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结合内径为60mm的等壁厚爆震室,建立其有限元模型并施加真实爆震载荷,确定其疲劳载荷谱类型为周期性常幅谱。通过有限元模型和静态载荷作用下的解析模型分析得出爆震室壁厚和动力放大系数之间的相互影响关系,壁厚通过动力放大系数对自身进行调整,该过程中内壁的等效应力最大值逼近目标应力,以此为基础提出爆震室等寿命设计方法。根据计算结果设计加工变壁厚爆震室试验段,通过试验测量变壁厚爆震室外壁3个测点的应变,并估算3个测点内壁处的疲劳寿命,发现3个疲劳寿命最大误差为8.82%,考虑到试验与数值计算的工况误差可认为3个测点处寿命相同,验证了爆震室等寿命设计方法的正确性。
Combined with an equal-thickness detonation chamber with an inner diameter of 60 mm, the finite element model was established and the true detonation load was applied. The fatigue load spectrum type was determined to be periodic amplitude spectrum. Through the analysis of the finite element model and the analytical model under the action of static load, the relationship between the detonation chamber wall thickness and the dynamic amplification factor is obtained. The wall thickness adjusts itself through the dynamic amplification factor. The equivalent stress The maximum value approximates the target stress, and based on this, the designing method of life span of detonation chamber is put forward. According to the calculation results, the experimental section of variable thickness detonation chamber was designed and processed. The strain of the three measuring points on the outer wall of the detonation chamber was measured through experiments. The fatigue life of the inner wall of the three measuring points was estimated. Is 8.82%. Considering that the working conditions error of the test and the numerical calculation can be considered as the same life span at three measuring points, the correctness of the life-span design method of the detonation chamber is verified.