The Analysis Of The Heat Transfer And Mechanical Properties Of Materials In Rapid Thermal Shock

In order to accurately describe the themoelastic problem, appeared some laser pulse, the microwave heating technology and the miniaturization of device structure recently, some generalized thermoelastic theories considering the limited speed of heat propagation based on the physical mechanism of the extraordinary heat transfer were proposed. The most of these theories,however would retreat classic thermoelastic theory in the steady state, and could not accurately reveal the material properties of the heat transfer and the thermoelastic in the microscale. In view of this, according to the concept of thermomass, the equivalent quality of the heat was considered. The new ideas and methods were presented to carry out the research about the generalized thermoelastic problem by using the Newtonian mechanics.In this paper, the properties of the heat transfer and the thermoelasticity induced by the rapid thermal shock were analyzed. Based on the concept of the thermomass, fully considered the the thermal inertia, the control equation of the heat conduction model was obtained, the thermo-mechanical uncoupling thermoelastic model and the coupling thermoelastic model were established. These models could describe the problem of the rapid thermal shock, and could describe the steady state problem under high heat flux. The semi-infinite body for the research was selected, and the partial differential equations of the heat conduction, motion and the constitutive for the semi-infinite body with the boundary subjected to a sudden temperature rise were established. By means of the Laplace transform and inverse transform techniques and the asymptotic was used by the transient characteristics of extraordinary heat transfer. Firstly, the analytical expression of temperature field was obtained based on the concept of thermomass.Then, in order to meet the engineering requirements, the analytical expression of displacement and thermal stress fields were obtained based on the uncoupling thermoelastic model. Finally,considering the coupling of temperature and strain, the analytical expression of various physical fields were obtained based on the coupling thermoelastic model.The numerical method was used to solve the above problems under the same conditions,and to verify the correctness of the analytical solutions, the results of numerical methods were compared with the analytical solution. By analytical solution of the various physical fields,qualitative analysis the influences of the time inertia and the space inertia and the couplingeffects induced by rapid thermal shock for the various physical fields distribution. The time of each field begins to establish including temperature, displacement and thermal stress, the profile of the temperature field, displacement field and thermal stress field, the peak values of jumps and the intervals of two jumps, the speed of thermal wave and thermoelastic wave are influenced by the time inertia and the space inertia of the thermomass movement and the coupling effect.Besides, compared with the thermoelastic model of L-S to reveal the space inertia effect for the various physical fields.