Effect of interphase thickness and fiber diameter on elastic properties of composites using multi-scale modelling

Abstract

Composite materials are the largely used engineering materials in aerospace and automobile industries due to their high specific strength and high specific stiffness. The composites’ properties are essential for the design and development of the machine parts. They vary with fiber content, fiber properties, matrix properties, and type of manufacturing process. More experiments are required to obtain the properties and the best combination of fibers and matrices. However, several analytical methods are available to find the properties of the composite to avoid the number of experiments. In the present study, the properties of CFRP, GFRP, Amino-functional multi-walled carbon nano-tubes (CNT) added CFRP, CNT added GFRP composites have been calculated using the properties of fiber, interphase between fiber and matrix, matrix, and CNT. The properties of CNT added epoxy are obtained using the Halpin-Tsai equation in the first stage. In the second stage, the properties of interphase are calculated using the properties of CNT added epoxy and fiber properties. In the third stage, the properties of CFRP and GFRP are calculated using three phase constitutive model by considering the properties of fiber, interphase, and CNT added matrix. The properties are calculated at fiber diameters: 8 μm and 14 μm while varying the fiber volume fraction (%): 0 to 70%, interphase thickness: 50 nm to 500 nm, the weight fraction of CNT (%) added in epoxy: 0 to 5%. The addition of CNT has improved the elastic properties of CFRP and GFRP. The elastic properties of the composites are improved significantly with an increase in the interphase thickness.