Electronic Thesis and Dissertation Repository


Master of Engineering Science


Mechanical and Materials Engineering


Jiang, Liying


Discontinuous fiber reinforced composites (DFRC) through injection molding have been widely used in the industrial fields due to their relatively high mechanical performance and low cost. This work is directed towards developing an accurate and efficient numerical simulation package to predict the elastic properties of the injection molded DFRC for fulfilling their potential applications and reducing the expensive experimental costs.

By combining the micromechanics modeling and finite element (FE) analysis, the elastic properties of the DFRC with the aligned fibers are firstly predicted to establish a database for developing semi-empirical formulation through data fitting. Then the elastic properties of DFRC with oriented fibers are calculated through orientation averaging. An integrated software package is developed to output the elastic properties of the composites for given composite constituents, fiber volume fraction, fiber aspect ratio and fiber orientation distribution. Experimental tensile tests are performed to validate the numerical results. Microscopy-based technique and image pixel analysis are performed to determine the fiber volume fraction gradient. In order to calibrate the numerical simulation results, the effects of fiber volume fraction gradient and fiber curvature on the elastic properties of the composites are investigated. Those factors will be further considered in the integrated software package to improve the accuracy of the numerical simulation. This work is expected to advance the development of numerical techniques for composite materials.