Menegotto-Pinto model

Figure I Stress-strain relationship of the Menegotto-Pinto model.

The applicability of a material model depends largely on the values that the user/engineer will choose for the parameters of the model. In most cases in order to select appropriate values, calibration of the model and hence experimental results are required. Usually this sort of information is not available and therefore default values have to be used. When the law employed is sensitive to its parameters, lack of experimental results may narrow considerably its applicability. For both the Monti-Nuti and the Menegotto-Pinto models, suggested values can be obtained from various publications. A typical range for the model parameters are listed in Table 1. Bold letters denote the values that have been found appropriate for a wide range of applications by the authors. 

Constitutive Law for Steel (Based on the Menegotto-Pinto Model)... 

The constitutive law describing the behavior of the steel material is the uniaxial Menegotto-Pinto model (1973). This computationally efficient nonlinear law is capable to model both kinematic and isotropic hardening as well as the Bauschinger effect, allowing for accurate simulation and reproduction of experimental results. The response of the steel material is defined by the following nonlinear equation ... 

The backbone of the Monti-Nuti model is that of the Menegotto-Pinto relationship ... 

Fig. 11 Menegotto-Pinto material constitutive model for structural steel typical cyclic stress-strain response...

The stiffness properties k( and force-displacement relationships of the uniaxial elements are defined according to constitutive stress-strain relationships implemented in the model for concrete and steel (Fig. 20.2) and the tributary area assigned to each uniaxial element. The reinforcing steel stress-strain behavior implemented in the wall model is the well-known nonlinear relationship of Menegotto and Pinto (1973) (Fig. 20.2b). The hysteretic constitutive relation developed by Chang and Mander (1994) (Fig. 20.2a) is used as the basis for the relation implemented for concrete because it is a general model that provides the... 

This model incorporates a set of experimental observations regarding the response of steel reinforcement into the widely-used stress-strain relationship of Menegotto and Pinto (1973). 

Experience has shown that a stress-strain relationship may fail to predict correctly the response when small reversals in the strain history occur this is the case when the structural model is subjected to a ground motion record. Initially this problem was identified in the model of Menegotto and Pinto (1973) by Filippou et al. (1983), who pointed out that, in order to avoid such an undesirable behaviour, the memory of the analytical model should extent over all previous branches of the stress-strain history. In terms of implementation this would be impractical and thus Filippou et al. (1983) proposed to limit the memory of the model to four controlling curves, which warrant that, at least at the structural level, this numerical problem is almost fully eliminated. 

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