QMUL > School of Engineering and Materials Science > Journal Papers Published by the Rubber Research Group
Author(s): V. Jha, A.G. Thomas, Y. Fukahori and J.J.C. Busfield
Journal: Constitutive Models for Rubber V edited by A. Boukamel, L. Laiarinandrasana, S. Meo & E. Verron, pp. 165-172
Previous work (Jha et al., 2007, Busfield et al., 2005, Hon et al., 2003) has shown that the stiffness of filled elastomers over a wide range of strains using micro structural finite element models can be achieved at low filler volume fractions with a reasonable accuracy. To do this an appropriate stored energy function such as that by Gent (1996) is required to show realistic stiffening at higher strains for unfilled rubbers. It has been noted that as the number of fillers present in the unit cell is increased from 1 to 4 that there was an increase in the predicted stiffening effect at a constant filler volume fraction. The question remains, however, as to how many filler particles would be required in the unit cell to ensure that the behaviour of the filler is accurately represented. In the present work two different types of micro-structural model are examined under strain with a range of up to 36 filler particles present. The first type having smooth spherical surfaces and the second having a more irregular surface constructed out of cubes. In this study the effect of the position of the filler particles is investigated by repositioning them into more random confirmations than that suggested by the single filler models. It appears that a large number of fillers have to be incorporated to predict the behaviour, especially at higher filler volume fractions when filler-filler interactions become significant. Also, the model made with basic cubic elements is stiffer than the real materials, as within the model there is a considerable amount of additional ‘occluded’ rubber that increases the effective filler volume fraction.
Related site: http://www.materials.qmul.ac.uk/rubber
Created: 12:22 Friday 24th May 2013