On the Fictitious Crack Model of Concrete Fracture

In this paper the sub-structure method introduced by Petersson is reformulated for the three point bending specimen in order to show how complete load-displacement relations without truncation of significance can be obtained. The problem of instability caused by the linearization of the softening in the fracture zone is discussed, and an alternative energy formulation is given and males it possible to distinguish between stable and unstable situations. The reformulated sub-structure method is implemented on computer in a way that makes it possible to use a multilinear stress-crack-opening-displacement relation for the material in the fracture zone, and some qualitative results are given