模糊可靠性疲劳寿命的分析与计算

针对随机栽荷下构件疲劳寿命预估中的可靠性问题,在模糊累积损伤疲劳寿命计算模型的基础上,根据恒幅疲劳寿命的分布及试验参数,依可靠性理论,导出了恒幅载荷下构件的可靠度工作寿命的数学方程,从而建立了承受随机载荷的构件的模糊可靠度疲劳寿命计算模型,同时还导出了传统累积损伤计算方法下可靠度疲劳寿命计算模型。采用这两种模型,通过实测载荷谱,对构件的可靠度疲劳寿命进行了预估,并与实际安全寿命进行比较。结果表明,所建立的模糊可靠度疲劳寿命计算模型预估的安全寿命与实际安全寿命相当吻合,相对误差仅为2．12％,传统可靠度疲劳寿命计算模型的预估误差为99．27％。

Analysis and calculation of reliability fatigue life under fuzzy accumulative damage

Based on the fatigue life calculation model under fuzzy accumulation damage, the mathematical equation of the reliability fatigue life under constant amplitude load is deduced by the probability distribution and test parameter of the constant amplitude fatigue life. The calculating model of varied amplitude reliability fatigue life under fuzzy accumulative damage is established, the calculating model of varied amplitude reliability fatigue life under the traditional accumulative damage model is developed. With the two calculating models, the structure reliability fatigue life is predicted by an experiment load spectrum. Compared with the real safety life, the relative error of the predicted reliability fatigue life by the fuzzy reliability fatigue life calculating model is only 2. 12%, but the error of the predicted reliability fatigue life by the traditional reliability fatigue life calculating model is 99.27 %. 3 tabs, 11 refs.