JP2011163784A - Sheet for measuring strain and strain measuring device - Google Patents

Abstract

Disclosed is a strain measuring sheet and a strain measuring apparatus capable of detecting a highly accurate strain even with a simple configuration and processing system.
A seal for measuring strain includes a transparent first layer portion on which a plurality of marks 11 and a transparent print layer 13 on which at least one of peripheral areas 12 of the marks 11 is printed are arranged on the surface; Second layer portion 15 having adhesiveness, and when the surface opposite to the first surface 13A is the second surface 13B of the first layer portion 14, the second surface 13B is on the front side. The first layer portion 14 and the second layer portion 15 are stacked facing each other, and the first layer portion 14 and the second layer portion 15 are subjected to strain measurement in a state where the second layer portion 15 is bonded to the strain measurement object W. It is made of a material that can be deformed in accordance with the elongation of the object W.
[Selection] Figure 3

Description

  The present invention relates to a strain measurement sheet adhered to a strain measurement object such as a test piece and a strain measurement apparatus using the same.

  In order to measure the strain of a strain measurement object, a method using a strain gauge is generally well known. However, when measuring with a strain gauge, only a strain in one axial direction can be measured. Therefore, when measuring a strain in two axial directions, it is necessary to mount them separately for each direction. In addition, when the strain measurement object is more easily deformed than the strain gauge, the strain gauge prevents the strain measurement object from being deformed, and an accurate strain cannot be measured.

  Therefore, it is proposed to take a set of signs that are mounted apart from each other in the direction of extension of the strain measurement object, and calculate the strain along with the load during deformation by calculating the distance between the signs from the image. (For example, refer to Patent Document 1). Further, there has been proposed a method for calculating the strain by directly measuring the deformation of the strain measurement object with a laser displacement meter (see, for example, Patent Document 2).

JP 2004-257925 A JP 2007-303917 A

  However, since the strain measuring apparatus as described in Patent Document 1 measures the distance between a set of signs, when measuring strain in a plurality of directions in a narrow area, a plurality of pairs of signs are attached to the area. It is necessary to make the sign itself small. For this reason, it is difficult to mount a plurality of pairs of small signs at a precise position in a narrow area. On the other hand, the strain measuring device described in Patent Document 2 is complicated in processing and expensive.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a strain measuring sheet and a strain measuring apparatus capable of detecting a highly accurate strain even with a simple configuration and processing system.

The present invention employs the following means in order to solve the above problems.
The strain measurement sheet according to the present invention includes a transparent first layer portion on which a transparent printing layer on which at least one of a plurality of marks and a peripheral region of these marks is printed is arranged on the surface, and a second having adhesiveness. And when the surface of the printed layer is the first surface and the surface opposite to the first surface is the second surface of the first layer portion, the second surface is the front side. In addition, the first layer portion and the second layer portion are laminated integrally facing each other, and the first layer portion and the second layer portion are bonded to the strain measurement object. It is made of a material that can be deformed in accordance with the elongation of the strain measurement object.

  The present invention does not depend on the material, size, thickness, etc. of the strain measurement object, and at least one of the plurality of marks and the peripheral area of these marks has various shapes, sizes, positions, The color is printed on the print layer of the first layer part. Then, by pulling the strain measurement object with the second layer part adhered to the strain measurement object, the first layer part and the second layer part are deformed in accordance with the elongation of the strain measurement object. Strain is measured by observing the deformation of the measurement object as the displacement of the mark. Since the mark is protected by the first layer part and the second layer part, the mark is not damaged against trauma.

  Further, the present invention is the strain measurement sheet, the first sheet having a first release layer portion having temporary adhesion and peelability to the second surface of the first layer portion, When the surface of the second layer portion facing the first surface of the first layer portion is the third surface, and the surface opposite to the third surface is the fourth surface, the fourth surface And a second sheet having a second release layer portion having provisional adhesiveness and peelability.

  In the present invention, the first surface and the third surface of the second layer portion are bonded together in a state in which at least one of a plurality of marks and a peripheral region of the marks is printed on the first surface of the first layer portion. The first layer portion and the second layer portion are stacked with the mark interposed therebetween. And by removing the second release layer part and bonding the fourth surface of the second layer part to the strain measurement object, and further removing the first release layer part to expose the second surface, the first layer The mark is placed on the strain measurement object in a state where the mark is visible through the section.

  The strain measuring apparatus according to the present invention includes a strain measuring sheet adhered to a strain measurement object, an imaging unit that images the mark, and the brightness of the imaged mark and the surrounding area. From the difference, a position calculation unit that calculates the center of gravity coordinates of the mark, and a strain calculation unit that calculates the strain of the strain measurement object from the center of gravity coordinates of the mark that is displaced according to the elongation of the strain measurement object. It is characterized by having.

  In the present invention, the strain measurement sheet according to the present invention is adhered to a predetermined position of the strain measurement object, and the displacement of the mark when the strain measurement object is pulled is measured.

  According to this invention, since the plurality of marks are displaced according to the deformation of the strain measurement object, the two-dimensional strain of the strain measurement object is calculated from the load at this time and the displacement state of each mark. Can do. At this time, in a state in which a predetermined interval between predetermined marks is maintained even if it is a small strain measurement object, without taking time and labor than when arranging a plurality of marks directly on the strain measurement object, and The mark can be adhered to the strain measurement object without applying an extra load to the mark itself. Further, since the second layer portion has adhesiveness, it can be adhered to a suitable place regardless of the material, size, thickness, etc. of the strain measurement object. Furthermore, the first layer portion and the second layer portion are made of a very flexible material. Accordingly, even if a soft material such as an aluminum foil or a thin material, for example, whose strain is changed by attaching a strain gauge, it can be adhered to the surface and accurate strain measurement can be performed.

  In addition, according to the present invention, the strain measurement sheet is configured by superposing two sheets separated from the first sheet and the second sheet, so that at least one of the mark and the peripheral area of the mark is formed. At the time of printing, only the first sheet is required, and handling can be facilitated.

  Further, according to the present invention, not only one-dimensional but also two-dimensional strain can be measured by an inexpensive method.

It is a schematic diagram showing a strain measuring device according to an embodiment of the present invention. It is a front view which shows the state with which the distortion | strain measurement seal | sticker which concerns on one Embodiment of this invention was mounted | worn with the distortion | strain measurement object. It is explanatory drawing which shows the manufacture process of the seal | sticker for distortion measurement which concerns on one Embodiment of this invention. In the Example which concerns on one Embodiment of this invention, when the load to a strain measuring object is (a) 250N, (b) 500N, (c) 750N, (d) 1000N of each strain measurement seal | sticker. It is a graph which shows the displacement of a mark. It is a graph which shows the comparison of the Example based on one Embodiment of this invention, and the strain measurement result by the conventional strain gauge.

An embodiment according to the present invention will be described with reference to FIGS.
As shown in FIGS. 1 and 2, the strain measuring device 1 according to the present embodiment grips a strain measuring object W and moves in a direction away from each other, and a strain measuring object. A strain measurement seal 10 attached to the object W, an imaging unit 30 that images the mark 11 disposed on the strain measurement seal 10, and a measurement processing unit 40 that calculates the strain of the strain measurement object W. ing.

  As shown in FIGS. 2 and 3, the strain measuring seal 10 includes a plurality of marks 11 and a transparent print layer 13 on which at least one of the peripheral regions 12 of the marks 11 is printed. 1 layer part 14 and the 2nd layer part 15 which has adhesiveness and is adhere | attached on the distortion | strain measuring object W are provided.

  Here, let the surface of the printing layer 13 be the first surface 13A and the surface opposite to the first surface 13A be the second surface 13B of the first layer portion 14. At this time, the strain measuring seal 10 is integrated so that the first surface 13A of the first layer portion 14 faces a third surface 15A of the second layer portion 15 described later, and the second surface 13B is on the front side. And is attached to the strain measurement object W.

  Before the strain measurement seal 10 is attached to the strain measurement object W, the water-soluble polymer layer 16a having temporary adhesion and peelability is disposed on the second surface 13B of the first layer portion 14. The first sheet 17 having the first release layer portion 16 and the surface of the second layer portion 15 facing the first surface 13A of the first layer portion 14 are opposite to the third surface 15A and the third surface 15A. When the side surface is the fourth surface 15B, a second release layer portion 18 provided with a water-soluble polymer layer (not shown) having temporary adhesiveness and peelability to the fourth surface 15B, The second sheet 20 has a third release layer portion (not shown) having temporary adhesion and peelability with respect to the three surfaces 15A. And the second surface 13B of the first layer part 14 and the first release layer part 16 are temporarily bonded, and the fourth surface 15B of the second layer part 15 and the second release layer part 18 are The third surface 15A and a third release layer portion (not shown) are temporarily bonded.

  The first layer portion 14 and the second layer portion 15 are not particularly limited as long as the first layer portion 14 and the second layer portion 15 are materials that can be deformed in accordance with the elongation of the strain measurement target object W in a state where the second layer portion 15 is bonded to the strain measurement target object W. It may be a well-known thing. For example, the first layer part 14 may be a non-water-absorbing transparent resin system such as a polyolefin resin system, and the second layer part 15 may be an acrylic pressure-sensitive adhesive. Further, the print layer 13 may be of a polymer type or porous fine particle type having an absorptivity of ink used for printing at least one of the plurality of marks 11 and the peripheral region 12 of the marks 11.

  The measurement processing unit 40 includes a position calculation unit 40A that calculates the barycentric coordinates of the mark 11 from the brightness difference between the imaged mark 11 and the peripheral region 12, and a mark that is displaced according to the elongation of the strain measurement object W. And a strain calculation unit 40B that calculates the strain of the strain measurement object W from 11 barycentric coordinates. Each process in position calculation part 40A and distortion calculation part 40B is not specifically limited, A publicly known processing method may be used.

Next, attachment of the strain measurement seal 10 to the strain measurement object W will be described with reference to FIG.
First, at least one of the plurality of marks 11 and the peripheral region 12 of these marks 11 is printed on the print layer 13 of the first layer portion 14 of the first sheet 17. In the present embodiment, for example, a plurality of circular marks 11 are printed in a relatively bright color, and the peripheral area 12 of the marks 11 is printed in a relatively dark color.

  Subsequently, the first surface 13A that is the surface of the printed layer 13, and the third surface 15A of the second layer portion 15 that is exposed by removing a third release layer portion (not shown) from the second sheet 20 are exposed. Adhere to face each other. Thus, the first layer portion 14 and the second layer portion 15 are laminated with the mark 11 interposed therebetween. And the 2nd mold release layer part 18 is removed from the 4th surface 15B of the 2nd layer part 15, and it adhere | attaches to the distortion | strain measurement object W, Furthermore, the 1st mold release layer part 16 is made into the 2nd surface of the 1st layer part 14. Remove from 13B and expose. Thus, the mark 11 is attached to the strain measuring object W in a state where the mark 11 is visible through the first layer portion 14.

A method for measuring the strain of the strain measurement object W in this state will be described.
First, both ends of the strain measurement object W are gripped by the gripping portions 2A and 2B, respectively. Next, a load in one direction opposite to each other is applied to the grip portions 2A and 2B, and the strain measurement object W is displaced. In addition, a captured image of the mark 11 is acquired by the imaging unit 30.

  At this time, the strain measurement seal 10 is also deformed together with the strain measurement object W. At this time, the coordinate change of the center of gravity of the mark 11 is read from the captured image by the position calculation unit 40A, and the strain of the strain measurement object W is calculated from the load at that time by the strain calculation unit 40B.

  According to the strain measurement seal 10, a plurality of marks 11 and a peripheral region 12 around these marks 11 regardless of the material, size, thickness, etc. of the strain measurement object W at the position where the strain measurement seal 10 is mounted. At least one of these can be printed with various shapes, sizes, positions, and color schemes suitable for measurement. And the mark 11 and the peripheral region 12 of these marks 11 can be protected by the first layer part 14 and the second layer part 15.

  Further, when the strain measurement object W is deformed in a state of being mounted on the strain measurement object W, the first layer portion 14 and the second layer portion 15 are deformed together, so that the plurality of marks 11 are also strained. It is displaced according to the deformation of the measuring object W. Therefore, the two-dimensional strain of the strain measurement object W can be calculated from the load at this time and the displacement state of each mark 11.

  At this time, it takes less time than the case where a plurality of marks 11 are directly arranged on the strain measurement object W, and even if it is a small strain measurement object, the mark is maintained in a state where a predetermined interval is maintained. The strain measurement object W can be bonded to the strain measurement object W without applying an extra load to itself. Furthermore, since the second layer portion 15 has adhesiveness, it can be bonded to a suitable place regardless of the material, size, thickness, etc. of the strain measurement object W. Therefore, the strain measurement object W is composed of a soft material such as an aluminum foil or a thin material, for example, in which the “strain” of the strain measurement object W is changed by attaching a “strain” gauge. Also, it is possible to accurately measure strain by bonding to the surface.

  In addition, since the strain measurement seal 10 is formed by superposing two sheets separated from the first sheet 17 and the second sheet 20, printing of at least one of the mark 11 and the peripheral region 12 of the mark 11 is performed. In this case, only the first sheet 17 is required, and handling can be facilitated.

  Further, according to the strain measuring device 1, by using the strain measuring seal 10, the displacement of the mark 11 following the deformation of the strain measuring object W can be measured. Two-dimensional strain can be measured by an inexpensive method.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  As the first sheet 17 and the second sheet 20 according to the above embodiment, respectively, a printing sheet and a white paste film of an inkjet exclusive transfer seal manufactured by A-One Co., Ltd. are used. Printing was performed so that a plurality of circular marks 11 were arranged at regular intervals. Then, as described above, the strain measurement target 10 which is a SUS304 JIS standard test piece (13B type) having a thickness of 25 mm, a width of 12 mm, and a thickness of 0.21 mm is manufactured. Attached to. In this state, a strain was measured by applying a load in one direction to the strain measurement object W. The results are shown in FIGS.

  FIG. 4 is a diagram in which the displacement of the mark 11 at each load is displayed in pixels and is further magnified 150 times to make it easier to understand visually. As shown in FIG. 4, it can be seen that the position of each mark 11 is also displaced according to the load. According to the measurement according to the present invention, as shown in FIG. 5, it was found that there is almost no difference from the measurement using a conventional strain gauge, and a highly accurate strain can be detected even with a simple configuration and processing system. .

  In addition, when the sheet | seat which concerns on a present Example was used, the distortion | strain of about 2/1000 was able to be measured with respect to the distortion | strain measuring object consisting of a 20-micrometer-thick copper foil. From this, (the longitudinal elastic modulus E when the first layer portion and the second layer portion are bonded) and (the first layer portion in a state where the first layer portion and the second layer portion are attached to the strain measurement object) And the thickness of the second layer part) is less than 1/100 of the product of (longitudinal elastic modulus E of strain measurement object W) and (thickness of strain measurement object W). We believe that this is possible.

DESCRIPTION OF SYMBOLS 1 Strain measuring device 10 Strain measuring seal 11 Mark 12 Peripheral area 13 Print layer 13A First surface 13B Second surface 14 First layer 15 Second layer 15A Third surface 15B Fourth surface 16 First release layer Unit 17 first sheet 18 second release layer unit 20 second sheet 30 imaging unit 40 measurement processing unit

Claims (3)

A transparent first layer portion on the surface of which a transparent printing layer on which at least one of a plurality of marks and a peripheral region of these marks is printed;
A second layer portion having adhesiveness;
With
When the surface of the printed layer is the first surface and the surface opposite to the first surface is the second surface of the first layer portion, the first layer portion is such that the second surface is the front side. And the second layer portion are laminated integrally facing each other,
The first layer part and the second layer part are made of a material that can be deformed according to the elongation of the strain measurement object in a state where the second layer part is bonded to the strain measurement object. Strain measurement sheet. A first sheet having a first release layer portion having temporary adhesion and peelability with respect to the second surface of the first layer portion;
When the surface of the second layer portion facing the first surface of the first layer portion is the third surface, and the surface opposite to the third surface is the fourth surface, the fourth surface A second sheet having a second release layer portion with provisional adhesiveness and peelability;
The strain measurement sheet according to claim 1, comprising: The strain measurement sheet according to claim 1 or 2 adhered to a strain measurement object;
An imaging unit for imaging the mark;
A position calculation unit that calculates the barycentric coordinates of the mark from the difference in brightness between the imaged mark and the surrounding area;
A strain calculator that calculates the strain of the strain measurement object from the barycentric coordinates of the mark that is displaced according to the elongation of the strain measurement object;
A strain measuring apparatus comprising:

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