Compliance rate change of tapered double cantilever beam specimen with hybrid interface bonds

This paper presents a combined numerical and experimental study of compliance rate change of Tapered Double Cantilever Beam (TDCB) specimens for Mode-I fracture of hybrid interface bonds. The easily machinable TDCB specimen, which is designed to achieve a constant rate of compliance change with respect to crack length, is developed for Mode-I fracture tests of hybrid material bonded interfaces, such as wood bonded to fiber-reinforced plastic (FRP) composite. The linearity of compliance crack-length relationship of the specimen is verified by both Rayleigh-Ritz method and finite element analysis. An experimental compliance calibration program for specimens with wood-wood and FRP-FRP bonded interfaces is carried out, and a constant rate change of compliance with respect to crack length is obtained for a specific range of crack length. Fracture tests are further performed using TDCB specimens for wood-wood and wood-FRP bonded interfaces to determine the critical loads for crack initiation and crack arrest, and using the constant compliance rate change of the specimens determined by experiment or analysis, the respective critical strain energy release rates, or fracture energies, are obtained. This study indicates that the constant compliance rate change obtained from experiment or finite element analysis for linear-slope TDCB specimens can be used with confidence for fracture studies of hybrid material interface bonds. (C) 1998 Elsevier Science Ltd. All rights reserved.