Microtomography on polypropylene foam under dynamic loading: 3D analysis of bead morphology evolution

A dynamic crash loading experiment is performed on polypropylene foam which is used in composite sandwich structures for safety applications. Several interrupted shocks are conducted, in between which, microtomographic acquisitions are made showing the change of the sample during its compression. These data can help construct and validate predictive models, although, because this material is multi-scale (constitutive beads at the mesoscopic scale are made of microscopic closed cells), image processing is required to extract useful quantitative measurements. Such processing is described here, so as to determine a representative volume for each bead of the sample, to associate values such as bead density to each bead and to each stage of the compression. This can help build a predictive model at the mesoscopic scale.