Note: Descriptions are shown in the official language in which they were submitted.
7()6~3
VIB~t~ O"IE'~EIt
rhis invention re1ate~ to devices for inve~3tigating
the properties of fluid 8y5 tems and i~ more partlcularly
concarned wi-th vibrorheometers.
~ his invention can be u~ed to ~tudy the rheolo~ical
propertie~ of polymer and disper3e sys-tems, lacquers, dye~,
glues, petroleum~ and bitumens. It can be al90 used for ex-
pres~ ana]y~i~ of polymerization and polycondensation pro~
cesses, and cross~ ked structure formation. The p~eeent
invention7 it c~n be added, oan be useful in all fields of
science dealin~ with investigation an~ si~ulatisn of rheo-
logical behavior of variou~ materials.
At pre~ent, behavior of fluid 3ystem~ i~ inYestigated
ln de~ices rnea~urin~ the reaction of a m~terial to a s~ec;i-
fic mechanic~l deformation under continuous shear and de~or-
mation at a constant rate, harmonic or ~nh~rmonic oscillQ-
tion~, or harmonic (anharmonic) o~cillations super~mposed
on the con-tinuou~ she~r, and other conditions.
Known in the art i~ a viDrorheometer (cf., for examplet
Vysokomolekulyacnye Soedineni~ ~olume 20-A, ~o. l1 1978,
G.Y. Yinogradov, A.Ya~ i~alkin et al., ~3etod Komplek~nogo
Issledovania Reologiche~kikh S~oistv Polimernykh Si~te3n,
i~ethod for Complex Investi~atio3l o~ Polymer Sy~tQm Rheoloj~y,
in Rus~ian, pp. 226-230) comprising a mea~urin~ uni~ of the
cone-and-plate type, the material to be studies being plaG-
ed in -the gap between the cone and pl~te. l'~e "plate" ele-
ment is mounted on a shaft 90 th~t it c~n tor~lan~lly
~L2~7(~3
vibrate in rela-tion to said ~ha~t and i~ rigidly ~ecured
to a volta~e meter, whi.le the "cone" element la rigidly ~3e-
cured to the shn~t of the drive havin~ a sy~tem of motors
and a reduction gear. A link mechani~m is u~ed to connect
the cone and the shaft so that two deformation degrees can
be realized dependin~ on the position of` the motor system
with respect to the output drive shaft~ In this vibrorheo-
meter two fixed positions of the motor sy~tem with re3pect
to the output drive shaft are pos3ible: the vertical posi-
tion wherein -the constant shear deformation i8 appliedj and
a horizontal position wherein the output reduction gear
~haft is perpendicular to the output drive shaft to effect
the harmonic oscillation mode of operation.
The link mechanism used in the drive o~ this prior-art
vi~ration rheometer is a serious disadvantage since one of
the important modes of operation is impos~ible to realize,
the superimposing of a ~Yide frequency ra~ge of harmonlc os-
cillations on the continuous shear de~ormation.
Also kncwn in the art is a ~ibrorheometer (cf.; for
ex~mple, Vibrorheometer, Vibror~ometr VR-74~ Technical ~e~-
cription e~d Operational Instruction~ 1939-00-00 TO~ Spet-
sialnoe konstruktorskoe byuro Instituta neftekhimiche~ko~o
sinteza im. A~V. Topchieva Akademii ~lauk SSSR, Mo~cow,1975,
in Rus3ian) which comprises a measurin~ unit compGsed of
two elements ar~an~ed with a ~ap therebetween, the material
to be studied bein~ placed in 9aid gap, one of these el~
~ent6 is ~ounted on a shaft so that it is capable of tor-
~ional ~i~rations ~ith respect to 9aid shaft carrying a
63
transducer which converts the angular displacement of
sald element into electrical signals, while the sec-
ond element is rigidly secured to an output shaft of
a servo drive which converts signals fed from a con-
-trol unit in-to the angular displacements of the ele-
ment, and a transducer which converts -the angular
displacement of the second element into electrical
signals and comprises a magnetic lens and a galvano-
magne-tic cell (Hall device) rigidly secured to the
output shaft of the servo drive.
The measuring unit is made up of two co-
axial cylinders, while the magnetic lens is four-pole
magnetic system set on a mount stationary wlth res-
pect to the output shaft of the servo drive. The
galvanomagnetic cell should always be within the
alternating magnetic field produced by the magnetic
lens in order to make the transducer to transform the
angular displacement of the second element of the
measuring unit into electrical signals. The voltage
across the output electrodes of the galvanomagnetic
cell is dictated by the difference bet~een the areas
of the galvanomagnetic cell, which are affected by
the positive and negative magnetic fields. ~urther-
more, this voltage is the function of the angular
displacement o~ the second element of the measuring
unit and the maximum volta~e, therefore, corresponds
to the deformation amplitude of the periodic deforma-
-tion.
This vibration rheometer can be used to
investigate polymer and disperse 5ys tems under dif~
ferent conditions: under continuous shear deformation
at a constant velocity, harmonic and anharmonic os-
7~i3
cillations, and superimposition of harmonic or anhar-
monic oscillations on the continuous shear deforma-
tion. This vibration rheometer can determine struc-
tural viscosity, tangential stresses, a complex dyna-
mic modulus, and, using the harmonic (anharmonic)
oscillation technique, components of the complex
dynamic modulus, which are the modulus of elasticity
and the loss modulus.
But, this vibration rheometer is deficient
in that the amplitude of the periodic deformation
cannot be measured using the superimposition of har-
monic (anharmonic) oscillations on the continuous
shear deformation technique since the magnetic lens
is stationary in relation to the output shaft of the
servo drive and the galvanomagnetic cell leaves the
magnetic field produced by this lens.
In summary, this vibration rheometer cannot
use the above mentioned technique to measure the
components of the complex dynamic modulus, the modu-
lus of elasticity and the loss modulus, which char-
acterize the elastic and dissipative properties of a
material and are, therefore, one of the basic rheo-
logical features of visco-elastic and visco-plastic
materials.
It is an object of this inventior~ to pro-
vide a vibration rheometex which is capable o~ meas-
uring a wid~r range of parameters, in particular,
determining the components of the complex d~namic
modulus, using superimposition of harmonic (anhar-
monic) oscillations on -the continuous shear deforma-
tion.
There is provided a vibration rheometer
comprising a measurin~ unit made up of two elements
disposed with a sap therebet~een, the material to be
studied being placed in said gap, one of said ele-
~ ~,7~3
-- 5
ments being secured on a sh~ft so that it is capableof torsional vibrations in relation to said shaft
which carries a transducer which transforms angular
displacements of said element into electrical sig-
nals, while the second element is riaidly secured to
an output shaft of a servo drive which transforms
signals fed from a control unit electrically connect-
ed thereto into the angular displacements of said
element, and a transducer which transforms the an-
gular displacements of the second element of the
measuring unit :into electrical signals and comprises
a magnetic lens and a galvanomagnetic cell rigidly
secured to the output shaft of the servo drive,
which, according to the invention, comprises a rotat-
ing drive having a motor and, mounted on the drive
shaft, a rotation speed transducer electrically con-
nected to the servo drive, and a motor rotation speed
setter connected to said motor, the magnetic lens
being arranged on a mount placed on the output shaft
of the servo drive so that it can rotate about this
shaft and ~inematically connected to the rotation
drive shaft so that ~he magnetic lens and the gal-
vanomagnetic cell rotate in synchronism.
The vibration rheometer according to the
invention permi.ts measurement of the components of
the complex dynamic modulus: the modulus of elasti-
city and the loss modulus, using the technique of
superimposing harmonic (anharmonic) oscillations
on the continuous shear deforma-
~27(~3
tion, ~Jhich ~ub~tantially widen~ the application field o~the in~t~lment for practical ~tudies o~ v~sco-~laatic and
visco-pla~tic materialsO
Given hereinbelow is a de tailed description o~ an
exemplary embodime~t-of the present invention, taken in
conjunction Y~ith -the accompanying drawing which shows a
longitudinal sectio~ view o~ a mcasuring unit ~nd a mount
for a magnetic lens o~ a vibration rheome~er, according to
~he i~vention.
A vibration rheometer comprises a m~asuring unit 1
made up of two elements 2 and 3, whlch are coa~ial cylind-
ere ln this embodiment o~ the i~vention, dispQsed with a
gap therebetween~ A material 4 to be ~tudied in placed i~
said gap. The element 2 i~ ~et on a sha~t 5 whose one e~d
i~ rigidly secured to the instrunent ~ody (~he dr~YJing o~-
ly shows conventionally the shaft end attach~ent)~ The ele-
ment 2 ia capable o~ torsional vibratlons in r~lation to
~aid sha~t 5 which mount~ a ~ran8ducer 6 which tra~o~m~
the ~ngular diaplacemen~ o~ the element 2 into electrical
~l~nal~ and i~ connected to a recorder 7. Ths ~h~ft 5 i~
a callbrated tor~ion bar, The recorder 7 comprises two
analog-digital ~ran~ducera~ a microcomput~r and a prl~ter~
I`he second ~lement 3 is rigidly ~ecured to an ou~put ~h~t 8
o~ a ~rvo dri~e g compr~ing an actuating m~chani~m 10
whi~h is a motor or a ~y~tem of motor3 conn~cted by ~ r~-
duction gear, a t~chogenerator 11, and ~n error ~enaor 12~
Th~ ~ervo drive ~ tr~n~form3 ~he qignal ~ed ~rom a cont~ol
unit 13 into ~he ~lgular dl~placemen~ o~ the element ~. The
63
control unit 13 i~ electrically coI~ected to the drive 9
and compri e~ several series-co:nnected units, 9uch a~ a ~e
nerator l4 o~ specifically ~haped signals (sinu~oidal,
saw-tooth7 square, meander, and other), a ~irs~ adder 15,
a second adder 169 and a power ampli~ier 17, HereD one in-
put of the fir~t adder 15 is connected to the output of
the tachogenerator 1~ 7 one input of the ~econd adder 16 i~
connected to the output of the error sensor 12~ while the
output of the power amplifier 17 is connected to -the input
of the actuator 10 o~ the servo dri~e 9.
The ~ibration rheometer al80 comprl~e~ a transducer
18 of the angular displacement of the ~econd element 3 of
the mea~uring unit 1 into ~lectrical ~ignal~ which compri~-
es a magnetic len~ 19, a galvanomagnetic cell 20 which i~
a Hall device rigidly secured to ~he ou~put sha~t 8 o~ the
servo drive 9/ Rnd a current collector 21 electrically con-
nected to the recoder 7. The galYanomagnetic element 20
is set in sy~netry with ~he poles of the ~agnetic l~n~ 19
which is a four-pole magnetic ~y3~em~ The area~ of ~ur~ace
o~ the galvanomagnetic element 20, which are affected by
th8 ma~netic field~ of opposite polarity~ are equal~ r~he.
output s1gnal o~ the curren~ collector 21 i~ ze~Q. The mag- :
netic len~ 19 is ~ecured on a mount 22 place~ on the output
aha~t 8 of th~ servo drivs 9 eo that it c~n rotate abou~
said sh~ft 8. In thi~ embod1~ent, the mount 22 i~ placed
on the output ~h~t 8 o~ bearin~s 23~
The ~ibration rheometer al~o compri~ss a rstation
driYe 24 haYing a motor 25 an~J located on a ~h~ft 26
~22~ 3
8 --
o~ said motor 25, a rotatlon speed tran~ducer 27 which i~
electricall~ connected with the servo drive 9?~ ~nd a rota
tion speed ~etter 28 ~or the shaft 26, which i~ connected
to the mo~or 25, The rotation speed tran~ducer 27 i~ con-
nected to the error sensor 12 of the servo drive 9. The
mount 22 of the magnetic lens 19 is kinematically connected
to the shQft 26 of the motor 25 of the rOtatiOn driv0 24
by me~ns of a gear transmis3ion.
The kine~atic connection o~ the rotation drive 24 with
the tra~sducer 18 and the electrical connec~tion of the trnn~-
ducer 27 with the error ~ensor 12 proYide for the ~ynchro-
nou~ rotation of the magnetic le~s 13 and the galvanomagne-
tic cell 20.
U~ing ~uperimpositio~ of ha-L~onic (~nharmonic) o~cil-
lation~ on the cont1nuo~ shear de~ormation~ the v~bration
rheometer operate~ as follows.
The output si~nal o~ -the rotation speed ~etter 2~ i3
~ed to the motor 25 and the sha~t 26 starts rotating at a
pre~cribed speed tu m ing, through the ~ear tran~mi~lon 29
and the bearing 23; the mount 22 carr~lng the magnetlC len~
19 of the angular di~placeme~t transducer 18. Simul~aneou~-
ly, the Iot~tiorl ~peed transducer 27 produces a ~ignal for
the error ~e~or lZ of the ~ervo driv~ 9~
At the ~ame tim~, the output signal of the generator
14 o~ the eontrol un~t 13 i~ ~ed to one input of the f ~ r~t
adder 15, while a damplng si~nal ~rom the taeho~enerat~r
~ ed to the other lnput thereof. The output ~nQl
of the flrst adder 15 i~ applied to one input of the ~e-
~ ~ 7(~ 3
cond adder 16~ while the output ~ignal of the error ~en~-
or 12 i~ appli~d to the other inpùt thereof~ ~he output
si~nal of the second adder 16 iB amplified by the powcr
amplifier 17 ~ld e~ecuted by the ac-tuator 10 of the ~ervo
driYe 9r The output shaft 8, together with the galvanomag-
netic cell 20 and ~he ~econd element 3 of the mea~uring
unit 1 which are rigidly ~ecured to said shaft 89 i8 set
into R rotsry and oqcillatory motion, ~7hile the mount 22
with the magnetic lens 19 only rotates. The galvanomagne-
tic cell 20 i9 con~tantly ~vithin the ma~netic field pro-
duced by th~ magnetic lena 19 and vibrate~ with th~ fxe-
quency of the generator 14. ~he output signal o~ ~he cur-
rent collector 21, which i~ the function of -the amplitude
of the periodic defo~mation, i~ deliver~d to ~l input of
the recorder 7.
The motion of ~he ~econd element ~ of the mea~u~ing
unit 1 i3 tran~mitted9 via the lrlve~ti~ated material 4, to
the fir~t element 2 rigidly secured on the 3haft 5 which
turn3 to a certain angle a~d ma~es tor~ional v i.brations
in relation to the ori~nal po~itlon with the ~requenc~
~i~en by the ~ener~tor 14~ The an~ular displacement tran~-
ducer 6 tran8~0rm3 this motion into an el~ctrlcal ~i~nal
which i3 proportlonal to the stre~se~ in the mat~r~al 4
and i~ ~upplie~ to tha other 1~put o~ the reoo~der 7.
The elgnal~ fed to the recorder 7 from ~he tr~n~ucer~ :
13 ~nd ~ characterizs the deformat~on impQrtcd to the ma
terial 4 and the g~re99e3 produced therein. Th~y axe con-
Yerted into ~n equivalent ~nary code and enta~d to tho
63
- 10
microcomputer which calculate~ the ba ic rheolo~lcal para~
meters in accordance vlith the program a~,~ollow~:
1. Deformation am~litude o~ the periodic deformation
~ ~2 _ 2~o~ Jof~> C05 ~ (rad) 9
Y~here ~ ~ ~ r R ~ the reduced de~ormation ~pli-
tude of the external cylinder
(hereinafter the element 3)j
R - the radiu~ of the external cyliI~d-
er;
r - the radiu~ of the i~ternal cylind-
er (hereina~ter the element 2);
AOR ~ the vibration amplitude o~ the ex-
ternal cylinder;
or ~ the reduced deformation amplitude
7~o R-r-
o~ the internal cylinder;
Aor ~ the vibration amplitude o~ the
internal cylinder;
S~ ~ the phase shi~t angle OI ~ ibra~
~ion~ of the i~te~n~l a~d e~tern-
- al ~ylinder~
2 . Yolt a~e amplitude ~0:
2 ~ - 7c.~2) ~4
~f? (fi~ ~"7J2 ~Pa) "
where C - the rlgidity of ths tor~ion bar
(a con~tant for a tor~ion bar~
- the moment o~ inertl~ produced
when the inter~al cylinder i8
t~iated in relation tG the ~h~ 5
7~)~3
- 11
c~ ~ the angular velocit;y of the
e~te ~nal c~l.inde r;
h - the thickne~ of layer of` the
material 4 .
3, The modulus o:~ elasticity G':
G' = ~o(R Ao co~r AoR) ~Pa).
7- 0 ( R~r)
49 .~he 10YB modulus G7 ':
G~ = 2 0 1~,_~ (Pa)O
7~0 ~R-2)- -
5,. The complex dynarnic modulu~ G*
¦G~ G~2 + G1~ ( Pa) .
Uslng ~he supe ~lmposi t.~on of harmonic ( anharmon~c ~
o~3cillatlon~ on the continllou~ shear deformation techni-
que i~ not only theoreticallg~ e3~ential but pr~ctieally ill-
dispen3able, ~ince ~he proce~ses thus de~cribed are wide-
ly met in the polymer processing technclogy.
Th0 vibration rheome~er accordin~ ~o th~ inventlon
Call al90 uae the pu~.el$r harmon~c ~anharmonic) G~cillation
technique or the continuou~ 3hear de~ormation method. In
the fir~t in3tance ~ th~ outpu~ slg~al of the sha~t rot~-
tion ~peed ~etter 2~ iB zero, ~Nhile in the second in~tE~ce,
the output ~ignal o~ the spacifically ~haped slgnal gener~t~
or 14 ~ zero, U~ing the harmonic ( an.harmonic ) o~cilll3tion
techr~que, the vlbration rheornet~r een determina th~ com-
plex dynamic modulus and its component~, th¢ ~t;ructural
.~Z~7(~i3
1 2 --
viscosity, ~nd tangential stresse~. U~ing the continuous
shear deformation method, i-t c~n only determine the struc~
tural visco~it~ and tan~erltial ~tress~s.
The proposed vibration rheometer is suitable for prac-
tical applications for investigation of properties o~ vis-
co-elastic and visco-plastic materials, since it supplies re-
levant information on the rheological behavior of such ma-
terial~ under different deformation conditions.
