FIELD OF THE INVENTION
The present invention relates to a device for on-line measurement of longitudinal
dynamic distribution of panel-type welded structures.
BACKGROUND OF THE INVENTION
Distortion is the perennial problem in any welded structures. The distortion
would result in many undesirable situations, particularly the longitudinal
distortion. The longitudinal distortion is the distortion that occurs parallel to the
weld axis. It is known that the distortion cannot be avoided but only be
minimized. Once distortion has occurred, it is common practice that one has to
go for correction of the distortion either mechanically or thermally. There are
many methods for controlling the distortion. If the pattern of distortion can be
known, then it would be easy to apply a particular technique to control the
distortion. A panel type welded structure comprises a plurality of tubes with
adjacent tubes joined together by flats or fins. These tubes are joined to the
flats / fins by welding. After welding, the conventional practice of measurement
of distortion is by using a measuring tape and the decision on correction or
acceptance is taken.
US Patent Document US 7441470 describes the method for measuring multi-
axial force, moment, force and acceleration with strain gauge as sensor. Our
invention is different in the sense that a device has been fabricated and strain
gauge is installed on the device and the system as a whole is used to measure
on-line dynamic distortion in panel welding,.
US Patent Document US 7434475 describes the method of forming a strain
sensor from a polymeric film includes the steps of selectively irradiating a surface
of the polymer with high energy radiation to change the composition of the
polymer and increase the electrical conductivity in selected portions of the
surface. Our invention relates to use of the strain gauge as sensor to measure
distortion, after the stain gauge installed in a device.
US Patent Document US 7395727 describe the method of Strain detection for
automated nano-manipulation with detection circuitry. Whereas our invention
relates use of strain gauge for measurement of strain and converting into
distortion.
US Patent Document US 7392711 describes an invention of insertable strain
gauge spanner which comprises a spanner body having a rod body and a driving
head insertable into the rod body; the rod body being installed with s strain
gauge, so that the twisting force from the driving head can be transferred to a
sensing end of the strain gauge; the twisting force being displayed in a window
of the strain gauge; Our invention is different in the sense that the strain gauge
is installed on a steel strip and the strip is mounted on a device and the set-up is
used for measurement of distortion during welding,.
US Patent Document US 7357037 describes an invention that provides a system
for measuring and remotely monitoring strain in an element having a strain
sensor, a telemetry circuit for transmitting strain data to a remote location, and
a reader module for transmitting energy to the telemetry circuit and receiving
said data. Our invention is different in the sense that the strain gauge with the
device can be used for
measurement of mechanical quantity in a near place to the component and the
measurement is dynamic.
US Patent Document US 7347101 describe an invention that deals with
measurement of strain in a structure using a sensor having an electromagnetic
resonator. On the other hand, our invention deals with measurement of
mechanical distortion with strain gauge as sensor.
OBJECTS OF THE INVENTION
It is therefore the object of the invention to propose a device for on-line
recording of the dynamic movement of a panel during welding to determine the
pattern of longitudinal distortion of panel type of structures.
SUMMARY OF THE INVENTION
According to the invention there is provided a device for recording on-line the
longitudinal dynamic movement of a panel structure during fabrication.
The device comprises is a support means having a horizontal base plate on
which a vertical plate being fixed and the two plates are reinforced, one each
thick steel sheet is butted together by screws on a first side and on the top of
the vertical plate, with a small slot configured at the center; and a steel strip
having a strain gauge at a first end being connected to a stain meter. This steel
strip is inserted firmly between the two
thick plates of the support means through the small slot and the screws are
tightened. At a second end of the steel strip a stylus pin is firmly attached. Then
the device is calibrated by applying a known distortion and the corresponding
strains are recorded. A correlation between the strain and the distortion is
drawn through the calibration.
During welding, the stylus pin is made to contact with the top surface of the
panel structure under fabrication, so that the longitudinal distortion is measured.
During fabrication by welding, the panel structure deforms because of distortion.
Since the stylus pin is in contact with the panel, it also bents and gets strained.
This strain is sensed by the strain gauge which is transmitted to the strain meter
for recording. The movement of the panel being a continuous phenomenon
during fabrication, the transient distortion of the panel in terms of strains is
recorded on-line. This strain is converted into distortion by adapting the
correlation graph between the distortion versus strains. From the trend of the
distortion, a decision on the sequence or any other techniques to be employed to
minimize the distortion is decided on-spot.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The proposed invention will be better understood by the following description
with reference to the accompanying drawings:
Figure 1 Shows a supporting means of the device according to the invention
Figure 2 Shows a steel strip with strain gauge installed of the device of
Figure 1
Figure 3 Shows the device of figure 1 in a mode of measurement of
distortion.
DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE
INVENTION
According to the invention there is provided a device comprising a support
means that are made of steel to the desired size.
The support means has a horizontal base plate (1) on which a vertical plate (2)
is fixed. To provide a better reinforcement, the horizontal bottom base (1) and
the vertical plate (2) are connected by a plurality of side stiffeners (3) on one
side of the vertical plate (2). On the other side and top of the vertical plate (2),
at least two steel sheets (4) are butted and held together by a plurality of screws
(5) with a slot (6) configured at the center.
A strain gauge (8) is installed at a first end of a steel strip (7). At a second end
of the steel strip (7), a stylus pin (9) is firmly attached. The strain gauge (8) is
connected to a stain meter (10) through an instrumentation cable (11). The steel
strip (7) is inserted firmly between the two steel sheets (4) and the screws (5)
are tightened. Then the device is calibrated by applying a known distortion and
the corresponding strains are recorded. A correlation between the strain and the
distortion is drawn through a calibration curved.
During fabrication by welding, the panel structure deforms because of distortion
and the distortion is sensed by the strain gauge (8) in terms of strains. This
strain is converted into distortion by adapting the correlation graph between the
distortion versus strains.
The disclosed invention as narrated herein above should not be read and
construed in a restrictive manner, as some modifications, adaptations and
alterations are possible within the scope and limit of the invention as defined in
the encompassed appended claims.
WE CLAIM
1. A device for on-line measurement of longitudinal dynamic distortion of
panel-type welded structures, comprising:
- a support means having a horizontal base plate (1), and a vertical plate
(2) attached to the horizontal base plate (1), the vertical plate (2)
comprising a first surface including a second surface, the second surface
of the vertical plate (2) rigidly connected to the horizontal base plate (1)
to provide stability of the support means;
- a pair of shaped plate (4, 4) each weldably jointed maintaining a gap in-
between upper part of the first face of the vertical plate (2), the shaped
plates (4, 4) being releasably attached together by at least four fastening
means (5), a slot (6) configured at the centre of the shaped plate (4)
disposed at the bottom;
- a steel sheet (7) insertable into said slot (6), and having a strain gauge
(8) installed at a first end connected to a strain meter (10), the second
end of the steel sheet (7) being provided with a rigidly affixed styles pin
(9); and
- the device is enabled to sustain a plurality of known distortions imparted
and provide corresponding strains generated thereupon so as to allow
developing a calibration graph;
- provide directly the strain values corresponding to said sensed values of
distortion by adapting the developed calibration graph.
2. The device as claimed in claim 1, wherein the strain gauge (8) is
connected to the strain meter (9) through an instrumentation cable (11).
3. A device for on-line measurement of longitudinal dynamic distortion of
panel-type welded structures as substantially described and illustrated
herein with reference to the accompanying drawings.

The invention relates to a device for on-line measurement of longitudinal
dynamic distortion of panel-type welded structures, comprising a support means
having a horizontal base plate (1), and a vertical plate (2) attached to the
horizontal base plate (1), the vertical plate (2) comprising a first surface
including a second surface, the second surface of the vertical plate (2) rigidly
connected to the horizontal base plate (1) to provide stability of the support
means; a pair of shaped plate (4, 4) each weldably jointed maintaining a gap in-
between upper part of the first face of the vertical plate (2), the shaped plates
(4, 4) being releasably attached together by at least four fastening means (5), a
slot (6) configured at the centre of the shaped plate (4) disposed at the bottom;
a steel sheet (7) insertable into said slot (6), and having a strain gauge (8)
installed at a first end connected to a strain meter (10), the second end of the
steel sheet (7) being provided with a rigidly affixed styles pin (9); and the device
is enabled to sustain a plurality of known distortions imparted and provide
corresponding strains generated thereupon so as to allow developing a
calibration graph; provide directly the strain values corresponding to said sensed
values of distortion by adapting the developed calibration graph.