小型双脉冲发动机金属膜片的承压与破裂

为了得到双脉冲发动机隔舱处金属膜片的适宜结构，本文中采用Johnson-Cook材料损伤模型对不同规格金属膜片的承压、破裂过程进行了数值模拟，确定某种规格金属膜片满足设计要求。针对符合要求的金属膜片结构，设计了一套测双向测压装置，对金属膜片的承压、破裂过程依次进行试验。验证了所采用的金属膜片在一脉冲工作时其结构完整没有发生破裂，在二脉冲工作时金属膜片沿着预制刻痕破裂且没有金属碎片脱离，承压和破裂均能满足发动机正常工作要求。通过数值模拟和实验进行对比，发现得到的结果接近，说明采用本文的数值模拟方法研究金属膜片承压与破裂是可行的。通过数值模拟发现，在相同金属膜片厚径比时，随着金属膜片直径的增大，破裂时所需的压强先增大后减小再增大。

Pressure-bearing and fracture behaviors of metal diaphragms in a small double-pulse engine

In order to obtain the suitable structure of the metal diaphragm in the double-pulse engine compartment, this study used the Johnson-Cook material damage model to numerically simulate the pressure-bearing and rupture process of metal diaphragms of different specifications. The results determined the metal diaphragm of a certain specification to meet the design requirements. A set of two-way pressure measuring device was designed to study the pressure-bearing and rupture behaviors of the metal diaphragm. The results show that the metal diaphragm has no structural rupture during one-pulse operation. During the two-pulse operation, the metal diaphragm breaks along the pre-cut and no metal fragments are detached. The pressure-bearing and rupture behavior can meet the working requirements in the engine. The results obtained by numerical simulation are in good agreement with the experiment data, which shows that it is feasible to use the numerical simulation method to study the bearing and cracking of metal diaphragm. Furthermore, simulation study shows that as the diameter increases with the thickness-diameter ratio of the metal diaphragm kept constant, the pressure required for the rupture increases at first and then decreases, and then it increases again.