摘要
对４种金属材料在Ⅱ型加载条件下的疲劳裂纹扩散行为进行的试验研究表明：在Ⅱ型加载条件下，裂纹可能仍沿Ⅱ型方向继续扩展，亦可能发生分支转变成Ⅰ型甚至Ⅰ＋Ⅱ型扩展，主要取决于材料本身的性质和它们的微观结构以及应力水平。当裂纹仍沿Ⅱ型方向扩展时，其扩展速率比相当应力水平的Ⅰ型裂纹扩展速率要大得多。
The behaviour of fatigue crack growth for four kinds of metallic materials under Mode Ⅱmetading was experimentally investigated．It showed that under Mede Ⅱ loading a fatigue crack maypropagate along the line of original Mede Ⅱ direction or transit from MOde Ⅱ growth to MOdeⅠoreven to mixed Mede Ⅰ＋Ⅱ growth，depending on the microstructure and properties of the materialand applied stress. Moreover，the rate of for Mede Ⅱ crack growth was measured and an expressionfor Mode Ⅱ fatigue crack growth similar to Mede Ⅰ fatigue crack growth was obtained. The results showed that（da／dN）_Ⅱ was much greater than（da／dN）_Ⅰ in the same stress intensityfactor amplitude △K.
基金
自然科学基金
关键词
Ⅱ型加载
疲劳
裂纹扩展
：fatigue crack growth，stress intensity factor，Mode Ⅱ.
