The recent rapid increases in the use of composite materials in Principal Structural Elements (PSE), particularly in CS-25 designs, has driven a generic expectation that the use of such materials should not reduce the level of safety provided by existing more conventional materials. The properties of metallic and composite structures can nevertheless differ significantly, e.g. composite materials are heterogeneous, so typically exhibit significantly more anisotropic behaviour (including more failure modes), than a metallic structure.
The LIBCOS study "Impact Behaviour of Loaded Composite Structure" assesses the comparative behaviour of composite and metallic structures concerning damage tolerance to high-velocity foreign object impacts (e.g. bird strike, hail, tyre rubber and metal fragments) and under various flight loads (tension and compression).