Keywords: high performance fibrous concrete, tension softening material model, non-linear finite element simulation.

It is well known that fibre reinforcements could enhance the tensile characteristics and post-cracking resistance of the cementitious composites. However, a general numerical model is limited to those in signifying the post-cracking phenomenon of both conventional and fibre reinforced concrete. In this paper, an attempt was made to simulate the complete pre-cracking and post-cracking response of cementitious composite by adopting ANSYS finite element software. The goal of this study is to utilize advanced modelling techniques, which is relative straight-forward for describing the elastic-plastic response of high performance fibrous concrete subjected to uniaxial tensile load. The tension softening material model proposed herein has shown to provide sensible solution for both material and structural analysis.

In most cases, the characteristic response of fibre reinforced concrete (FRC) includes three distinct regions of un-cracked elastic deformation, crack formation and fibre pullout resistance, and composite failure. This behaviour is shown to be markedly different from plain concrete which latter deformation after the concrete matrix reaches its peak tensile strength is negligible. In the conventional reinforced concrete design practice, resistance of cracked concrete is generally neglected. This does not frequently prove critical in many structural design computations. Even so, at the present time, non-linear finite element analysis including post-cracking resistance of concrete has become progressively more evident for precise predictions of stress-deformation performance utterly [1].

A number of analytical and semi-empirical models to predict the stress-deformation response have been proposed. However, it is usually complicated in applying those models for structural performance analysis. Moreover, models using the fracture mechanics approach, which involve critical crack-opening displacements and resistance-curve analysis, are not in a form that can be readily applied to the analysis of FRC members [2].

Since FRC has superior tensile properties, particularly post-peak resistance over ordinary concrete. For these reasons, a universal numerical model including post-cracking response becomes more essential for this purpose. The purpose of this paper is to discuss the proposed Tension Softening Material (TSM) Model in validating the complete stress-deformation response of experimental specimens which include both material and structural simulations.

From the entire verification test cases, the tension softening material (TSM) model proposed herein could have proved its ability in determining the complete stress-deformation or load- deflection response for both material and structural performance analysis. For ultimate load or stress prediction substance, it's also capable to give a reasonably accurate approximation. Subsequently, it has given a breaking point and will be of great significance within the world of fibre reinforced concrete. Further research is required to have more modelling validations to amplify the confidence level of using the TSM model for wide range of finite element analysis.

1

V.S. Gopalaratnam and S.P. Shah, "Softening Response of Plain Concrete in Direct Tension", ACI Journal, 82-27, pg. 310-323, 1985.

2

T.Y. Lim, P. Paramasivam, and S.L. Lee, "Analytical Model for Tensile Behavior of Steel-Fiber Concrete", ACI Materials Journal, 84-M30, pg. 286-298, 1987.

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