DAMAGE TOLERANCE FOR COMPOSITE STRUCTURES OF LAUNCHERS - INFLUENCE OF A THERMAL SHIELD

摘要

This study presents the characterisation works performed on laminates used for launchers fairing considering damage tolerance demonstration. An experimental investigation concerning the low velocity impact response of shielded composite structures is conducted. Compression After Impact tests are also carried out. The main studied material is a high modulus carbon fiber composite: M46J/M18. The results are also compared to a classical aeronautical material, T300/914, which impact behaviour is well known. The shield is a thermal protection made with natural agglomerated cork pellets. The created degradations are examined by ultrasonic non destructive inspections, and also by micrographic observations. Those analyses show that the damage threshold is lower on M46J/M18 than on T300/914. The thermal shield appears to be a good mechanical protection towards impact as well as a good impact revealing material. Nevertheless, the damage survey shows that the nature of the delamination changes if the panel is shielded. An average loss of characteristic in compression of 50% is observed for each case.