Micromechanics based analysis of randomly distributed fiber reinforced composites using simplified unit cell model

2005 ◽  
Vol 71 (3-4) ◽  
pp. 327-332 ◽  
Author(s):  
M.M. Aghdam ◽  
A. Dezhsetan
Keyword(s):  
Cell Model ◽  
Unit Cell ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Unit Cell Model ◽  
Fiber Reinforced

Coefficients of thermal expansion of unidirectional fiber-reinforced composites using unit-cell model

2018 ◽  
Vol 53 (11) ◽  
pp. 1425-1436
Author(s):  
PC Upadhyay ◽  
JP Dwivedi ◽  
VP Singh
Keyword(s):  
Thermal Expansion ◽  
Cell Model ◽  
Unit Cell ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Unit Cell Model ◽  
Fiber Reinforced ◽  
Two Phase ◽  
Thermal Expansion Coefficients ◽  
Three Phase

Coefficients of thermal expansion of some uniaxially fiber-reinforced composites have been evaluated using three-phase unit-cell model. Results have been compared with the values predicted by two other models based on composite cylinders assembly (CCA), and also with some earlier reported experimental values. An extension of the two-phase unit-cell model has also been presented for the evaluation of thermal expansion coefficients of three-phase composites. The formulation has been used to evaluate the overall coefficients of thermal expansion of AS-graphite/epoxy system with a low modulus coating on the fibers. The results have been compared with the results obtained from the Sutcu's recursive concentric cylinders model for composites containing coated fibers. From the comparison of results of the unit-cell models (both, two-phase and three-phase) with the results obtained from some other models available in the literature, it is concluded that the overall thermal properties of fiber-reinforced composites evaluated by the unit-cell model can be used as effectively as by any other model.

A micromechanical unit cell model with an octagonal fiber for continuous fiber reinforced composites

2020 ◽  
Vol 54 (28) ◽  
pp. 4495-4513
Author(s):  
Yuanchen Huang ◽  
Carlos Alberto Cimini ◽  
Sung Kyu Ha
Keyword(s):  
Cross Section ◽  
Cell Model ◽  
Unit Cell ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Unit Cell Model ◽  
Continuous Fiber ◽  
Fiber Model ◽  
Amplification Factors ◽  
Stress Amplification

This paper presents a novel micromechanical unit cell model for continuous fiber reinforced composites, which features a fiber with an octagonal cross-section embedded in surrounding matrix, and was named as octagonal fiber model. The cross-section of octagonal fiber model was subdivided into five by five sub-regions, and the conditions of equilibrium and deformation compatibility were applied to derive expression of effective ply properties, and stress amplification factors, which correlate microstresses in sub-regions with ply stresses. For E-glass/epoxy and carbon/epoxy material systems with different fiber volume fractions, effective ply properties and stress amplification factors in sub-regions were evaluated using derived formulae. Results from octagonal fiber model were then compared with those from multiple analytical methods and finite element unit cell model. It was shown that effective ply properties predicted by octagonal fiber model were generally in good agreement with those from finite element model, and octagonal fiber model outperformed other analytical counterparts in estimating stress amplification factors, demonstrating the potential of octagonal fiber model.

scholarly journals Influence of Unit Cell Size and Fiber Packing on the Transverse Tensile Response of Fiber Reinforced Composites

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2565 ◽  
Author(s):  
Royan J. D’Mello ◽  
Anthony M. Waas
Keyword(s):  
Cell Size ◽  
Unit Cell ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Unit Cell Size ◽  
Tensile Response ◽  
Transverse Tensile ◽  
Macro Scale ◽  
Unit Cells

Representative volume elements (RVEs) are commonly used to compute the effective elastic properties of solid media having repeating microstructure, such as fiber reinforced composites. However, for softening materials, an RVE could be problematic due to localization of deformation. Here, we address the effects of unit cell size and fiber packing on the transverse tensile response of fiber reinforced composites in the context of integrated computational materials engineering (ICME). Finite element computations for unit cells at the microscale are performed for different sizes of unit cells with random fiber packing that preserve a fixed fiber volume fraction—these unit cells are loaded in the transverse direction under tension. Salient features of the response are analyzed to understand the effects of fiber packing and unit cell size on the details of crack path, overall strength and also the shape of the stress-strain response before failure. Provision for damage accumulation/cracking in the matrix is made possible via the Bazant-Oh crack band model. The results suggest that the choice of unit cell size is more sensitive to strength and less sensitive to stiffness, when these properties are used as homogenized inputs to macro-scale models. Unit cells of smaller size exhibit higher strength and this strength converges to a plateau as the size of the unit cell increases. In this sense, since stiffness has also converged to a plateau with an increase in unit cell size, the converged unit cell size may be thought of as an RVE. Results in support of these insights are presented in this paper.

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