admin

Homogenization jupyter notebook for students and professors teaching homogenization

During the COVID period, I supervised two Master’s students for three months, tasking them with developing an educational Jupyter notebook on homogenization. The notebook implements classic mean-field models, including Mori-Tanaka, self-consistent, generalized self-consistent, the four-phase model, Voigt, Reuss, and Hashin-Shtrikman bounds. Although I haven't promoted it yet, I believe it could be highly beneficial to...

Microstamp: Stamps for DIC

We have been developping stamps to apply precise patterns on sample surfaces for local strain measurements using digital image correlation (DIC) during mechanical and thermal testing. Typically, when local strain measurements are needed in mechanical tests, sample surfaces are marked with spray paint or an airbrush to create a speckle pattern with good gray-level contrast....

Nonlinear behavior of a soft matrix highly filled with randomly spherical particle or voids

When highly reinforced a soft matrix, like an elastomer matrix, undergoes incredibly localized high strain where particles nearly touch. Therefore, it requires extensive remeshing efforts in an order to estimate numerically the equivalent homogeneous behavior of such a composite. We did that, using Abaqus *MAP SOLUTION option. This allowed to provide original numerical stress-strain responses...

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

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...

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

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...

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

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...

Damping optimization of polymer structures

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...

Creep behavior of soft adhesives

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...

Impact of the microstructure on the mechanical behavior of PEBAX foams

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...