Improving the Understanding of Tufted Energy Absorbing Sandwich Structures

Tufting has been shown to be an effective method for improving the performance of sandwich structures against edgewise impact loading. However, the mechanisms that take place during failure, and the role the tufts play within this are not well characterised. Experimental testing has therefore been carried out to improve the understanding of the failure behaviour of these structures, with the particular focus of this study being on investigating the behaviour of the tufts themselves. Firstly quasi- static edgewise crushing tests were carried out to visually identify the failure behaviour of the tufts, indicating that the tufts ‘drift’ and collide as they fail. Follow up testing was then carried out on the interaction between the tufts and the surrounding foam core. Whilst it was observed that single tufts only have a very small contribution to the overall energy absorption of a tufted panel, this contribution can increase significantly with the addition of multiple tufts, and allowing interactions to occur between them. This behaviour could therefore be designed into the structure to help maximise the energy absorption during an impact event.