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PROCEEDINGS OF THE FIFTEENTH UK CONFERENCE OF THE ASSOCIATION OF COMPUTATIONAL MECHANICS IN ENGINEERING
Edited by: B.H.V. Topping
On the Modelling of Temperature Loading of Concrete using a Discrete Approach
C.J. Pearce and P. Grassl
Department of Civil Engineering, University of Glasgow, United Kingdom
C.J. Pearce, P. Grassl, "On the Modelling of Temperature Loading of Concrete using a Discrete Approach", in B.H.V. Topping, (Editor), "Proceedings of the Fifteenth UK Conference of the Association of Computational Mechanics in Engineering", Civil-Comp Press, Stirlingshire, UK, Paper 83, 2007. doi:10.4203/ccp.85.83
Keywords: temperature, concrete, fracture, discrete.
This paper deals with the modelling of temperature loading of concrete using a discrete approach. Recent extreme events, including accidents, arson and terrorism, have highlighted that the performance of concrete subject to combined thermal and mechanical loading is not fully understood. One of the most extreme consequences of rapid thermal loading is concrete spalling, for which there is no real consensus as to the exact failure mechanism.
The rationale behind the work presented here is to further explore and potentially explain the behaviour of concrete through meso-scale simulations subject to combined thermal and mechanical loading. This paper is a first step by the authors to explore these issues by separating out the various different processes and thereby identify those that are dominant. Considerations here will focus on the thermo-mechanical behaviour of concrete at the meso-scale with the extension into moisture transport to appear in later publications.
The domain is decomposed into Voronoi cells which are dual to the Delaunay triangulation. This triangulation is used to represent the domain by a network of one-dimensional heat conduction elements. The mechanical response is modelled by rigid bodies connected by springs, where the geometry of the rigid bodies is determined by the Voronoi tessellation. A NAFEMS benchmark test is simulated to evaluate the performance of the discrete modelling approach. It is shown that the use of a network of one-dimensional conduit elements results in an accurate description of heat conduction. Furthermore, the influence of temperature loading on concrete cracking is studied by means of a numerical test of a restrained two-dimensional concrete specimen. The influence of the temperature on the mechanical response is modelled in a staggered approach. It is shown that the discrete approach seems to be suitable for modelling the problem of thermally induced cracking.
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