Computational & Technology Resources
an online resource for computational,
engineering & technology publications
Civil-Comp Proceedings
ISSN 1759-3433
CCP: 88
PROCEEDINGS OF THE NINTH INTERNATIONAL CONFERENCE ON COMPUTATIONAL STRUCTURES TECHNOLOGY
Edited by: B.H.V. Topping and M. Papadrakakis
Paper 261

Numerical Simulation of Textile Reinforced Concrete Using a Microplane-Type Model with Initial Anisotropy

A. Scholzen, R. Chudoba and J. Hegger

Institute of Structural Concrete, RWTH Aachen University, Germany

Full Bibliographic Reference for this paper
A. Scholzen, R. Chudoba, J. Hegger, "Numerical Simulation of Textile Reinforced Concrete Using a Microplane-Type Model with Initial Anisotropy", in B.H.V. Topping, M. Papadrakakis, (Editors), "Proceedings of the Ninth International Conference on Computational Structures Technology", Civil-Comp Press, Stirlingshire, UK, Paper 261, 2008. doi:10.4203/ccp.88.261
Keywords: microplane model, initial anisotropy, anisotropic damage, cementitious composites, textile reinforced concrete, tension-stiffening effect.

Summary
Textile reinforced concrete (TRC) is a new composite material that consists of a fine grained concrete matrix reinforced with layers of textile fabric made out of for example alkali-resistant glass or carbon. In order to allow an efficient calculation, a smeared crack approach and an implicit representation of the reinforcement was applied. The model presented in this paper is based on the microplane damage model [1]. This microplane formulation can be placed in the framework of continuum damage mechanics. Within the model the stress and strain tensors are projected onto a set of generic microplanes with a defined orientation which makes it possible to apply unidirectional damage laws at the microplane-level. The overall macroscopic response is then obtained using the principle of energy equivalence.

The direction-dependent representation of the material structure into oriented micro-planes provides a flexible way to introduce the initial anisotropy [2,3]. In the present case the anisotropy is captured by the definition of orientation-dependent damage laws. The aim of this approach is to model both the tension-stiffening effect characteristic for TRC specimens in the reinforcement-direction as well as the strain softening behaviour in the non-reinforced direction. To achieve this, the damage laws of the microplanes with normal direction corresponding to the reinforcement-direction are associated with modified damage laws that exhibit a horizontal asymptote at the desired level of residual integrity. At this point the saturated crack pattern with multiple cracks in the reinforcement-direction has been reached. The transition from the reinforced direction to the non-reinforced direction can be described by an appropriate transition function. To exemplify the computational proceeding, a simple linear transition has been applied.

The proposed approach is reviewed in numerical simulations on the material point level for the two-dimensional case. The general procedure is motivated for the case for isotropic quasibrittle materials and is then extended to anisotropic materials using the example of a TRC specimen reinforced in one direction only. The results obtained should be regarded as a preliminary study of the model behavior. Nevertheless, it demonstrates the capability of the model to reproduce the transition from the reinforced to non-reinforced direction in terms of the stress-strain response.

References
1
Jirasek M., "Comments on microplane theory", Mechanics of Quasibrittle Materials and Structures, Hermes Science Publications, Paris, 55-77, 1999.
2
Ozbolt J., Li Y., Kozar I., "Microplane model for concrete with relaxed kinematic constraint", International Journal of Solid and Structures, Vol. 38, 2683-2711, 2001. doi:10.1016/S0020-7683(00)00177-3
3
Cusatis G., Beghini A., Bazant Z.P., "Spectral Stiffness Microplane Model for QuasiBrittle Composite Laminates: I. Theory", Journal of Applied Mechanics, ASME, in press, 2007. doi:10.1115/1.2744036

purchase the full-text of this paper (price £20)

go to the previous paper
go to the next paper
return to the table of contents
return to the book description
purchase this book (price £145 +P&P)