PSI - Issue 71

Akash S.S. et al. / Procedia Structural Integrity 71 (2025) 180–187

182

transverse isotropic. A UD composite material made up of T300 carbon fiber with fiber diameter of 7 µ m and epoxy matrix is considered inthis study. The material properties of the considered fiber and matrix are given in Table 1. Table 1: Elastic properties of matrix and fiber considered in this study [Source: YinX. et al. (2008)]

Material

T300 Carbon Fiber

Matrix

Young’s Modulus (GPa)

241

3.12

Poisson’s ratio

0.38

0.2

SVEs are modelled and simulated in ABAQUS ® using python scripting. A fully parameterized python script is written to automate the modelling, simulation and extraction of results from the SVEs for different random fiber diameter distributions. For each fiber diameter distribution, six load cases are simulated to estimate the elastic constants in all directions. This is schematically represented in Figure 1(a). The SVE is modelled as a cuboid with cylindrical carbon fibers of randomly generated diameters within a tolerance band of 10% embedded in the epoxy matrix. The python script is written such that the matrix around the fibers is created maintaining a volume fraction of approximately 55%vol in all SVEs. An example of a SVE created using the python script is shown in Figure 1(b). The material properties of the fibers and matrix are assigned according to Table 1. Static analysis is assigned for each model with different loading and boundary conditions for each load case as represented in Figure 1(a). The integration point volume is also requested as field output in the simulations to perform spatial averaging 3 of the stress and strain components. The spatially-averaged stresses and strains of different load cases are used to calculate the effective elastic constants of the material from the SVE. The calculated elastic constants for each fiber diameter distribution are collected and stored in a CSV file.

(a)

(b)

Fig. 1: (a) Schematic representation of di ff erent loading conditions for estimating the e ff ective material properties [Omairey et al. (2019)] (b) SVEwith 100 fibers (Volume fraction = 0.55) and fiber diameter distribution with mean 6.9997 µ m and standard deviation 0.0372 µ m (Dimension of SVE = 82x82 µm) 3. Spatial Averagingforestimatingelasticconstants In classical lamination theory [C.T. Sun et al. (1996)] the composite lamina is treated as a homogeneous orthotropic material with certain effective moduli that represent the ’average’ material properties of the composite.