Determination of parameters of a viscous-cohesive fracture model by inverse analysis

Abstract

The quasi-brittle, loading rate dependent behaviour of the concrete, characterized by a fracture process zone (FPZ) ahead of the crack front, can be described through a viscous-cohesive model. In this paper, a viscous cohesive model proposed in a former paper is evaluated for a group of high strength concrete beams loaded at rates from 10-5 mm/s to 10+1 mm/s. A software has been developed to enable the automatic determination of the viscous-cohesive model parameters through inverse analysis on load-versus loading-point displacement (P-d) from threepoint bend tests on notched prismatic specimens. The strategy allowed the sensitivity analysis of the parameters related to viscous behaviour. The analysis of results shows that the formerly proposed model can be improved for a better simulation of the loading rate dependence on the cohesive fracture process.

Design of reinforced concrete beams with steel fibers in the ultimate limit state

“…The design routine of SOUSA and GETTU (2006) model was incorporated in an algorithm based on Java plataform. The program named fitFG includes a user-friendly graphic interface (SANTOS et al [14]). The algorithm determines the constitutive relation in tension of FRC materials using inverse analysis using experimental results of 3PB tests.…”

Reforço de vigas de concreto armado utilizando concreto de ultra alto desempenho reforçado com fibras

“…Por outro lado, os ensaios de compressão diametral e flexão são de mais fácil execução O comportamento pós pico do CUADRF comumente é analisado por meio de ensaios de flexão em vigas ranhuradas. É possível obter o comportamento visco-coesivo do material por meio de análise inversa dos resultados carga e deslocamento de ensaios de flexão de três pontos em vigas ranhuradas(KANG et al, 2010;SANTOS;SOUSA, 2015;UCHIDA et al, 1995). A determinação do comportamento pós pico é fundamental para modelagem do CUADRF em análises estruturais com o aparecimento de fissuras.A modelagem do comportamento pós fissuração do CUADRF é realizada com precisão utilizando modelos bi ou tri lineares(KANG et al, 2010;YOON, 2014;YOON, 2013).…”