基于改进卷积神经网络的航空发动机剩余寿命预测

完成了不同拧紧力矩下复合材料层合板与金属板单钉连接拉伸静强度实验。建立了三维有限元模型，对层合板失效过程进行了分析。基于实验数据调整了层合板初始刚度，对数值模型进行了修正。修正后数值计算模型的连接强度与实验数据基本吻合。由分析可知，拉伸实验曲线达到强度极限前呈现近似双线性特征，斜率突变处发生了载荷衰减波动。试件接触面经历了初始静摩擦-瞬时动摩擦-静摩擦平衡的动态过程。M6螺栓拧紧力矩为8 N·m时，静载拉伸强度最大。连接强度的试验值与计算值误差均在6.7%以内。合适的拧紧力矩可获得最佳的连接强度，拧紧力矩过大会导致连接强度降低。

A Remaining Useful Life Prediction for Aero Engine Based on Improved Convolution Neural Networks

A three dimensional finite element model of the joint assembly is built, and the failure evolution process of the composite laminate is analyzed. The numerical analysis model is modified by regulating initial stiffness coefficients of the laminate based on the strength test data. The joint strength of the modified numerical model is fitted well with that of static loading test. It follows that the approximate dual linear characteristics is found in the tensile test curves before the ultimate strength is met, and tensile load attenuation surge happens at the point where the gradient discontinuity occurs. The contact faces of the tensile test specimen encounter a process from initial static friction state, transient slide friction state to final static friction equilibrium state. When there is a M6 bolt with 8 N·m tightening torque, its tensile strength is the maximum, and the relative errors of joint strength between the numerical analysis results and that of the tensile test are all less than 6.7%. The best joint strength can be obtained to proper tightening torque, whereas excessive tightening torque may lead to strength reduction.