The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Radova Kovacevic - One of the best experts on this subject based on the ideXlab platform.
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thermo Mechanical Model with adaptive boundary conditions for friction stir welding of al 6061
International Journal of Machine Tools & Manufacture, 2005Co-Authors: Vijay Soundararaja, Srdja Zekovic, Radova KovacevicAbstract:Abstract Thermo-Mechanical simulation of friction stir welding can predict the transient temperature field, active stresses developed, forces in all the three dimensions and may be extended to determine the residual stress. The thermal stresses constitute a major portion of the total stress developed during the process. Boundary conditions in the thermal Modeling of process play a vital role in the final temperature profile. The heating and cooling rates with the peak temperature attained by the workpiece determine the thermal stress. Also, predicting realistic peak temperature becomes important as the operating temperature at the interface of tool-workpiece is very close to the solidus temperature of the aluminum workpiece. The convection heat-transfer coefficients of the surfaces exposed to air can be theoretically determined using Newton's law of cooling. Contact conductance depends on the pressure at the interface and has a non-uniform variation. The actual pressure distribution along the interface is dependent on the thermal stress from local temperature and non-linear stress–strain state. Therefore, applying an adaptive contact conductance can make the Model more robust for process parameter variations. A finite element thermo-Mechanical Model with Mechanical tool loading was developed considering a uniform value for contact conductance and used for predicting the stress at the workpiece and backplate interface. This pressure distribution contours are used for defining the non-uniform adaptive contact conductance used in the thermal Model for predicting the thermal history in the workpiece. The thermo-Mechanical Model was then used in predict stress development in friction stir welding.
Jiankang Chen - One of the best experts on this subject based on the ideXlab platform.
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a new chemo Mechanical Model of damage in concrete under sulfate attack
Construction and Building Materials, 2016Co-Authors: Jiankang Chen, Chen Qian, Hui SongAbstract:Abstract Damage evolution is detected via the degradation of modulus of concrete immersed in sulfate solution. The mechanism of the damage is investigated by using SEM method, and it is proved that the internal expansion stress induced by delayed ettringite leads to the nucleation of micro-cracks. The criterion of damage nucleation is proposed in terms of the tension strength of concrete. The differential equation with respect to the internal expansion stress is derived by virtue of chemical reaction rate on delayed ettringite formation, and a new chemo-Mechanical Model of corrosion damage in concrete under sulfate attack is then proposed.
Johannes Zeleny - One of the best experts on this subject based on the ideXlab platform.
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Thermo-Mechanical Model of spindles
CIRP Annals - Manufacturing Technology, 2010Co-Authors: Hanwen Cao, Johannes ZelenyAbstract:This paper presents a Finite-Element-method-based thermo-Mechanical Model of spindles with rolling bearings. The heat generated in the bearings and the motor is transferred to the ambient air, the motor coolant and the spindle structure, and causes thermal expansion of spindle parts. The experimentally validated thermo-Mechanical spindle Model predicts temperature distribution and thermal growth, as well as bearing stiffness and contact loads, under specified operating conditions. Transient changes in temperatures, deformations, viscosity of the lubricant, and bearing stiffness are considered in the solution. The predicted bearing properties are used to estimate the changes in the dynamic behavior of spindles. © 2010 CIRP.
Vijay Soundararaja - One of the best experts on this subject based on the ideXlab platform.
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thermo Mechanical Model with adaptive boundary conditions for friction stir welding of al 6061
International Journal of Machine Tools & Manufacture, 2005Co-Authors: Vijay Soundararaja, Srdja Zekovic, Radova KovacevicAbstract:Abstract Thermo-Mechanical simulation of friction stir welding can predict the transient temperature field, active stresses developed, forces in all the three dimensions and may be extended to determine the residual stress. The thermal stresses constitute a major portion of the total stress developed during the process. Boundary conditions in the thermal Modeling of process play a vital role in the final temperature profile. The heating and cooling rates with the peak temperature attained by the workpiece determine the thermal stress. Also, predicting realistic peak temperature becomes important as the operating temperature at the interface of tool-workpiece is very close to the solidus temperature of the aluminum workpiece. The convection heat-transfer coefficients of the surfaces exposed to air can be theoretically determined using Newton's law of cooling. Contact conductance depends on the pressure at the interface and has a non-uniform variation. The actual pressure distribution along the interface is dependent on the thermal stress from local temperature and non-linear stress–strain state. Therefore, applying an adaptive contact conductance can make the Model more robust for process parameter variations. A finite element thermo-Mechanical Model with Mechanical tool loading was developed considering a uniform value for contact conductance and used for predicting the stress at the workpiece and backplate interface. This pressure distribution contours are used for defining the non-uniform adaptive contact conductance used in the thermal Model for predicting the thermal history in the workpiece. The thermo-Mechanical Model was then used in predict stress development in friction stir welding.
Hui Song - One of the best experts on this subject based on the ideXlab platform.
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a new chemo Mechanical Model of damage in concrete under sulfate attack
Construction and Building Materials, 2016Co-Authors: Jiankang Chen, Chen Qian, Hui SongAbstract:Abstract Damage evolution is detected via the degradation of modulus of concrete immersed in sulfate solution. The mechanism of the damage is investigated by using SEM method, and it is proved that the internal expansion stress induced by delayed ettringite leads to the nucleation of micro-cracks. The criterion of damage nucleation is proposed in terms of the tension strength of concrete. The differential equation with respect to the internal expansion stress is derived by virtue of chemical reaction rate on delayed ettringite formation, and a new chemo-Mechanical Model of corrosion damage in concrete under sulfate attack is then proposed.
