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RISS 인기검색어
- 검색키워드
- 저자 : A. Mohammadzadeh (검색결과 3 건)
- 무료
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Numerical solution of non-Fourier heat transfer during laser irradiation on tooth layers
S. Falahatkar,A. Nouri-Borujerdi,M. Najafi,A. Mohammadzadeh 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.12
This study reports on the simulation of temperature distribution of human tooth under a laser beam based on non-Fourier models. The temperature in the tooth depth that directly results from the conduction heat transfer process is caused by the lengthy thermal relaxation time in the tooth layers. A detailed tooth composed of enamel, dentin, and pulp with unstructured shape, uneven boundaries, and realistic thicknesses was considered. A finite difference scheme was separately adopted to solve time-dependent equations in solid layers and soft tissue of the tooth. In this study, a dual-phase-lag non-Fourier heat conduction model was applied to evaluate temperature distribution induced by laser irradiation. Results show that for the laser-irradiated tooth, the phase lag time of heat flux (τ q ) greatly affects the temperature of the early stage, whereas the phase lag time of the temperature gradient (τ T ) significantly influences the temperature of the later stage. Prediction of temperature profile in the tooth based on this investigation is more real using the non-Fourier model (i.e., τ q = 16 and τ T = 2 millisecond) compared with experimental studies. Meanwhile, the Fourier model (τ q = τ T ) or classical Fourier form (τ q = τ T = 0) and the thermal wave model (τ q = 16 and τ T = 0) led to unreal heated point on the enamel. The effects of laser parameters, such as laser exposure time and laser intensity on the pulp, were also investigated. Increasing the laser duration and simulation time after laser irradiation was a logical approach to pulp ablation compared with increasing the laser intensity.
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Sh. Yousefzadeh,A. A. Jafari,A. Mohammadzadeh,M. Najafi 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.5
In this study, the dynamic response of a functionally graded material (FGM) circular plate in contact with incompressible fluid under the harmonic load is investigated. Analysis of the plate is based on First-order Shear Deformation Plate Theory (FSDT). The governing equation of the oscillatory behavior of the fluid is obtained by solving Laplace equation and satisfying its boundary conditions. A new set of admissible functions, which satisfy both geometrical and natural boundary conditions, are developed for the free vibration analysis of moderately thick circular plate. The Chebyshev-Ritz Method is employed together with this set of admissible functions to determine the vibrational behaviors. The modal superposition approach is used to determine the dynamic response of the plate exposed to harmonic loading. Numerical results of the force vibrations and the effects of the different geometrical parameters on the dynamic response of the plate are investigated. Finally, the results of this research in the limit case are compared and validated with the results of other researches and finite element model (FEM).
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Yousefzadeh, Sh.,Jafari, A.A.,Mohammadzadeh, A.,Najafi, M. Techno-Press 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.65 No.5
In this study, the dynamic response of a functionally graded material (FGM) circular plate in contact with incompressible fluid under the harmonic load is investigated. Analysis of the plate is based on First-order Shear Deformation Plate Theory (FSDT). The governing equation of the oscillatory behavior of the fluid is obtained by solving Laplace equation and satisfying its boundary conditions. A new set of admissible functions, which satisfy both geometrical and natural boundary conditions, are developed for the free vibration analysis of moderately thick circular plate. The Chebyshev-Ritz Method is employed together with this set of admissible functions to determine the vibrational behaviors. The modal superposition approach is used to determine the dynamic response of the plate exposed to harmonic loading. Numerical results of the force vibrations and the effects of the different geometrical parameters on the dynamic response of the plate are investigated. Finally, the results of this research in the limit case are compared and validated with the results of other researches and finite element model (FEM).
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