Abstract
The effect of fiber length on the mechanical and dynamical properties of PET short fiber-CR composite was investigated. The extension and tensile strength of the composites filled with fibers of length under 2mm decreased with increasing the fiber content, while the tensile strength of the composites filled with fibers of length over 2mm changed from decrease to increase and their extension decreased noticeably at about 5vol% of the fiber content. Stress-strain curves of the composites showed that the composites filled with fibers under 2mm length yielded and that the tensile stress of the composites filled with fibers of length over 4mm increased linearly to failure without yield. The composites filled with fibers of 2mm length yielded at a low fiber content and failured at a high fiber content. The dynamic storage moduli of the composites were determined as following equations: E′c=E′r+0.34•L• (E′f-E′r)•Vf at L<3.1mm and E′c=E′r+(E′f-E′r)•Vf at L>3.1mm, where E′c, E′r and E′f are dynamic storage moduli of composite, CR, and PET fiber, L and Vf are length and volume fraction of the fiber.
