Calculation method of elastic modulus for carbon fiber-reinforced plastics considering inhomogeneous interphase

Abstract

The characteristic of interphase has a significant influence on the macroscopic performance of carbon fiber-reinforced plastics (CFRP). To investigate the effect of interphase on composite elastic modulus, a representative volume element (RVE) of unidirectional CFRP with inhomogeneous interphase was established. Based on the bridging model, a theoretical calculation method of composite elastic modulus was given. The elastic modulus of T300/BSL914C composites was obtained by the theoretical method. Results are in good agreement with the finite element method and experimental data. Four types of interphase models were given including inhomogeneous transversely isotropic, inhomogeneous isotropic, homogeneous transversely isotropic, and homogeneous isotropic. The results demonstrate that interphase type has an influence on the prediction of CFRP composites’ elastic modulus. With the increase of thickness, the prediction error of elastic modulus caused by interphase type increases rapidly. Furthermore, the relationship between composite elastic modulus and interphase thickness and stiffness is analyzed. With the increase in thickness, the changes in shear modulus G 12 and Poisson’s ratio ν23 are more evident than in other elastic properties, and with the enhancement of interphase stiffness, the increase of G 12 is the most significant.

Experimental and Numerical Study on Mechanical Behavior of Steel/GFRP/CFRP Hybrid Structure under Bending Loading with Adhesive Bond Strength Assessment

“…Micromechanical models were implemented in the program, which were used to generate composite material constants based on the following inputs: elastic modulus of fibers ( E f ) and matrix ( E m ), Poisson’s ratio of fibers ( v f ) and matrix ( v m ), and volume fraction of fibers ( V f ) and matrix ( V m ). Based on the data available from the literature, the Poisson’s ratio of carbon and glass fibers is equal to 0.2 and 0.17, respectively [ 41 , 42 ]. In this present study, the matrix volume fraction, V m (percentage by volume), of single-ply CFRP and GFRP polymer composites was calculated according to the following equation where m cs is the mass of single-ply polymer composite with dimensions of w 1 × w 2 × t , m rf is the mass of dry reinforcement fabric with dimensions of w 1 × w 2 , ρ m is the density of the matrix, and V cs is the volume of the single-ply polymer composite with dimensions of w 1 × w 2 × t ( Figure 14 ).…”

“…Micromechanical models were implemented in the program, which were used to generate composite material constants based on the following inputs: elastic modulus of fibers (E f ) and matrix (E m ), Poisson's ratio of fibers (v f ) and matrix (v m ), and volume fraction of fibers (V f ) and matrix (V m ). Based on the data available from the literature, the Poisson's ratio of carbon and glass fibers is equal to 0.2 and 0.17, respectively [41,42]. In this present study, the matrix volume fraction, V m (percentage by volume), of single-ply CFRP and GFRP polymer composites was calculated according to the following equation…”