JP2005091171A - Method and device for testing rubbing strength, and test piece therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method, a device and a test piece for testing rubbing strength capable of testing the rubbing strength in a bonding face end part of the test piece between a metal material and a synthetic resin material, without providing an initial crack. <P>SOLUTION: In this rubbing strength testing method for testing the rubbing strength in the bonding face end part of the test piece 1 bonded with the metal material and the synthetic resin material, by measuring a crack occurrence load in the bonding face end part by a three-point bending test, a support space for supporting the test piece 1 is brought into a length of precluding plastic deformation from being caused in a metal material layer of the test piece 1. The test piece 1 has a prism shape, and a longitudinal-directional neutral axis of a bending stress is positioned on a bonding face between the metal material and the synthetic resin material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sliding strength test method and apparatus that can accurately grasp the shear strength at the end of a test piece having a two-layer structure of a metal material and a synthetic resin material, and the test piece.

  When testing the sliding strength at the edge of the bonded surface of a composite material, conventionally, a composite material end peeling test using a three-point bending test or an end notch bending test similar to a single material has been performed. I have been. The end peel test is a test method in which a tab is attached to the end of a test piece, and the adhesive strength of the adhesive surface is measured when the tab is peeled up and down. The end notch bending test is a test method in which a crack is created in the center of the end of the test piece in advance and the test piece is attached to a bending jig so that the initial crack length is approximately 25 mm (see Non-Patent Document 1). ).

  A conventional end notch bending test apparatus using a test piece having an initial crack at the end will be described with reference to the drawings. FIG. 7 is a schematic diagram of a fracture toughness test apparatus using a test piece having an initial crack at the end. As shown in FIG. 7, the test apparatus is provided with two support bases 82 parallel to each other on a reference horizontal plane, and supports the beam-shaped test piece 81 with the two support bases 82. The support portion of the test piece 81 of the support base 82 has a top portion whose side cross-sectional shape is an arc shape so as to contact the test piece 81. A load applying means 83 for applying a bending load to the test piece 81 is provided in the vicinity of the middle point between the support points that are the contact points between the top and the test piece 81.

  The test piece 81 has a prismatic shape, and an initial crack having a depth a parallel to the bonding surface of the test piece 81 is provided at one end of the test piece 81 in the longitudinal direction of the test piece 81. The surface on which the initial crack is provided is generally different from the adhesion surface of the test piece. A fracture toughness test is performed by placing the test piece 81 provided with the initial crack horizontally on the two support tables 82 of the test apparatus.

At the time of the test, the bending load P is applied using the weight applying means 83 in the vicinity of the middle point of the distance l between the support points that supports the test piece 81. When the bending load P is applied, an initial crack provided in advance at one end of the test piece 81 grows, and the shear force acting on the surface where the crack progresses causes the end of the test piece 81 having the initial crack. COD (Crack Opening Displacement), which is a relative displacement, occurs between the upper surface and the lower surface. Based on the relationship between the COD and the bending load P, the fracture toughness of the test piece is obtained.
Reef A, Leif A. Carlsson, R. Byron Pipes, Hiroshi Fukuda, two other translations, "Experimental evaluation of high performance composite materials", Kokon Shoin, p. 134-138

  However, for example, in the case of a test piece having a two-layer structure composed of a metal material and a synthetic resin material, the difference in the adhesive surface strength due to the presence of irregularities on the surface of the metal material cannot be measured in the edge peeling test. There is a problem that it takes time and effort to bond the tab to the test piece, and the test efficiency is poor. Also, in the end notch bending test, it is necessary to provide an initial crack at the end, so the initial crack initiation strength can be measured in principle with the metal material layer and the synthetic resin material layer adhered at the end. In addition, since the film is already inserted at the end of the adhesive surface between the metal material layer and the synthetic resin material layer, the adhesive strength at the end of the adhesive surface between the metal material layer and the synthetic resin material layer is directly measured. There was a problem that it was not possible.

  In addition, when an initial crack in the horizontal direction is provided at the end in accordance with the adhesion surface between the metal material and the synthetic resin material of the test piece, delamination occurs more easily than a normal material that does not have a two-layer structure. Even when a bending load is applied, the initial crack may grow, so that there is a problem that the measured test result lacks reliability.

  The present invention has been made in view of such circumstances, and it is possible to test the sliding strength at the end of the bonding surface between the metal material and the synthetic resin material of a test piece having a two-layer structure without providing an initial crack. An object of the present invention is to provide a sliding strength test method and apparatus, and a test piece. Furthermore, it aims at providing the sliding strength test method and apparatus which can evaluate a test result accurately, and a test piece.

  In order to achieve the above object, the sliding strength test method according to the first invention is characterized in that the sliding strength at the end of the bonding surface of a test piece formed by bonding a metal material and a synthetic resin material is determined by a three-point bending test. In the sliding strength test method for testing by measuring the crack initiation load at the end, the support interval for supporting the test piece is a length that does not cause plastic deformation in the metal material layer of the test piece. And

  The sliding strength test method according to the second invention is characterized in that, in the first invention, the support interval l of the test piece by the support means is an interval satisfying (Equation 4).

Here, t ₁ represents the thickness of the metal material layer of the test piece, σ ^Y represents plastic stress, and τ ^B _int represents the shear strength at the bonding surface between the metal material and the synthetic resin material.

Further, the sliding strength test method according to the third aspect of the present invention is the second aspect of the present invention, wherein the shear strength τ ^B _int at the bonding surface between the metal material and the synthetic resin material of the test piece is the shear strength in the shear strength distribution in the longitudinal direction. It is the maximum value of.

Further, in the second aspect of the present invention, the shear strength test method according to the fourth invention is the shear strength τ ^B _int at the bonding surface between the metal material and the synthetic resin material of the test piece is the shear strength in the shear strength distribution in the longitudinal direction. It is the average value of.

  Further, the sliding strength test method according to the fifth invention is the surface property parameter Rs calculated based on (Equation 5) using the amplitude and wavelength of the surface profile of the metal material of the test piece in the first to fourth inventions. And a correlation between the measured crack initiation load at the edge portion of the adhesion surface and the measured value.

Here, a _i represents the amplitude of the i-th frequency component of the surface profile, λ _i represents the wavelength of the i-th frequency component of the surface profile, and i represents a natural number from 1 to n.

  The test piece according to the sixth invention is a test piece used in the sliding strength test method of the first to fifth inventions, and has a prismatic shape, and the neutral axis of the bending stress in the longitudinal direction is a metal material and a synthetic resin material. It is located on the adhesive surface.

  The test piece according to the seventh invention is characterized in that, in the sixth invention, the thickness of the metal material layer and the synthetic resin material layer satisfy the relationship of (Equation 6). To do.

Where t ₁ is the thickness of the metal material layer, t ₂ is the thickness of the synthetic resin material layer, E ₁ is the Young's modulus of the metal material, and E ₂ is the Young's modulus of the synthetic resin material. Respectively.

  The test piece according to an eighth aspect of the invention is characterized in that, in the sixth or seventh aspect, the metal material is a steel material.

  The test piece according to a ninth invention is characterized in that, in the sixth to eighth inventions, the synthetic resin material is an epoxy synthetic resin.

  Further, the sliding strength test apparatus according to the tenth invention comprises a supporting means for supporting the test piece at two points and a load applying means for applying a bending load in the middle of the support interval of the test piece. Slidable by bonding a metal material and a synthetic resin material, and testing the sliding strength at the end of the adhesive surface of the test piece by measuring the crack initiation load at the end of the adhesive surface by a three-point bending test. In the strength test apparatus, the support interval of the test piece by the support means is a length that does not cause plastic deformation in the metal material layer of the test piece.

  In the first, second, and tenth inventions, when a three-point bending test is performed on a test piece having a two-layer structure of a metal material layer and a synthetic resin material layer, the test piece in a three-point bending test apparatus The support interval 1 is determined within a range in which plastic deformation does not occur in the metal material portion of the test piece. As a result, it is possible to accurately measure the generated bending load of the initial crack generated at the end of the test piece within the range of elastic deformation.

  In the third invention, the maximum value of the support interval 1 at which plastic deformation does not occur in the metal material portion of the test piece is obtained based on the maximum value of the shear strength at the bonding surface between the metal material and the synthetic resin material. As a result, the three-point bending test can be performed within a range in which plastic deformation does not occur in the metal material.

  In the fourth invention, the maximum value of the support interval l at which plastic deformation does not occur in the metal material portion of the test piece is obtained based on the average value of the shear strength at the bonding surface between the metal material and the synthetic resin material. Thereby, a 3 point | piece bending test can be implemented in the range in which plastic deformation does not arise in a metal material as the whole test piece.

  Further, in the fifth invention, in the means for obtaining the correlation of the crack generation load that is the measurement result of the three-point bending test, not only the amplitude of the surface profile of the metal material at the bonding surface between the metal material and the synthetic resin material, The surface profile of the metal material is subjected to frequency analysis, and the surface property parameter for evaluating the correlation is calculated using the ratio between the amplitude and the wavelength of each frequency component obtained from the frequency component. Thereby, the correlation of the crack generation load can be obtained by considering the roughness of the surface of the metal material in addition to the unevenness distribution on the surface as well as the unevenness distribution on the surface.

  In the sixth and seventh inventions, the test piece used in the above-described sliding strength test method is a prismatic test piece having a two-layer structure made of a metal material and a synthetic resin material, and has a neutral axis of bending stress. However, it coincides with the adhesion surface between the metal material and the synthetic resin material in the test piece. Thereby, it is not necessary to make an initial crack in the test piece, and a crack occurrence portion at the end portion of the test piece due to the shear stress generated by applying a bending load is an adhesion surface between the metal material and the synthetic resin material.

  In the eighth and ninth inventions, a steel material such as steel or stainless steel is used as the metal material, and an epoxy synthetic resin is used as the synthetic resin material.

  In the first, second, and tenth inventions, a three-point bending test is performed on a test piece having a two-layer structure of a metal material layer and a synthetic resin material layer, and a bending load that causes an initial crack in the test piece is applied. When determining, since the support interval l of the test piece is determined within a range in which plastic deformation does not occur in the metal material portion of the test piece, the sliding strength of the end due to the shearing force at the bonding surface between the metal material and the synthetic resin material is determined. It becomes possible to measure accurately.

  In the third aspect of the invention, the range in which plastic deformation does not occur in the metal material portion of the test piece is obtained on the basis of the maximum value of the shear strength at the bonding surface between the metal material and the synthetic resin material. It can be determined within a range in which plastic deformation does not occur reliably in the material portion, and it is possible to accurately measure the sliding strength of the end due to the shearing force at the bonding surface between the metal material and the synthetic resin material.

  Further, in the fourth invention, the range in which plastic deformation does not occur in the metal material portion of the test piece is obtained based on the average value of the shear strength at the bonding surface between the metal material and the synthetic resin material. It can be determined within a range in which plastic deformation does not occur in the metal material portion, and it is possible to accurately measure the sliding strength of the end due to the shearing force at the bonding surface between the metal material and the synthetic resin material.

  Further, in the fifth invention, in order to obtain the correlation of the crack generation load, which is the measurement result of the three-point bending test, not only the height of the unevenness on the surface of the metal material at the bonding surface between the metal material and the synthetic resin material. The surface of the metal material is calculated by frequency analysis of the uneven distribution in the longitudinal direction of the metal material and calculating the surface property parameter for evaluating the correlation using the ratio between the amplitude and the wavelength of each frequency component obtained by the frequency analysis. By taking into account the distribution of the height of the unevenness of the surface, more accurately determining the correlation of cracking load, without carrying out a three-point bending test on the unevenness state of all the surfaces polished with paper, It is possible to estimate the crack generation load by grasping the state of the metal material surface.

  According to the sixth and seventh inventions, even if the test piece used in the sliding strength test method is a prismatic test piece having a two-layer structure composed of a metal material and a synthetic resin material, the metal material and the synthetic resin material are used. It is possible to accurately measure the initial crack generation load at the end portion of the test piece due to the shear stress of the bonding surface caused by bending without causing an initial crack on the bonding surface.

  In the eighth and ninth inventions, it is possible to reliably measure the sliding strength by using a steel material such as steel or stainless steel as the metal material and using an epoxy synthetic resin as the synthetic resin material. Become.

(Embodiment 1)
FIG. 1 is a schematic diagram showing the configuration of a test apparatus used in the sliding strength test method according to Embodiment 1 of the present invention. As shown in FIG. 1, two support bases 2 and 2 for supporting a prismatic test piece 1 are installed on a base base 4 having a horizontal flat plate. The support bases 2 and 2 are prismatic members whose side cross-sectional shape is substantially triangular, and have a top portion whose side cross-sectional shape is an arc shape so as to support the test piece 1. The test apparatus is provided with a load application device (load application means) 3 for applying a bending load above the middle point of the two support bases 2 and 2. The load application device 3 is attached to the cross head so as to be in contact with the width direction of the test piece 1 placed horizontally during the test, and applies a load by pressing the cross head against the test piece 1 at a constant speed. .

  The value of the load P applied by the load applying device 3 is transmitted to the arithmetic processing means 13 connected by the signal line. A strain gauge 10 is affixed to one end of the test piece 1 in order to detect that a crack has occurred on the bonding surface between the metal material and the synthetic resin material of the test piece 1. The strain at one end detected by the strain gauge 10 is transmitted to the arithmetic processing means 13 such as a computer or a microprocessor via a signal line. When it is detected that the measured value at the strain gauge rapidly fluctuates beyond a predetermined ratio, the load applied at that time is detected as the initial crack generation load.

  Based on the initial crack generation load P, the calculation processing means 13 calculates the correlation with the surface property parameter indicating the unevenness of the surface of the steel material such as steel or stainless steel. Details of the calculation contents will be described later. The calculation result is displayed on the display, LCD, etc. by the output means 14, or printed out on a printer, plotter, etc.

  FIG. 2 is a perspective view of a test piece used in the sliding strength test method according to Embodiment 1 of the present invention. As shown in FIG. 2, the test piece 1 is a prismatic beam member having a two-layer structure, and an epoxy-based synthetic resin material layer 12 is attached to a metal material layer 11 made of steel such as steel or stainless steel. It has been. And the strain gauge 10 is arrange | positioned in the position shown with the broken line of FIG. 2 so that it may straddle the metal material layer 11 and the synthetic resin material layer 12 in the one end part of the test piece 1. FIG.

  In the sliding strength test method according to the first embodiment, a three-point bending test is performed without making an initial crack between the metal material layer 11 and the synthetic resin layer 12 of the test piece 1. Specifically, the test piece 1 is placed horizontally so as to be supported by the two support bases 2, a bending load is applied from above by the load applying device 3, and the adhesive surface between the metal material layer 11 and the synthetic resin layer 12 is applied. Causes initial cracks. The applied load at the time when the initial crack occurs is measured as the initial crack generation load.

  In order to cause an initial crack at the bonding surface between the metal material layer 11 and the synthetic resin layer 12 when the three-point bending test is performed, the surface where the neutral axis of the bending stress exists is the metal material layer 11 and the synthetic resin layer 12. It is necessary to match with the adhesive surface. Therefore, by providing the relationship of (Equation 7) between the thickness of the metal material layer 11 and the thickness of the synthetic resin layer 12, the surface where the neutral axis of the bending stress exists is the metal material layer 11 and the synthetic resin. It becomes an adhesive surface with the layer 12.

However, the thickness of t ₁ is a metal material layer 11, the thickness of t ₂ is the synthetic resin layer 12, E ₁ is the Young's modulus of the metallic material layer 11, E ₂ is the Young's modulus of the synthetic resin layer 12, Each one is shown.

  Further, when the three-point bending test is performed, it can be assumed that the elastic deformation due to the bending stress of the metal material layer 11 shifts to plastic deformation depending on the arrangement interval of the support base 2. When shifting to plastic deformation, the shear strength at the end of the specimen cannot be accurately determined.

  Therefore, the support interval 1 of the test piece 1 by the support base 2 needs to be an interval smaller than the limit length at which the elastic deformation due to the bending stress shifts to the plastic deformation. When the support interval 1 of the test piece 1 by the support base 2 satisfies (Equation 8), plastic deformation does not occur in the metal material layer 11 of the test piece 1.

Here, t ₁ indicates the thickness of the metal material layer 11, σ ^Y indicates the plastic stress of the metal material, and τ ^B _int indicates the shear strength at the bonding surface between the metal material and the synthetic resin material.

The shear strength τ ^B _int at the bonding surface between the metal material and the synthetic resin material varies depending on the degree of unevenness on the surface of the metal material. Therefore, the shear strength τ ^B _int distribution at the bonding surface between the metal material and the synthetic resin material in the longitudinal direction of the test piece 1 is obtained, and the constraint condition of the support interval l is changed as necessary. That is, usually, the constraint condition of the support interval l is obtained using the distribution average value of the shear strength τ ^B _int . In the case of a material having a high probability of plastic deformation due to the properties of the test piece 1, the constraint condition of the support interval l is obtained using the maximum value of the shear strength τ ^B _int . Thereby, without causing plastic deformation in the metal material layer 11, it becomes possible to obtain the load P at the time when the initial crack is generated at the end of the bonding surface of the test piece 1 with high reliability.

The distribution average value of the shear strength τ ^B _int is obtained, for example, by obtaining the shear strength at the bonding surface between the metal material and the synthetic resin material for each of five test pieces and dividing the sum by five. Use the value. As the maximum value of the shear strength τ ^B _int , for example, the shear strength at the bonding surface between the metal material and the synthetic resin material of 5 to 10 test pieces is obtained, and these maximum values are used.

  As described above, according to the first embodiment, even when the test piece used in the sliding strength test method is a prismatic test piece having a two-layer structure made of a metal material and a synthetic resin material, it is synthesized with the metal material. It is possible to accurately measure the initial crack generation load at the end portion of the test piece due to the shear stress of the bonding surface caused by bending without causing an initial crack on the bonding surface with the resin material.

  Further, since the support interval l of the test piece is determined within a range in which plastic deformation does not occur in the metal material layer of the test piece, the edge sliding strength due to the shearing force at the bonding surface between the metal material and the synthetic resin material is high. It can be obtained with reliability.

(Embodiment 2)
In the second embodiment, the means for obtaining the correlation based on the parameter representing the surface property of the steel material with respect to the shear strength at the edge of the bonding surface when using the steel material as the metal material and the epoxy-based synthetic resin as the synthetic resin material. Will be described.

The test piece 1 has a prismatic shape and is a two-layer composite beam composed of a steel material and an epoxy-based synthetic resin. The test piece 1 was produced by cutting a steel plate in a predetermined direction with emery paper and cutting it out from an original plate which was poured and cured with an epoxy synthetic resin. The average main dimension of the test piece 1 was 15 mm in height, 16 mm in width, and 51 mm in length, and the average thickness t ₁ of the steel material part was 2 mm.

  As the load application means 3, a Tensilon static load tester was used, and the crosshead speed was set to 1 mm / min and applied to the upper surface of the test piece 1 on the epoxy synthetic resin side. The support interval l of the test piece 1 was 20 mm. FIG. 3 is a diagram showing the results of obtaining the load at the time when the initial crack occurred under such conditions.

  In FIG. 3, the paper number is the number of the emery paper obtained by polishing the steel surface. The larger the number, the smaller the unevenness. The smaller the emery paper number, that is, the rougher the surface of the steel material, the larger the load when the initial crack occurs.

  Next, the surface profile of the steel material that is the test piece 1 is measured. The specific measurement method is that the polishing direction by the emery paper is 0 degree, and the surface is linearly with a nominal accuracy of 1 μm in directions of 0, 90, and 135 degrees within a circle of 5 mm in diameter with the center point of the test piece 1 as the origin. Measure the height of unevenness. After performing smoothing by applying inclination correction to each measured unevenness height, frequency analysis is performed. The surface property parameter Rs is calculated by (Equation 9) using the frequency analysis component of the surface profile.

Here, a _i represents the amplitude of the i-th frequency component of the surface profile, and λ _i represents the wavelength of the i-th frequency component of the surface profile.

  FIG. 4 is a diagram showing a result of plotting the initial crack generation load shown in FIG. 3 against the surface property parameter Rs obtained by (Equation 9). As a comparison, FIG. 5 is a diagram showing a result of plotting the initial crack generation load shown in FIG. 3 against the arithmetic average value Ra of the unevenness height of the surface profile. FIG. 6 is a diagram showing a result of plotting the initial crack generation load shown in FIG. 3 against the root mean square deviation RMSQ from the average surface.

  FIG. 4 is compared with FIG. 5 and FIG. Based on the regression lines 51, 61, and 71 of the plot, the root mean square values of the deviations are 83.2, 76.3, and 67.5, respectively. The results plotted against the surface property parameter Rs are as follows. It can be seen that the best linearity is shown. Further, when attention is paid to the initial crack generation load in the paper numbers 1000 and 400, in FIG. 5 and FIG. 6, the paper number 1000 is evaluated to be rougher than the paper number 400, and the roughness of the polished surface is increased. Has been evaluated in reverse. On the other hand, in FIG. 4, the evaluation reversal phenomenon by the paper number does not occur. Therefore, the method of evaluating the correlation based on the surface property parameter Rs can obtain the correlation with the initial crack generation load with higher accuracy.

  As described above, according to the second embodiment, a correlation that accurately reflects the uneven distribution on the surface of the metal material with respect to the bending load P at the time when the initial crack occurs at the end of the adhesion surface of the test piece having a two-layer structure. Thus, by calculating the surface property parameter Rs, it is possible to estimate the initial crack generation load on the test piece 1 with high accuracy.

It is a schematic diagram which shows the structure of the sliding strength test apparatus which concerns on Embodiment 1 of this invention. It is a perspective view of the test piece used for the sliding strength test method which concerns on Embodiment 1 of this invention. It is a figure which shows the result of having calculated | required the load at the time of an initial stage crack generating. It is a figure which shows the result of having plotted the initial stage crack generation load with respect to the surface property parameter Rs. It is a figure which shows the result of having plotted the initial crack generation load with respect to arithmetic mean value Ra of the uneven | corrugated height of a surface profile. It is a figure which shows the result of having plotted the initial crack generation load with respect to the root mean square deviation RMSQ from the average surface. It is a schematic diagram of the fracture toughness test apparatus using the test piece which provided the initial stage crack in the edge part.

Explanation of symbols

1 Test piece 2 Support base (support means)
3 Load application device (load application means)
4 Foundation table 10 Strain gauge 11 Metal material layer 12 Synthetic resin material layer 13 Arithmetic processing means 14 Output means

Claims (10)

A sliding strength test method for testing the sliding strength at the bonding surface end of a test piece formed by bonding a metal material and a synthetic resin material by measuring the crack initiation load at the bonding surface end by a three-point bending test In
The sliding strength test method according to claim 1, wherein the support interval for supporting the test piece is set to a length that does not cause plastic deformation in the metal material layer of the test piece. The sliding strength test method according to claim 1, wherein the support interval l of the test piece by the support means is an interval satisfying (Equation 1).

However,
t ₁ : thickness of the metal material layer of the test piece σ ^Y : plastic stress τ ^B _int : shear strength at the bonding surface between the metal material and the synthetic resin material The shear strength test according to claim 2, wherein the shear strength τ ^B _int at the bonding surface between the metal material and the synthetic resin material of the test piece is the maximum value of the shear strength in the shear strength distribution in the longitudinal direction. Method. The shear strength test according to claim 2, wherein the shear strength τ ^B _int at the bonding surface between the metal material and the synthetic resin material of the test piece is an average value of the shear strength in the shear strength distribution in the longitudinal direction. Method. Using the amplitude and wavelength of the surface profile of the metal material of the test piece, calculating the correlation between the surface property parameter Rs calculated based on (Equation 2) and the crack initiation load at the end of the adhesion surface. The sliding strength test method according to any one of claims 1 to 4, wherein:

However,
a _i : amplitude of i-th frequency component of surface profile λ _i : wavelength of i-th frequency component of surface profile i: natural number from 1 to n In the test piece used for the sliding strength test method according to any one of claims 1 to 5,
A test piece having a prismatic shape, wherein a neutral axis of a bending stress in a longitudinal direction is located on an adhesive surface between a metal material and a synthetic resin material. The test piece according to claim 6, wherein the thickness of the metal material layer and the thickness of the synthetic resin material satisfy the relationship of (Equation 3).

However,
t ₁ : layer thickness of the metal material t ₂ : layer thickness of the synthetic resin material E ₁ : Young's modulus of the metal material E ₂ : Young's modulus of the synthetic resin material   The test piece according to claim 6 or 7, wherein the metal material is a steel material.   The test piece according to claim 6, wherein the synthetic resin material is an epoxy-based synthetic resin. A supporting means for supporting the test piece at two points, and a load applying means for applying a bending load in the middle of the support interval of the test piece,
The test piece is formed by bonding a metal material and a synthetic resin material, and the sliding strength at the end of the adhesive surface of the test piece is measured for the crack initiation load at the end of the adhesive surface by a three-point bending test. In the sliding strength test equipment to be tested by
The sliding strength test apparatus according to claim 1, wherein the support interval of the test piece by the support means is a length that does not cause plastic deformation in the metal material layer of the test piece.

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