Plenary Lecture

Propagation of Delamination in Composite Laminates: Local or Global?

Professor Simon S. Wang
Department of Aeronautical and Automotive Engineering
Loughborough University
Leicestershire, UK
E-mail: s.wang@lboro.ac.uk

Abstract: Fibre reinforced composite laminates are very attractive to manufacturers of light weight structures in several industrial sectors, such as aeronautical, automotive and ship industries. However, delamination has always been a major concern in their applications due to the possibility of caused catastrophic structural failures. Consequently, their competing ability is considerably compromised against advanced metallic alloys. To improve the situation, it is of paramount importance at present time to understand the mechanics of delamination and its propagation. This lecture focuses on this topic. Analytical, numerical and experimental studies are reported.
The propagation of mixed-mode delamination is investigated using existing experimental results and various analytical partition theories. These are (i) Williams partition theory; (ii) Suo-Hutchinson partition theory; and (iii) Wang-Harvey partition theories. The Wang-Harvey classical partition theory seems to offer the best and most simple explanation for all the experimental observations. No recourse to fracture surface roughness or new failure criteria is required. It is in excellent agreement with the linear failure locus and is significantly closer than other partition theories. It is also demonstrated that the global partition of energy release rate when using the Wang-Harvey shear deformable or averaged partition theories or 2D elasticity exactly corresponds with the partition from the Wang-Harvey classical partition theory. It is therefore concluded that the excellent performance of the Wang-Harvey classical partition theory is either due to the failure of materials generally being based on global partitions or that for the specimens tested, the through-thickness shear effect is negligibly small or that the experimental results are of global nature. Further experimental investigations are definitely required.

Brief Biography of the Speaker: Simon S. Wang received his BSc and MSc education from Tsinghua University of China between 1978 and 1985. He obtained his PhD from Birmingham University of UK in 1990 and worked as a post doctoral research fellow in the same institution from 1991 to 1996. He joined Loughborough University of UK in 1996 as a lecturer and became a senior lecturer in 2003. He is now a concurrent professor of Hebei University of Engineering of China. He is the author of over 100 academic papers in international journals and conferences. He has been frequently invited to give plenary and keynote presentations in international conferences and research lectures in prestigious research institutions.