One-Dimensional Dual-Phase-Lag Non-Fourier Heat Conduction And Associated Thermal Stress And Thermal Fracture

The Fourier heat conduction theory is the empirical summary of scientific workers through a large number of scientific experiments. In this theory, it is supposed that the speed of thermal is not finite. Namely, when the medium is subjected to the transient heat shock, the medium inside each position can simultaneously obtain the heat. But in real life, the propagation rate of the fastest heat transfer phenomenon of light does not reach infinity. Therefore, it is obvious that the classical heat conduction model is too idealistic, which leads to great errors and losses in the application of the Fourier heat conduction model in practical engineering. So the study of non-classical heat conduction is more important. The reasons that classical heat conduction model is too idealistic is not taking into account the delay time of heat conduction process. At present, the study of non-classical heat conduction has been very well and detailed. But single-phase-lag non-classical model is the main model of non-classical heat conduction. In the process of heat conduction, the delay of time is existed. But the time delay of the temperature gradient is the same as that of the heat flux. So the single-phase-lag non-classical heat conduction model is more practical than the classical heat conduction model, But this model is still the ideal model. So this dissertation will study the dual-phase-lag non-classical heat conduction model that two kinds of thermal relaxation time are not the same.Based on the classical heat conduction theory, the method of Laplace transformation and the method of numerical inversion are used to solve the non classical thermal shock problem of a one-dimensional infinite plate material in the thermal shock. The temperature field, thermal stress field and thermal stress intensity factor of different conditions are solved. It obtains that the temperature field and elastic fields and stress intensity factor under different boundary conditions. The images of the temperature, stress and thermal stress intensity factor of different heat conduction models were plotted by MATLAB software. Numerical results for the thermal stress intensity factors are analyzed in detail. And numerical results of two kinds of heat conduction models are compared. Therefore, when the plate is very thin, the thermal shock resistance of the solid material is predicted by the dual-phase-lag non-classical heat conduction model.It is found that the stress intensity factor of the thermal shock and cold shock stress increases first and then decreases when the heat shock time increases. But when the time is long enough, the thermal stress intensity factor of the non-classical heat conduction model is the same as that of the classical heat conduction model. Finally, the thermal shock resistance of the material is given according to the two criteria. According to the non-classical heat conduction model, the thermal shock resistance is related to the thickness of the plate. When the thickness of the plate is larger, the thermal shock resistance of the plate is stronger. And under the same conditions, the thermal shock resistance of the classical heat conduction model and the single-phase non-classical heat conduction model is overestimated. The conclusion of this dissertation is important to analyze the thermal shock performance of the small thickness of solid materials under thermal shock.