The Application of Weibull Statistics on Fragmentation Data

In the past two decades testing of single fibre model composites has received much attention from the international research community. In the beginning the main aim was the understanding of how the interfacial bond can be improved and assessed rapidly, without the need of much material and many tests. However, now days the interest has also moved to more theoretical aspects of single fibre composites testing involving modelling and understanding of the stress state at the interface. Much work has been carried out and many mathematical models may be found in the literature for the different types of single fibre testing. In general there are two main approaches to the problem of single fibre interpretation. The first approach deals with the statistical aspects of the fibre fragment length distribution, while the second one is focused on the stress analysis and distribution at the interface. In the case of thermoplastic composites the stress state at the interface is not as much complicated as it is for thermosets, at least if the thermoplastic matrix is above its glass transition temperature. In these simplified cases that cover all the polyolefin based composites, the principal relation of Kelly and Tyson holds true when saturation has been achieved. However, the problem of fragment length distribution still remains.