Paper number 340

TESTING AND FAILURE ANALYSIS OF A CFRP WINGBOX CONTAINING A 150J IMPACT

E. Greenhalgh¹ , B. Millson¹ , R. Thompson¹ and P. Sayers¹

1Mechanical Sciences Sector, DERA, Farnborough, GU14 0LX, UK

Summary

This paper describes the mechanical testing and failure analysis of a multispar CFRP wingbox which was subjected to 150J impact on a spar foot. The wingbox was loaded in bending to failure, with the impacted skin under compressive load. The structure failed at the impact site at a strain of -3900; a load intensity of 1170 kN/m. The first event was delamination growth near the backface which was driven along interfaces containing 90° plies, followed by formation of a narrow band of delaminations close to the upper surface. Skin delamination extended parallel to the spars whilst delaminations developed close to and within the spar feet. Finally, the skin and spars failed in compression. This work has improved the understanding of failure in large composite structures containing impact damage and demonstrated read across between structural elements and full-scale structural tests.

Keywords

wingbox, structural test, fractography, impact, delamination, compression.