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研究了连续纤维增强复合材料低压涡轮轴结构在给定低循环载荷作用下的疲劳寿命估算方法.考虑连续纤维增强复合材料结构特性,研究了基于局部应力应变法的低周疲劳寿命预测方法,并对预测方法的有效性进行了验证.基于此方法,计算了某型航空发动机低压涡轮轴的最大应力、应变和疲劳寿命.结果表明:在0°~90°范围内,45°铺层角度的复合材料层疲劳寿命值最大;当金属厚度不变,外层金属和首层复合材料层的疲劳寿命随复合材料厚度增加而增大;当轴结构壁厚保持6mm不变,减小复合材料层的厚度,同时相应增大最内层或最外层金属包套的厚度,其结构疲劳寿命都随着复材层的厚度减小而减小;外层金属包套的寿命则远大于首层复合材料的疲劳寿命.
The fatigue life estimation method of low-pressure turbine shaft structure with continuous low-pressure cyclic loading under given cyclic loading is studied. Considering the structural characteristics of continuous fiber-reinforced composite materials, the prediction method of low cycle fatigue life based on local stress-strain method The validity of the prediction method is verified.Based on this method, the maximum stress, strain and fatigue life of a low-pressure turbine shaft of an aero-engine are calculated.The results show that in the range of 0 ° ~ 90 °, The fatigue life of the composite layer is the largest; when the metal thickness is constant, the fatigue life of the outer layer metal and the first layer composite layer increases with the thickness of the composite material; when the thickness of the shaft structure remains unchanged 6mm, The thickness of the innermost layer or the outermost metal cladding is correspondingly increased, and the fatigue life of the structure decreases with the decrease of the thickness of the composite layer; the life of the outer metal cladding is much longer than that of the first layer Fatigue life of composite materials.