01 Measurement data
Column order: temperature [°C / K]; shear rate [s⁻¹]; viscosity [Pa·s]; optional pressure [MPa]. Decimal commas are supported with semicolon/tab separators. An optional header row is accepted.
02 Reference parameters
D2 estimation uses the entered Ã2 as a fixed model assumption. The example value 51.6 K is not a material-specific measurement.
These values are fixed. Enter a material-specific D₂; 373.15 K is an example only. D₃ = 0 assumes pressure independence. The fit determines n, τ*, D₁ and A₁.
Load measurements or try the example.
03 Measurement & model No data
Compare your measurement curves
Measured points and fitted curves appear after calculation.
The spread band is based on the logarithmic deviations of the measurements from the fitted model. It is not a confidence interval and does not account for complete measurement or parameter uncertainty.
04 Model parameters SI units
| Parameter | Value | Unit | Method |
|---|---|---|---|
| No model calculated yet. | |||
Transfer parameters to the material editor for a simulation
The export is a parameter table, not a native material file. Check your version’s equation and unit conventions before use.
05 Request a simulation
We would be happy to carry out a simulation for you. Contact us to discuss your part and requirements.
Request a simulationModel equations, input data and limitations
Cross-WLF convention
η = η₀ / [1 + (η₀ · γ̇ / τ*)1−n]
η₀ = D₁ · exp[−A₁(T − T*) / (A₂ + T − T*)]
T* = D₂ + D₃p · A₂ = Ã₂ + D₃p
T in K, p in Pa; 0 < n < 1. The fit minimizes squared ln(η) residuals from multiple starting points. Each measurement receives equal weight. A₁ uses the natural exponential convention, not base-10 WLF coefficients. τ* is a stress in Pa, not a shear rate.
For reliable parameters
At least 12 points at 3 temperatures are required. Include a broad shear-rate range covering the Newtonian plateau and the transition to shear thinning. A close curve fit does not prove that parameters are uniquely determined. A₁ and τ* have no universal minimum: their fitted values depend on the material, reference parameters and measured range. Search bounds are numerical limits, not recommended material ranges: D₁ = 1–10³⁰ Pa·s, τ* = 1–10⁹ Pa, A₁ = 0.01–150, n = 0.01–0.99.
Use corrected shear rates and viscosities. Raw pressure/flow signals and Bagley or Rabinowitsch corrections are not processed. Extrapolation beyond the measured range is not validated. D₃ is prescribed, not fitted.
The coefficients are determined to the best extent possible based on the entered data. Use of the parameters in simulation software is at your own risk.