Influence of Matrix Toughness on Damage Initiation and Growth in Carbon Fiber Fabric Composites

Progression of fatigue damage in toughened carbon fiber fabric composites by using matrix material of high toughness has been examined with hole-notched specimens. The matrix is toughened by impregnating solid rubber particles a fraction of a micron in diameter. The damage progression in the materials is mainly investigated as two-dimensional information by using analyses of stress distribution data obtained through the thermoelastic stress analysis (TSA). In particular, a new TDA technique developed by improving ordinary TSA has been applied to ascertain smaller (mesoscopic) failure. With the TDA data, improved matrix resin toughness actually influences to inhibit damage development in early fatigue process in the laminates. In addition, the finite element analysis is discussed in terms of a stress distribution and a strain level of damage initiation in the laminated materials.