基于局部应力应变场强法的结构声疲劳寿命估算

针对带有缺口薄壁结构的声疲劳寿命估算问题,研究了基于局部应力应变场强的缺口结构随机疲劳寿命估算方法。该方法能同时考虑局部应力应变梯度和多轴应力应变对疲劳损伤的影响。以薄壁开孔柱壳结构为对象,在声激振响应分析基础上,计算出孔边局部位置处的应变场强谱,并估算出疲劳寿命。对比分析表明,该方法对带有缺口薄壁结构声疲劳寿命估算具有可行性。

Acoustic Fatigue Life Predication for Thin-Walled Structure Based on Local Stress-Strain Field Intensity

Acoustic fatigue of thin-walled structures subjected to high intensity acoustic loadings belongs to random multi-axial fatigue,and the prediction for acoustic fatigue life is the basis of structural dynamics strength analysis and design.Aiming at the problem of sonic fatigue prediction for thin-walled structures with gaps,this paper mainly discussed the random fatigue life prediction method for thin-walled structures with gaps based on local stress-strain field intensity.The influences of both the local stress-strain gradient and multi-axial stress-strain on fatigue damage are considered simultaneously.As a numerical example,the thin-walled cylindrical shells with gaps are selected,based on the vibrational response analysis to acoustic excitation,the stress-strain field intensity spectrum in the local position of gap edges are calculated,and the fatigue life is estimated.Comparative analysis show that the method is of feasibility for acoustic fatigue prediction for thin-walled structures with gaps.