A selection of papers from an international meeting on: advances in multi-scale modelling of composite material systems & components

Abstract

The driving force to get new lightweight composite materials into the air comes from the increasing cost of fuel worldwide. An airline industry’s response to higher fuel charges is to make aircraft lighter and fuel efficient. What appears to be a paradox is that as the cost of fuel is going up, so is the size of airframe; the new Airbus superjumbo A380 is an example. New composite materials including those based on carbon fibre (CFRP) and the glass fibre-metal laminate called GLARE are replacing aluminium alloys, and modern civil airliners like Boeing’s brand new Dreamliner 787 and the Airbus A350 may contain up to 50% by weight of composite material. The infrastructure required to support these new advances includes: fibre production and resin processing, manufacture of innovative fibre pre-preg architecture, new machine tools and assembly jigs, advanced fabrication processes and factory-of-the-future design, structure formulation of composite material systems, and revised test methods. In addition, is the need for improved design techniques to optimise airframe layout thereby maximising acceptable (safe) working loads. And at the same time, we must reduce fabrication costs through automation and low temperature curing matrix systems, and certify practical advanced inspection techniques for defect detection and repair. Demands in modern aircraft include efficient aerodynamic design and lightweight materials combined with high efficiency engines to fly the aircraft, and providing electrical power for all the electrical systems. Keeping cost down is essential, which can only be achieved by using less fuel and reducing dramatically maintenance expense. The expectation is for materials to last longer and for structures to operate safely and reliably at increasingly higher stresses. In the case of engine components, we expect the material to work successfully at greater elevated temperature. The requirement is to push the performance of the structure to its limit thereby stretching composite materials to their boundary of strength and endurance. Innovation in design and advancement in material ‘‘know-how’’ through discovery is no longer the single option. We see airframes made from composites, arriving at the probability of a successful outcome of a safe design by using intuition and our experience of circumstances that we have encountered before. But if we are to imagine the future differently, disaster as an act of God or of bad luck has to go. Predictive engineering design by intelligentinformed empiricism is the only ‘‘show in town’’. There has been an invisible college of continuum mechanicians, scattered in universities, who have for decades studied the behaviour of composite materials based on an idealization of what behaviour is all about, and coming up with countless models without any reference whatsoever to microstructure; neither have they cared about mechanisms that act at the small end of the size-scale, nor structurally-based constitutive equations. Consequently, current design codes for composite material structures in critical loading situations do not take creep, fatigue and environmental-induced mechanisms into account. To predict a result, say lifetime or a stress P. W. R. Beaumont (&) Engineering Department, Cambridge University, Trumpington Street, Cambridge CB2 1PZ, UK e-mail: pwb1000@hermes.cam.ac.uk J Mater Sci (2006) 41:6505–6509 DOI 10.1007/s10853-006-0209-2