We believe that simulation is an essential tool to understand the physical world and explore yet-unseen scenarios.
Our aim is to always create the best model that can correctly explain experimental results.
“Best” can be the lightest or more accurate model, following the client needs.
Simulation of Physical Systems
- Non linear mechanics
- Multi-physics (thermo and poromechanics)
Implementation and validation of material constitutive laws
- Verification (comparison with analytical solutions) and non-regression tests
- Validation by comparison between measurements and models
Design of testing devices for materials and structures
Concrete beam cross-section with prestressing and ordinary reinforcement
Strains over the cross-section
selection of works
Simulation of Cracking of (Reinforced) Concrete
In the domain of civil engineering, the modeling of reinforced concrete structures in their damaged state is important for many reasons, for example :
- in order to understand their behaviour in the non-linear regime and determine residual margins before failure.
- to assess durability in case of leakage of liquid or gas through reservoir walls or when the penetration of aggressive agents must be taken into account.
Cracking of a prestressed reinforced beam via a smeared crack model
Simulation with a scalar damage model of a specimen with a rigid inclusion.
Image from: Mivelaz, P. (1996) "Étanchéité des Structures en Béton Armé: Fuite à Travers un Élément Fissuré." Ph.D. Thesis, Ecole Polytechnique Fédérale de Lausanne
Simulation with a scalar damage model of the reinforced beam above.
design of equipment to test the creep behaviour of composites
In the production of pultruded shapes, E-glass fibers are mostly used for the reinforcement.
They are characterized by lower cost but also by a reduced stiffness with respect to other fibers, e.g. carbon fibers.
Creep tests have been performed on composite pultruded specimens subjected to two kind of long term forces, i.e., uniaxial traction and shear force.
During tests, temperature and humidity have been kept constant and equal to 20 °C and 60% RH, respectively. The specimens have been kept under constant loading for more than 2 years, so providing information on the material long-term behavior out of the usual time range.
Leverage systems for the creep tests on pultruded composite specimens.
Mechanical systems for the load transmission for specimens under shear.
Detail of the instrumentation adopted for the specimens under tension.
Material Constitutive Laws for Creep of Concrete
Taking into account creep is very important to study structures in the long-term. In fact, delayed deformations can seriously affect the service behaviour or even lead to structural collapse. To achieve this goal, one have to go through different, necessary steps:
- Implementation of the material constitutive law into a finite element code
- Calibration of laws parameters from experimental tests
- Validation on a structure
Creep coefficient for the unstiffened and stiffened specimens under tension: experimental data and numerical predictions.
Experimental and numerical creep deflection vs. time curve with calibrated parameters of the behavior law.
Scheme of the numerical procedure to model tertiary creep.
Evaluation of Crack Propagation in a turbine blade
Evaluation of crack propagation scenarios in a turbine blade using X-FEM.
Non-linear behaviour is taken into account in modelling :
- contact on the fastener
- large strains
Deformed shape due to centrifugal force: small and large deformation modeling