Measurement of Dynamic Interlaminar Fracture Toughness of FRP Laminates Using Dynamic Displacement Measuring Apparatus

摘要

Dynamic mode II and mixed-mode interlaminar fracture toughnesses of CFRP laminates were measured using an instrumented impact testing system at a low impact speed (0.9m/s). The system consists of a drop weight impact tester and a dynamic displacement measuring apparatus constructed of an optical fiber, a position sensing detector and a laser light source. The results show that if load data obtained from the strain gage installed at the dart is used to estimate the dynamic interlaminar fracture toughness, it can cause the overestimation of the dynamic toughness and results in an erroneous understanding of the experimental results. It is also shown that the dynamic toughness can be evaluated accurately based on the displacement data measured by the displacement measuring apparatus. It is thus concluded that the displacement-based analysis is more accurate and reliable than the load-based analysis in the measurement of the dynamic interlaminar fracture roughness of FRP laminates.