A critical appraisal of existing models for nonlinear finite element analysis of reinforced concrete response
[摘要] ENGLISH ABSTRACT: This study entails the appraisal of the constitutive models available for the nonlinear finite element analysis of reinforced concrete, using the DIANA finiteelement package and following generally accepted guidelines for non linear finiteelement analyses. The constitutive models considered are plasticity and totalstrain based (fixed and rotating crack) models. The appraisal consists of theanalysis of various experiments performed on reinforced concrete beams thatare governed by compressive, shear and tensile dominated failures. Theinvestigation is not limited to the accuracy of the results obtained using thesemodels but also of the consistency of the results obtained with regard to variousmesh types and sizes, as well as a study of the individual influence of severalmaterial parameters. The intention of the study was to provide the reader with anindication of the performance capacity (accuracy and consistency) of theavailable constitutive models, where the notion of the use of the results obtainedfrom non linear finite element analyses for design purposes is considered.The results obtained were varied. The models performed reasonably well in thecompressive and tension dominated studies, with the importance of accuratematerial parameters being emphasized especially for the more advancedcementitious materials investigated. The total strain rotating crack model alsoshowed a proclivity of simulating incorrect failure modes as well as exhibitingreluctance towards stress redistribution. All models used for the shear dominatedstudy yielded mostly inaccurate and inconsistent results, but it was found that thefour node quadrilateral element with selective reduced integration performed thebest. The plasticity model did not capture shear failure well, and convergencewas often not attained. The constant shear retention factor of the total strainfixed crack model was found to yield more detailed response curves for thesmaller mesh sizes. The results of the tension dominated beams inspired moreconfidence in the models as quite accurate values were attained, especially bythe plasticity model used.The ability of the available models to simulate realistic structural behaviour undervarious failure modes is very limited, as is evident from the results obtained. Thedevelopment of a more advanced and robust model is required, which canprovide consistently accurate results and failure modes, and even 'anticipate'potential failure modes not considered by the user.
[发布日期] [发布机构] Stellenbosch University
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