| 초록 |
Fiber fracture is one of the dominant failure phenomena to determine total mechanical performance inside composites. Fiber fracture location was measured and compared via either conventional optical microscopic method or nondestructive acoustic emission (AE). Polyvinylidene fluoride (PVDF) film is used as a polymer sensor. PVDF film has high flexibility and mechanical toughness. Interfacial properties and source location for single fiber/epoxy composite were studied using PVDF and lead-zirconate-titanate (PZT) sensors. Interfacial shear strength (IFSS) measured by PVDF sensor was smaller than that of PZT sensor. The correspondence between PZT detected location and optically observed location for fiber fracture was generally established well with small error range, whereas for PVDF sensor error range was higher compared with PZT case due to their rather lower sensitivity. The fiber break source location by PVDF sensor can be a valuable method to measure interfacial properties of composite nondestructively for non- or semi-transparent polymer composites. Copolymer, poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE) could be compared to PVDF sensor in terms on their sensing and source location and testing temperature range etc. Acknowledgement: This study was supported by NRL program, MST through KRISS, via ReCAPT, GNU. |
