R.S. Olivito¹, F.A. Zuccarello¹

Structural Durability & Health Monitoring, Vol.2, No.1, pp. 19-28, 2006, DOI:10.3970/sdhm.2006.002.019

Abstract During the last decades FRP materials have been utilized in many civil engineering applications for their good performances in substituting traditional restoration techniques, especially in reinforcing and restoring damaged structures. At present, the use of composite materials is greatly increasing as a consequence of the fact that conservation and restoration of existing historic heritage are becoming key issues for civil engineers and architects. This paper deals with the behavior of brick masonry models subjected to cyclic loads with the aim of studying their performances and durability. Firstly the models were damaged by imposing a strain More >

R. Han¹, M.S. Ingber¹, H.L. Schreyer¹

CMC-Computers, Materials & Continua, Vol.4, No.3, pp. 163-176, 2006, DOI:10.3970/cmc.2006.004.163

Abstract Decohesion is an important failure mode associated with fiber-reinforced composite materials. Analysis of failure progression at the fiber-matrix interfaces in fiber-reinforced composite materials is considered using a softening decohesion model consistent with thermodynamic concepts. In this model, the initiation of failure is given directly by a failure criterion. Damage is interpreted by the development of a discontinuity of displacement. The formulation describing the potential development of damage is governed by a discrete decohesive constitutive equation. Numerical simulations are performed using the direct boundary element method. Incremental decohesion simulations illustrate the progressive evolution of debonding zones More >

G. Haasemann¹, M. Kästner¹ and V. Ulbricht¹

CMC-Computers, Materials & Continua, Vol.3, No.3, pp. 131-146, 2006, DOI:10.3970/cmc.2006.003.131

Abstract Novel textile reinforced composites provide an extremely high adaptability and allow for the development of materials whose features can be adjusted precisely to certain applications. A successful structural and material design process requires an integrated simulation of the material behavior, the estimation of the effective properties which need to be assigned to the macroscopic model and the resulting features of the component. In this context two efficient modelling strategies - the Binary Model (Carter, Cox, and Fleck (1994)) and the Extended Finite Element Method (X-FEM) (Moës, Cloirec, Cartraud, and Remacle (2003)) - are used to… More >

C. Tapp¹, W. Hansel, C. Mittelstedt, W. Becker²

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.6, pp. 563-574, 2004, DOI:10.3970/cmes.2004.005.563

Abstract A heuristic algorithm for the weight minimization of sandwich plates is presented. The method is based on a preexisting algorithm for the layerwise topology optimization of symmetric laminates under in-plane loads. The presented algorithm uses structural analyses based on finite elements and explicitly accounts for the special sandwich situation. During the optimization procedure the algorithm adds or subtracts material from the layers of the face sheets and the core of the sandwich plate in regions of high or low stresses respectively. The orientation angles of the layers of the sandwich facings are not varied inorder More >

P. Raghavan¹, S. Ghosh²

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.2, pp. 151-170, 2004, DOI:10.3970/cmes.2004.005.151

Abstract This paper presents an adaptive multi-level computational model that combines a conventional displacement based finite element model with a microstructural Voronoi cell finite element model for multi-scale analysis of composite structures with non-uniform microstructural heterogeneities as obtained from optical or scanning electron micrographs. Three levels of hierarchy, with different resolutions, are introduced in this model to overcome shortcomings posed by modeling and discretization errors. Among the three levels are: (a) level-0 of pure macroscopic analysis; (b) level-1 of macro-micro coupled modeling, used for signaling the switch over from macroscopic analyses to pure microscopic analyses; and More >

Hiroshi Okada¹, Yasuyoshi Fukui¹, Noriyoshi Kumazawa¹

CMES-Computer Modeling in Engineering & Sciences, Vol.5, No.2, pp. 135-150, 2004, DOI:10.3970/cmes.2004.005.135

Abstract A method to obtain the effective mechanical properties of particulate composite materials is presented in this paper. The methodology is based on the boundary element method (BEM) coupled with analytical solutions for ellipsoidal inclusions such as Eshelby's tensor. There is no numerical integration for the surfaces or the domains of distributed particles, and, therefore, proposed technique is very efficient. Homogenization analysis based on representative volume element (RVE) is carried out considering a unit cell containing many particles (up to 1000). By using a conventional BEM approach (i.e., multi-region BEM), it would be extremely difficult to More >

H. Okada¹, C. T. Liu², T. Ninomiya¹, Y. Fukui¹, N. Kumazawa¹

CMES-Computer Modeling in Engineering & Sciences, Vol.6, No.4, pp. 333-348, 2004, DOI:10.3970/cmes.2004.006.333

Abstract Formulations and applications of an element overlay technique for the mesoscopic analyses of composite structures are presented in this paper. As a zooming technique, the element overlay technique has been applied to various engineering problems. A finite element mesh having finer mesh discretization is superposed at the region to zoom the spatial resolution of analysis. Such a numerical technique is known as the s-version FEM (S-FEM). This paper aims at developing an S-FEM technique that is suited for the mesoscopic analysis of particulate composite materials. Local finite element models that contain the second phase material… More >

J.T. Verbis¹, S.V. Tsinopoulos², D. Polyzos²

CMES-Computer Modeling in Engineering & Sciences, Vol.3, No.6, pp. 803-814, 2002, DOI:10.3970/cmes.2002.003.803

Abstract In the present work the iterative effective medium approximation (IEMA) is appropriately used for wave dispersion and attenuation predictions in fiber-reinforced composites that microscopically exhibit a non-uniform fiber distribution. Two types of composites with such irregular topology of fibers are considered. The first contains a regular distribution of clusters of fibers embedded in a composite matrix with uniformly distributed fibers, and the second a uniform distribution of matrix-rich inclusions embedded in a fiber-rich regular composite medium. The resulting from the application of the IEMA scattering problems are solved numerically by means of a two dimensional More >