰接改为刚接时,由于钢梁长度增加受惯性荷载影响增大,并且由于支座对梁体约束减弱,冲击力整体大幅降低,梁跨挠度增大。

Numerical Simulation Study of Hot-rolled H-steel Beam Under Impact Loading

In order to study the dynamics performance and failure mode of hot-rolled H-steel beam under impact load, a refined finite element model was established for the impact test of H-steel beam, and the accuracy of the finite element model was verified by comparing with the experimental results. Based on the finite element model, the load redistribution and internal force change of steel beam under impact load were analyzed. Then the extended parameter analysis was carried out to study the effects of steel strength, hammer head geometry, local reinforcement, impact position and boundary conditions on the impact resistance of steel beams. The results show that under the impact load, the steel beam appears local buckling and bears asymmetric shear at the end of the response stage. The main failure forms are local buckling and torsional deformation. When the steel strength is improved, the overall impact resistance of the steel beam is enhanced accordingly. The change of hammer head geometry leads to the change of contact stiffness and the change of impact force time history curve. When the impact zone is provided with local reinforcement, the stiffness and stability of the impact zone are improved, and the impact resistance of the steel beam is improved. When the impact position is closer to the support, the steel beam can better resist the damage caused by impact load because the time interval from the occurrence of impact force to the occurrence of support reaction is shortened. When the steel beam boundary condition is changed from hinged to rigid connection, the influence of inertial load increases due to the increase of steel beam length, and the restraint of support to beam body is weakened, the overall impact force is greatly reduced and the beam span deflection is increased.