A Micromechanics Model for Thermoelastic Properties of Plain Weave Fabric Composites

1994 ◽  
Vol 116 (4) ◽  
pp. 517-523 ◽  
Author(s):  
H. T. Hahn ◽  
R. Pandey
Keyword(s):  
Representative Volume Element ◽  
Composite Laminates ◽  
Volume Element ◽  
Thermoelastic Properties ◽  
Micromechanics Model ◽  
Plain Weave ◽  
Representative Volume ◽  
Thermal Expansion Coefficients ◽  
Weave Fabric ◽  
Effective Thermal Expansion

A micromechanics model is presented to predict thermoelastic properties of composites reinforced with plain weave fabrics. A representative volume element is chosen for analysis and the fiber architecture is described by a few simple functions. Equations are developed to calculate various phase fractions from geometric parameters that can be measured on a cross section. Effective elastic moduli and effective thermal expansion coefficients are determined under the assumption of uniform strain inside the representative volume element. The resulting model is similar to the classical laminated theory, and hence is easier to use than other models available in the literature. An experimental correlation is provided for a number of Nicalon SiC/CVI SiC and Graphite/CVI SiC composite laminates.

Strength prediction of woven composite rings using progressive damage modeling

2020 ◽  
Vol 29 (6) ◽  
pp. 851-873
Author(s):  
H Khayyam Rayeni ◽  
AH Mazaheri ◽  
F Taheri-Behrooz
Keyword(s):  
Representative Volume Element ◽  
Stiffness Matrix ◽  
Volume Element ◽  
Progressive Damage ◽  
Equivalent Stiffness ◽  
Woven Composite ◽  
Damage Initiation ◽  
Plain Weave ◽  
Representative Volume ◽  
Composite Pipe

The ultimate failure of the woven composite pipes has been investigated using progressive damage modeling. The composite pipe specimens were made of (E) glass plain weave fabrics according to the ASTM D2290 standard. The hoop strength of these specimens has been obtained from the tensile tests. The damage initiation and propagation of composite pipe have been predicted by a numerical multi-scale method. For this purpose, the damage of the yarns and resin of the plain weave laminate was investigated by modeling a representative volume element. Then, the macroscopic stresses and strains of the representative volume element were calculated to obtain the equivalent stiffness matrix using suitable boundary conditions. Then, the mechanical properties of the laminate and material properties degradation coefficients were derived by this equivalent stiffness matrix. Hashin and Von Mises failure criteria were utilized in USDLFD subroutine to predict the damage initiation of the yarn and resin in the representative volume element, respectively. The sudden degradation method has been used to investigate the damage propagation in these constituents. Then, the woven composite ring was modeled in ABAQUS software and its ultimate strength was predicted by UMAT subroutine using obtained degradation coefficients of the representative volume element from the previous step. Finally, the numerical results were compared with the experimental data which show good agreement between the results.

scholarly journals Representative volume element based micromechanical modelling of rod shaped glass filled epoxy composites

2021 ◽  
Vol 3 (2) ◽  
Author(s):  
Aanchna Sharma ◽  
Yashwant Munde ◽  
Vinod Kushvaha
Keyword(s):  
Representative Volume Element ◽  
Poisson’S Ratio ◽  
Volume Fraction ◽  
Tensile Modulus ◽  
Volume Element ◽  
Poisson's Ratio ◽  
Epoxy Composites ◽  
Micromechanical Modeling ◽  
Representative Volume ◽  
Shaped Glass

AbstractIn this study, Representative Volume Element based micromechanical modeling technique has been implemented to assess the mechanical properties of glass filled epoxy composites. Rod shaped glass fillers having an aspect ratio of 80 were used for preparing the epoxy composite. The three-dimensional unit cell model of representative volume element was prepared with finite element analysis tool ANSYS 19 using the periodic square and hexagonal array with an assumption that there is a perfect bonding between the filler and the epoxy matrix. Results revealed that the tensile modulus increases and Poisson’s ratio decreases with increase in the volume fraction of the filler. To study the effect of filler volume fraction, the pulse echo techniques were used to experimentally measure the tensile modulus and Poisson’s ratio for 5% to 15% volume fraction of the filler. A good agreement was found between the RVE based predicted values and the experimental results.

Localization simulation of forming-induced residual stresses of composite using prescribed boundary

2021 ◽  
pp. 073168442094118
Author(s):  
Qi Wu ◽  
Hongzhou Zhai ◽  
Nobuhiro Yoshikawa ◽  
Tomotaka Ogasawara ◽  
Naoki Morita
Keyword(s):  
Residual Stresses ◽  
Representative Volume Element ◽  
Computational Cost ◽  
Volume Element ◽  
Thermoplastic Composite ◽  
Structural Deformation ◽  
Element Analysis ◽  
Micro Scale ◽  
Representative Volume ◽  
Localization Approach

A novel localization approach that seamlessly bridges the macro- and micro-scale models is proposed and used to model the forming-induced residual stresses within a representative volume element of a fiber reinforced composite. The approach uses a prescribed boundary that is theoretically deduced by integrating the asymptotic expansion of a composite and the equal strain transfer, thus rendering the simulation setting to be easier than conventional approaches. When the localization approach is used for the finite element analysis, the temperature and residual stresses within an ideal cubic representative volume element are precisely simulated, given a sandwiched thermoplastic composite is formed under one-side cooling condition. The simulation results, after being validated, show that the temperature gradient has an impact on the local residual stresses, especially on the in-plane normal stress transverse to the fiber, and consequently, influences the structural deformation. This newly designed localization approach demonstrates the advantages of enhanced precision and reduced computational cost owing to the fast modeling of the finely meshed representative volume element. This is beneficial for a detailed understanding of the actual residual stresses at the micro-scale.

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