The consequences of the drastic economical and technical requirements for future supersonic civil transport [1] on the materials selection for the different parts of the aircraft structure have been detailed and discussed elsewhere [2]. As a result, Aerospatiale, BAe and DASA decided to increase their effort on materials studies and to launch specific research programmes on aluminium alloys and carbon fibre reinforced polymers (CFRPs). Major research programmes were initiated on aluminium alloys in 1992 [3] and on organic matrix composites in 1994 [4].