Quick Start
Choose a loading mode
Select Uniaxial, Equibiaxial, Planar / Pure Shear, Simple Shear or Volumetric loading.
Choose a material model
Select the constitutive law to inspect or fit. The selected model is highlighted in the live charts.
Enter experimental data
Select the deformation and stress definitions, then paste two columns directly from Excel into the 30-row table.
Select the datasets used for fitting
The dataset selector chooses which table is visible. The checkboxes decide which test modes participate in the combined calibration.
Choose the fitting objective
Use Abaqus relative stress error for Abaqus-style comparison, or Standard least squares / RMSE when absolute stress error is preferred.
Fit and inspect the response
Use Fit Selected Model or Fit All Models, then inspect the curves, metrics and extrapolated behavior before transferring coefficients to FEA.
Available material models
| Model | Parameters | Notes |
|---|---|---|
| Linear elastic reference | E | Small-strain reference only |
| Neo-Hookean | μ | Simple one-parameter hyperelastic model |
| Mooney–Rivlin | C10, C01 | Two-invariant form |
| Ogden N=1 | μ, α | Abaqus-style normalization |
| Arruda–Boyce | μ, λm | Chain-locking formulation |
| Yeoh | C10, C20, C30 | First-invariant polynomial form |
| Reduced Polynomial N=2 | C10, C20 | Compact higher-order form |
| Van der Waals | μ, λm, a, β | β can be fitted or held fixed |
| Ogden Hyperfoam N=1 | μ1, α1, ν1 | Inherently compressible; no D or D1 |
Hyperfoam: the tool automatically treats this law as compressible. Its effective ν1 may be fixed or included in the fit. D/D1 is intentionally hidden because Abaqus HYPERFOAM does not use a separate D parameter.
Display range versus fit range
Display Min / Max controls the chart domain, deformation slider and generated curve range.
Fit Min / Max controls which experimental points can participate in calibration when “Restrict fit” is enabled.
Use Experimental Range automatically uses the minimum and maximum of the active dataset. The range settings are stored independently for each loading mode.
This separation is intentional: you can calibrate only over a trusted experimental interval while still displaying the model outside that range to inspect extrapolation.
Entering experimental data
The tool supports up to 30 points per loading mode and accepts direct two-column paste from Excel.
| Mode | Deformation input | Stress input |
|---|---|---|
| Uniaxial / Biaxial / Planar | Stretch λ or engineering strain % | Nominal / engineering stress; Cauchy stress is available for incompressible behavior |
| Simple shear | γ or engineering shear % | Shear stress τ |
| Volumetric | Volume ratio J or volume change % | Compression pressure p |
For compressible normal loading, the tool requires nominal / engineering stress because converting Cauchy stress to nominal stress requires additional lateral-deformation or volume information.
Fitting the material parameters
Fit Selected Model calibrates the currently selected constitutive law. Fit All Models fits the implemented models to the same selected datasets for comparison.
Abaqus relative stress error
This objective emphasizes relative stress error and is intended for comparison with Abaqus-style hyperelastic calibration.
Standard least squares / RMSE
This objective minimizes absolute stress residuals and may be more appropriate when absolute error across the measured stress range is the engineering priority.
A low fitting error does not prove parameter uniqueness, physical stability or reliable extrapolation. Always inspect the material response outside the calibration points.
Which example should I load?
Load Hyperelastic Benchmark (Abaqus)
Loads the SI Hypertest rubber dataset: 23 uniaxial, 16 biaxial, 13 planar and 4 volumetric points. Stress is displayed in MPa. The loader selects Neo-Hookean, compressible behavior and the Abaqus relative-stress objective. Select another hyperelastic model before fitting if required.
Load Hyperfoam Demo
Loads synthetic one-term Ogden Hyperfoam data with μ₁ = 0.5 MPa, α₁ = 2 and ν₁ = 0.20: 14 points each for uniaxial, equibiaxial and planar loading, 13 shear points and 9 volumetric points. The loader selects Hyperfoam, compressible behavior, fitting of ν₁ and absolute least squares.
The Hyperfoam example demonstrates parameter fitting using generated model data. It is separate from the published rubber benchmark and from measured material data. Both loaders replace the current datasets and clear previous fit results.
Excel export
The Excel workbook records the tool identity and version, material parameters, test inputs, converted data, generated stress and energy curves, fit metrics and charts.
When results are referenced in a report, use:
Educational and preliminary engineering use
This tool does not replace material testing, constitutive-model verification or solver-level validation. The user remains responsible for checking units, experimental definitions, parameter identifiability, extrapolation, stability and the final FEA implementation. MakeCoTech provides no warranty and accepts no responsibility for analysis failure, design decisions or material-model failure resulting from use of the tool or its outputs.
MakeCoTech Hyperelastic Explorer v1.0
Reference name: MakeCoTech Hyperelastic Explorer v1.0, MakeCoTech, 2026.