Polymer – Mechanics of Polymers

VUMAT for finite strain viscoelasticity

July 30, 2026 by admin

Together with my student Damien Ollion, we have converted the finite-strain viscoelastic UMAT originally developed with Florian Gouhier into a VUMAT for Abaqus/Explicit. The implementation reproduces the constitutive model of Reese and Govindjee (1998) for a generalized Maxwell model and includes the following features: A comprehensive How-to-use.pdf document is provided. It presents the constitutive equations, illustrates the...

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Abaqus finite strain Polymer Shape memory polymer soft polymers viscoelasticity

Impact of microstructure in the mechanical behavior of soft foams

July 29, 2026 by admin

Following our previous investigation of the beahvior of hyperelastic classic Voronoi closed-cell foams submitted to severe compression, we have extended the study to assess the influence of microstructure on the mechanical response of highly porous foams. To this end, two additional classes of microstructures were generated: mechanically grown Voronoi (M-Voro) closed-cell foams and open-cell foams...

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foams Polymer soft polymers viscoelasticity

F.E. simulations of closed-cells foams under extreme compression

January 26, 2026 by admin

The mechanical response of isotropic elastomeric closed-cell foams with Classical Voronoi microstructures is examined through three-dimensional finite element simulations. The study focuses on finite-strain uniaxial compression, complemented by infinitesimal-strain shear and hydrostatic loading. Random foam geometries with porosities between 77% and 95% and narrow pore-size distributions were generated by subtracting irregular Voronoi polyhedra, constructed from...

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finite element foams Polymer Porous materials soft polymers

Comparison between two fracture tests, SENB vs. DCDC applied to acrylate polymers

November 25, 2024 by admin

We have compared the mode I opening critical energy release rate (GIc) measured using the single edge notch bending test and double cleavage drilled compression test on an elastic fragile PMMA and a bulk viscoplastic acrylate used as a glue for wind turbine blades. The study details the experimental procedure, for the crack initiation and...

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DCDC Fracture phase-field Polymer SENB

Damage phase-field approach vs. Cohesive zone model for double cleavage drilled compression fracture test

November 25, 2024 by admin

The double cleavage drilled compression (DCDC) test has been introduced for glass but also extended to test polymer. It is a slender prismatic specimen with a hole in its middle and cracks that are initiated at both poles. It is interesting because the loading is uniaxial compression and the cracks are submitted to opening mode...

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cohesive zone model DCDC Fracture phase-field Polymer viscoplasticity

Damping optimization of polymer structures

September 22, 2023 by admin

Polymers are viscoelastic and therefore are interesting for damping applications, especially when used at temperatures laying in their glassy-to-rubbery transition where the material is showing significant viscoelasticity. During his PhD co-advised by Gregoire Allaire, Samuel Amstutz and me, Antoni Joubert has worked on the shape optimization of thin structures such as beams and plates to...

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damping Polymer shape optmization viscoelasticity

Impact of the microstructure on the mechanical behavior of PEBAX foams

August 30, 2021 by admin

Five PEBAX foams provided by Arkema and obtained by mold-opening foam injection process has been studied. One one side, the microstructures have been characterized by DSC for the chemical and physical properties, and by scanning electron microscope image analysis for the structural properties. On the other side, the linear elasticity as well as the non-linear...

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foam microstructure Polymer viscoelasticity

Bouncing balls: An illustration of the viscoelasticity and temperature dependent behavior of polymers

December 20, 2017 by admin

Why are we playing with rubber bouncing balls when we are kids ? Can metal or ‘plastic’ balls bounce as well ? And why do squash players warm up their balls before starting the game ? Let us have a little of recreation time bouncing balls and answer these questions. For that, some polymer balls are made in lab. The polymer is an...

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Network Polymer Time-temperature superposition viscoelasticity