Tao Zhang, Jinglan Deng^*, Jihui Wang

CMES-Computer Modeling in Engineering & Sciences, Vol.124, No.2, pp. 545-559, 2020, DOI:10.32604/cmes.2020.09536

Abstract The out-of-plane fold is a common defect of composite materials during the manufacturing process and will greatly affect the compressive strength as well as the service life. Making it of great importance to investigate the influence of out-of-plane defects to the compressive strength of laminate plates of composite materials, and to understand the patterns of defect evolution. Therefore, the strip method is applied in this article to create out-of-plane defects with different aspect ratios in laminated plates of composite materials, and a compressive performance test is conducted to quantify the influence of out-of-plane defects. The result shows that the compressive… More >

Decheng Feng^{1, 2, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.3, pp. 997-1014, 2020, DOI:10.32604/cmes.2020.07265

Abstract In the present paper, a hierarchical multi-scale method is developed for the nonlinear analysis of composite materials undergoing heterogeneity and damage. Starting from the homogenization theory, the energy equivalence between scales is developed. Then accompanied with the energy based damage model, the multi-scale damage evolutions are resolved by homogenizing the energy scalar over the meso-cell. The macroscopic behaviors described by the multi-scale damage evolutions represent the mesoscopic heterogeneity and damage of the composites. A rather simple structure made from particle reinforced composite materials is developed as a numerical example. The agreement between the fullscale simulating results and the multi-scale simulating… More >

Kuan-Ting Liu¹, Chun-Lin Lu¹, Nyan-Hwa Tai², Meng-Kao Yeh^{1, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.122, No.2, pp. 661-674, 2020, DOI:10.32604/cmes.2020.07792

Abstract In this study, the deformation and stress distribution of printed circuit board (PCB) with different thickness and composite materials under a shock loading were analyzed by the finite element analysis. The standard 8-layer PCB subjected to a shock loading 1500 g was evaluated first. Moreover, the finite element models of the PCB with different thickness by stacking various number of layers were discussed. In addition to changing thickness, the core material of PCB was replaced from woven E-glass/epoxy to woven carbon fiber/epoxy for structural enhancement. The non-linear material property of copper foil was considered in the analysis. The results indicated… More >

Ugo Galvanetto, Paul Robinson, Agostino Cerioni, Carlos Lopez Armas

Structural Durability & Health Monitoring, Vol.5, No.2, pp. 161-190, 2009, DOI:10.3970/sdhm.2009.005.161

Abstract This paper presents a simple mathematical model to investigate various formulations of interface elements which are used to simulate fatigue driven delamination in composite materials. To illustrate the effectiveness of the model it is used to evaluate the performance of several different static constitutive laws and damage definitions coupled with a particular fatigue degradation strategy. It is shown that the model can be used to readily assess the robustness and reliability of the different formulations by examining hundreds of thousands of sets of parameter values in a rational and efficient manner. More >

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 history until they reached a… 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 to alloweasy manufacturing. Several variantsofthe… 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 boundary element method. The obtained… More >

Ryosuke Matsuzaki^1,*, Taishi Nakamura¹, Yusuke Yamagata¹, Akira Todoroki², Masahito Ueda³, Yoshiyasu Hirano⁴

The International Conference on Computational & Experimental Engineering and Sciences, Vol.22, No.4, pp. 171-171, 2019, DOI:10.32604/icces.2019.05205

Abstract When continuous carbon fiber composites are molded with a 3D printer, three-dimensional complex structure can be integrally molded, which leads to reduction of manufacturing time and cost. In addition, because the curved continuous fibers can be printed in a plane when the 3D printer is utilized, the design space and capability of 3D printed composites will drastically expand compared with using just straight fibers such as conventional prepreg. However, printing accuracy of composite materials may be affected uniquely by parameters such as number of fibers in tow, printing curvature, compaction pressure etc. In this study, we investigated to construct an… More >

V.C. Santos¹, P.S. Lopes¹, R. Gärtner², A.B. Jorge¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.4, No.2, pp. 53-58, 2007, DOI:10.3970/icces.2007.004.053

Abstract This work presents an approach for weight and reliability optimization of aeronautical armors. Military and police helicopters are usually exposed to highly risky situations, with a high probability for these aircrafts to be hit by projectiles. In this context, floor aircraft armor can be used to protect the crews' lives. However, the armoring of an aircraft causes an increase in weight. If this extra weight is poorly arranged, the changes in aircraft centroid position may even destabilize the aircraft. Thus, it is essential to design an armor not only to protect the aircraft, but also not to conflict with aircraft… 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 (c) level-2 regions of pure… More >