viscoelasticity – 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

Is it possible to characterize the linear viscoelasticity of an anisotropic carbon fibers reinforced thermoplastic polymer?

November 25, 2024 by admin

When dealing with isotropic polymer, it is easy to characterize the linear viscoelasticity in the lab via dynamic mechanic analysis in tension, torsion. What about for a transversely isotropic material such as a carbon fibers reinforced polymer? Actually, one may find out that it is not possible to directly assert any of the five parameters...

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carbon fibers composites FFT homogenization viscoelasticity

A finite strain viscoelastic model with damage and tension/compression asymmetry

November 25, 2024 by admin

In an effort to bring some clarification on the vast literature on finite strain viscoelastic models, initially defined for elastomers, a review of the pioneering models on finite strain viscoelastic from Le Tallec et al. (1993), Lion (1997) and Reese and Govindjee (1998) has shown that these models are totally equivalent [1]. It is not...

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finite strain GitHub Model Propellants rubbers UMAT viscoelasticity

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

Creep behavior of soft adhesives

April 27, 2023 by admin

Single-lap joint creep behaviour of two soft adhesives We have submitted two hot melt pressure sensitive adhesives (HMPSA) to bonded joint creep tests. While glassy state adhesives such as epoxys are often studied in the literature, data on soft adhesives that are in the rubbery state are scarce. These adhesives have applications such as sealing...

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adhesives soft polymers 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

Linear viscoelasticity of IPN – FFT analysis

August 30, 2021 by admin

The objective of the study was to characterize and model the linear viscoelasticity of interpenetrated polymer networks showing two clear distinct phase transitions. For this purpose we made in lab some acrylate IPNs by UV curing. In order to avoid fracture of the sample during the making process, the first single network is a lightly...

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FFT homogeneization IPN 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

Shape memory property of amorphous polymer networks. Experimental characterization (2)

December 1, 2016 by admin

In a previous post, I have presented some of our results obtained during stress-free shape memory recovery of amorphous polymer networks submitted to large deformation torsion tests. These tests introduce large deformation but moderate strain. In order to provide a rather complete set of data on the strain recovery and `stress recovery’ for amorphous polymers, including large strain, uniaxial...

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Shape memory polymer strain recovery Stress recovery temperature viscoelasticity