【摘要】 提出了一种结构随机振动疲劳寿命估算的样本法,通过该样本法能够处理在频域内用谱密度描述的宽带随机振动载荷的情况。利用该样本法,首先将频域内的随机振动载荷信号通过抽样使其转换为时域信号;然后用有限元法计算结构危险点的应力谱,再采用变程法过滤掉小载荷而获得危险点的应力谱;最后用传统的疲劳寿命估算方法进行寿命估算,获得危险点疲劳寿命的均值和方差。算例结果表明,采用样本法获得的预测结果与试验值吻合得很好。更多还原

【Abstract】 A sample approach was proposed herein,which was for fatigue life prediction.The approach can estimate the lifetime of structures under broad band random vibration loading in the frequency domain described by power spectral density.Firstly,random vibration loading in the frequency domain was converted to the repeated loading in the time domain.Secondly,the stress-time history at the damage location of the structure was obtained by FEM analysis and the stress spectrum of random vibration was formed by range counting method.Consequently,the structural fatigue life is estimated by the traditional method.Its expectation and variance at damage location is gained.An example was employed to demonstrate the suitability of the approach.The predicted results show a good agreement with the experimental data.更多还原