Thermal Stress Analysis Of Space Heat Pipe Under Alternating Thermal Load

Based on the theory of thermoelasticity,a quasi-static thermoelastic coupling model of axisymmetric isotropic heat pipes subjected to thermal shock on the external surface is established.By introducing thermoelastic potential function and Lough displacement function,the coupled temperature field and displacement field are separated into independent equations to solve.The general form of temperature and stress field is derived strictly by Laplace transform and residue theorem.The distribution of temperature field and stress field is shown in detail by numerical simulation.The results show that the coupling term has significant effect.The buckling and instability critical velocity and non-linear vibration of composite heat pipe is studied with the thermal effect composed of thermal expansion coefficient and temperature variation.Firstly,the variables about thermal expansion coefficient and temperature gradient can be expressed by vector diameter,which means the equation of thermal effect expressed by vector diameter is obtained.Secondly,the model of the elastic Bernoulli-Euler beam considering thermal effect is established to analysis the instability and vibration.The partial differential control equation is established by Hamiltonian principle,and then,according to the eigenvalue method after Galerkin truncation and order reduction,the static state is studied when solving the bifurcation points on post-buckling.The approximate solution of strong nonlinear vibration is obtained by harmonic balance method.The thermal effect on vibration is also discussed.The simulation images show that the increase of temperature and thermal expansion coefficient makes the heat pipe more vulnerable to instability,which has obvious influence on the dynamic characteristics.The research content has more practical reference significance than the dynamic analysis of the heat pipe without considering the temperature effect.