Change of Scale Strategy for the Microstructural Modelling of Polymeric Rohacell Foams
J. Aubry, P. Navarro, S. Marguet, J.-F. Ferrero, O. Dorival, L. Sohier and J.-Y. Cognard

Source CMC: Computers, Materials & Continua, Vol. 39, No. 1, pp. 21-47, 2014
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Keywords Rohacell foam, mechanical behaviour, microstructure, change of scale strategy
Abstract In this paper a numerical model dedicated to the simulation of the mechanical behaviour of polymeric Rohacell foams is presented. The finite elements model is developed at the scale of the microstructure idealized by a representative unit cell: the truncated octahedron. Observations made on micrographs of Rohacell lead to mesh this representative unit cell as a lattice of beam elements. Each beam is assigned a brittle linear elastic mechanical behaviour in tension and an elastoplastic behaviour in compression. The plasticity in compression is introduced as a way to mimic the buckling of the edges of the cells observed in experimental crushing tests. A contact law introduced between the beams stands for densification. A change in scale is then realized by increasing the length of the edges of the unit cell. Several computations show the ability of the proposed approach to preserve the physical degradation phenomena and the loads while drastically decreasing the computational time.
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