• Journal of Korean Association for Spatial Structures
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• v.3 no.4 s.10
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• pp.85-92
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• 2003

In this work, a finite element model is presented for geometrically non-linear analysis of shell structures. Finite element by using a three-node flat triangular shell element is formulated. The non-linear incremental equilibrium equations are formulated by using an updated Lagrangian formulation and the solutions are obtained with the incremental/iterative Newton-Raphson method and arc length method. Some of results are presented for shell structures. The obtained results are in good agreement with the results available in existing literature.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.4
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• pp.287-295
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• 2012

Hydrodynamic performance of a movable submerged breakwater was analyzed using energy dissipation model. Based on two-dimensional boundary element method the equation of motion including a viscous dissipation term proportional to velocity squared was solved by Newton-Raphson method. Energy dissipation coefficients as well as reflection and transmission coefficients of a submerged flat plate were calculated with various plate lengths and thickness. Both real and imaginary components of body displacement and forces were used to solve the motion of breakwater accurately. The effect of the magnitude of dissipation coefficient on the body displacement was evaluated. The results from the potential theory with no dissipation term were found to be an overestimate in resonance frequency.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.2
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• pp.262-270
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• 1988

A numerical solution of the elastohydrodynamic lubrication problem for an axially profiled cylindrical roller is presented. The problem is analyzed using finite difference method and Newton-Raphson method. The effect of side leakage and compressibility of lubricants are considered and axially nonuniform grid is constructed over the computation zone. Isobars, contours and section graphs show pressure variation and film shape. Contours plot is very similar to the previously reported experimental observations based upon optical interferometry. The maximum pressure and the minimum film thickness occur near the start of the profiling. The method used makes it possible to design an optimum axial profile of the roller to increase the life of rolling bearings.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.4
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• pp.91-99
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• 1996

A hybrid approach employing both the genetic algorithm and the newton-raphson method is proposed for the electrical impedance computed tomography (EICT) image reconstruction. Computational experiments based on the new concept have shown promising results for several noise-free models. In particular, the resistance distribution of the tested models having resistivity ratio up to 100:1 has been reconstructed sucessfully. Using the proposed mehtod, it is also possible to get the reconstruction by the conventional iterative approaches be difficult to vonverge to a robust solution. If the compution power is enhanced further, the proposed method is expected to stimulate the practical applications of the EICT technology in the near future.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.78-80
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• 2005

The load flow calculation is one of the most critical issues in electrical power systems. Generally, load flow has been calculated by Gauss-Seidel method and Newton-Raphson method but these methods have some problems such as non-convergence due to heavy load and initial value. In this paper, to overcome such problems, the power flow is calculated by genetic algorithm. At the heavy load, the solution for problem can not be obtained by the Newton-Raphson method. However, it can be solved in case of using genetic algorithm. In this paper, the strong point of this method would be demonstrated in application to an example system.

• Tribology and Lubricants
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• v.12 no.3
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• pp.115-122
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• 1996

In this paper, a finite difference method and the Newton-Raphson method are used to evaluate the Hamrock and Dowson's EHL film thickness formulas in elliptical contact problems. The minimum and central film thicknesses are compared with the Hamrock and Dowson's numerical results for various dimensionless parameters and with their film thickness formulas. The results of present analysis are more accurate and physically reasonable. The minimum film thickness formula is similar with the Hamrock and Dowson's results, however, the central film thickness formula shows large differences. Therefore, the Hamrock and Dowson's central film thickness formula should be replaced by following equation. $H_{c} = 4.88U^{0.68}G^{0.44}W^{0.096}(1-0.58e^{-0.60k})$ More accurate film thickness formula for general elliptical contact problems can be expected using present numerical methods and further research should be required.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2000.10a
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• pp.331-338
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• 2000

In this paper, a non-linear finite element formulation for the spatial cable-net structures is simulated and using this formulation, the characteristics of structural behaviors for the elastic catenary cable are examined In the simulating procedure for the elastic catenary cable, nodal forces and tangential stiffness matrices are derived using catenary parameters of the exact solutions by a governing differential equation of catenary cable, cable self-weights and unstressed cable length. Dynamic Relaxation Method that considers kinetic damping is used for the structure analysis and Newton Raphson Method is used to verify the accuracy of solutions. In the analysis of two dimensional cable, the results obtain from the elastic catenary elements are shown more accurate than does of truss elements and in the case of spatial cable-net structures, Dynamic Relaxation Method is more stable to be converged than Newton Raphson Method.

• Journal of Powder Materials
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• v.30 no.1
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• pp.29-34
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• 2023

A fixed-point iteration is proposed to integrate the stress and state variables in the incremental analysis of plastic deformation. The Conventional Newton-Raphson method requires a second-order derivative of the yield function to generate a complicated code, and the convergence cannot be guaranteed beforehand. The proposed fixed-point iteration does not require a second-order derivative of the yield function, and convergence is ensured for a given strain increment. The fixed-point iteration is easier to implement, and the computational time is shortened compared with the Newton-Raphson method. The plane-stress condition is considered for the biaxial loading conditions to confirm the convergence of the fixed-point iteration. 3-dimensional tensile specimen is considered to compare the computational times in the ABAQUS/explicit finite element analysis.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1999.06a
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• pp.182-188
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• 1999

A theoretical study of elastohydrodynamic lubrication of elliptical contacts with both rolling and spin has been carried out. A finite difference method and the Newton-Raphson method are applied to solve the problem. The velocity vectors resulting from combined spin and rolling/sliding motion lead to asymmetric pressure distributions and film shapes. Film contours and variations of the minimum and central film thicknesses are compared with various spin-roll ratios. At high spin-roll ratios the minimum film thickness is considerably reduced, whereas the central film thickness decreases less dramatically, The present numerical scheme can be used in the analysis of general elliptical contact problems.

• Tribology and Lubricants
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• v.28 no.4
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• pp.153-159
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• 2012

Tapered roller bearings are widely used in high axial-load and radial-load applications. In this study, a numerical analysis is performed to study a finite line contacts EHL problem between a tapered roller and raceway in tapered roller bearings. Converged solutions are obtained for moderate load and material parameters using a finite difference method with non-uniform grids and the Newton-Raphson method. The contours and sectional plots of pressure distribution and film shape are compared. The pressure distribution and film shapes near both ends of the roller are very different from those in the central part and are transversely asymmetric. The maximum pressure and absolute minimum film thickness always occur at the small end of the roller.