Objectives
A systematic way to produce general honeycomb configurations with off-the-shelf composites mass-production techniques is the Kirigami approach. Kirigami can be synthesised into a mathematical framework, and create complex 3D cellular shapes by thermoforming/autoclaving commercial composites. An initial trial has shown that by using Kirigami patterns it is possible to create 3D lattices with very rich and damped dispersive content, but still further work is needed to use Kirigami in a systematic way to produce honeycomb topologies for vibroacoustics. The sandwich core periodic topology research work will be organised as follows:
1- Develop Kirigami 3D tessellation patterns based on centre symmetric topology configurations using mathematical formulations that can create systematic honeycomb topologies and be easily implemented in CAD/CAM tools. The Kirigami patterns will also accommodate topologies for inserts of different materials and devices, to be also used as potential platform for multiphysics resonating periodic materials for vibroacoustics.
2- Perform numerical wave propagation analysis using Bloch wave theory to investigate the bandgap behaviour of the Kirigami 3D honeycombs. The numerical simulations will be carried out in a parametric form to identify optimised cell configurations able to perform bandgaps at specific frequency bandwidths, and compatible with mechanical and manufacturing constraints. Numerical models of the honeycombs with face skins for sandwich applications will be also developed. The phase constant surfaces obtained from the numerical predictions will be also used to extrapolate the global vibration and acoustic response of assembled honeycomb structures.
3- Manufacturing samples of the down selected Kirigami topologies using state-of-the-art production processes for thermoplastics and thermoset composites using a combination of CNC cutting-autoclaving/thermoforming with modular moulds. The samples will be used to produce sandwich panels with skin laminates having aerospace or automotive grade.
4- Perform modal analysis, vibration and acoustic transmissibility tests of the sandwich panels to measure the vibroacoustics behaviour of the Kirigami sandwich panels with the new honeycomb topologies, and compare the results with predicted data from the numerical simulations. Selected mechanical tests will be also performed (flatwise compression, transverse shear) to assess the structural integrity of the sandwich concepts.
Expected Results
A generic strategy using Kirigimi for the optimal design of sandwich cores with high vibroacoustic performances