Stress-strain response and volume change of a highly filled rubbery composite: Experimental measurements and numerical simulations

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThe stress-strain response of a rubbery polymer network highly filled with micrometric glass beads was measured at low strain rate in uniaxial tension. The volume change of the glass bead filled material upon stretching was recorded by video extensometry and X-ray tomography scans were used to identify the type of damage within the composite material. The modeling used a cohesive-zone model from the literature depending on the polymer/glass adhesion energy that was measured by peeling polymer strips from a glass plate. Nonlinear finite element simulations were performed on representative three-dimensional microstructures defined by periodic cubic unit cells containing randomly dispersed spherical particles. Good reproductions of both the composite response and the volume change were obtained prior to the appearance of inner cracks.

Representative volume elements for the simulation of isotropic composites highly filled with monosized spheres

“…Since quantitative comparison with experimental data is scarce in the literature, a model composite made of a rubbery matrix highly filled with sifted glass beads was prepared and tested in uniaxial tension in the present study. This was already the case in the work of Gilormini et al (2017), where a finite element analysis (FEA) was applied to a single microstructure generated through a much simpler and less validated procedure than here.…”

Relationship between local damage and macroscopic response of soft materials highly reinforced by monodispersed particles

“…Classically, attention is rather focused on the adhesion energy Γ, which is directly related to the physics of adhesion. However there is no obvious way to estimate this property at the scale of the particles precisely (see Tan et al, 2005or Gilormini et al, 2017, for attempts to estimate the cohesive parameters experimentally). Therefore, the displacement at failure δ f has been preferred, whose order of magnitude can be compared to the dimensions of the particles.…”

“…Finally, a more complex cohesive-zone model defined by Park et al (2009) has been examined. A modified thermodynamically consistent version (Gilormini et al, 2017) has been implemented in Abaqus via a suitable UEL routine. This involved a smoother evolution of the traction separation law but to the cost of up to eight parameters when normal and tangent adhesion behaviors differ.…”

“…In propellants as in other elastomers filled with micron size particles, it is common to observe matrix debonding at the filler surface (Cornwell and Schapery, 1975;Oberth and Bruenner, 1965;Li et al, 2018), which demands to account for a damageable adhesion at the matrix/filler interface. For this purpose, cohesive-zone models (Tvergaard and Hutchinson, 1993;Park et al, 2009) have already been introduced in finite element simulations involving spherical particles dispersed in a matrix (Segurado and Llorca, 2005;Matouš and Geubelle, 2006;Spring and Paulino, 2015;Cho et al, 2017;Gilormini et al, 2017). The account for matrix adhesion damage has shown to produce a realistic macroscopic behavior that could not be reproduced otherwise (Inglis et al, 2007).…”

“…Early studies (Böhm et al, 2004;Llorca and Segurado, 2004;Segurado and Llorca, 2005, among others) were focusing on ductile matrices with infinitesimal strain formalism. More recently, account for composites with hyperelastic matrices, for which softening may result from the matrix/filler interface damage only, were considered in finite strain in two-dimensional (Moraleda et al, 2009;Toulemonde et al, 2016;Zhang et al, 2018;Li et al, 2018) and three-dimensional representations (Spring and Paulino, 2015;Gilormini et al, 2017). While some of these contributions have focused on the impact of the cohesive zone model parameters on the macroscopic behavior (Spring and Paulino, 2015;Toulemonde et al, 2016), others have looked at the distribution of stresses in the matrix (Moraleda et al, 2009;Li et al, 2018).…”