Yuanzhong Hu¹, Yuchuan Liu, Hui Wang

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.4, pp. 447-454, 2002, DOI:10.3970/cmes.2002.003.447

Abstract Scuffing, a major cause of failure in automobile engines, is considered as a dynamic process in this study. Local adhesions may occur randomly in lubricated contacts due to the existence of asperity contact and breakdown of lubricating films. Scuffing would take place if the local events develop rapidly into a large-scale plastic deformation and catastrophic failure. A system dynamic model established in the present paper allows one to predict dynamic behavior of a tribological system through numerical solutions of a group of differential equations. Results show that a transition to adhesion begins when the surface temperature goes beyond a critical… More >

George D. Manolis¹, Stavros Pavlou²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.3, pp. 399-416, 2002, DOI:10.3970/cmes.2002.003.399

Abstract A free-space Green's function for problems involving time-harmonic elastic waves in variable density materials under plane strain conditions is developed herein by means of Hormander's method in the context of matrix algebra formalism. The challenge when solving problems involving inhomogenous media is that the coefficients appearing in the governing equations of motion are position-dependent. Furthermore, an additional difficulty stems from the fact that these governing equations are vectorial, which implies that coordinate transformation techniques that have been successful with scalar waves can no longer be used. Thus, the present work aims at establishing the necessary background that will allow for… More >

Ch. Zhang²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.3, pp. 381-398, 2002, DOI:10.3970/cmes.2002.003.381

Abstract A 2-D time-domain boundary integral equation method (BIEM) for transient dynamic analysis of cracked orthotropic solids is presented in this paper. A finite crack in an unbounded orthotropic solid subjected to an impact loading is considered. Hypersingular time-domain traction boundary integral equations (BIEs) are applied in the analysis. A time-stepping scheme is developed for solving the hypersingular time-domain traction BIEs. The scheme uses a convolution quadrature formula for temporal and a Galerkin method for spatial discretizations. Numerical examples are given to show that the presented time-domain BIEM is highly efficient and accurate. More >

J. Herrmann¹, M. Junge¹, L. Gaul¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.6, pp. 487-504, 2012, DOI:10.3970/cmes.2012.086.487

Abstract The influence of an acoustic field on the dynamic behavior of a flexible structure is a common issue in automotive applications. An example is the pressure-induced structure-borne sound of piping and exhaust systems. Efficient model order reduction and substructuring techniques accelerate the finite element analysis and enable the vibroacoustic optimization of such complex systems with acoustic fluid-structure interaction. This research reviews the application of the Craig-Bampton and the Rubin method to fluid-structure coupled systems and presents two automotive applications. First, a fluid-filled piping system is assembled by substructures or superelements according to the Craig-Bampton method. Fluid and structural partitions are… More >

A. Ramachandra Murthy¹ , G.S. Palani¹ , Nagesh R. Iyer¹ , Smitha Gopinath¹ and V. Ramesh Kumar¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.5, pp. 409-434, 2012, DOI:10.3970/cmes.2012.086.409

Abstract This paper presents the details of projectile impact on reinforced concrete structural components. Nonlinear explicit transient dynamic analysis has been carried out by using finite element method. Concrete damage model has been employed to represent the nonlinear behaviour of target under impact load. Various methods of modeling of reinforcement have been explained. A brief note on equation of state for concrete, contact algorithms and nonlinear explicit transient dynamic analysis has been given. Numerical studies have been carried out to compute the response of concrete target due to impact of projectile. The computed penetration depth have been compared with the corresponding… More >

Yixiong Wei¹, Qifu Wang^1,2, Yingjun Wang¹, Yunbao Huang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.3, pp. 241-274, 2012, DOI:10.3970/cmes.2012.086.241

Abstract In this study, we propose a novel method to accelerate the process of elastodynamic analysis in 3D problems with BEM (boundary element method). With applying the DRBEM (dual reciprocity boundary element method) to form new integral equations for reducing complexity;the modified FMM (fast multipole method)is introduced to simplify the computation process and save storage space by avoiding intermediate coefficientmatrices. At the same time, FMM-DRBEM is reprogrammed in parallel byapplying GPU with CUDA (Compute Unified Device Architecture)for improving efficiency further.The main features in this paper are: ( 1 )with respect to defects of classical method for elastodynamic, modified FMM-DRBEM algorithm is… More >

S.V. Tsinopoulos¹, D. Polyzos², D.E. Beskos^3,4

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.2, pp. 113-144, 2012, DOI:10.3970/cmes.2012.086.113

Abstract This paper reviews the theory and the numerical implementation of the direct boundary element method (BEM) as applied to static and dynamic problems of strain gradient elastic solids and structures under two- and three- dimensional conditions. A brief review of the linear strain gradient elastic theory of Mindlin and its simplifications, especially the theory with just one constant (internal length) in addition to the two classical elastic moduli, is provided. The importance of this theory in successfully modeling microstructural effects on the structural response under both static and dynamic conditions is clearly described. The boundary element formulation of static and… More >

H. Çerdik Yaslan¹

CMES-Computer Modeling in Engineering & Sciences, Vol.86, No.1, pp. 29-38, 2012, DOI:10.3970/cmes.2012.086.029

Abstract This paper presents the approximate analytical solutions to the time fractional differential equations of elasticity for 3D quasicrystals with initial conditions. These equations are written in the form of a vector partial differential equation of the second order. The time fractional vector partial differential equations with initial conditions are solved by variational iteration method (VIM). The fractional derivatives are described in the Caputo sense. Numerical example shows that the proposed method is quite effective and convenient for solving kinds of time fractional system of partial differential equations. More >

Y. Miao¹, T.G. HE¹, H. Luo^1,2, H.P. Zhu¹

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.6, pp. 481-498, 2012, DOI:10.3970/cmes.2012.085.481

Abstract Combined the hybrid boundary node method (Hybrid BNM) and the dual reciprocity principle, a truly boundary-type meshless method, namely, dual hybrid boundary node method (Dual Hybrid BNM) is presented for solving transient dynamic fracture problems. The enriched basis functions in moving least squares (MLS) approximation is presented for simulating the singularity of the stress field on the tip of the fracture. The solution in Dual Hybrid BNM is divided into particular solution and complementary solution. The complementary solution is solved by means of Hybrid BNM, and the particular solution is approximated by using radial basis functions (RBF). The inner nodes… More >

Jiaoyan Li¹, Xianqiao Wang², James D. Lee¹

CMES-Computer Modeling in Engineering & Sciences, Vol.85, No.5, pp. 463-480, 2012, DOI:10.3970/cmes.2012.085.463

Abstract This paper presents a novel multiple time scale algorithm integrated with the concurrent atomic/atom-based continuum modeling, which involves molecular dynamic (MD) simulation and coarse-grained molecular dynamic (CG-MD) simulation. To capture the key features of the solution region while still considering the computational efficiency, we decompose it into two sub-regions in space and utilize the central difference method with different time steps for different sub-regions to march on in time. Usually, the solution region contains a critical field and a non-critical far field. For the critical field (named atomic region) modeled by MD simulation, a relatively small time step is used… More >