H Y P E R F I T
A fitting utility for parameter identification ...
... of hyperelastic constitutive models
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Supported constitutive models:
Hyperelastic models:
- Neo Hooke
- Mooney-Rivlin
- Klosner-Segal
- Yeoh
- Polynomial
- Varga
- Ogden
- Van der Waals
- Arruda-Boyce
- Gent
- Pucci-Saccomandi
- Demiray
- Fung (anisotropic)
- Choi-Vito (anisotropic)
- Holzapfel, 2000 (anisotropic)
- Holzapfel, 2000, double layer (anisotropic)
- Holzapfel, 2000, with dispersion (anisotropic)
- Holzapfel, 2005 (anisotropic)
- Gasser (anisotropic with distributed fibers)
- Blatz-Ko (foam)
- Hill-Storakers (foam)
- Ogden (foam)
Models with Mullins effect:
- Ogden-Roxburgh
- Kachanov
- Miehe
- Marckmann
Visco-hyperelastic models:
- Bergström-Boyce
Note: - green models are fully available in FREEWARE version (LIMITED license)
Supported load protocols:
- Uniaxial (1) tension/compression
- Uniaxial (2) tension/compression
- Planar tension/compression
- Equi-biaxial tension/compression
- Biaxial tension/compression
- Volumetric tension/compression
Supported weights and normalizations:
- Manual weight factor for individual data-set - user can change significance of any data-set
- Automatic correction of different number of data-points in individual data-sets - user does not have to provide equivalently sampled data-sets
- Manual weight factor for individual data-point - user can change significance of any data-point
- Automatic correction of different data-point density along the data-set - user does not have to provide perfectly sampled data-sets
Supported optimizing methods:
- Linear least squares method
- Non-linear: Gradient descent method
- Non-linear: Simplex method
Supported residua:
- Square of (stress) difference
- Absolute value of (stress) difference
- Both residua are available in their absolute and/or relative formulations
Specific features:
- Any parameter can be fixed by the user at any (known) value
- Any parameter can also be constrained by user-specified low-limit or high-limit value
- Multiple data-sets (unlimited number of stress-strain curves) can be used for a single fit
- Instant stress-strain results can be seen (on-line) during iteration process
- Iteration history is available and can be exported into a file
- Each stress-strain data can be simply activated/deactivated
- Solution can be interrupted and continued with (e.g.) changed parameters
Future features (planned to be implemented):
- Time-dependent (visco-elastic) material models (Bergstrom-Boyce, ...) will be implemented
- Other optimizing method (Levenberg–Marquardt algorithm, ...) will be implemented
- Specific weight for each axis in biaxial protocol will be implemented