中文摘要：

针对具有应变软化材料的混凝土荷载．挠度曲线在极值点附近往往出现跳跃或后跳特性的问题，提出了一种适宜于混凝土材料拉应变软化的局部弧长法．该方法采用相对位移参数结合结构中局部裂缝区的约束方程，能有效跟踪复杂的平衡路径包括后跳现象．算例结果表明局部弧长法的这些优越性，并且分别指出了切口深度以及弹性模量对裂缝口滑动位移的影响．

英文摘要：

The pre/post-peak load-displacement curve of concrete is usually characterized by snapthrough or snap-back. Accordingly, this paper presents a local arc-length methord which is capable of overcoming snap-back and is advanced by arc-length. The method adopts relative displacement parameter with constraint equation at local fracture process zone in structure, and can track complex eguilibrium paths including snap-back with efficiency. The numerical example validates these priorities of local arclength and points out the effect of notch depth and modulus on the crack sliding displacement.