Assessment of Impact Damage in Twin-walled Composite Structures

Kurzfassung

The presentation describes recent progress on damage assessment in novel aircraft sandwich structures subjected to foreign object impacts from both hard and soft impactors. A gas gun impact test programme was carried out on twin-walled composite panels under a range of impact conditions. Impact damage to the outer skins, core and inner skins was characterised by a number of NDE techniques, including ultrasonic C-scan, X-ray and lock-in thermography. The high velocity impact test programme was then used to validate simulation methods developed for the prediction of structural damage in composite structures under impact loads. Composites ply damage models and interply delamination models have been developed and implemented in commercial explicit FE codes. The failure models and code developments were applied to predict transverse impact damage in the sandwich skin laminates and penetration into the core. The paper assesses the effectiveness of NDE methods in capturing impact damage in these twin-walled structures and summarises the status of FE modelling techniques for damage modelling in composite aircraft structures.