Flexural behaviour, modeling

Flexural behaviour modelled by stress-strain relations in tension... 

Flexural behaviour modelled by crack bridging functions... 

A simple theoretical model based on composite beam theory associated with the traditional strength of the materials was developed to describe the behaviour of the panels in the elastic range. A three-dimensional finite elements analysis on the whole panel was also performed to simulate its flexural behaviour. 

Katz and Li [61,62] modelled the flexural behaviour by simulating the fibre partially as a beam resting on an elastic foundation and partially as a cantilever... 

The modelling of flexural behaviour and strength can be carried out by two different modes (i) modelling the tensile curve and determining the flexural behaviour by considering a continuous beam in flexure, with different characteristic functions for the tensile and compressive behaviour and (ii) modelling... 

The stress-strain curve in tension, modelled for FRC, has been used to develop an analytical description of the flexural behaviour (<7b and load vs. deflection curves) of FRC. In such treatments the improvement in flexural behaviour is the result of two effects enhancement in post-cracking strength and in ductility. 

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]. 

The shape of the stress-strain curves of GRC composites, such as those shown in Figure 8.12, can be predicted by the ACK model (Chapter 4), as it clearly shows the three zones predicted by this model elastic, multiple cracking and post-multiple cracking. Thus, the concepts of this model, and their various modifications, have been used to analyse the mechanics of GRC when loaded in tension [46,53-56]. The tensile stress-stress relation was used to predict the flexural behaviour, based upon the concepts discussed in Section 4.7 [57]. An essential element in an analysis of this kind is the determination of the fibre-matrix interfacial bond strength. 

Petit, C. Ebinger, C. 2000. Flexure and mechanical behaviour of cratonic lithosphere gravity models of the East African and Baikal rifts. Journal of Geophysical Research, 105, 19 151-19162. 

The aim of this chapter is therefore to propose a creep model based upon the experimental results of flexural creep testing. A fnrther aim is to build a numerical model which is able to predict the time-dependent behaviour of the unsaturated... 

Flexural creep testing on polymer concrete using an unsaturated polyester resin based on rPET was carried out to predict creep behaviour, and mechanical and empirical models were proposed using experiment results. The following conclusions were obtained from the results ... 

For the prediction of crack growth in reinforced concrete beams sijbjected to fatigue, our model must take the behaviour of the tension reinforcement into account. In a previous work (6) we derived, from a model based on fracture mechanics, S-N relationship for embedded ribbed bars located in the tension zone of flexural members ... 

Interpretation of test results of the actual composite (stress-strain curves and crack spacing) to determine the interfacial shear strength values indirectly using analytical models which accounted for the composite behaviour in tension and flexure. Results of such interpretations will be discussed separately in Section 4.5. 

Figure 4.48 Schematic behaviour of an FRC beam loaded in flexure with fibres bridging over the crack which develops at the centre of the beam and is modelled...

Fracture mechanics has been applied to model some of the fracture characteristics asbestos-cement composites, especially those related to crack bridging by the fibres. Mai [12] analysed the behaviour of both notched beams in flexural loading and double cant lever beams (DCB) to determine the critical stress intensity factor, /Cc and the specific work of fracture, WF, which measures the average fracture energy per apparent unit crack surface over the entire fracture process. The effect of fibre content on these parameters is shown in Figure 9.15. The trends resemble those observed for the effect of fibre content on strength (Figure 9.14). 

---