基于细观损伤力学的梁柱焊接节点断裂破坏预测分析

应用细观损伤力学模型预测分析单调荷载作用下梁柱焊接节点的裂纹萌生与扩展。分别依据节点部位的母材、热影响区和焊缝金属缺口试样的单轴拉伸试验，标定材料细观损伤力学模型的参数；通过有限元分析模拟，预测焊接节点的开裂位置以及断裂破坏的过程，与已有试验结果以及基于微孔扩展模型和应力修正临界应变模型的有限元分析结果相比，建议的细观损伤力学模型的有限元分析结果具有更好的预测精度；针对不同焊接孔几何形状对节点断裂性能的影响进行有限元分析，结果表明，孔的几何形状对节点的断裂破坏模式的影响显著，长圆孔比圆孔具有更好的节点延性，开裂延缓，但是两种孔形的节点承载力差别很小。

Fracture prediction of welded beam-to-column joints based on micromechanics damage model

A micromechanics damage model which replaces a traditional method for fracture problem is used in this paper to investigate the crack initiation and propagation of welded beam-to-column joints subjected to monotonic loading. Firstly, parameters used in the micromechanics damage model for the area at steel base metal, heat affected zone and weld metal were calibrated respectively through uniaxial tension tests of notched specimens. Next, the position of a crack initiation and its growth in the welded joint were predicted by means of finite element numerical simulation. Compared with the available test results and numerical results based on a void growth model and a stress-modified critical strain model, the numerical results from the micromechanics damage model had better prediction accuracy. Finally, the effect of different shapes of welding access hole on fracture behavior of welded joints was studied numerically. It is concluded that the shape of a hole plays an important role in fracture mode. An oblong hole has better ductility and slower cracking than a round hole, but both shapes of holes show nothing different in load carring capacity.