Calibration of nonlocal damage model from size effect tests

By C. L. Bellégo, J. Dube, Gilles Pijaudier-Cabot, B. Gérard. 2003

167 citations recorded by the source corpus.

The calibration of nonlocal models which contain an internal length has been among the major issues conditioning the implementation of this kind of failure models. Direct calibration from uniaxial testing, where the state of strain remains homogeneous throughout the specimen, is impossible. The softening law is not directly accessible because the strains cannot remain homogeneous during the entire test. In the absence of local information on the displacement field and on micro cracking in the fracture process zone, the calibration has to rely on inverse analysis. This paper presents such a procedure based on three point bend size effect tests on notched specimens. The complete load deflection curves are used for the identification of the constitutive relations. Manual calibration is discussed first. It is emphasised that calibration on the load deflexion curve from a single experiment is not objective. We show that Bazant's size effect law, which is related to peak loads only, may serve as a helpful guide to reach the closest fit. Then, automatic calibration is described. An optimal set of model parameters can be obtained within a reasonable number of iterations.

Subfields: Materials Chemistry, Mechanics of Materials

View Paper: https://www.semanticscholar.org/paper/9b9603541a8aa9d3b5f5dd8684dadaa5ff94ba83

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In Materials Chemistry

In Mechanics of Materials

Citations in the corpus

Experimental Investigations of Fracture Process in Concrete by Means of X‐ray Micro‐computed Tomography (2016, background): “A characteristic length is usually related to material microstructure and is determined with an inverse identification process of experimental data [62].”
Failure and size effect for notched and unnotched concrete beams (2013, methodology): “Let us note that the final optimisation process discussed in Refs [30, 41], based for example on a Marquardt–Levenberg algorithm, has not been carried out.”
Meso-scale approach to modelling the fracture process zone of concrete subjected to uniaxial tension (2009, methodology): “Previous modelling efforts have been focused on an indirect determination of the FPZ by inverse analysis [8, 2, 24, 21, 22].”
A simplified implementation of a gradient-enhanced damage model with transient length scale effects (2013, methodology): “The application of inverse procedures [5,11–13] through fitting of series of experimental results enables a phys-”