钢桥面板横隔板多裂纹扩展三维数值模拟及其特性研究

Study on 3D Numerical Simulation and Its Characteristic of Multi-crack Propagation of Steel Bridge Deck Slab Diaphragm

针对正交异性钢桥面中横隔板弧形开孔处存在的多裂纹这一特殊情况,采用通用有限元软件ANSYS建立了含多裂纹的有限元数值模型。基于所建立的数值模型,通过计算精度较高的相互作用积分法得到裂纹尖端应力强度因子K,并将其作为基本参量对多裂纹的扩展特性进行分析研究。研究结果表明:正交异性钢桥面板中初始存在多条裂纹时,随着荷载循环作用次数的增加,裂纹扩展将发展成以其中一条裂纹作为主裂纹进行扩展,剩余裂纹则在扩展至一定长度后停止扩展;横隔板弧形开孔边缘产生的角裂纹后期将扩展成穿透型裂纹,该处疲劳裂纹扩展到后期为穿透型疲劳裂纹。

Aiming at this special case of multiple cracks existing at the arc-shaped opening of diaphragm in orthotropic steel bridge deck, the multi-crack finite element numerical model is established by the general finite element software ANSYS. Based on the established numerical model, the crack tip stress intensity factor K is achieved by the higher computational accuracy of interaction integral method, and as a basic parameter, the multi-crack propagation characteristics are analyzed and studied. The study result shows that when the initial multiple cracks exist in the orthotropic steel bridge deck slab, with the increment of load cyclic action times, the crack propagation will develop into one crack as the main crack for propagation, and the residual cracks will stop the propagation after the propagation is to a certain length. The angle crack generated at the diaphragm arc-shaped opening edge will develop into the penetrating crack in the later period. The fatigue crack at this place will develop into the penetrating fatigue crack in the later period.