真实爆震载荷作用下爆震室等寿命设计方法

Design method of equal life on detonation combustor under actual detonation loading

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。

According to the equal wall thickness detonation combustor of 60mm inner di- ameter, the finite element model was established and the real detonation load was applied. The fatigue load spectrum was confirmed as a constant amplitude spectrum. The relationship between the wall thickness and the dynamic magnification factor of detonation combustor was found by calculating analytical model under static loading and finite element model. The wall thickness adjusted itself through the dynamic magnification factor. In the process, target stress was approached by the equivalent stress of the inner wall. On this basis, the design method of equal life detonation combustor was presented. According to the calculation re- suits, the test section of the variable wall detonation combustor was designed and processed. The strain of three measuring points on the outer wall of variable wall thickness was meas- ured; the fatigue life of the inner wall of these three measuring points was estimated, and the maximum error of the fatigue life was 8. 82%. Considering the working conditions＇ error be- tween the test and numerical calculation, the life of these three measuring points was the same, proving the validity of the design method of equal life detonation combustor.