Modelling the elastic response of a polyurethane open cell foam based on a minimal surface energy approach

Abstract

Within the present study the elastic response of a flexible open cell polyurethane foam was studied by means of experimental compression tests and finite element (FE) modelling. The compression tests revealed a pronounced sample size effect which was taken into account using an analytical model. In order to eliminate the sample size and damage effects, a minimal sample size of at least 50 times the cell size was necessary in the case of the flexible foam. Surface evolver software was used to model the open cell foam structures. The FE unit cells are based on the well-known Kelvin cell and the more complex Weaire-Phelan cell topology. In both cases the cross sectional shape of the cell edges was completely determined by the minimisation of the surface energy. The thus build FE-models possess a good resemblance to real open cell foam structures. The influence of relative density and shape anisotropy on the elastic properties of the cellular structures was analysed using the FE-models.

Effect of the shape and the distribution of cells on the effective thermal conductivity of polyurethane foam

“…This gas leaves the foam after blowing. This category is called in the literature open cell PU foam 42–44 . Its thermal conductivity is about 0.033–0.038 W/m K for densities between 6.83 and 17.2 kg/m 3 42 …”

“…This category is called in the literature open cell PU foam. [42][43][44] Its thermal conductivity is about 0.033-0.038 W/m K for densities between 6.83 and 17.2 kg/m 3 . 42 The category CCC4 is called in the literature closed cell PU foam.…”

Microstructure characterization and stochastic modeling of open‐cell foam based on μCT‐image analysis

“…Other improved packing algorithms followed, for example, [22,25], and several works on the elastic, plastic and crushing behavior of such idealized foams have been published, for example, [16,34,35,40,72]. The results from Buffel et al [15,16] show that the elastic modulus for the Kelvin and Weaire-Phelan model are nearly identical over different volume ratios. Contrarily, by comparing idealized with random foam structures, van der Burg et al [78] show that disorder significantly affects the mechanical properties.…”

“…The intrinsic volumes (12), (15), and ( 16) of the pore system are not direct input parameters of our stochastic foam generation but describe the microstructure. The negative Euler number of 𝜒 = −6759 indicates an open-cell foam.…”