高温环境下薄壁试件随机振动疲劳研究

Random Vibration Fatigue of Thin-walled Test Piece at High Temperature

目的研究高温环境下薄壁试件的随机振动疲劳问题。方法综述国内外随机振动疲劳研究现状,制定有效的研究方案。首先,通过有限元法完成薄壁试件的动力学响应数值仿真计算与分析,基于改进的雨流循环计数法预估薄壁试件的疲劳寿命。然后,开展高温环境下薄壁试件随机振动疲劳试验,获取危险位置动力学响应与疲劳寿命。结果高温强振动环境下,结构的危险位置主要出现在固支边界或形状突变位置,且基频处的动力学响应峰值是结构疲劳寿命的主要影响因素,随温度和振动量级的增加,结构疲劳寿命呈抛物线降低趋势。结论通过仿真与试验的比对,验证了高温环境下薄壁试件随机振动疲劳仿真计算方法的有效性与可靠性。

Objective To study the random vibration fatigue problem of thin-walled test piece in high temperature environment.Methods The current research status of random vibration fatigue at home and abroad was reviewed,and an effective research plan was developed.First,the dynamic response of the thin-walled test piece was calculated and analyzed by the finite element method.The fatigue life of the thin-walled test piece was estimated based on the improved rain-flow cycle counting method.Then,a random vibration fatigue test of thin-walled test piece at high temperature was conducted to obtain the dynamic response and fatigue life in the dangerous locations.Results In the high temperature and strong vibration environment,the dangerous position of the test piece mainly occurred at the boundary of fixed support or shape change.The peak of dynamic response at the fundamental frequency was the main influencing factor of the structural fatigue life.What’s more,the fatigue life of the test piece was the reduced like a parabolic line with the increase of temperature and vibration amplitude.Conclusion Through comparison of simulation and experiment,the validity and reliability of the simulation method for random vibration fatigue of thin-walled test piece in high temperature environment are verified.