JP3724715B2 - Bonding strength measurement method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for measuring joint strength, and more specifically, joint strength for accurately measuring the joint strength in the shear direction of joint surfaces obtained by overlapping two members and joining them using brazing, welding, or an adhesive. It relates to a measurement method.
[0002]
[Prior art]
FIG. 2A shows a method conventionally used for measuring the joining strength in the shearing direction of the joining surface where two flat test pieces are joined together. As shown in this figure, the test piece 21 and the test piece 22 are overlapped in a certain range from one end thereof, and the overlapped portion is joined by brazing, welding, adhesive or the like. In addition, B represents a joining surface and F and F ′ represent a state in which a tensile load is applied.
[0003]
In the conventional measuring method shown in FIG. 2, two flat test pieces are subjected to a shear force on the joint surface by applying a tensile load F, F ′ to the center of the surface at each other end, and the joint surface is sheared. The joint strength of the joint surface was measured by measuring the tensile load at the time.
[0004]
[Problems to be solved by the invention]
However, in the conventional bonding strength measurement method of the type in which two conventional test pieces are overlapped and bonded, the action axes of F and F ′ do not coincide with each other, and the deviation H in the height direction between F and F ′ (FIG. 2). A moment proportional to (b) is generated. Therefore, it has not been possible to obtain an accurate joint strength of the joint surface only by measuring the magnitude of the tensile load F (= F ′) during shearing.
[0005]
That is, when the acting axes of the tensile loads F and F ′ do not coincide with each other and the moment acts on the test pieces 21 and 22, the test piece is warped as shown in FIG. 2C, and all the applied tensile loads are sheared. As a result of not acting on the direction, even if the magnitude of the tensile load at the time of shearing was measured, it could not be used as it was.
[0006]
Therefore, in the conventional method, the correction calculation using the correction term is performed on the measured value of the tensile load at the time of shearing, and the joint strength in the shear direction is obtained indirectly.
[0007]
In addition, when the test piece is weak to bending and is a low ductility (brittle) metal or the like, and the test piece is strongly bonded, the test piece itself is bent (warped) before the joint surface is sheared. Sometimes it broke.
[0008]
The present invention does not indirectly measure the joint strength in the shear direction of the joint surface by using the correction term by matching the axis of action of the tensile load acting on the joint surface, but directly uses the tensile load during shearing as it is. The present invention provides a bonding strength measuring method that can be employed as the bonding strength.
[0009]
[Means for Solving the Problems]
The method for measuring the bonding strength of the present invention is the bonding strength in the shear direction of the bonding surface (B) in which a part of the flat plate-like base material (2, 2 ′) and the thin flat plate-like connecting material (4) are bonded together. Is a bonding strength measurement method for measuring a base material and a connecting material by positioning two base materials facing each other with the upper surface (8) being flush with each other, and linking the connecting material over the upper surface. After joining, a tensile force (F, F ′) is applied to the two base materials to apply a shearing force to the joint surface, and the tensile load when the base material is sheared from the connecting material is measured.
A reinforcing material (12) is bonded to the upper surface of the thin flat connecting material (4),
The reinforcing material (12) has a tensile are parallel to upright to pulling direction to apply a load, the thickness of the warp to the connecting member when applying a tensile load is so hardly, top and vertical connecting members It is the flange-shaped thick board (14) which has in a certain direction, It is characterized by the above-mentioned.
[0010]
According to the bonding strength measuring method of the present invention, since the action axes of the tensile loads (F, F ′) can be matched, the base material (2, 2 ′) and the connecting material (4) are almost warped. The measured value of the tensile load during shearing can be used as it is as the bonding strength. Note that F and F ′ have opposite directions of action and have the same size due to the law of action and reaction.
[0014]
When the tensile load applied to the base material and the shearing force acting on the joint surface are not completely on the same plane, a bending moment acts on the connecting material, causing warpage of the connecting material, and as a result, close contact with the connecting material. Warpage also occurs in the joined base material. When the base material is warped, a shearing force and a tensile force act on the joint surface, so that the tensile load value when the joint surface shears cannot be directly used as the joint strength. Then, this is reinforced by joining a reinforcing material to the upper surface of a connecting material, and the curvature of a connecting material is suppressed. Thereby, it becomes possible to employ | adopt the tensile load value at the time of the shearing of a joint surface as joining strength as it is. Note that, instead of joining the reinforcing material, increasing the thickness of the connecting material itself is also effective in suppressing warpage of the connecting material. In that sense, it can be said that the present invention provides a measuring method in the case where a thin flat plate is used for the connecting material itself.
[0016]
The present invention, since Fit takes erected parallel to the direction pulling the flange-like slab on the upper surface of the connecting member, it is possible to effectively suppress warpage generated in the coupling member.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.
[0018]
Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. FIG. 1 shows an embodiment of the bonding strength measuring method of the present invention. Here, FIG. 1 (a) is a perspective view of an embodiment of the present bonding strength measuring method, and FIG. 1 (b) is a side view thereof. In this embodiment, the bonding strength of the bonding surface B is measured.
[0019]
In order to carry out the bonding strength measuring method of the present invention, two base materials 2 and 2 'made of thin strip-shaped metal plates are arranged in a state of a flat table in a state where the longitudinal axes thereof coincide with each other and one end on the short side faces each other. It is positioned at a certain distance above it. Here, the base materials 2 and 2 ′ have the same thickness, and therefore the two base materials have their upper surfaces flush with each other.
[0020]
Further, a connecting material 4 is stretched between the base materials 2 and 2 ′, and the base materials 2 and 2 ′ and the connecting material 4 are joined by brazing. The base material 2, 2 ′ and the connecting material 4 are joined in a certain range from the opposite ends of both base materials, and the area of the joint surface B ′ between the base material 2 ′ and the connecting material 4 is: The area of the joint surface B between the base material 2 and the connecting material 4 is larger, and the base material 2 ′ and the connecting material 4 are joined more firmly than the base material 2 and the connecting material 4. Therefore, when shearing occurs at the joint surface, it occurs at the joint surface B between the base member 2 and the connecting member 4.
[0021]
Here, the connecting member 4 is made of a rectangular metal plate (may be the same metal as the base member or a different metal) having the same width as the short sides of the base members 2 and 2 ′. On the upper surface, two thick plates 14 are welded in a flange shape in parallel with the longitudinal direction of the connected base material.
[0022]
The other end on the short side of the base material 2 ′ is firmly fixed to the fixed wall, and the other end on the short side of the base material 2 is the tip of the rod provided in a tensioning device such as a hydraulic cylinder (not shown). It is sandwiched between chuck mechanisms. A tensile load F is applied to the base material 2 in the same horizontal plane in the longitudinal direction by the tension device.
[0023]
When a tensile load F is applied to the base portion 2, a bending moment acts on the connecting member 4, so that the connecting member tends to bend downward as shown in FIG. However, a flange-shaped thick plate 14 is joined to the upper surface of the connecting material 4 by welding, and this thick plate 14 prevents the connecting material 4 from warping. Therefore, in reality, the connecting material 4 hardly warps, and therefore, the base materials 2 and 2 ′ tightly bonded to the connecting material 4 hardly warp. When the planar state of the connecting member 4 and the base members 2, 2 ′ is maintained, almost all of the applied tensile load F acts as a shearing force on the joint surface B. When this shearing force exceeds the bonding strength, the bonding surface B is broken.
[0024]
Therefore, according to the bonding strength measuring method shown in the present embodiment, the tensile load value at the time of fracture can be directly adopted as the bonding strength of the bonding surface.
[0025]
Further, when the base materials 2 and 2 ′ have a certain thickness, it is preferable that the tensile load applied to the base material is applied in substantially the same plane as the upper surface 8 of the base material.
[0026]
That is, by making the tensile load applied to the base material and the shearing force acting on the joint surface substantially on the same plane, the bending moment acting on the connecting material 4 is reduced, and the joint strength in the shear direction of the joint surface is more accurate. Can be measured.
[0027]
【The invention's effect】
As described in detail above, according to the present invention, the joint surface is sheared indirectly using a correction term by preventing the warpage occurring in the connecting material and matching the action axes of the tensile loads acting on the joint surface. Instead of measuring the bonding strength in the direction, it is possible to provide a method for measuring the bonding strength in which the tensile load value at the time of shearing can be directly adopted as the bonding strength in the shearing direction.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a bonding strength measuring method of the present invention.
FIG. 2 is a diagram showing an embodiment of a conventional method for measuring bonding strength.
[Explanation of symbols]
2, 2 'Base material 4 Connecting material 8 Upper surface 12 Reinforcement material 14 Thick plates 21, 22 Test piece B, B' Joint surface F, F 'Tensile load H Misalignment

Claims (3)

Bonding strength measurement method for measuring the bonding strength in the shearing direction of the bonding surface (B) in which a part of the flat plate-like base material (2, 2 ') and the thin flat plate-like connecting material (4) are bonded together. The two base members are positioned so that the upper surfaces (8) thereof are flush with each other, the connecting members are stretched over the upper surfaces, and the base members and the connecting members are joined together. By applying a tensile load (F, F ′) to the material, a shear force is applied to the joint surface, and the tensile load when the base material is sheared from the connecting material is measured,
A reinforcing material (12) is bonded to the upper surface of the thin flat connecting material (4),
The reinforcing material (12) has a tensile are parallel to upright to pulling direction to apply a load, the thickness of the warp to the connecting member when applying a tensile load is so hardly, top and vertical connecting members It is the flange-shaped thick board (14) which has in a certain direction, The joining strength measuring method characterized by the above-mentioned. The reinforcing material (12) is thin in a direction perpendicular to the tensile direction and parallel to the upper surface of the connecting material, and is perpendicular to the tensile direction and spaced in a direction parallel to the upper surface of the connecting material. The joint strength measuring method according to claim 1, wherein two are provided . The method for measuring the bonding strength according to claim 2 , wherein the reinforcing member (12) extends from one end portion to the other end portion of the connecting member in a tensile direction .

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