Abstract:

A coupling analytical method for vibration fatigue crack growth of a cracked plate was proposed for the sake of improving the analytical precision of vibration fatigue life. Firstly, the crack was replaced by an additional external force and the vibration equation of the cracked plate was derived in view of mechanics balance principle, and the crack terms were obtained by using stress relational expression introduced by Rice and Levy. Then, crack propagation was simulated by Paris equation and a coupling relation was considered through vibration analysis and the crack growth calculation was carried out simutaneously. Influence factors of vibration fatigue crack growth for the cracked plate were discussed in the end. Results indicate that the crack length and the thickness of the plate are very important to natural frequency and impacts of damping and exciting force on the rate of crack growth are obviously.

Key words: vibration fatigue, crack growth, natural frequency, cracked plate

摘要：

为提高含裂纹板的振动疲劳分析精度,提出一种振动疲劳裂纹扩展耦合分析方法。首先,利用附加载荷等效代替裂纹作用,由力学平衡原理推导含裂纹板的振动方程,基于Rice与Levy应力关系式形成方程的裂纹项;然后,运用Paris方程模拟裂纹扩展,通过振动分析与裂纹扩展计算同步进行的方式考虑振动与裂纹扩展的耦合作用,讨论振动对含裂纹板裂纹扩展的影响。分析表明,结构固有频率与裂纹大小和板厚密切相关;阻尼大小和激振力变化对裂纹扩展速率的影响显著。
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关键词: 振动疲劳, 裂纹扩展, 固有频率, 含裂纹板