柔性结构疲劳寿命的预测方法

讨论柔性构架结构疲劳寿命的预测方法,建立刚柔耦合多体动力学模型,计算结构危险点的动载荷时间历程;利用有限元准静态分析法,获得应力影响因子;利用模态分析技术获得结构固有频率和模态振型,确定结构的危险点位置.基于危险应力分布的动载荷历程,结合材料特性曲线以及线性损伤理论,进行标准时域的柔性结构应力应变的循环计数,损伤预测和寿命估计.应用该方法对构架结构进行疲劳寿命预测,结果表明,该预测方法预测精度有效,可以有效提高结构耐久性设计质量.

Prediction method of fatigue life of flexible structure

Prediction method of fatigue life of flexible framed structure was discussed,dynamic model of rigidity-flexibility coupled multi-body was established,and time history of dynamic load at the critical point of the structure was computed.Influential factors of stresses were obtained by using the finite element analysis method for quasi-static conditions.The natural frequency and vibration modes of the structure as well as the location of its critical point were determined by using the model analysis technique.Based on the dynamic load history of critical stress distribution and employing the material characteristic curves and its linear damage theory,the cyclic counting of stresses and strains,damage prediction,and life estimation of the flexible structure were performed in standard time domain.The fatigue life prediction of the framed structure was conducted with this method and it was shown by the result that the prediction accuracy was valid and the design quality of structure durability would be effectively improved.