加劲肋厚度对节点开裂行为的影响分析

Influence of stiffener thickness on cracking behavior of joints

为研究节点域横向加劲肋厚度对钢框架节点开裂行为的影响,利用ANSYS有限元程序建立一系列以加劲肋厚度为变量的节点模型,通过引入裂纹发展方程,计算得出各单元在每循环下的裂纹长度,并对低周往复荷载作用下各节点的开裂过程进行深入分析。分析结果表明:等效塑性应变是导致节点开裂的重要因素,其值变化在一定程度上决定着节点焊缝的开裂规律;当节点域横向加劲肋较薄时,增大加劲肋厚度会导致节点裂纹开裂速度加快,当加劲肋厚度超过一定值后,裂纹开裂速度趋于稳定。

In order to study the influence of stiffener transverse thickness in panel zone on the cracking behavior of steel frame joints,a series of joint models with the stiffener thickness as the variables are established by ANSYS finite element program. By introducing the crack growth equation,the length of the crack under each cycle is calculated,and the cracking process of each joint under low cyclic loading is analyzed thoroughly. The results show that the plastic equivalent strain is a significant factor to cause the cracking of the joint; that the change of the value determines the development of cracks to a certain extent; that,when the stiffener of the panel zone is thin,increasing its thickness will lead to the acceleration of crack growth,and when the stiffener thickness exceeds a certain value,the cracking rate tends to be stable.