Initial Elastic Properties of Unidirectional Ceramic Matrix Composite Fiber Tows

Abstract

The initial elastic properties of two unidirectional ceramic matrix composite tows, comprised of continuous, cylindrical flbers surrounded by one or more matrices, have been calculated using three different methods. The first uses finite element (FE) analysis of the tow to calculate values for elastic and shear moduli and Poisson's ratios in the three principal directions, and in the absence of confirmatory experimental data is regarded as the most accurate for a wide range of fiber/matrix geometries and materials. The other two models are (i) rule of mixtures, ROM/volume averaging and (ii) the approximate equations of Halpin-Tsai and analytical relations based on slab representation for composite materials that rely on the elastic properties and volume fractions of the constituent materials. Initial elastic properties of the tows determined by the FE method are presented, and they are compared with predictions made by the other two techniques.

Comparison of Multiscale Method of Cells-Based Models for Predicting Elastic Properties of Filament Wound C/C-SiC

“…Once these parameters are quantified, along with the volume fraction of each phase, the geometry of the C/C-SiC RUC is completely defined. Following Blacklock and Hayhurst [10], the geometric parameters for the C/C-SiC RUC are given in Table I, and the volume fractions of the constituents are given in Table II. Through homogenization and application of periodic boundary conditions, the response of the RUC represents that of an infinitesimal point in a continuum at a higher scale.…”

“…Predictive micromechanics and multiscale models of the thermomechanical behavior of C/C-SiC can be effective tools for taking full advantage of the customizable nature of the C/C-SiC material system. Blacklock and Hayhurst [10] developed a hierarchical multiscale framework (microscale model is homogenized a priori and output is utilized as input at the meso-or macroscale) for predicting the elastic properties of C/C-SiC utilizing the finite element method (FEM). Furthermore, several authors have developed analytical micromechanical models to predict the non-linear mechanical response due to damage evolution of C/C-SiC [11,12,13,14,15,16].…”

“…Hierarchical (one-way coupling in space) multiscale modeling with HFGMC, denoted as "MsHFGMC". The three models are validated against results from a hierarchical multiscale FEM model for a repeating unit cell of C/C-SiC in the available literature [10]. Furthermore, the multiscale models are used in conjunction with classical lamination theory to predict the stiffness of C/C-SiC plates manufactured via a filament winding process recently developed by DLR [22].…”

“…The various novel multiscale frameworks developed for C/C-SiC are presented along with the underlying micromechanics theories. Then, validation results of the multiscale models as compared to data from existing computational results [10] are given. Finally, the multiscale models are used to predict the elastic properties of filament wound plates and compared to experiment.…”

Micro-XCT-based finite element method for predicting the elastic modulus of needle carbon-fiber-reinforced ceramic matrix composites

“…To calculate these elastic parameters, a variety of methods have been developed in recent years. The typical methods include the homogenization method [1,2], the finite element method [3][4][5][6], and the general method of cell [7][8][9], all of which require a representative volume element (RVE) [10] as an input. The most common RVE is the minimum periodic structure after simplifying the real microstructure of composite.…”