An experimental study on the manufacturing of engineered defects in composite plates
Alireza Zarei, Saeed Farahani, Srikanth Pilla
Abstract
Composite materials are finding their way to various applications where their safe usage is of concern. In this regard, accurate inspection techniques must be developed and verified. Composite samples with predefined defects are needed to objectively and accurately assess various damage detection techniques. This study presents a methodology for manufacturing composite plates with engineered defects. The three most common damages in composite parts - delamination, fiber breakage, and matrix crack - are investigated here. This approach can be used by researchers working on damage detection techniques to fabricate composite samples and control the type, size, and location of the embedded defects. Manufacturing and verifying such samples with engineered defects are indispensable to all damage detection studies on composite materials. The samples in this study were 25.4 mm thick, 305×305 mm square plates manufactured via the vacuum infusion method. Stitched triaxial fiberglass fabric and epoxy vinyl ester resin were used as the reinforcement and matrix. The sizes, shapes, and locations of the defects were predetermined and kept constant in all the manufactured samples with high consistency. X-ray tomography was used to verify the characteristics of the defects in the composite plates. The X-ray images showed that defects occurred in their predefined locations, shapes, and sizes with high accuracy.