Abstract
For automotive applications of composites to secure safety and reliability of its structure and functionality are critical issues. Carbon fiber reinforced polymer-matrix composites (CFRP) are widely used under vibrating load condition in various automotive and aerospace applications as well as in structural engineering. Today, more application of CFRP is strongly desired for automotive lightweighting. In this paper damage development of non-crimp fabric carbon fiber reinforced polyamide 6 (NCF-CF/NY6) composite plates that are orthotropic laminates has been investigated through a lock-in thermography system under cyclic constant amplitude loading. The instrument system can offer thermoelastic stress image (TSA image) of materials based on an algorithm. We demonstrate that damages in notched CF/NY6 laminate are clearly obtained as image information (TDA image) by post-processing the TSA images obtained before and after loading: it provides the feature of damage. The specific morphology derives identification of the various type of the damage, i.e. transverse cracks, notch induced splitting and delamination. It is found that the results offer the development of damage in [90°/0°]s and [0°/90°]s laminates as distinctly different modes, respectively. Intensity information of TDA images is also discussed to be corresponded to damage density and distribution feature based on scanning electron microscopy examination.
