KR102450953B1 - The Specimen for Shear Strength Measurement Test for Bonding Glass and Glass-ceramic to Metal - Google Patents

Abstract

The present invention relates to a specimen for a shear strength measurement test for measuring shear strength for bonding glass and glass-ceramic to metal, and more specifically, to a specimen for a shear strength measurement test for bonding glass and glass-ceramic to metal, wherein the maximum measurable strength range of shear strength for bonding is improved by approximately 60 % using the specimen for a shear strength measurement test having the shape of a doubly overlapping sandwich joint including adhesive layers, wherein two upper glass layers, two intermediate metal layers and two lower glass layers are formed for each layer between an upper metal layer and a lower metal layer, and the adhesive layers are formed between the upper metal layer and the intermediate metal layers, which are in contact with an upper surface and a lower surface of the upper glass layers, and between the intermediate metal layers and the lower metal layer, which are in contact with an upper surface and a lower surface of the lower glass layers.

Description

The Specimen for Shear Strength Measurement Test for Bonding Glass and Glass-ceramic to Metal

The present invention relates to a specimen for measuring shear strength for measuring the shear strength for bonding between glass and glass ceramics and metal.

The bonding between glass and glass-ceramic materials of optical components such as brittle reflectors or lenses in satellite cameras and metal materials such as titanium and invar. Specimens for measurement were presented.

In general, the shape of the specimen for measuring shear strength applicable to bonding between glass and glass-ceramics and metals is, for example, the block shear joint specimen presented in ASTM D4501-01 of the American Society for Testing and Materials, and the MIL-PRF-13830B of the United States military standard. There is a single overlapping sandwich joint specimen geometry.

However, when performing a shear strength measurement test using the previously presented block shear joint specimens and single overlap sandwich joint specimens, breakage due to stress concentration in the glass and glass-ceramic layers occurred, making it impossible to measure the normal bonding shear strength of the adhesive. have. Because of this, it is not possible to obtain the bond shear strength limit value according to the bonding surface and adhesive properties, so if the bonding strength is applied as the design value without experimental verification, the reliability of the satellite camera system cannot be guaranteed.

In addition, when the experimentally verified glass and glass-ceramic breakage strength is applied as the bonding shear strength design value of the adhesive, problems such as system enlargement due to mechanical excessive design and optical performance degradation due to increase in adhesive application area may occur. .

Korean Patent Registration No. 10-1510540

In consideration of the above points, the present invention utilizes highly brittle materials such as glass and glass ceramics, which were limited in testing the properties of adhesives between glass and glass ceramics and metals, and measures the shear strength of the adhesives to the limit level. An object of the present invention is to provide a specimen for measuring the shear strength of glass and glass ceramics and metal-to-metal joints having a specimen shape in which stress concentration is relieved.

The specimen for measuring shear strength of the present invention for achieving the above object is an upper metal layer, an upper glass layer comprising a first glass layer and a second glass layer formed under the upper metal layer, and formed under the first glass layer A lower portion comprising a first intermediate metal layer and a second intermediate metal layer formed under the second glass layer, a third glass layer formed under the first intermediate metal layer, and a fourth glass layer formed under the second intermediate metal layer a glass layer, and a lower metal layer formed under the third glass layer and the second glass layer, between the upper metal layer and the upper glass layer, between the upper glass layer and the middle metal layer, the middle metal layer and the and an adhesive layer formed both between the lower glass layer and between the lower glass layer and the lower metal layer.

In the specimen for measuring shear strength of the present invention, the first glass layer and the second glass layer are provided on both ends of the lower surface of the upper metal layer, wherein the first glass layer and the second glass layer are spaced apart from each other may be formed in parallel.

In the specimen for measuring shear strength of the present invention, the third glass layer and the fourth glass layer are provided on both ends of the upper surface of the lower metal layer, wherein the third glass layer and the fourth glass layer are spaced apart from each other at a predetermined distance. may be formed in parallel.

In the specimen for measuring shear strength of the present invention, the third glass layer is formed in the lower region of the first intermediate metal layer corresponding to the position of the first glass layer, and the fourth glass layer is located at the position of the second glass layer. It may be formed in a corresponding lower region of the second intermediate metal layer.

In the specimen for measuring shear strength of the present invention, the adhesive layer is a first upper adhesive layer bonding to the lower surface of the upper metal layer and the upper surface of the first glass layer, the lower surface of the first glass layer and the first middle A first lower adhesive layer bonded to the upper surface of the metal layer, a second upper adhesive layer bonded to the lower surface of the upper metal layer and the upper surface of the second glass layer, the lower surface of the second glass layer and the second middle A second lower adhesive layer bonded to the upper surface of the metal layer, a third upper adhesive layer bonded to the lower surface of the first intermediate metal layer and the upper surface of the third glass layer, the lower surface and the lower surface of the third glass layer A third lower adhesive layer bonded to the upper surface of the metal layer, a fourth upper adhesive layer bonded to the lower surface of the second intermediate metal layer and the upper surface of the fourth glass layer, and the lower surface and the fourth glass layer It may be formed of a fourth lower adhesive layer bonded to the upper surface of the lower metal layer.

In the specimen for measuring shear strength of the present invention, the first upper adhesive layer, the first lower adhesive layer, the second upper adhesive layer, the second lower adhesive layer, the third upper adhesive layer, the third lower adhesive layer, It is preferable that the width length of the upper glass layer and the lower glass layer is longer than the width length of any one selected from the 4 upper adhesive layer and the fourth lower adhesive layer.

In the specimen for measuring shear strength of the present invention, the thickness of the upper glass layer and the lower glass layer is preferably equal to or greater than a certain thickness so that the stress generated on the upper and lower surfaces of the upper and lower glass layers is spaced apart from each other.

In the specimen for measuring shear strength of the present invention, in the intermediate metal layer, the length of the first intermediate metal layer and the second intermediate metal layer are the same, and the length of the first intermediate metal layer or the second intermediate metal layer is the length of the upper metal layer and the length of the second intermediate metal layer. longer than the length of the underlying metal layer.

In the specimen for measuring shear strength of the present invention, the thickness of the upper metal layer and the lower metal layer is preferably formed to be thicker than any one selected from the upper glass layer, the middle metal layer, and the lower glass layer.

In the specimen for measuring shear strength of the present invention, the upper glass layer and the lower glass layer are preferably made of any one glass material selected from glass and glass ceramics.

In the specimen for measuring shear strength of the present invention, the use of a highly brittle material, which was limited due to an insufficient shear strength measurement test result, can be more freely utilized. In particular, in the high-tech, high-performance defense industry, optical systems such as satellite cameras must use specific optical materials according to band characteristics, but when testing adhesive properties, the effect of the optical materials is dramatically reduced, enabling precise measurement without damage. .

In addition, by sufficiently verifying the shear strength of the adhesive to the threshold level through the specimen for measuring the shear strength of the present invention, the area required to apply the adhesive in the same product can be reduced by up to 39%. Such reduction in adhesive not only reduces the weight of the entire optical system due to a reduction in bonding mass, but also facilitates the point bonding method, thereby improving the optical performance of each optical component.

1 is a front cross-sectional view of a specimen for measuring shear strength for bonding between glass and glass ceramic and metal according to an embodiment of the present invention.
2 is a perspective view of a specimen for measuring shear strength for bonding between glass and glass ceramic and metal according to an embodiment of the present invention.
3 is a side view of a specimen for measuring shear strength for bonding between glass and glass ceramic and metal according to an embodiment of the present invention.
4 is a plan view of a specimen for measuring shear strength for bonding between glass and glass ceramic and metal according to an embodiment of the present invention.
5 is a view showing the appearance of the glass layer in the specimen for measuring the shear strength for the bonding between glass and glass ceramic and metal of the present invention.
6 is a graph showing the relationship between the thickness of the metal layer and the stress in the specimen for measuring shear strength for the bonding between glass and glass ceramics and metals of the present invention.
7 is a graph showing the relationship between the excess width of the glass layer and the stress in the specimen for measuring shear strength for the bonding between glass and glass ceramic and metal of the present invention.
8 is a graph showing the relationship between the thickness of the glass layer and the stress in the specimen for measuring shear strength for the bonding between glass and glass ceramic and metal of the present invention.
9 is a view showing the shape of a double overlap shear joint specimen.
10 is a view showing the action stress applied to the glass layer in the specimen for measuring the shear strength for the bonding between glass and glass ceramic and metal of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. This embodiment is not limited to the embodiment described herein, since it may be implemented in various different forms by those of ordinary skill in the art to which the present invention pertains as an example.

On the other hand, in the present specification, "specimen" is a molded article for testing having a certain shape and dimensions for measuring physical properties, and is also referred to as a test piece.

Also, in the present specification, the "glass layer" is made of any one or more materials selected from glass and glass ceramics.

1 shows a specimen for measuring shear strength for bonding between glass and glass-ceramic and metal according to an embodiment of the present invention.

As shown in FIG. 1, the specimen for measuring shear strength has a sandwich type, in which the glass layer is alternately overlapped with the metal layer. An upper glass layer 45 , an intermediate metal layer 20 and a lower glass layer 46 are formed between the lower metal layer 12 , and the upper glass layer 45 , the middle metal layer 20 and the lower glass layer 46 are formed. Two pieces of silver are stacked side by side in parallel with each other by a certain distance apart.

Between the upper metal layer 11 and the intermediate metal layer 20 in contact with the upper and lower surfaces of the upper glass layer 45 , and the intermediate metal layer in contact with the upper and lower surfaces of the lower glass layer 46 . Between 20 and the lower metal layer 12, there are adhesive layers 31, 32, 33, 34, 35, 36, 37, 38 formed by applying an adhesive.

The upper glass layer 45 and the lower glass layer 46 are made of any one glass material selected from glass and glass ceramics.

The upper glass layer 45 formed under the upper metal layer 11 is a first glass layer 41 and a second glass layer 42 arranged in parallel at both ends of the lower surface of the upper metal layer 11 at a predetermined distance apart. is made of

A first upper adhesive layer 31 between the lower surface of the upper metal layer 11 and the upper surface of the first glass layer 41, the lower surface of the upper metal layer 11, and the second glass layer 42 The upper metal layer 11, the first glass layer 41, and the second glass layer 42 are adhered to each other with a second upper adhesive layer 32 between the upper surfaces of the .

An intermediate metal layer 20 is formed under the first glass layer 41 and the second glass layer 42 , and the first intermediate metal layer 21 and the second intermediate metal layer 22 constituting the intermediate metal layer 20 . ) are spaced apart from each other by a predetermined distance, and a first intermediate metal layer 21 is formed under the first glass layer 41 , and a second intermediate metal layer 22 is formed under the second glass layer 42 . do.

In the intermediate metal layer 20, the first intermediate metal layer 21 and the second intermediate metal layer 22 have the same length, and the length of the first intermediate metal layer 21 or the second intermediate metal layer 22 is It is formed to be longer than the length of the upper metal layer 11 and the length of the lower metal layer 12 .

A first lower adhesive layer 33 and a lower surface of the second glass layer 42 and the second intermediate between the lower surface of the first glass layer 41 and the upper surface of the first intermediate metal layer 21 . The first glass layer 41 and the second glass layer 42 are interposed between the upper surface of the metal layer 22 as a second lower adhesive layer 34 , the first intermediate metal layer 21 and the second intermediate metal layer 22 . ) are attached to each other.

A lower glass layer 46 is formed under the first intermediate metal layer 21 and the second intermediate metal layer 22 , and a third glass layer 43 and a fourth glass layer ( 44) are positioned side by side at a predetermined distance, a third glass layer 43 is formed under the first intermediate metal layer 21, and a fourth glass layer 44 is formed under the second intermediate metal layer 24 .

A third upper adhesive layer 35 and a lower surface of the second intermediate metal layer 22 and the fourth glass between the lower surface of the first intermediate metal layer 21 and the upper surface of the third glass layer 43 The third glass layer 43 and the fourth glass layer 44 are interposed with a fourth upper adhesive layer 36 between the top surface of the layer 44 , the first intermediate metal layer 21 and the second intermediate metal layer 22 . ) are attached to each other.

The third glass layer 43 is formed in the lower region of the first intermediate metal layer 21 corresponding to the position of the first glass layer 41 , and the fourth glass layer 44 is the second glass layer. It is formed in the lower region of the second intermediate metal layer 22 corresponding to the position (42).

One end of the first intermediate metal layer 21 and the second intermediate metal layer 22 spaced a certain distance from each other is formed at the same position as one end of the first glass layer 41 and the second glass layer 42, One end of the third glass layer 43 and the fourth glass layer 44 is formed at the same position as one end of the first intermediate metal layer 21 and the second intermediate metal layer 22 . That is, the third glass layer 43 , the first intermediate metal layer 21 , and the first glass layer 41 are sequentially stacked on each other, and the fourth glass layer 44 , the second intermediate metal layer 22 and the second Glass layers 42 are sequentially stacked on each other.

A lower metal layer 12 is formed under the third glass layer 43 and the second glass layer 44 , and the third glass layer 43 and the second glass layer are formed at both ends of the upper surface of the lower metal layer 12 . A fourth glass layer 44 is provided, but the third glass layer 43 and the fourth glass layer 44 are formed parallel to each other with a predetermined interval therebetween.

Here, between the upper surface of the lower metal layer 12 and the lower surface of the third glass layer 43 , the third lower adhesive layer 37 , the upper surface of the lower metal layer 12 , and the fourth glass layer 44 . ), the lower metal layer 12, the third glass layer 43, and the fourth glass layer 44 are bonded to each other with a fourth lower adhesive layer 38 between the lower surfaces.

As shown in FIG. 2, in the specimen for measuring the shear strength of the glass and glass-ceramic and metal-to-metal bonding of the present invention, the first intermediate metal layer 21 and the second intermediate metal layer 22 are fastened to the measuring device by bolts. Separately, fastening holes 51 and 52 may be formed at the other end that is not bonded to the glass layer.

3 and 4, the first glass layer 41 and the second glass layer than the width and length of the upper metal layer 11, the lower metal layer 12, and the middle metal layer 20 in the specimen for measuring shear strength of the present invention. (42), the width of the third glass layer 43 and the fourth glass layer 44 is formed to be longer, so that both ends in the width direction of each of the glass layers 41, 42, 43, 44 form an adhesive area. is formed and protrudes outward.

Therefore, in the specimen for measuring shear strength of the present invention, the first upper adhesive layer, the first lower adhesive layer, the second upper adhesive layer, the second lower adhesive layer, the third upper adhesive layer, the third lower adhesive layer, The width length of the upper glass layer and the lower glass layer is longer than the width length of any one selected from the 4 upper adhesive layer and the fourth lower adhesive layer.

5 is a view showing the appearance of the glass layer in the specimen for measuring shear strength of the present invention, the excess of the width and length of the glass layer outside the contact agent layer, which is the contact area with the metal layer in the glass layer, is expressed as W _GS , and the glass layer The thickness of is denoted by t _GS , and the thickness of the metal layer is denoted by h _MD .

As shown in FIG. 5 , in the specimen for measuring shear strength of the present invention, the thickness and width and length of the glass layer and the metal layer constituting the specimen for measuring shear strength are set so that the stress concentration is minimized with the glass layer. Here, the glass layer means at least one selected from the first glass layer 41 , the second glass layer 42 , the third glass layer 43 , and the fourth glass layer 44 , and the metal layer is the upper metal layer 11 . ) and means at least one selected from the lower metal layer 12 .

6 to 8 are graphs showing the shear stress behavior with respect to the thickness and width and length of the glass layer and the metal layer in the specimen for measuring the shear strength for the bonding between glass and glass ceramic and metal of the present invention.

6 to 8, the result values were interpreted based on the REF (reference) shape, and the height REF value of the upper metal layer and the lower metal layer was 39% of the width of the metal layer and the adhesive layer, and the width of the glass layer REF The value is 9.4% of the width of the metal layer and the adhesive layer, and the REF value of the glass layer is 9.4% of the width of the metal layer and the adhesive layer.

6 is a graph showing the relationship between the thickness and stress of the upper metal layer and the lower metal layer in the specimen for measuring shear strength. As the thickness (h _M ) of the upper metal layer or the lower metal layer increases, the stress concentration in the glass layer increases as shown. It was confirmed that the stress value (s _G ) in the glass layer tends to converge to a constant value.

7 is a graph showing the relationship between the excess width of the glass layer and the stress in the specimen for measuring shear strength, and as shown, the excess width of the simple glass layer (W _GS ) is a specific value where the stress concentration in the glass layer is minimized. It was confirmed that there is an excess of width, and if it is out of this range, stress concentration is induced in the glass layer again.

8 is a graph showing the relationship between the thickness of the glass layer and the stress in the specimen for measuring shear strength, as shown, as the thickness (t _GS ) of the glass layer increases, the stress concentration of the glass layer is relieved, such a glass It was confirmed that the relationship between the layer thickness (t _GS ) and the stress value (s _G ) in the glass layer maintained a linear direction.

6 to 8, the thickness of the upper glass layer 45 and the lower glass layer 46 in the shear strength measurement specimen is the upper glass layer 45 and the lower glass layer 46, respectively. It is formed over a certain thickness to a level that the stress generated on the upper and lower surfaces of the surface can be separated from each other.

In addition, the thickness of the upper metal layer 11 and the lower metal layer 12 is thicker than the thickness of any one selected from the upper glass layer 45 , the middle metal layers 21 , 22 , and the lower glass layer 46 . is formed with

Table 1 below shows the results of confirming the maximum measurable range of joint shear strength when the double-overlapping sandwich joint shape is applied to the specimen for measuring shear strength of the present invention for three types of combinations between glass and glass ceramic and metal of the present invention. .

In Table 1 below, the specimen material A is a metal titanium (Titanium, also referred to as 'a') and glass/glass ceramics are silicon (Silicon, also referred to as '1') bonding, and the specimen material B is a metal titanium (a) and Glass/glass ceramics are Germanium (also called 'j') junctions, and specimen material C is metal (Invar, also called 'b') and glass/glass ceramics with Zerodur (also called 'k'). )) a combination of junctions was applied.

Here, the expected failure stress indicates the expected failure stress for each glass/glass ceramic material obtained through stress analysis based on the test value. The maximum measurable range was indicated by applying the B-value to the actual specimen test performance data.

9 shows the shape of the double overlap shear joint specimen 200 of the American Society for Testing and Materials standard ASTM D3528-96, a first intermediate metal layer 221 as a metal layer between the upper glass layer 211 and the lower glass layer 212. ) and the second intermediate metal layer 222 are stacked side by side in parallel with each other separated by a certain distance, between the upper surfaces of the two metal layers 221 and 222 in contact with the lower surface of the upper glass layer 211, and the lower glass layer ( There are adhesive layers 231 , 232 , 233 , 234 formed by applying an adhesive between the upper surface of the 212 and the lower surfaces of the two metal layers 221 and 222 . At this time, the upper glass layer 211, the lower glass layer 212, the first intermediate metal layer 221, the second intermediate metal layer 222, the first upper adhesive layer 231 of the double overlap shear joint specimen 200, The second upper adhesive layer 232 , the first lower adhesive layer 233 , and the second lower adhesive layer 234 all have the same length without protruding in the width direction.

Psalter
texture Expected stress to failure (MPa) Maximum measurable range (MPa) Measurable range of the specimen of the present invention compared to the existing one Double Overlapping Shear Joints
(existing) Double Overlapping Sandwich Joint
(the present invention) A(a-i) 19.74 5.04 8.26 +63.9% B(a-j) 29.67 7.46 12.41 +66.4% C(b-k) 23.99 6.05 10.19 +68.4%

As shown in Table 1 above, when the shape of the specimen for measuring shear strength of the present invention is applied, the maximum measurable range of the bond shear strength of the specimen material A is improved to 63.9% compared to the existing one, and the maximum measurement of the bond shear strength of the specimen material B is possible The range is improved to 66.4% compared to the existing one, and the maximum measurable range of the joint shear strength of the specimen material C is improved to 68.4% compared to the existing bar. It was confirmed that it was effectively improved to 60% or more.

Table 2 below is a specimen for measuring shear strength generally applied to the bonding between glass and glass ceramics and metal. These are the results of confirming the stress generated in the glass and the glass breakage state in the sandwich joint specimen and the specimen for measuring the shear strength of the present invention in the double overlap sandwich joint.

Specimen shape Bond shear test strength
(MPa) glass stress
(Von-Mises) glassy state block shear joint
(ASTM D4501-01) 6.0 up to 20.2 MPa damage Single Overlapping Sandwich Joint (MIL-PRRF-13830B) up to 43.5 MPa damage Double Overlapping Sandwich Joint
(the present invention) up to 14.3 MPa no breakage

As shown in Table 2 above, when the shear strength measurement test is performed by applying 6 MPa as the general joint design strength, in the case of a block shear joint specimen, the maximum stress generated in the glass is 20.2 MPa, and in the case of a single overlapping sandwich joint specimen, the maximum stress occurring in the glass It was confirmed that glass breakage due to stress concentration occurred at a stress of about 43.5 MPa.

However, in the case of the double-overlapping sandwich joint shape of the present invention, it was confirmed that the maximum stress generated in the glass was significantly reduced to about 14.3 MPa, and thus, there was no breakage of the glass.

Figure 10 shows the stress distribution analysis results for the applied stress to the glass layer in a 6 MPa shear test environment as the joint design strength in the specimen for measuring shear strength of the present invention, the right figure of Figure 10 shows the stress concentration phenomenon This is an example that strongly occurs, and the left figure of FIG. 10 is a view of the observed stress concentration phenomenon in the double-overlapping sandwich joint shape of the present invention.

In the stress distribution analysis, the closer to red, the greater the applied stress, and the closer to blue, the smaller the applied stress. Here, as shown in the right figure of FIG. 10 , the thinner and narrower the surface painted in red, the stronger the stress concentration phenomenon occurs.

As shown in the left figure of FIG. 10 , the red color appears to be evenly distributed over a large area close to half of the bonding surface, and the stress concentration phenomenon in the glass layer of the specimen for measuring shear strength having the shape of a double-overlapping sandwich joint of the present invention is relatively was found to have been alleviated.

11: upper metal layer
12: lower metal layer
20: middle metal layer
21: first intermediate metal layer
22: second intermediate metal layer
31: first upper adhesive layer
33: first lower adhesive layer
32: second upper adhesive layer
34: second lower adhesive layer
35: third upper adhesive layer
37: third lower adhesive layer
36: fourth upper adhesive layer
38: fourth lower adhesive layer
41: first glass layer
42: second glass layer
43: third glass layer
44: fourth glass layer
45: upper glass layer
46: lower glass layer
51, 52: fastening hole
100: specimen for measuring shear strength
200: double overlap shear joint specimen
211: upper glass layer
212: lower glass layer
221: first intermediate metal layer
222: second intermediate metal layer
231: first upper adhesive layer
233: first lower adhesive layer
232: second upper adhesive layer
234: second lower adhesive layer

Claims (10)

upper metal layer;
an upper glass layer comprising a first glass layer and a second glass layer formed under the upper metal layer;
an intermediate metal layer comprising a first intermediate metal layer formed under the first glass layer and a second intermediate metal layer formed on a lower surface of the second glass layer;
a lower glass layer comprising a third glass layer formed under the first intermediate metal layer and a fourth glass layer formed on a lower surface of the second intermediate metal layer; and
and a lower metal layer formed under the third glass layer and the second glass layer;
An adhesive layer formed between the upper metal layer and the upper glass layer, between the upper glass layer and the middle metal layer, between the middle metal layer and the lower glass layer, and between the lower glass layer and the lower metal layer; Specimens for measuring shear strength. According to claim 1,
The first glass layer and the second glass layer are provided on both ends of the lower surface of the upper metal layer, wherein the first glass layer and the second glass layer are formed parallel to each other at a predetermined distance. Specimens for measurement. According to claim 1,
The third glass layer and the fourth glass layer are provided on both ends of the upper surface of the lower metal layer, wherein the third glass layer and the fourth glass layer are formed parallel to each other at a predetermined distance. Specimens for measurement. According to claim 1,
The third glass layer is formed in the lower region of the first intermediate metal layer corresponding to the position of the first glass layer,
The fourth glass layer is a specimen for measuring shear strength, characterized in that formed in the lower region of the second intermediate metal layer corresponding to the position of the second glass layer. According to claim 1,
The adhesive layer is
a first upper adhesive layer bonded to the lower surface of the upper metal layer and the upper surface of the first glass layer;
a first lower adhesive layer bonded to the lower surface of the first glass layer and the upper surface of the first intermediate metal layer;
a second upper adhesive layer bonded to the lower surface of the upper metal layer and the upper surface of the second glass layer;
a second lower adhesive layer bonded to the lower surface of the second glass layer and the upper surface of the second intermediate metal layer;
a third upper adhesive layer bonded to the lower surface of the first intermediate metal layer and the upper surface of the third glass layer;
a third lower adhesive layer bonded to the lower surface of the third glass layer and the upper surface of the lower metal layer;
a fourth upper adhesive layer bonded to the lower surface of the second intermediate metal layer and the upper surface of the fourth glass layer; and
A specimen for measuring shear strength comprising a; a fourth lower adhesive layer bonded to the lower surface of the fourth glass layer and the upper surface of the lower metal layer. 6. The method of claim 5,
A specimen for measuring shear strength, characterized in that the width length of the upper glass layer and the lower glass layer is longer than the width length of the adhesive layer. According to claim 1,
The thickness of the upper glass layer and the lower glass layer is a specimen for measuring shear strength, characterized in that the predetermined thickness or more so that the stress generated on the upper surface and the lower surface of each of the upper glass layer and the lower glass layer is spaced apart from each other. According to claim 1,
In the intermediate metal layer, the length of the first intermediate metal layer and the second intermediate metal layer are the same,
A specimen for measuring shear strength, characterized in that the length of the first intermediate metal layer or the second intermediate metal layer is longer than the length of the upper metal layer and the length of the lower metal layer. According to claim 1,
The thickness of the upper metal layer and the lower metal layer is a specimen for measuring shear strength, characterized in that it has a thickness greater than any one selected from the upper glass layer, the middle metal layer, and the lower glass layer. According to claim 1,
The specimen for measuring shear strength, characterized in that the upper glass layer and the lower glass layer are made of any one glass material selected from glass and glass ceramic.

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