A Morphological Study of Porosity Defects in Graphite-Epoxy Composites

The presence of porosity in a structural material generally has a detrimental effect on the strength and mechanical properties of the component [1]. Excessive porosity is especially undesirable in laminated composites such as graphite-epoxy as it substantially degrades the interlaminar shear strength, the compressive strength and the transverse flexural strength, Detailed morphological knowledge of the pores such as their geometrical shape, orientation and location of occurrence in the laminate is valuable in several areas. In the nondestructive evaluation of porosity in composites using ultrasound, such morphological data will aid the model development of the interaction of the ultrasonic field with the voids and help the interpretation of the ultrasonic measurement results. In the investigation of the effects of defects, data on the pore morphology serve as inputs to models of the stress distribution around the defects and the interaction between the defects.