THE BLISTER TEST - TRANSITION FROM PLATE TO MEMBRANE BEHAVIOR FOR AN ELASTIC-MATERIAL

The crack extension force has been calculated for the blister test whe n the blister is in transition from place-like to membrane behaviour. Simple equations are given for the crack extension force that are accu rate to better than 1%. The mode-mixity of interfacial fracture in the blister test is discussed and it is shown that the interfacial fractu re energy is likely to increase with decrease in thickness of the film . In practical tests, the behaviour of a blister is likely to be neare r to a plate than a membrane.