Fictitious Crack Model

Figure 10.7 Curves (i(s) and (r(tv) for the fictitious crack model proposed by Hillerborg (1978).

Crack Stabilization this refers to the arrest of the cracks generated upon first cracking of the matrix, and which have begun to propagate across the fibres. Crack bridging the action of fibres across the crack, which cannot be considered a discontinuity, but rather as an element that can transfer loads, but it is characterized by a unique relation of stress vs. crack opening (width), a-co curve. This approach, which is frequently referred to as the smeared crack approach, can be considered within the framework of the fictitious crack model. 

Figure 4.18 Analysis of tensile loading by the fictitious crack model (after Hillerborg [28]).

The flexural behaviour of FRC can be described in terms of the opening up of a crack in the tensile zone, with the fibres bridging over the crack. Figure 4.48. This concept can be quantified in terms of the fictitious crack concept, based on a characteristic cr-Various models have been developed based on this concept, and an overview of this topic and its practical implications was presented by Rl LEM committee TC -162 TDF [56]. This section fol lows the RILEM document [56]. 

In the models assuming a plane fictitious crack surface, direct function of the crack opening angle, [Pg.164]

The elastic stresses in the outer zone can be calculated from the Irwin model by assigning a fictitious length a -I- Ty to the crack. 

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