Brookfield YR-1 Rheometer - Manual (Page 50)

Brookfield Engineering Labs., Inc. Page 50 Manual No. M02-215-B0412
APPENDIX D - Calculations
The following equations can be used to calculate the shear stress values after each packet of
data is obtained from the YR-1:
τ =
TxYMCxT
10
where:
τ = Yield Stress (Pascals)
TK = Model Torque Constant from Table A-2 in Appendix A
YMC = Yield Multiplier Constant from Table A-1 in Appendix A
T = % Torque reading
The following equations can be used to calculate the strain data after each packet of data is
obtained from the YR-1:
γ
= θ
M
– (S x T)
where:
γ = Strain (rad)
θ
M
= Angular rotation of motor shaft (rad)
S = Radial Spring Factor (rad/% torque)
T = % Torque reading (%)
θ
M
=
ω x t x
2 π
60
where:
θ
M
= Angular distance of motor shaft (rad)
ω
= Rotational speed (rpm)
t = time of test (seconds)
S = θ
cal
x (2π) x 0.01
where:
S = Radial spring factor (rad/%torque)
θ
cal
= Spring windup angle (revolutions)
θ
cal =
(
V
cal
x t
cal
)
60000