Impact Damage Detection of Toughened CFRP Laminates with Time Domain Reflectometry.

摘要

Laminated Carbon Fiber Reinforced Polymer (CFRP) composites are very effective in weight saving in aeronautical structural components. It is, however, difficult to detect damage such as delamination, matrix cracks, and local fiber breakages caused by low velocity impact loading. In the previous study in 2009, Time Domain Reflectometry (TDR) method was applied to a unidirectional laminated CFRP structure for the first time. In 2010, the research applied the TDR method for the CFRP laminates. In the present study, therefore, actual impact damage is employed instead for the TDR. Electrical contact between fiber fragments exists in these micro-buckling regions although the electrical resistance becomes very high at the micro-buckling point. We have to investigate the applicability of the TDR method for the impact damage. A low speed impact test is performed to a cross-ply CFRP plate, and impact damage is made at the surface of the CFRP plate. TDR is applied to the cross- ply CFRP plate. The result shows that the reflected signal can be observed after the impact test. This result indicates that the TDR method is useful for detection of the low speed impact damages.