NUMERICAL MODELLING OF FOUR-POINT BENDING TEST USING COHESIVE FRACTURE MODELS
William Guedes Machado1; Eleazar Cristian Mejia Sanchez2; Deane Roehl1
1 Pontifícia Universidade Católica do Rio de Janeiro; 2 Instituto Tecgraf / Puc-Rio
doi:10.20906/CPS/CILAMCE2015-0881
Resumo
The bending test has become an important test method for concrete to determine the material properties, tensile strength, and predict the mixed-mode crack path. In this work, the novel bend testing procedure for mixed mode fractures in concrete proposed by Galvez is used to model mixed-mode fracture. This procedure allows submitting the specimen test to non-proportional loading, generating different crack paths by changing the action of an actuator. The tests were performed for two specimen sizes and two mixed-mode loading conditions. Two cohesive models are used to simulate fracture in four-point bending test: a potential-based cohesive zone model proposed by Paulino et al. and a bilinear model proposed by Camanho, et al. The numerical results such as curves of load-CMOD and load-displacement were compared with experimental results. The evaluation of the performance of these cohesive models is very important aiming at the study of complex problems in order to identify critical loads, stress/strain behavior in post-critical regime and crack paths in mixed-mode conditions. The numerical results show that cohesive elements can be used as an attractive alternative to model mixed-mode fracture.
Palavras-chave: Cohesive fracture; Four point bending; Cohesive element; Finite element methods