I have a theoretical question about shear rheology: constant strain and frequency sweep. I can test this on a sample but I am trying to answer based on theory. If my geometry on the computer is set for cone but I use a parallel plate, how would my G' shift, will it shift up or down?
Article The free surface in parallel-plate and cone-plate viscometers.
Article Errors in parallel-plate and cone-plate rheometer measuremen...
Article Parallel Plate and Cone-Plate Normal Stress Measurements on ...
Article Cone-Plate and Parallel Plate Rheometry of Some Polymer Solutions
Article Analysis of the finite cone‐plate viscometer and of the fini...
Article A comparative study of the effects of cone-plate and paralle...
Article Experiments Investigation of the Parallel-plates Enthalpy Exchangers
Article Experiments Investigation of the Parallel-plates Enthalpy Exchangers
Article Evaluation of a parallel plate membrane exchange system
Article The Exciting Mechanism of the Parallel-Plate EMP Simulator
Hi,
the two parameters that you measure are torque M and angular displacement θ. The shear stress σ and strain γ are given by the equations:
σ [Pa] =Kσ·M
γ [-] =Kγ·θ
where Kσ and Kγ are stress and strain related constants for a given geometry.
For cone-plate, the constants are:
Kγ = 1/ β
Kσ = 3 / (2πR3)
β is the tip angle in radians, and R is the cone radius.
For plate-plate, the constants are:
Kγ = R / H
Kσ = 2 / (πR3)
H is the gap, and R is the plate radius.
The shear modulus is then defined as:
G [Pa] = σ / γ = Kσ·M / (Kγ·θ)
If your cone and plate have the same radius, then the moduli readings match if
3β = 4H.
Remember that β is fixed, but H could be varied.
- Badges
- Science topic
- Similar topics
- Instrumentation Engineering
- Instruments