Determination of the mode I crack tip opening rate and the rate dependent cohesive properties for structural adhesive joints using digital image correlation

The present work addresses two key issues relating to the study of rate effects in adhesively bonded joints. Firstly, accurate determination crack tip strain and secondly cohesive zone length. rate-dependent fracture behaviour adhesive joints with either a toughened epoxy or ductile polyurethane was investigated under mode I loading rates ranging from 0.1 mm/min 1.0 m/s digital image correlation (DIC) analysis. traction-separation laws (TSLs) were determined by measuring J-integral values opening displacements simultaneously. An analytical method is proposed correlate velocity external rate. lengths zones measured, compared results obtained thickness-independent -dependent models. properties adhesives exhibited very different dependences. tool developed using DIC approach successfully determines for TSLs investigated.