Hui Huang^1,*, Yongbing Li¹, Shuhui Li¹, Ninshu Ma²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.30, No.3, pp. 1-1, 2024, DOI:10.32604/icces.2024.011348

Abstract The sequentially coupled thermo-mechanical finite element analysis (FEA) with implicit iteration scheme is widely adopted for welding process simulation because the one-way coupling scheme is believed to be more efficient. However, such computational framework faces the bottleneck of scalability in large-scale analysis due to the exponential growth of computational burden with respect to the number of unknowns in a FEA model. In the present study, a fully coupled approach with explicit integration was developed to simulate fusion welding induced temperature, distortion, and residual stresses. A mass scaling and heat capacity inverse scaling technique was proposed More >

Chein-Shan Liu¹, Jian-Hung Shen², Chung-Lun Kuo¹, Yung-Wei Chen^2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.2, pp. 1317-1335, 2024, DOI:10.32604/cmes.2023.030618 - 29 January 2024

Abstract This study sets up two new merit functions, which are minimized for the detection of real eigenvalue and complex eigenvalue to address nonlinear eigenvalue problems. For each eigen-parameter the vector variable is solved from a nonhomogeneous linear system obtained by reducing the number of eigen-equation one less, where one of the nonzero components of the eigenvector is normalized to the unit and moves the column containing that component to the right-hand side as a nonzero input vector. 1D and 2D golden section search algorithms are employed to minimize the merit functions to locate real and… More >

David Tae, Kumar K. Tamma^*

CMES-Computer Modeling in Engineering & Sciences, Vol.135, No.2, pp. 843-885, 2023, DOI:10.32604/cmes.2023.023071 - 27 October 2022

Abstract We propose a novel computational framework that is capable of employing different time integration algorithms and different space discretized methods such as the Finite Element Method, particle methods, and other spatial methods on a single body sub-divided into multiple subdomains. This is in conjunction with implementing the well known Generalized Single Step Single Solve (GS4) family of algorithms which encompass the entire scope of Linear Multistep algorithms that have been developed over the past 50 years or so and are second order accurate into the Differential Algebraic Equation framework. In the current state of technology,… More >

Tao Xue¹, Yazhou Wang², Masao Shimada², David Tae², Kumar Tamma^2,*, Xiaobing Zhang^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.134, No.3, pp. 1469-1487, 2023, DOI:10.32604/cmes.2022.021616 - 20 September 2022

Abstract In this work, a consistent and physically accurate implementation of the general framework of unified second-order time accurate integrators via the well-known GSSSS framework in the Discrete Element Method is presented. The improved tangential displacement evaluation in the present implementation of the discrete element method has been derived and implemented to preserve the consistency of the correct time level evaluation during the time integration process in calculating the algorithmic tangential displacement. Several numerical examples have been used to validate the proposed tangential displacement evaluation; this is in contrast to past practices which only seem to… More >

Yi Ji^1,2, Yufeng Xing^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.2, pp. 549-575, 2021, DOI:10.32604/cmes.2021.014244 - 21 January 2021

Abstract Based on the weighted residual method, a single-step time integration algorithm with higher-order accuracy and unconditional stability has been proposed, which is superior to the second-order accurate algorithms in tracking long-term dynamics. For improving such a higher-order accurate algorithm, this paper proposes a two sub-step higher-order algorithm with unconditional stability and controllable dissipation. In the proposed algorithm, a time step interval [tk, tk + h] where h stands for the size of a time step is divided into two sub-steps [tk, tk + γh] and [tk + γh, tk + h]. A non-dissipative fourth-order algorithm is used in the rst… More >

Sun-Beom Kwon¹, Jae-Myung Lee^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.1, pp. 41-89, 2019, DOI:10.31614/cmes.2019.03879

Abstract A direct time integration scheme based on Gauss-Legendre quadrature is proposed to solve problems in linear structural dynamics. The proposed method is a one-parameter non-dissipative scheme. Improved stability, accuracy, and dispersion characteristics are achieved using appropriate values of the parameter. The proposed scheme has second-order accuracy with and without physical damping. Moreover, its stability, accuracy, and dispersion are analyzed. In addition, its performance is demonstrated by the two-dimensional scalar wave problem, the single-degree-of-freedom problem, two degrees-of-freedom spring system, and beam with boundary constraints. The wave propagation problem is solved in the high frequency wave regime More >

Delfim Soares Jr.¹

CMES-Computer Modeling in Engineering & Sciences, Vol.107, No.3, pp. 223-247, 2015, DOI:10.3970/cmes.2015.107.223

Abstract In this work, an explicit time marching procedure, with solution-adaptive time integration parameters, is introduced for the analysis of hyperbolic models. The proposed technique is conditionally-stable, second-order accurate and it has controllable algorithm dissipation, which locally adapts at each time step, according to the computed solution. Thus, spurious modes can be more effectively dissipated and accuracy is improved. Since this is an explicit time integration technique, the new procedure is very efficient, requiring no system of equations to be dealt with at each time-step. Moreover, the technique is simple and easy to implement, being based More >

Delfim Soares Jr.¹

CMES-Computer Modeling in Engineering & Sciences, Vol.105, No.5, pp. 341-360, 2015, DOI:10.3970/cmes.2015.105.341

Abstract In this work, a second-order time-marching procedure for dynamics is discussed, in which enhanced accuracy is enabled. The new technique is unconditionally stable (according to its parameter selection), it has no amplitude decay or overshooting, and it provides reduced period elongation errors. The method is based on displacement-velocity relations, requiring no computation of accelerations. It is efficient, simple and very easy to implement. Numerical results are presented along the paper, illustrating the good performance of the proposed technique. As it is described here, the new method has no drawbacks when compared to the Trapezoidal Rule More >

I-Yao CHAN, Chein-Shan Liu, Weichung Yeih

The International Conference on Computational & Experimental Engineering and Sciences, Vol.20, No.2, pp. 53-54, 2011, DOI:10.3970/icces.2011.020.053

Abstract In this study, we adopt the fictitious time integration method to treat the image reconstruction problem. The distorted image is considered as a result of diffused data from the initial perfect image by using a nonlinear diffusion equation. The image reconstruction problem then becomes an inverse problem by using the data in the final time to recover the data in the initial time. This inverse problem is known as the backward in time nonlinear diffusion problem which is highly ill-posed. We propose to use the fictitious time integration method to tackle this highly ill-posed image More >

Chein-Shan Liu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.16, No.2, pp. 53-54, 2011, DOI:10.3970/icces.2011.016.053

Abstract We consider an inverse problem for identifying a time-space-dependent heat transfer coefficient h(x,t) in a two-dimensional heat conduction equation, with the aid of an extra measurement of temperature at the top side of a rectangular plate. Finite differences are used to discretize the governing equation and boundary conditions of Neumann type, and then the Fictitious Time Integration Method (FTIM) is used to solve a large scale linear system of unknown variables. The numerical results show that the FTIM is effective and robust against noise. More >