基于相场模型的再生冷却推力室热机疲劳寿命分析  

Analysis of thermo-mechanical fatigue life of regenerativelycooled thrust chamber based on phase field modeling

作　　者：孙燊 易敏 SUN Shen;YI Min(State Key Laboratory of Mechanics and Control for Aerospace Structures,Nanjing University of Aeronautics and Astronautics(NUAA),Nanjing 210016,China)

机构地区：[1]南京航空航天大学航空航天结构力学及控制全国重点实验室,江苏南京210016

出　　处：《火箭推进》2024年第1期78-86,共9页Journal of Rocket Propulsion

基　　金：国家科技重大专项(J2019-IV-0014-0082);国家级青年人才项目;江苏高校优势学科建设工程资助项目。

摘　　要：为了分析再生冷却推力室在服役过程中的应力/应变情况,研究循环热力载荷下推力室的变形与疲劳失效行为,建立热-弹-塑性耦合的疲劳断裂相场模型,并计算断裂序参量的演化过程,预测推力室结构的热机疲劳寿命。通过热传导方程计算结构的温度分布及热应变,根据应力平衡方程和相场演化方程计算热循环作用下结构中应力/应变和序参量演化,根据序参量达到临界值的循环数预测结构的热机疲劳寿命。结果表明:推力室内壁下表面中心点最先断裂失效,疲劳寿命约为91次。循环温度载荷作用下,内壁下表面中心点处残余拉伸应变不断累积,导致表面塌陷及内壁变薄,最终破坏。利用相场疲劳断裂模型研究推力室结构的热机疲劳失效行为,为预测发动机推力室结构疲劳寿命及辅助发动机再生冷却通道优化设计提供了新思路与方法。In order to analyze the stress and strain distribution of the regeneratively cooled thrust chamber in service and investigate the deformation and fatigue behavior under cyclic thermo-mechanical load,a thermal-elastic-plastic coupled fatigue fracture phase field model is established.The evolution of fracture order parameter is calculated and the fatigue life of the thrust chamber structure can be estimated.The distribution of temperature and the thermal eigenstrain is solved by the heat conduction equation.The stress-strain response and order parameter evolution are solved by using the stress equilibrium equation and phase field equation,respectively.The fatigue life of the thrust chamber structure could be evaluated by the cycle number when the order parameter reaches a critical value.The results indicate that the failure occurs first at the middle point of the lower surface of the thrust chamber wall,with a fatigue life of about 91 cycles.Under the cyclic temperature load,residual tensile strain is accumulated at that point.The inner wall's lower surface tends to collapse and be thinner until the structure fails.The phase field fatigue fracture model provides a novel methodology for predicting the fatigue life of the engine thrust chamber structure and helping the optimal design of the engine regeneratively cooled channel.

关 键 词：再生冷却推力室 热机疲劳 断裂 相场模型 寿命预测 

分 类 号：V434.24[航空宇航科学与技术—航空宇航推进理论与工程]