M.R. Khoshravan¹, M. Hosseinzadeh¹

CMES-Computer Modeling in Engineering & Sciences, Vol.45, No.2, pp. 179-206, 2009, DOI:10.3970/cmes.2009.045.179

Abstract A sandwich panel's optimum core height and composite face thickness, under defined loading, have been computed in order to reach the structure's lowest weight and highest stiffness. The Tsai-Hill criterion was used in order to control the support of transverse loading by the panel. Regarding the relationships in the sandwich materials, the studied material was modeled with the MATLAB package. The Genetic Algorithm (GA) that is based on statistics was used. Our goal was to obtain the best methods of the GA in order to present an optimization method for the sandwich structure. Hence, a sensibility analysis was performed. In… More >

Surkay D. Akbarov^1,2,3, A. R. Mamedov³

CMES-Computer Modeling in Engineering & Sciences, Vol.42, No.3, pp. 257-296, 2009, DOI:10.3970/cmes.2009.042.257

Abstract Within the scope of the piecewise homogeneous body model through the use of the three-dimensional geometrically non-linear exact equations of the theory of elasticity, an approach for the investigation of problems with the micromechanics of a periodically curved fiber near the free convex cylindrical surface is proposed and employed. The main difficulties in finding the solution to these problems are caused by the impossibility of employing the summation theorem for cylindrical functions to satisfy the boundary conditions on the cylindrical surface. For this purpose the cosine and sine Fourier series presentation of the sought values is proposed to satisfy the… More >

A.N.Guz¹, V.A.Dekret¹

CMES-Computer Modeling in Engineering & Sciences, Vol.42, No.3, pp. 177-186, 2009, DOI:10.3970/cmes.2009.042.177

Abstract Stability problem of composite material reinforced by periodical rows of short fibers is solved. The problem is formulated with application of equations of linearized three-dimensional theory of stability. The composite is modeled as piecewise-homogeneous medium. The influence of geometrical and mechanical parameters of the composite to the critical strain is investigated. More >

S.H. Pyo¹, H.K. Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.40, No.3, pp. 271-306, 2009, DOI:10.3970/cmes.2009.040.271

Abstract This paper presents a micromechanical approach for predicting the elastic and multi-level damage response of aligned and randomly oriented whisker-/ short fiber-reinforced composites. Based on a combination of Eshelby's micromechanics and the evolutionary imperfect interface approach, the effective elastic moduli of the composites are derived explicitly. The modified Eshelby's tensor for spheroidal inclusions with slightly weakened interface [Qu (1993b)] is extended in the present study to model whiskers or short fibers having mild or severe imperfect interfaces. Aligned and random orientations of spheroidal reinforcements are considered. A multi-level damage model in accordance with the Weibull's probabilistic function is then incorporated… More >

H. T. Wang¹, Z. H. Yao²

CMES-Computer Modeling in Engineering & Sciences, Vol.29, No.1, pp. 1-14, 2008, DOI:10.3970/cmes.2008.029.001

Abstract Carbon nanotubes (CNTs) may provide ultimate enhancement in stiffness and strength for composite materials. This paper presents a rigid-fiber-based boundary integral equation formulation for the numerical simulation of debonding process and the corresponding strength of CNT reinforced composites. The CNT/matrix interfaces are assumed to fail when the interfacial shear force reaches a prescribed threshold, and the CNTs and matrix are considered to be detached in the failed areas. The matrix with one or several tens of originally well-bonded CNTs is subjected to an incremental tensile load and the effective stress-strain relations are readily obtained by the introduction of CNT/matrix debonding… More >

Vadiraja D. N.¹, A. D. Sahasrabudhe²

CMES-Computer Modeling in Engineering & Sciences, Vol.27, No.1&2, pp. 49-62, 2008, DOI:10.3970/cmes.2008.027.049

Abstract Rotating beams are flexible structures, which are often idealized as cantilever beams. Structural modelling of rotating thin-walled composite beam with embedded MFC actuators and sensors using higher shear deformation theory (HSDT) is presented. A non-Cartesian deformation variable (which represents arc length stretch) is used along with two Cartesian deformation variables. The governing system of equations is derived from Hamilton's principle and solution is obtained by extended Galerkin's method. Optimal control problem is solved using LQG control algorithm. Vibration characteristics and optimal control for a box beam configuration are discussed in numerical examples. Gyroscopic coupling between lagging-extension motions is found to… More >

Wenzhong Tang¹, Suresh G. Advani¹

CMES-Computer Modeling in Engineering & Sciences, Vol.8, No.2, pp. 165-176, 2005, DOI:10.3970/cmes.2005.008.165

Abstract An optimization method is proposed to simulate the motion of long flexible fibers in shear flow. The fiber is modeled as spheres connected by massless rigid rods and ball-socket joints. The optimization method is mathematically justified and used to obtain the position of a fiber at the next time step from its current position. Results for a single fiber in simple shear flow agree well with those reported in the literature. The usefulness of the method is demonstrated by simulating the motion of two interactive fibers subjected to shear flow field, and by studying the viscosity of dilute suspensions of… More >

Changyu Hwang¹, Philippe H. Geubelle²

CMES-Computer Modeling in Engineering & Sciences, Vol.1, No.4, pp. 45-56, 2000, DOI:10.3970/cmes.2000.001.497

Abstract This paper presents the formulation and numerical implementation of a spectral scheme specially developed to simulate dynamic fracture events in unidirectional and cross-ply fiber-reinforced composites. The formulation is based on the spectral representation of the transversely isotropic elastodynamic relations between the traction stresses along the fracture plane and the resulting displacements. Example problems involving stationary or dynamically propagating cracks in fiber-reinforced composites are investigated and compared with reference solutions available in the literature and/or experimental observations. More >

Qiuren Ou^1,2,*, Peijun Ji², Jun Xiao¹, Ling Wu²

FDMP-Fluid Dynamics & Materials Processing, Vol.15, No.1, pp. 27-37, 2019, DOI:10.32604/fdmp.2019.04787

Abstract The properties of resin transfer molding (RTM) cyanate ester and its T800 grade carbon fiber composites were studied with the rheometer, differential scanning calorimetry (DSC), FT-IR, dynamic mechanical analyzer (DMA), thermal gravimetric analysis (TGA), mechanical property testing, and scanning electron microscopy (SEM). The results showed that the temperature of cyanate ester suitable for RTM process was 70℃. Curing process of the resin was 130℃/2 h+160℃/2 h+200℃/2 h+220℃/4 h. Glass transition temperature and heat decomposition temperature of the cured resin are 289℃ and 415℃, respectively. Mechanical properties of T800/RTM cyanate composites are 13.5% higher than that of T700/RTM cyanate composites and… More >

S.A. Yıldızel^1,2, A.U. Öztürk¹

CMC-Computers, Materials & Continua, Vol.52, No.1, pp. 41-52, 2016, DOI:10.3970/cmc.2016.052.041

Abstract In this study, artificial neural networks trained with swarm based artificial bee colony optimization algorithm was implemented for prediction of the modulus of rapture values of the fabricated glass fiber reinforced concrete panels. For the application of the ANN models, 143 different four-point bending test results of glass fiber reinforced concrete mixes with the varied parameters of temperature, fiber content and slump values were introduced the artificial bee colony optimization and conventional back propagation algorithms. Training and the testing results of the corresponding models showed that artificial neural networks trained with the artificial bee colony optimization algorithm have remarkable potential… More >