A Non-contact and Non-destructive Method to Determine Process Induced Fiber Orientation of Compression Molded SMC

Understanding process induced fiber orientation distribution of composite body panels using nondestructive techniques is of prime interest. A compression molded sheet molding compound (SMC) panel is a good example of composite panels which are heavily affected by the molding process. Determination of the directionally dependent local coefficient of linear thermal expansion by digital image correlation yields information that is utilized to determine the local fiber misorientation and calculate the local SMC tensile modulus. In our current study, this methodology is utilized to determine the directional CLTE, permitting evaluation of the SMC properties in a multitude of directions not possible in destructive testing techniques. After obtaining the directionally dependent CLTE, a micromechanical approach is utilized to calculate the local SMC tensile modulus and glass fiber misorientation angle.