The following summary, relevant to composites, caught my eye when reading about a CAA recommendation when reviewing the loss of a Puma helicopter
http://www.eurocopter.com/site/FO/do...a-41-22-00.pdf
With respect to fixed wing aircraft there are examples of loss due to explosive delamination of the wing after lightning strike (these losses relate to aircraft not certified against lightning strike, e.g. gliders).
The following accident report gives a good lightning summary (although the loss here may be partly attributable to the different conductivity of aluminium versus steel).
http://www.pas.rochester.edu/~cline/...t%20report.htm
The use of different composites in new commercial aircraft (reported 50% by weight for Boeing's dreamliner, for example) opens up a whole new area of research in thermal and electrical conductivity and is an active area of materials research which means that although enough is known to mitigate against the known risks and thereby obtain certification, the book is still open and will continue to be so as composites become integral to the whole of the aircraft (acoustic damping, thermal transfer and the electrical system).
Each lightning strike will be a minor test but this is true of the current generation of commercial aircraft (made of more traditional materials). The risks are not significantly greater but are not negligible either.
In an ideal world we would (literally) avoid the potential for lightning strikes.