The Experts below are selected from a list of 2802 Experts worldwide ranked by ideXlab platform
Chun-kung Chen - One of the best experts on this subject based on the ideXlab platform.
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Inverse Calculation of the friction coefficient for upsetting a cylindrical mild steel by the experimental load
Journal of Materials Processing Technology, 2006Co-Authors: Chun-kung ChenAbstract:Abstract This paper sought to render the simulation of metal forming process closer to the reality in order to better control the results of metal forming. The friction on the upsetting workpiece and die contact face has always been a subject of great concern. This study focused on the variation of the friction coefficient during the upsetting process and the concept of treating the solution of unknown parameters as an Inverse problem. The Inverse Calculation of upsetting a cylindrical mild steel in this paper was based on the load values measured in the upsetting experiment to solve the variation of the friction coefficient during the upsetting process. By means of the Inverse algorithm presented in this paper, physical phenomena that better approximated the reality could be obtained, which added to the completeness of the simulation of the entire upsetting forming process.
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Inverse Calculation of the friction coefficient during the warm upsetting of molybdenum
International Journal of Mechanical Sciences, 2005Co-Authors: Chun-kung ChenAbstract:Abstract This study focused on the variation of the friction coefficient during the upsetting process and the concept of treating the solution of unknown parameters as an Inverse problem. Based on the experimental measurement data, the Levenberg–Marquardt method, a numerical optimization approach was used in conjunction with the constrained function, convergence criterion and the axial symmetry thermo-elastic-plastic finite element method to solve, Inversely, the variation of friction coefficient during the upsetting process. The Inverse Calculation steps of the warm upsetting of the molybdenum proposed in this paper was based on the load values measured in the upsetting experiment. The Inverse Calculation procedures were taken to solve the variation of the friction coefficient during the warm upsetting process. The results related to stress distribution, strain distribution, temperature distribution and shape variation were then compared with those reported in other studies. The comparison further confirmed the justification of using the load to solve the friction coefficient Inversely. By means of the Inverse algorithm presented in this paper, physical phenomena that better approximated the reality could be obtained, and the entire upsetting forming simulation could be more complete.
Johan Blaauwendraad - One of the best experts on this subject based on the ideXlab platform.
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spectral element technique for efficient parameter identification of layered media part ii Inverse Calculation
International Journal of Solids and Structures, 2001Co-Authors: Rafid Alkhoury, C Kasbergen, A Scarpas, Johan BlaauwendraadAbstract:Abstract In Part I of this series of articles a forward model was presented for the simulation of wave propagation in a multi-layer system by means of the spectral element method. In the current article and, on the basis of the forward model, a procedure is presented for Inverse Calculation of the system parameters. The proposed procedure is based on iterative comparisons of measured versus theoretically determined system transfer functions. The performance of three minimization algorithms; factored Secant update, modified Levenberg–Marquardt and Powell hybrid for solving the resulting system of nonlinear equations is evaluated. For the problem under consideration, the Powell hybrid algorithm exhibits better stability and convergence characteristics. As an application, the Inverse procedure is utilized for the determination of pavement layer moduli and thicknesses via the use of the falling weight deflectometer (FWD) test. The Calculations show that the developed procedure is accurate and computationally efficient. As a result of these Calculations, modifications to the standard practice of FWD measurements and instrumentation are suggested.
Zeng Xiangying - One of the best experts on this subject based on the ideXlab platform.
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Inverse Calculation of biochemical oxygen demand models based on time domain for the tidal Foshan River
Water Science and Technology, 2014Co-Authors: Li Er, Zeng XiangyingAbstract:To simulate the variation of biochemical oxygen demand (BOD) in the tidal Foshan River, Inverse Calculations based on time domain are applied to the longitudinal dispersion coefficient (E(x)) and BOD decay rate (K(x)) in the BOD model for the tidal Foshan River. The derivatives of the Inverse Calculation have been respectively established on the basis of different flow directions in the tidal river. The results of this paper indicate that the calculated values of BOD based on the Inverse Calculation developed for the tidal Foshan River match the measured ones well. According to the calibration and verification of the Inversely calculated BOD models, K(x) is more sensitive to the models than E(x) and different data sets of E(x) and K(x) hardly affect the precision of the models.
I V Avgust - One of the best experts on this subject based on the ideXlab platform.
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Calculation ALGORITHM FOR SHIELDED STRIP LINES WITH FINITE STRIP THICKNESS MICROSTRIP-, SLOT-, AND MICRO-COPLANAR
2020Co-Authors: I V AvgustAbstract:Common algorithm for three typs of transmission lines is.based upon the moditied Fourier method (reexpansion). To algehraizate the summatory equation system the direct and Inverse Calculation formulas are used in contrast to the Galerkin's method
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Calculation algorithm for shielded microstrip-, slot-, and micro-coplanar strip lines with finite strip thickness
4th International Conference on Antenna Theory and Techniques (Cat. No.03EX699), 2003Co-Authors: I V Avgust, M.a. Syvozalizov, V.v. KhoroshunAbstract:A common algorithm for the three types of transmission lines is based upon the modified Fourier method (re-expansion). To convert the summation equation system to algebraic form, the direct and Inverse Calculation formulas are used in contrast to the Galerkin method.
Rafid Alkhoury - One of the best experts on this subject based on the ideXlab platform.
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spectral element technique for efficient parameter identification of layered media part ii Inverse Calculation
International Journal of Solids and Structures, 2001Co-Authors: Rafid Alkhoury, C Kasbergen, A Scarpas, Johan BlaauwendraadAbstract:Abstract In Part I of this series of articles a forward model was presented for the simulation of wave propagation in a multi-layer system by means of the spectral element method. In the current article and, on the basis of the forward model, a procedure is presented for Inverse Calculation of the system parameters. The proposed procedure is based on iterative comparisons of measured versus theoretically determined system transfer functions. The performance of three minimization algorithms; factored Secant update, modified Levenberg–Marquardt and Powell hybrid for solving the resulting system of nonlinear equations is evaluated. For the problem under consideration, the Powell hybrid algorithm exhibits better stability and convergence characteristics. As an application, the Inverse procedure is utilized for the determination of pavement layer moduli and thicknesses via the use of the falling weight deflectometer (FWD) test. The Calculations show that the developed procedure is accurate and computationally efficient. As a result of these Calculations, modifications to the standard practice of FWD measurements and instrumentation are suggested.
