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The ultrashort pulse laser ablation model of silicon based on the generalized thermoelastic theory with spatio-temporal nonlocal effect

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JOURNAL OF THERMAL STRESSES 2023年第12期46卷 1329-1358页

作者： Li, Yan Zhao, Luke He, Tianhu Tian, Xiaogeng Liao, Kai Xi An Jiao Tong Univ State Key Lab Strength & Vibrat Mech Struct Xian Peoples R China Lanzhou Univ Technol Sch Sci Lanzhou Peoples R China Xi An Jiao Tong Univ State Key Lab Mfg Syst Engn Xian Peoples R China Xi An Jiao Tong Univ State Key Lab Strength & Vibrat Mech Struct Xian 710049 Peoples R China

The present work is devoted to establishing the ultrashort pulse laser ablation generalized thermoelastic model with spatio-temporal nonlocal effect and investigating the transient responses of the process of silicon ablated by the picosecond pulse laser. The research is divided into three cases. 1) The solid silicon before the target surface melting is studied, and the transient responses of the final state of this case are taken as the initial conditions of the Case Two. 2) The liquid silicon after the target surface melting is researched, and the heat flux taken away by vaporization is considered in the boundary condition. 3) The solid silicon after the target surface melting is discussed, and the moving solid-liquid interface is regarded as the coordinate origin. The coupled governing equations containing spatial nonlocal parameter, time delay factor, and kernel function are established and solved by the Laplace transform together with its numerical inversion. The melting time and depth of target are emphatically discussed. The temperature, displacement and stress with different laser intensity, spatial nonlocal parameter, time delay factor, kernel function as well as time are obtained and illustrated graphically.

关键词： Ablation generalized thermoelastic theory spatio-temporal nonlocal effect ultrashort pulse laser processing vaporization

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Investigation of a half-space heated by laser pulses based on the generalized thermoelastic theory with variable thermal material properties

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WAVES IN RANDOM AND COMPLEX MEDIA 2022年第1期32卷 120-136页

作者： Li, Yan He, Tianhu Lanzhou Univ Technol Sch Sci Lanzhou Peoples R China Xi An Jiao Tong Univ State Key Lab Strength & Vibrat Mech Struct Xian Peoples R China

The present work devotes to investigating the transient responses of a half-space with variable thermal material properties based on the generalized thermoelastic theory with memory-dependent derivative. The bounding surface is assumed to be traction free and heated by a non-Gaussian laser beam. The material characteristic parameters are assumed as the linear function of temperature. The coupled governing equations containing thermal time-delay factor and kernel function, which can be chosen to adapt to specific problems, are formulated and solved by the Laplace and Kirchhoff transformations. Numerical results of the non-dimensional temperature, displacement as well as stress under different time, variable thermal conductivity, thermal time-delay factor and kernel function are obtained and illustrated graphically. It is hoped that the obtained results would be helpful in designing the temperature-dependent structures heated by a non-Gaussian laser beam in engineering.

关键词： generalized thermoelastic theory memory-dependent derivative non-Gaussian laser beam temperature dependence

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Research on coupled thermo-hydro-mechanical dynamic response characteristics of saturated porous deep-sea sediments under vibration of mining vehicle

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Applied Mathematics and Mechanics(English Edition) 2021年第9期42卷 1349-1362页

作者： Wei ZHU Xinyu SHI Rong HUANG Liyue HUANG Wenbo MA Post-doctoral Research Station of Statistics School of Mathematics and Computational ScienceXiangtan UniversityXiangtan 411105Hunan ProvinceChina School of Mathematics and Computational Science Xiangtan UniversityXiangtan 411105Hunan ProvinceChina School of Mathematic and Computational Science Hunan University of Science and TechnologyXiangtan 411201Hunan ProvinceChina College of Civil Engineering and Mechanics Xiangtan UniversityXiangtan 411105Hunan ProvinceChina

The excessive deformation of deep-sea sediments caused by the vibration of the mining machine will adversely affect the efficiency and safety of *** with the deep-sea environment,the coupled thermo-hydro-mechanical problem for saturated porous deep-sea sediments subject to the vibration of the mining vehicle is *** on the Green-Lindsay(G-L)generalized thermoelastic theory and Darcy’s law,the model of thermo-hydro-mechanical dynamic responses for saturated porous deep-sea sediments under the vibration of the mining vehicle is *** obtain the analytical solutions of non-dimensional vertical displacement,excess pore water pressure,vertical stress,temperature,and change in the volume fraction field with the normal mode analysis method,and depict them *** normal mode analysis method uses the canonical coordinate transformation to solve the equation,which can quickly decouple the equation by ignoring the modal coupling effect on the basis of the canonical *** results indicate that the vibration frequency has obvious influence on the vertical displacement,excess pore water pressure,vertical stress,and change in volume fraction *** loading amplitude has a great effect on the physical quantities in the foundation,and the changes of the physical quantities increase with the increase in loading amplitude.

关键词： deep-sea sediment thermo-hydro-mechanical dynamic generalized thermoelastic theory normal mode analysis dynamic response characteristic

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Influence of thermal contact resistance on dynamic response of bilayered saturated porous strata

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Journal of Central South University 2022年第6期29卷 1823-1839页

作者： WEN Min-jie TIAN Yi WU Wen-bing WANG Kui-hua XIONG Hou-ren Research Center of Coastal Urban Geotechnical Engineering Zhejiang UniversityHangzhou 310058China Key Laboratory of Soft Soils and Geoenvironmental Engineering of Ministry of Education Zhejiang UniversityHangzhou 310058China Faculty of Engineering China University of GeosciencesWuhan 430074China Jiaxing Key Laboratory of Building Energy Efficiency Technology Jiaxing UniversityJiaxing 314001China

Porous materials can be found in a variety of geophysical and engineering *** existence of thermal contact resistance at the interface between bilayered saturated porous strata would result in a significant temperature difference at the *** attempt is made to study the thermo-hydro-mechanical coupling dynamic response of bilayered saturated porous strata with thermal contact resistance and elastic wave *** corresponding analytical solutions for the dynamic response of bilayered saturated porous strata under a harmonic thermal load are derived by the operator decomposition method,and their rationality is verified by comparing them with existing *** influences of thermal contact resistance,thermal conductivity ratio,and porosity ratio on the dynamic response of bilayered saturated porous strata are systematically *** disclose that with the increase of thermal contact resistance,the displacement,pore water pressure and stress decrease gradually,and the temperature jump at the interface between two saturated porous strata increases.

关键词： dynamic response bilayered saturated porous strata thermal contact resistance generalized thermoelastic theory elastic wave impedance

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The phase change thermoelastic analysis of biological tissue with variable thermal properties during cryosurgery

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JOURNAL OF THERMAL STRESSES 2020年第8期43卷 998-1016页

作者： Li, Xiaoya Luo, Pengfei Qin, Qing-Hua Tian, Xiaogeng Xi An Jiao Tong Univ Sch Aerosp Shaanxi Engn Res Ctr Nondestruct Testing & Struct State Key Lab Strength & Vibrat Mech Struct Xian 710049 Peoples R China Australian Natl Univ Rest Sch Elect Energy & Mat Engn Coll Engn & Comp Sci Acton ACT Australia

In this work, the coupling phase change heat transfer process and thermal stress behavior of biological tissue during cryosurgery are studied in the context of a generalized thermoelastic theory. The nonlinear governing equations are constructed while considering the variable thermal properties and solved by a time-domain finite element method based on the effective heat capacity formulation. A 2-D tumor and normal tissue model is adopted for simulating the freezing process in cryosurgery. The effects of temperature-dependent thermal properties and relaxation time on the responses of biological tissue are discussed and illustrated graphically.

关键词： Cryosurgery finite element method generalized thermoelastic theory phase change variable thermal properties

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Thermomechanical response in a two-dimension porous medium subjected to thermal loading

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INTERNATIONAL JOURNAL OF NUMERICAL METHODS FOR HEAT & FLUID FLOW 2020年第8期30卷 4103-4117页

作者： Saeed, Tareq Abbas, Ibrahim King Abdulaziz Univ Dept Math Fac Sci Jeddah Saudi Arabia Sohag Univ Dept Math Fac Sci Sohag Egypt King Abdulaziz Univ Nonlinear Anal & Appl Math Res Grp NAAM Dept Math Jeddah Saudi Arabia

Purpose The purposes of this study, a mathematical model of generalized thermoelastic theory subjected to thermal loading is presented to study the wave propagation in a two-dimensional porous medium. Design/methodology/approach By using Fourier-Laplace transforms with the eigenvalue approach, the physical quantities are analytically obtained. Findings The derived method is evaluated with numerical results, which are applied to the porous medium in simplified geometry. Originality/value Numerical outcomes for all the physical quantities considered are implemented and represented graphically. The variations of temperature, the changes in volume fraction field, the displacement components and the stress components have been depicted graphically.

关键词： Porous medium Eigenvalues approach generalized thermoelastic theory Laplace-Fourier transforms

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Thermomechanical response of porous biological tissue based on local thermal non-equilibrium

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JOURNAL OF THERMAL STRESSES 2019年第12期42卷 1481-1498页

作者： Li, Xiaoya Qin, Qing-Hua Tian, Xiaogeng Xi An Jiao Tong Univ Shaanxi Engn Res Ctr Nondestruct Testing & Struct Sch Aerosp State Key Lab Strength & Vibrat Mech Struct Xian 710049 Shaanxi Peoples R China Australian Natl Univ Coll Engn & Comp Sci Res Sch Engn Acton ACT Australia

Understanding of heat transfer and related thermomechanical interaction in biological tissue is very important to clinical applications. It is quite natural to treat the living tissue as a porous medium, such as the living tissue in the presence of blood. Based on a non-equilibrium heat transfer model, the thermomechanical response of porous biological tissue exposed to an instantaneous thermal shock is investigated in this work. The governing equations are established based on local thermal non-equilibrium model in the context of the generalized thermoelastic theory and solved by time-domain finite-element method. The effect of porosity coefficient on the thermal-mechanical response of the porous tissue is studied and illustrated graphically. Comparisons are made between the proposed results and those from the local thermal equilibrium models to reveal the difference of these two models in terms of thermoelastic response.

关键词： Local thermal non-equilibrium generalized thermoelastic theory finite-element method porosity coefficient

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Thermal Wave Effect and Sintering Activation Energy at the Initial Stage of Field Assisted Sintering Process for Non-conductive Al_2O_3 Powders

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Journal of Wuhan University of Technology(Materials Science) 2018年第6期33卷 1416-1421页

作者： ZHANG Long Department of Theoretical and Applied Mechanics Chongqing University of Science and Technology Department of Engineering Mechanics Chongqing University

The effect of thermal wave at the initial stage for non-conductive Al_2 O_3 powders compact in field assisted sintering technique(FAST) was investigated. The Lord and Shulman type generalized thermoselastic theory was introduced to describe the influence of thermal-mechanical interaction, as well as the heat transport and thermal focusing caused by thermal wave propagation. The expression of vacancy concentration difference of the particles was deduced by considering transient thermal stress. Subsequently, the relationship between activation energy and vacancy concentration difference was obtained. The mechanism of surface diffusion, volume diffusion, simultaneous surface and volume diffusion was analyzed. The numerical simulations indicate that low sintering temperature can obtain high local temperature by the superposition effect of thermal wave. Vacancy concentration differences were improved during FAST compared with hot-pressure and pressureless sintering, thereby decreasing the sintering time. By contrast, the activation energy declined with the decrease of vacancy concentration difference in the neck growth process.

关键词： field assisted sintering technique generalized thermoelastic theory thermal wave vacancy concentration difference sintering activation energy

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DYNAMIC RESPONSE OF SATURATED SOIL SUBJECT TO TIME HARMONIC SOURCES UNDER generalized thermoelasticITY

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JOURNAL OF POROUS MEDIA 2018年第5期21卷 441-456页

作者： Xiong, Chunbao Guo, Ying Diao, Yu Tianjin Univ Sch Civil Engn Weijin Rd 92 Tianjin 300072 Peoples R China

This work concerns the problems associated with a two-dimensional poroelastic half-space soil medium subject to both normal force and thermal loading within the context of generalized thermoelastic theory with one relaxation time. By remaining faithful to Biot's theory of dynamic poroelasticity, we idealize the foundation material as a uniform, fully saturated, poroelastic half-space medium. We then deduce the general solutions of nondimensional vertical displacement, excess pore water pressure, vertical stress, and temperature distribution using normal mode analysis and depict them graphically. Throughout this paper, we discuss the differences between the coupled thermo-hydro-mechanical dynamic model (THMD) and the thermo-elastic dynamic model (TMD).

关键词： generalized thermoelastic theory relaxation time coupled thermo-hydro-mechanical dynamic thermo-elastic dynamic poroelastic normal mode analysis

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Wave reflection in semiconductor nanostructures

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Theoretical & Applied Mechanics Letters 2018年第3期8卷 160-163页

作者： Feixiang Tang Yaqin Song State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace Xi'an Jiaotong University

Based on nonlocal thermoelastic theory, this article studies the reflection of waves in nanometersemi-conductor media. Firstly, the governing equations are established based on couplednonlocal elasticity theory, plasma diffusion equation, and moving equation. Then, using theharmonic method, the solution of the dissipation equation and the analytic expression of thereflection coefficient rate are obtained. Finally, the influences of nonlocal parameters on wavevelocities are showed graphically. It is found that after the introduction of nonlocal effect, thephase and group velocities all show the attenuation, and as the frequency increases, the nonlocalparameter is bigger, and the decay rate is faster. The reflection coefficient rate varies greatly withdifferent theories, with different reflection coefficient rates depending on the incident angle.

关键词： Nonlocal theory generalized thermoelastic theory Wave velocity Reflection coefficient rate

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