建筑结构钢材及其焊缝循环本构模型的实验研究

Experimental Study of a Cyclic Constitutive Model of Building Structure Steel and Its Weld

为研究钢结构的超低周疲劳断裂问题,探究钢材的循环本构关系,使用普通钢Q235B和Q345B共18个标准圆棒试件,采用等幅循环加载,研究试件滞回性能、破坏形态和损伤退化特性,在Chaboche本构模型的基础上,利用实验滞回曲线,标定了Q235B和Q345B钢材本构模型的参数,并利用ABAQUS对实验结果进行有限元模拟.通过混合强化材料实验研究表明,Q345B钢材及其焊缝在低周往复加载时的耗能能力要高于Q235B钢材及其焊缝,采用Chaboche本构模型可以准确地模拟钢材的循环滞回特性,有限元与实验结果比对较吻合,为预测钢材循环往复韧性断裂提供了可行办法.

In order to study the problem of the ultra-low cycle fatigue fracture of steel structures and to find the cyclic constitutive relationship of steel,18 standard round bar specimens of common steels Q235B and Q345B were used in this paper.Cyclic loading was used to study the hysteretic behavior of the specimens.Based on the Chaboche con-stitutive model,the parameters of the Q235B and Q345B steel constitutive models were calibrated by the experimen-tal hysteresis curve.The experimental results were simulated by ABAQUS.The author,through the mixed rein-forced material test study,showed that energy dissipation capacity of Q345B steel and its weld in the low-cycle recip-rocating load was higher than that of Q235B steel and its weld.This can produce better plasticity,demonstrating that the use of the Chaboche constitutive model can simulate the cycle hysteretic behavior of steel accurately.The experiment result was in good agreement with the finite element result.It provides a practical method for predicting the cyclic ductile fracture of steel.