循环非弹性应变下低碳钢对接焊缝的性能

评估钢结构构件的材质和细部构造在极限荷载作用下的无弹性需求范围。描述了对非弹性有要求部位(屈服应力相对较低的钢板和接头全部焊透的对接焊缝细部构造)的循环响应和低周循环疲劳寿命,对不同的基底材质和对接试样进行大振幅循环应变试验,设计了多种焊接方式来缓和焊接试样的应力集中现象、降低其残余应力、改善焊趾外观。采用单轴材料模型和低周疲劳模型描述试样的循环应力-应变响应和低周循环疲劳寿命。研究表明,线性累积损伤模型也适用于预测不同应变历史下试样的破坏情况。对接焊缝仅略微降低试样的低周循环疲劳寿命,不同的焊接方式对低周循环疲劳寿命的影响最小。

Behavior of Butt-Welds and Treatments Using Low-Carbon Steel Under Cyclic Inelastic Strains

The materials and details used to construct sacrificial structural steel components must be evaluated for the full range of inelastic demands imposed by extreme loading events. This study characterizes the cyclic response and low-cycle fatigue life of a plate steel material designed to have a relatively low yield stress and various complete joint penetration butt-weld details considered for use in applications where inelastic behavior is expected. Large amplitude cyclic strain tests were performed on the base material and butt-welded specimens. The welded specimens utilized several different weld treatment details designed to mitigate stress concentrations, reduce tensile residual stresses, and improve weld-toe geometry. Uniaxial material models and a low-cycle fatigue model were used to characterize the cyclic stress-strain response and low-cycle fatigue life of the specimens. A linear damage accumulation model was also applied and found to adequately predict the failure of specimens subjected to more arbitrary strain histories. The presence of butt-welds were found to only slightly decrease the low-cycle fatigue life and the various weld treatments were found to have minimal impact.