INTEMA   05428
INSTITUTO DE INVESTIGACIONES EN CIENCIA Y TECNOLOGIA DE MATERIALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Multi-axial constitutive models for large deformation behavior of rubbers and elastomers
Autor/es:
NAHUEL RULL; PATRICIA FRONTINI
Lugar:
Merseburg.
Reunión:
Conferencia; International Scientific Conference Polymeric Materials in Merseburg.; 2018
Institución organizadora:
PolyMerTec
Resumen:
In service, industrial elastomeric parts are subjected to severe multiaxial mechanical loading conditions. Identifying relevant constitutive equation from common uniaxial tension? compression experiments such leads to poor prediction of the mechanical responses for non-uniaxial loading conditions. To overcome this limitation, the experimental database has to be enriched with supplementary data issued from other loading condition experiments. In case of flat specimens experimental set-ups leading to pure shear, equibiaxial tension or bulge tests are generally performed. Considering such experiments, the problem reduces to the determination of the constitutive equation, i.e. the stress?strain relationship, from the measurement of load and extension to identify the constitutive equation. The objective of this work is to develop an overall experimental characterization program and a FEM modeling routine that will allow for the accurate prediction of constitutive behavior of different elastomeric systems. Here, the mechanical behavior up to large strain levels of carbon black filled Nitrile and Isoprene rubbers ( NBR 60, NBR 70, NBR 80 and IR 45 ), silicone rubber MVQ 60 and 3 three Polyurea elastomers obtained by sol-gel chemistry, has been assessed by subjecting the samples to multiaxial stress strain configurations and different timedependent strain histories. Due to the complexity of experimental set-ups of these tests and the eventual inhomogeneity of the deformation in some of the specimens, deformation has been measured using strain optical measurements. Depending on the kind of material, different features of the stress-strain behavior has been displayed, including hyperelastic behavior, hysteresis, strain-stiffening, cyclic softening, rate-dependence, Mullins effect , nonlinear viscoelasticity and even ?glass-like? behavior with a yield event. From experimental data a proper 3D constitutive model was calibrated using an inverse method calibration technique. The Bergstrom-Boyce (BB) model was used to capture non-linear viscoelastic response while the Three Network (TN) model was used to capture vicoplasticity. Numerical results are in good agreement with experimental data.