Identify whether the relevant flow stretches the material or shears it before carrying one viscosity report into a different deformation question.
Identify the Deformation and Model
RheoSense describes extensional viscosity as resistance to stretching and explains that similar shear viscosities can accompany different extensional responses. The imposed deformation mode belongs in the material report. Primary reference: shear and extensional response.
Review a Hypothetical Comparison
Consider two fictional materials that both show shear viscosity 1 Pa·s at one stated shear rate. Their separately measured extensional viscosities at one identified stretching rate are 10 and 30 Pa·s. Equal shear readings therefore do not establish equal stretching response. These numbers are not a universal relation between the two viscosity types.
Keep the Evidence with the Decision
Sketch the deformation that motivates the enquiry, such as an identified converging flow or filament extension. Keep the extensional mode, rate, temperature and prior flow history with the measured quantity. Distinguish uniaxial, planar and other extension definitions rather than merging their numerical results under one generic stretching label. Ask what assumptions were used to separate simultaneous shear contributions.
The actual process can include a mixture of deformation modes and does not inherit an instrument flow field merely because the same product name is used. Request the relevant response when stretching matters to the formulation question. The fictional comparison supplies no nozzle limit, polymer property or HM filling performance. Its useful output is a deformation-to-measurement map with the missing mode left explicit.
Does the measured shear response describe the required stretching-flow behavior?
This blank worksheet is for your own project. It contains no H M machine trial result.
| Review field | Reference or result | Responsible person |
|---|---|---|
| Process deformation sketch | To complete | To complete |
| Extension mode and rate definition | To complete | To complete |
| Temperature and prior-flow history | To complete | To complete |
| Mixed-flow correction and report boundary | To complete | To complete |
Customer Questions
Does equal shear viscosity force equal extensional viscosity?
No. The material responses can differ.
Are all extension modes interchangeable?
No. Preserve the particular deformation definition.
Do the values define a filling limit?
No. They only illustrate different measured responses.
Primary References
These references support the technical principles discussed in this guide. The worked examples and review questions are educational.
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