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为了得到双脉冲发动机中金属膜片式隔舱的设计方法,通过圆板大挠度理论和断裂力学理论推导出金属膜片预制缺陷处应力强度因子的计算式,通过三维虚拟裂纹闭合法数值计算了预制缺陷处的应力强度因子,数值计算结果与公式计算结果一致性较好。通过多孔圆板强度理论,建立了支撑件强度校核方法,并与数值计算结果对比,校核方法所得应力值略高于数值结果,说明按该方法校核支撑件强度更有利于提高隔舱的承载能力。为了进一步验证公式方法的准确性,进行了隔舱相关试验。膜片实际平均打开压强与公式设计值误差仅为5.0%;通过热流模拟试车考核了隔舱承压性能,支撑件结构保持完整。数值分析及实验结果说明,文中所推导方法可用于设计膜片的结构尺寸和校核支撑件强度,所得方法可直接应用金属膜片式隔舱设计中。
In order to obtain the design method of metal diaphragm bay in double pulse engine, the formula of stress intensity factor of metal diaphragm prefabricated defect is deduced from the theory of large deflection of disc and the theory of fracture mechanics. The 3D virtual fracture closure method is used to calculate The stress intensity factor at the prefabricated defect is consistent with the numerical calculation results. Based on the strength theory of porous circular plate, the method of checking the strength of the support was established and compared with the numerical calculation. The stress value obtained by the method of checking was slightly higher than the numerical results, which indicated that checking the strength of the support by this method was more conducive to improving the compartment Carrying capacity. In order to further verify the accuracy of the formula method, a compartment-related test was conducted. The actual average opening pressure of the diaphragm is only 5.0% of the error of the design value of the formula. The pressure-bearing performance of the compartment was tested by the heat flow simulation test, and the structure of the supporter remained intact. Numerical analysis and experimental results show that the method deduced in this paper can be used to design the structure size of the diaphragm and check the strength of the support. The obtained method can be directly applied to the design of the metal diaphragm compartment.