Yuantian Qin^1,2, Yucheng Zhang^1,*, Vadim V. Silberschmidt²

CMES-Computer Modeling in Engineering & Sciences, Vol.139, No.3, pp. 2865-2891, 2024, DOI:10.32604/cmes.2024.046113

Abstract This paper proposes a novel approach for identifying distributed dynamic loads in the time domain. Using polynomial and modal analysis, the load is transformed into modal space for coefficient identification. This allows the distributed dynamic load with a two-dimensional form in terms of time and space to be simultaneously identified in the form of modal force, thereby achieving dimensionality reduction. The Impulse-based Force Estimation Algorithm is proposed to identify dynamic loads in the time domain. Firstly, the algorithm establishes a recursion scheme based on convolution integral, enabling it to identify loads with a long history and rapidly changing forms over… 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

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, the coupling of altogether different… More >

S. Pradeepkumar^*, P. Nagaraj

Sound & Vibration, Vol.56, No.3, pp. 221-233, 2022, DOI:10.32604/sv.2022.014889

Abstract Vibrational characteristics in small horizontal axis wind turbine system are presented in this study with a system concept called tactile response and substructuring. The main focus is on managing the dynamic properties like vibration, noise, and harshness that occur during the operational mode. Tactile response is defined as the response of subsystem which is induced when a human body touches a vibrating system. Sub structuring is a computational method used to reduce the dynamic behavior of a large complex system with a smaller number of degrees of freedom without disturbing the mesh size of the model. Sub structuring has the… More >

Carlos A. Felippa^*

CMES-Computer Modeling in Engineering & Sciences, Vol.129, No.3, pp. 1209-1241, 2021, DOI:10.32604/cmes.2021.016803

Abstract This paper considers Lagrangian finite elements for structural dynamics constructed with cubic displacement shape functions. The method of templates is used to investigate the construction of accurate mass-stiffness pairs. This method introduces free parameters that can be adjusted to customize elements according to accuracy and rank-sufficiency criteria. One- and two-dimensional Lagrangian cubic elements with only translational degrees of freedom (DOF) carry two additional nodes on each side, herein called side nodes or SN. Although usually placed at the third-points, the SN location may be adjusted within geometric limits. The adjustment effect is studied in detail using symbolic computations for a… 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

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 >

Alan Alonso-Rivers¹, Rolando Salgado-Estrada^2,*

Structural Durability & Health Monitoring, Vol.14, No.3, pp. 187-204, 2020, DOI:10.32604/sdhm.2020.010743

Abstract A dynamic simulation method for cracked structures is implemented to determine their dynamic response with the purpose of evaluating their structural behavior. The procedure makes possible the simulation of three-dimensional cracked structures. The excitation force is randomly generated to simulate wind gusts. It is assumed the structure remains in the elastic range, which allows for each mode that contributes to its dynamic response to be decoupled. The results indicate that the presence of damage causes changes in the modals parameters of the structure as accurate as other similar methods proposed for simpler structures. Therefore, it is concluded that the proposed… More >

Zhiqiang Ma^1,2, Lingshuang Kong^1,2, Xianlong Jin^1,2,*

CMES-Computer Modeling in Engineering & Sciences, Vol.116, No.1, pp. 51-67, 2018, DOI:10.31614/cmes.2018.01739

Abstract Many engineering applications need to analyse the system dynamics on the macro and micro level, which results in a larger computational effort. An explicit-implicit asynchronous step algorithm is introduced to solve the structural dynamics in multi-scale both the space domain and time domain. The discrete FEA model is partitioned into explicit and implicit parts using the nodal partition method. Multiple boundary node method is adopted to handle the interface coupled problem. In coupled region, the implicit Newmark coupled with an explicit predictor corrector Newmark whose predictive wave propagates into the implicit mesh. During the explicit subcycling process, the variables of… More >

L. Gaul, M. Fischer¹, U. Nackenhorst²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 815-824, 2002, DOI:10.3970/cmes.2002.003.815

Abstract A sequential FEM--BEM approach is employed to calculate the dynamic behavior and sound radiation of rotating wheels. The equations of motion for the wheel are developed in the frame of an Arbitrary Eulerian Lagrangian description with a time-independent formulation for steady state rolling and a spatial description of vibrations. The noise radiation caused by the vibration modes is computed by the symmetric hybrid boundary element method. More >

R.Kanapady¹, K.K.Tamma²

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.2, pp. 189-208, 2004, DOI:10.3970/cmes.2004.006.189

Abstract An integrated design of generalized single step LMS methods for applications to nonlinear structural dynamics is described. The design of the mathematical framework encompasses all the traditional and new and recent optimal algorithms encompassing LMS methods, and readily permits the different a-form, v-form and d-form representations in a unique mathematical setting. As such, the theoretical developments and implementation aspects are detailed for subsequent applications to nonlinear structural dynamics problems. The developments naturally inherit a consistent treatment of nonlinear internal forces under the present umbrella of predictor multi-corrector generalized single step representations with a wide variety of algorithmic choices as options… 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 to demonstrate the advantage of… More >