Numerical and experimental studies on theudfracture behavior of rubber-toughened epoxyudin bulk specimen and laminated composites

摘要

To study the toughening mechanisms of liquid rubber (LR) and core-shell rubber (CSR) inudbulk epoxy and composite laminate, experimental and numerical investigations wereudcarried out on compact tension (CT) and double-cantilever-beam (DCB) specimens underudmode-I loading. The matrix materials were pure epoxy (DGEBA), 15% LR (CTBN) and 15%udCSR modified epoxies. Experimental results and numerical analyses showed that bothudliquid rubber (LR) and core-shell rubber (CSR) could improve significantly the fractureudtoughness of pure epoxy (DGEBA). However, the high toughness of these toughenedudepoxies could not be completely transferred to the interlaminar fracture toughness of theudunidirectional carbon fibre reinforced laminate. The main toughening mechanism of CSR inudbulk epoxy was the extensive particle cavitation, which greatly released the crack-tipudtriaxiality and promoted matrix shear plasticity. The poor toughness behavior of CSR in theudcarbon fibre laminate was thought to be caused by the high constraint imposed by the stiffudfibre layers. No particle cavitation had been observed in LR modified epoxy and the mainudtoughening mechanism was merely the large plastic deformation near the crack-tip due toudthe rubber domains in the matrix which results in a lower yield strength but a higherudelongation-to-break.