Published Resources Details
Journal Article
- Title
- Is there really no need to be able to predict matrix failures in fi bre-polymer composite structures? Part 1: Explanation of fatal fl aws in existing theories
- In
- Australian Journal of Mechanical Engineering
- Imprint
- vol. 12, no. 2, June 2014, pp. 139-159
- Url
- http://dx.doi.org/10.7158/M12-AGM01.2014.12.2.
- Description
2012 A G M Michell Medal
- Abstract
A logic-based case is presented that it is necessary to be able to predict matrix failures in fibre-polymer composites, even though some 50 years after the introduction of the advanced fibre-polymer composites there is still no widely accepted theory capable of actually doing so. This lack is due to the widespread malpractice of artificially homogenising distinct fibre and matrix constituents into an "equivalent" anisotropic solid, to simplify the mathematics. The enormous residual thermal stresses in the matrix, even when the lamina is stress-free, are not widely recognised; these detract appreciably from the ability of the matrix to withstand applied mechanical loads. The extreme thermal mismatch between the fibres and the polymer causes the resin to try to shrink during cool-down after cure at high temperature, but the strong stiff fibres prevent this from happening. Such internal residual stresses cannot possibly exist in truly homogeneous materials, so the consequences are overlooked whenever homogenised material models are used in analyses when they should not have been. The case is made that it is impossible to predict matrix failures using any theory in which the fibre and resin constituents have been artificially homogenised, despite the myriad of theories claiming to do so that cannot.