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The overview of fracture mechanics models for concrete

Akram Amanda

Architecture Civil Engineering Environment

2021

Vol. 14, no. 1

47--58

Fracture mechanics of concrete is a complex matter still thoroughly researched from different angles. It is not an easy task to describe fracture process in concrete, as there are many factors affecting crack development and propagation. Practical applications of fracture mechanics could allow engineers to design concrete structures more effectively and safely. At the minimum, it could help estimate the “safe” period of time left before the unstable, dangerous crack propagation. This utilitarian goal was the reason for many researchers to invent numerous theoretical models in order to describe the crack occurrence better. However, dealing with various analytical problems was not a simple matter and thus existing models of fracture mechanics for concrete have different limitations. Over the years first fracture theories for concrete were reviewed repeatedly. All of these investigations lead to modifications of older models in order to overcome found drawbacks, which proved not to be an easy task. Recently, new approaches to fracture analyses seemed to produce promising results, like universal size effect law (USEL) or modified two parameter fracture model (MTPM) with alternative ways for evaluating fracture parameters. In the paper some of them will be discussed together with other fracture models, starting from some of the very first ones introduced for concrete, like fictitious crack model (FCM) and crack band model (CBM).

Identification of parameters of concrete damage plasticity constitutive model

Jankowiak T., Łodygowski T.

Foundations of Civil and Environmental Engineering

2005

No. 6

53-69

The paper presents a method and requirement of the material parameters identification for concrete damage plasticity constitutive model. The laboratory tests, which are necessary to identify constitutive parameters of this model have been presented. Two standard applications have been shown that test the constitutive model of the concrete. The first one is the analysis of the three-point bending single-edge notched conrete beam specimen. The second presents the four-point bending single-edge notched conrete beam specimen under static loadings. In conclusion, the comparison of crack patterns in the numerical and laboratory [2,9] tests has been presented and discussed.

W pracy przedstawiono metodę identyfikacji parametrów materiałowych betonu klasy B50. Przyjęto model matematyczny betonu plastycznego ze zniszczeniem. Określono, jakie testy laboratoryjne są niezbędne do identyfikacji parametrów konstytutywnych tego modelu. Przetestowano użyteczność modelu konstytutywnego w wybranych dwóch zadaniach brzegowych (zginanie trójpunktowe oraz czteropunktowe belki betonowej z nacięciem). Porównano otrzymane mechanizmy zniszczenia ze znanymi wynikami eksperymentów laboratoryjnych [2, 9].