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为了研究双脉冲发动机中金属膜片的打开特性,分别选取Ductile damage模型和Brittle cracking模型来模拟膜片静态和动态打开过程。数值计算发现膜片分别在3.46MPa静态内压载荷和1.95MPa动态内压载荷作用下打开。为了验证计算结果的有效性,进行了膜片的冷流静态打开和热流动态打开试验,膜片分别在平均3.75MPa静态载荷和平均2.2MPa动态载荷作用下打开,数值计算结果与试验结果一致,说明了数值计算方法的有效性。计算结果和试验结果表明,膜片的静态打开压强明显高于动态打开压强,分析认为是由于膜片的塑性变形、材料本身特性及预制缺陷处的应力松弛引起的。根据隔舱的冷流及热流单项试验可以发现,膜片的打开形式与预期一致,满足双脉冲发动机的使用要求。
In order to study the opening characteristics of the metal diaphragm in the double pulse engine, the Ductile damage model and the Brittle cracking model were selected to simulate the static and dynamic opening of the diaphragm. The numerical results show that the diaphragm is opened under static internal pressure of 3.46MPa and dynamic internal pressure of 1.95MPa respectively. In order to verify the validity of the calculation results, the static open cold flow and the open heat flow test of the diaphragm were carried out. The diaphragm was opened under the static load of average 3.75MPa and the dynamic load of 2.2MPa on average respectively. The numerical results were consistent with the experimental results. The effectiveness of numerical methods is illustrated. The calculated results and the experimental results show that the static open pressure of the diaphragm is obviously higher than the dynamic open pressure, which is considered as the plastic deformation of the diaphragm, the material itself and the stress relaxation at the prefabricated defects. According to the compartment of the cold flow and heat flow single test can be found, the diaphragm opens in the same form as expected to meet the dual-pulse engine requirements.