Paul R. Dawson¹, Donald E. Boyce², Ronald Rogge³

CMES-Computer Modeling in Engineering & Sciences, Vol.10, No.2, pp. 123-142, 2005, DOI:10.3970/cmes.2005.010.123

Abstract Computational mechanics provides a powerful environment for modeling the evolution of material structure during deformation processes and for associating that evolution with changes to the mechanical properties. In this paper, we illustrate a two-scale formulation that links the mechanical loading applied at the scale of a component (the continuum scale) to the responses of the material at the scale of the crystals that comprise it (the crystal scale). Employing the capabilities offered by computational mechanics, we can better understand how heterogeneity of deformation arising at both the continuum and crystal scales influences the behaviors observed experimentally. Such an understanding is… More >

R. Mathur¹, S. G. Advani², B. K. Fink³

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.5, pp. 587-602, 2003, DOI:10.3970/cmes.2003.004.587

Abstract Real number-coded hybrid genetic algorithms for optimal design of resin injection locations for the resin transfer molding process are evaluated in this paper. Resin transfer molding (RTM) is widely used to manufacture composite parts with material and geometric complexities, especially in automotive and aerospace sectors. The sub-optimal location of the resin injection locations (gates) can leads to the formation of resin starved regions and require long mold fill times, thus affecting the part quality and increasing manufacturing costs. There is a need for automated design algorithms and software that can determine the best gate and vent locations for a composite… More >

M. Kröger¹, M. Müller², J. Nievergelt²

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.5, pp. 559-570, 2003, DOI:10.3970/cmes.2003.004.559

Abstract We present a novel method for generating starting polymer structures for molecular simulations in the dense phase. The work describes the ingredients of an algorithm for the creation of large, dense or diluted amorphous polymeric systems close to equilibrium and provides measures for its quality. The model systems are made of semiflexible (wormlike) repulsive multibead chains. The key feature of the method is its efficiency, in particular for large systems, while approaching given local and global chain characteristics. Its output has been proven to serve as an excellent basis for subsequent off-lattice molecular dynamics computer simulation. By combining chain growing… More >

R.Kanapady¹, K.K.Tamma²

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.1, pp. 103-118, 2003, DOI:10.3970/cmes.2003.004.103

Abstract Of general interest here is the time dimension aspect wherein discretized operators in time may be continuous or discontinuous; and of particular interest and focus here is the design of time discretized operators in the context of discontinuous state-phase for computational dynamics applications. Based on a generalized bi-discontinuous time weighted residual formulation, the design leading to a new unified set of hierarchical energy conserving and energy dissipating time discretized operators are developed for the first time that are fundamentally useful for time adaptive computations for dynamic problems. Unlike time discontinuous Galerkin approaches, the design is based upon a time discontinuous… More >

T. Nishioka¹, J. Furutuka¹, S. Tchouikov¹, T. Fujimoto¹

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.1, pp. 129-146, 2002, DOI:10.3970/cmes.2002.003.129

Abstract The governing condition of dynamic crack bifurcation phenomena had not been fully elucidated until our recent experimental studies. We found from the experimental results that the energy flux per unit time into a propagating crack tip or into a fracture process zone governs the crack bifurcation. Regarding the numerical simulation of dynamic crack bifurcation, to the authors' knowledge, no accurate simulations have been carried out, due to several unresolved difficulties. In order to overcome the difficulties, for the analysis of dynamic crack bifurcation, we developed a moving finite element method based on Delaunay automatic triangulation. Using the moving finite element… More >

Y. Ochiai

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.4, pp. 435-446, 2001, DOI:10.3970/cmes.2001.002.435

Abstract The boundary element method (BEM) is useful in solving the steady heat conduction problem of orthotropic bodies without heat generation. However, for cases with arbitrary heat generation, a number of internal cells are necessary. In this paper, it is shown that the problem of steady heat conduction in orthotropic bodies with heat generation can be solved without internal cells by the triple-reciprocity BEM. In this method, the distribution of heat generation is interpolated using integral equations. In order to solve the problem, the values of heat generation at internal points and on the boundary are used. Furthermore, a new interpolation… More >

M.Ganesh¹, D. Sheen²

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.2, pp. 183-194, 2001, DOI:10.3970/cmes.2001.002.183

Abstract A parallel numerical algorithm is introduced and analyzed for solving inhomogeneous initial-boundary value parabolic problems. The scheme is based on the method recently introduced in Sheen, Sloan, and Thomée (2000) for homogeneous problems. We give a method based on a suitable choice of multiple parameters. Our scheme allows one to compute solutions in a wide range of time. Instead of using a standard time-marching method, which is not easily parallelizable, we take the Laplace transform in time of the parabolic problems. The resulting elliptic problems can be solved in parallel. Solutions are then computed by a discrete inverse Laplace transformation.… More >

Xiang-YangLi¹, Shang-Hua Teng², Peng-Jun Wan³

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.1, pp. 97-116, 2001, DOI:10.3970/cmes.2001.002.097

Abstract To conduct numerical simulations by finite element methods, we often need to generate a high quality mesh, yet with a smaller number of elements. Moreover, the size of each of the elements in the mesh should be approximately equal to a given size requirement. Li et al. recently proposed a new method, named biting, which combines the strengths of advancing front and sphere packing. It generates high quality meshes with a theoretical guarantee. In this paper, we show that biting squares instead of circles not only generates high quality meshes but also has the following advantages. It is easier to… More >

A. El-Zafrany¹

CMES-Computer Modeling in Engineering & Sciences, Vol.2, No.1, pp. 27-38, 2001, DOI:10.3970/cmes.2001.002.027

Abstract In a recent publication, the author has introduced boundary integral equations for thick plate bending problems, for cases with generalized types of loading. Internal bending moments and shear forces, required for stress analysis, were calculated by means of a finite difference procedure, which requires fine boundary element meshes to achieve an acceptable degree of accuracy. In this paper, boundary integral equations for internal bending moments and shear forces are presented for thick Reissner plates in bending. Domain loading terms in those boundary integral equations have also been simplified for a variety of loading types including concentrated loading, linearly-distributed loading, and… More >

S. Guimarães¹, J.C.F. Telles²

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.3, pp. 131-139, 2000, DOI:10.3970/cmes.2000.001.433

Abstract The paper discusses further applications of the hyper-singular boundary integral equation to obtain the Green's function solution to general geometry fracture mechanics problems, such as curved multifracture crack simulation, static and transient dynamic in 2-D, 3-D and plate bending problems. This numerical Green's function (NGF) is implemented into alternative boundary element computer programs, as the fundamental solution, to enhance the scope of alternative applications of the NGF procedure.
The results to some typical linear fracture mechanics problems are presented. More >