正交异性钢桥面横隔板弧形切口焊接残余应力分析

为研究轮载压应力作用下弧形切口疲劳开裂机理，建立正交异性钢桥面板热弹塑性有限元模型，采用生死单元模拟了横隔板焊缝焊接过程，实现了焊接过程和焊缝凝结过程的热力耦合分析，得到了横隔板的焊接温度场和热应力场，获得了弧形切口残余应力分布，并结合现场疲劳试验对弧形切口进行疲劳寿命评估.研究表明，焊接温度沿弧形切口变化显著，切口最小净截面处焊接残余拉应力达到了近300 MPa，耦合轮载作用下的压应力响应，弧形切口就会产生疲劳开裂的现象.

Residual stress analysis of floorbeam cutout at orthotropic steel bridge deck

In order to investigate the cracking mechanism of cutout under compressive stress by live loads, the thermal elastic-plastic FEM model of orthotropic steel bridge deck was adopted and element birth and death was used to simulate the welding process of foorbeam, then the coupled thermal-mechanical simulation of the welding and weld condensation processes were realized, the welding thermal field and stress field of the foorbeam were obtained, as well as the residual stress distribution of cutout was acquired, Meanwhile, the fatigue life of the cutout was evaluated by the field fatigue test. The research shown that the variation of welding temperature along the cutout was significant, the residual tensile stress at the minimum net section of the cutout reached nearly 300 MPa. Coupling the compressive stress under the wheel loading, the fatigue cracking occured at the floorbeam cutout.