The influence of randomly oriented CNTs on the elastic properties of unidirectionally aligned composites

The modification of composites by CNTs is critically important to improve its strength and mechanical properties and widespread its practical applications in many areas of outdoor, construction buildings, engineering, and technology sectors. This paper examines the influence of CNTs on the elastic properties of unidirectionally aligned composites. The nano-inclusions, whose properties could be characterized by three parameters (length, diameter, Young's elastic modulus), are assumed to be ellipsoidal and randomly arranged. The unidirectionally aligned glass fibers were used as a macro-filler. The elastic properties of two systems: Matrix + CNT + Glass fibers and Matrix + Glass fibers were determined and compared using of Eshelby's and Mori-Tanaka's theories of inclusions. For the modified by CNTs composite of the four independent elastic constants, the transverse Young's modulus E-22, in-plane shear modulus G(12), out-plane shear modulus G(23) and the plane-strain bulk modulus K-23 appear to significantly increase with increasing CNT's concentration and length/diameter ratio while the longitudinal Young's modulus E-11 increase insignificantly.