THE EQUIVALENT ELASTIC CRACK .1. LOAD-Y EQUIVALENCES

The use of crack growth resistance curves (R-DELTAa) to predict the be haviour of cracked specimens is a well established practice for cerami c and cementitious materials. When the cohesive crack model can be app lied to these materials it is shown that the use of R-DELTAa curves is equivalent to setting up an elastic equivalence that greatly simplifi es the computations. This equivalence has its drawbacks and limitation s. This paper analyzes a class of equivalences - the load (P) versus a nother variable - between cracked cohesive materials and linear elasti c ones, ascertaining its applicability to the interpretations of fract ure data.