含裂纹悬臂梁的振动与疲劳耦合分析

Coupling analysis for vibration and fatigue of a cracked cantilever beam

基于Paris方程和同步分析方法考虑振动与疲劳裂纹扩展耦合之影响,提出一种含裂纹梁的振动疲劳寿命分析思路。振动分析过程中,利用线性弹簧等效裂纹段,复弹性模量引入阻尼损耗因子,得到考虑裂纹扩展、激励频率和阻尼等因素影响的动应力响应。结果表明:裂纹扩展、激励频率和阻尼等因素对疲劳寿命具有重要的影响。通过振动分析与疲劳裂纹扩展寿命估算同步进行,可进一步提高疲劳寿命估算精度。

An analytical method about vibration and fatigue of a cracked cantilever beam was proposed based on timing analysis and Paris equation.Coupling relationship between vibration and fatigue crack growth was considered by using timing analysis methods.Crack part was replaced with a linear spring and damping loss factor was introduced with complex elastic modulus during vibration analysis.So crack growth,excitation frequency and damping were considered in vibration analysis.Results indicated that crack length,excitation frequency and damping have important effects on the fatigue life of the beam;in the resonance region,the rate of crack growth is obvious and the speed decreases with increase in damping.The prediction precision of fatigue life could be further improved using this new analytical method.