Abstract: In order to study the thermal stress of the front body of the ramjet intake port with different modulus in tension and compression (Here in after is referred to as bi-modulus), a module which can analyze the stress of materials with bi-modulus was obtained by secondary development which is based on Ansys. Taking the ZrB₂ which is the part of engine that is made of ZrB₂-SiC as research object, since the Mach number is 6.0, the total temperature is 1660K, and the total pressure is 2.85MPa, the internal uneven temperature field of the front body was calculated by flow field and heat conduction. The tensile and compressive modulus of ZrB₂ at different temperatures were measured experimentally, and the compressive modulus was twice the tensile modulus. The tensile and compressive elastic modulus and the calculated temperature field were imported into the developed stress module to obtain the thermal stress of the ZrB₂. These results were compared with the thermal stress distribution curves obtained by flow-solid-thermal coupling without considering the bi-modulus. The results show that the maximum error of thermal stress of ZrB₂ which don’t consider property of bi-modulus is higher than 300%, which is seriously beyond the engineering requirements. The results illustrate the importance of different modulus theory and demonstrate the engineering practical value of the developed stress modulus for bi-modulus materials.

Key words: Ramjet;Front body;Bi-modulus;Thermal stress;Secondary development;Temperature field

摘要： 为研究拉压不同模量（以下简称双模量）冲压发动机进气道前缘体的热应力状态，在Ansys基础上，利用二次开发，得到了可分析具有双模量属性材料应力的模块。以ZrB₂-SiC为材料的发动机前缘构件的ZrB₂部分为研究对象，以来流马赫数6.0，总温1660K，总压2.85MPa为条件，经流场及热传导计算得到前缘体内部不均匀温度场。实验测得ZrB₂材料在不同温度下的拉、压模量，其压缩模量为拉伸模量的两倍，将拉、压弹性模量以及计算的温度场导入到所开发的模块中进行热应力分析，得到此前缘体ZrB₂部分的热应力分布状态。将此结果与不考虑双模量情况下进行流-固-热耦合分析得到的热应力分布曲线进行对比。结果表明，不考虑ZrB₂材料的双模量属性的结果最大误差高达300%，严重超出了工程上的要求精度。对比结果说明了不同模量理论的重要性，同时证明了所开发的不同模量应力分析模块的工程实用价值。

关键词: 冲压发动机;前缘体;拉压不同模量;热应力;二次开发;温度场