不同板件宽厚比H型钢梁在冲击作用下的动态响应分析

Dynamic Response Analysis of H Steel Beam with Different Width-thickness Ratio of the Plate under Impact Load

通过Abaqus软件创建了钢梁受冲击的三维有限元模型,与霍静思教授的试验结果相比较验证了模型的有效性。基于该模型从冲击力时程、跨中挠度时程和不同板件塑性变形耗能三个方面进行分析,研究了腹板高厚比、翼缘宽厚比、边界条件和长度对H型钢梁在冲击作用下的动态响应。分析表明在截面外尺寸不变的情况下,随着腹板高厚比的增加,冲击力峰值、平台值下降;冲击力持续时间增加,翼缘宽厚比规律与腹板高厚比类似但影响程度要小于腹板高厚比。当钢梁两端固定或一端固定一端铰支时,钢梁各板件的塑性耗能从大到小依次为:腹板、上翼缘、下翼缘;但随着钢梁两端约束作用减弱,下翼缘的耗能逐渐增大。当钢梁两端铰支时,随着长度的增加,腹板、上翼缘、下翼缘的塑性耗能发生两次转变,下翼缘的耗能超过腹板成为钢梁的主要耗能板件。

A 3 D finite element model（ FEM） of steel beam under impact load using ABAQUS was created.With the comparison of the experimental results from Professor Huo Jingsi,the effectiveness of the model is verified. Based on the model,the dynamic response of flange width-thickness ratio,web height-thickness ratio,boundary condition and the length of steel beam from three aspects as follow： impact process,mid-span deflection process and plastic deformation energy dissipation of plates were studied. The results show that under the condition of constant section dimension,with the increasing of the ratio of web height-thickness,the impact peak and platform are decreasing,and the impact duration is increasing. The principle of flange width-thickness ratio resembles web height-thickness ratio,but the influence is less than that of web. When the steel beam is fixed at both ends or one end fixed the other hinged,the plastic energy consumption from large to small is： web,upper flange,lower flange.However,with the weakening restraint of both ends of the beam,the energy consumption of lower flange increasing gradually. When the ends of beam are hinged and the length is increasing,the plastic energy consumption of web,upper flange and lower flange will convert two times. Then,the energy consumption of lower flange will exceed the web,and the lower flange become the main energy consumption plate of steel beam.