摘要
利用铝合金ＬＹ１２ＣＡ制十字型试样进行Ⅱ型裂纹的疲劳扩展试验，施加若干次短瞬的Ⅱ型超载、发现Ⅱ型裂纹的超载行为与Ⅰ型裂纹的不同，裂纹的扩展速率可几倍於未超载时相同应力强度因子幅度下的扩展速率；而且超载后的短瞬期间，裂纹在塑性区内仍保持较快的速率扩展。试验研究表明：Ⅱ型超载和Ⅰ型超载也许分别受不同的机制控制；它更类似于Ⅲ型超载。
The effects of sevcralinstantaneous overload on the fatigue crack growthproperties for an aluminum alloy LY-12CZ have been examined eperimentally. The resultscompared to equivalent tests for Mode Ⅰ (tensile opening) showed a corresponding accelerationfo]]owing overloads, but Mode Ⅰ cracks show a pronounced transient retardation. It is noticedthat the crack growth rate on Mace Ⅱ overloading is greater than that of the same stress intensityfactors and no overload. The embrittling effect of the larger plastic zone caused by the overloadcan speed up crack growth after the overload. It seems that different mechanisms may controlMode Ⅰ and Mode Ⅱ overload.
出处
《实验力学》
CSCD
北大核心
1994年第4期357-366,共10页
Journal of Experimental Mechanics
基金
国家自然科学基金
关键词
裂纹
超载
剪切减聚力
疲劳裂纹扩展
Mode Ⅱ cracks, overload, cruciform specimen, the shear decohesion.
