1 Department of Mechanical Engineering, Technical University of Denmark 2 Manufacturing Engineering, Department of Mechanical Engineering, Technical University of Denmark 3 University of Roma ‘Tor Vergata’
A new forming procedure was developed to produce shape memory composite structures having structural composite skins over a shape memory polymer core. Core material was obtained by solid state foaming of an epoxy polyester resin with remarkably shape memory properties. The composite skin consisted of a two-layer unidirectional thermoplastic composite (glass filled polypropylene). Skins were joined to the foamed core by hot compression without any adhesive: a very good adhesion was obtained as experimental tests confirmed. The structure of the foam core was investigated by means of computer axial tomography. Final shape memory composite panels were mechanically tested by three point bending before and after a shape memory step. This step consisted of a compression to reduce the panel thickness up to 60%. At the end of the bending test the panel shape was recovered by heating and a new memory step was performed with a higher thickness reduction. Memory steps were performed at room temperature and 120 °C so as to test the foam core in the glassy and rubbery state, respectively. Shape memory tests revealed the ability of the shape memory composite structures to recover the initial shape also after severe damaging (i.e. after room temperature compression). Compressing the panel at a temperature higher than the foam resin glass transition temperature minimally affects composite stiffness. Copyright © 2013 Trans Tech Publications Ltd.
Key Engineering Materials, 2013, Vol 554-557, p. 1930-1937
Composite materials; Composite structures; Coremaking; Filled polymers; Forming; Glass; Polypropylenes; Structure (composition); Shape memory effect; Shape memory polymers
Main Research Area:
16th annual ESAFORM Conference on Material Forming, 2013