A new technique to characterize the fiber/matrix interphase properties under high strain rates

Dynamic interphase-loading apparatus (DILA) has been developed to directly characterize the fiber/matrix interphase propel ties of composites under hi gh loading rates. This apparatus uses a micro-mechanical method (micro-inde ntation) that is based on the debonding of a fiber from the matrix at the i nterphase region. Displacement rates up to 3000 mu m/s that cause deformati on of the interphase under high shear strain rates were obtained using the fast expansion capability of piezoelectric actuators (PZT). Transient force and fiber displacement for a specific displacement rate is measured during the test. The data are reduced to apparent average interphase shear streng th and energy absorbed during debonding and frictional sliding during the m icro-debonding process. An E-glass-fiber/epoxy-amine interphase was tested under various lending rates to demonstrate the capability of the test appar atus. Test results showed that the strength and energy-absorbing capability of the E-glass/epoxy-amine interphase are sensitive to loading rate. (C) 2 000 Elsevier Science Ltd. All rights reserved.