You should join OSTIV - the scientific and technical organization for soaring. www.OSTIV.org. They have a Sailplane Development Panel, and a sub-group on Crashworthiness. On the sub-group page, there is a Safe and Crashworthy Cockpit
Short report by W. Röger, FH Aachen, from February 2007; it is interesting. There have been papers describing improved crashworthiness over the years in OSTIV. You can search the index for details on glider safety.

There is also a program for reporting cockpit damage, so that there is data that designers can use to design safer cockpits (disturbing but not graphic pictures of testing). As they say, without data, you are a person with an opinion.

OSTIV does good work, and we all benefit.