Experimental method for dynamic residual strength characterisation of aircraft sandwich structures

Abstract

This study investigates the effect of dynamic loading on the residual of sandwich structures used in aircraft interiors comprising glass fibre phenolic resin face sheets and Nomex® honeycomb core. A dynamic edgewise compression test method for residual strength testing of sandwich structures has been developed using a modified compressive Split Hopkinson Pressure Bar apparatus. Dynamic edgewise compression at strain rates of approximately 50 s⁻¹ for undamaged specimens showed an average increase of 26% in compression strength compared with equivalent static edgewise compression tests. For low levels of indentation damage there was a 27% reduction in residual dynamic compressive strength compared with a 15% reduction in residual static compressive strength for equivalent prior damage. This new experimental method provides insights into the dynamic edgewise response of composite sandwich structures to aid in the design and development of future aeronautical structures.

Keywords:

• sandwich
• honeycomb
• dynamic
• aircraft

Acknowledgements

The work presented has been supported by The University of Auckland Doctoral Scholarships, The Foundation for Research Science and Technology of New Zealand through grant UOAX0710, Fulbright NZ – Ministry of Research Science and Technology, The US Office of Naval Research grant number N00014-09-1-0618, The New Zealand Defence Force – Defence Technology Agency and Altitude Aerospace Interiors. Thanks to the Georgia Institute of Technology staff for their technical and professional assistance, especially Dr Min Zhou, Siddharth Avachat and Rick Brown.