Towards the size estimation of a Representative Elementary Domain in semi-crystalline polymers

Like in any heterogeneous material, predicting the macroscopic mechanical behavior of semi-crystalline polymers from scale transition approaches requires to estimate the size of a Representative Volume Element (RVE). However, no quantitative estimation has been reported so far in the literature for these materials. This study is a step forward, by estimating the minimal domain over which the microscopic strain must be spatially averaged to match the macroscopic strain, in a stretched linear low-density polyethylene. A statistical RVE determination method inspired from the work by Kanit et al. (2006) was applied to strain fields acquired at the spherulitic scale from in-situ Digital Image Correlation in a Scanning Electron Microscope. Results show that the size of a representative domain significantly exceeds the size of a single spherulite. Several spherulites are actually contained, depending on the wanted estimation accuracy and on the number of realizations one is ready to generate. (C) 2016 Elsevier Ltd. All rights reserved.