JPS6276429A - Interlayer tensile test method for laminated plate - Google Patents

Abstract

PURPOSE:To measure the interlayer tensile strength of a laminated plate in the condition of the original plate thickness as it is by placing the plate so as to make the groove hole coincident with the hole axis of the hole of the supporting stand by putting down the surface to provide the groove hole, on the supporting stand having a hole larger than the outer shape of the groove hole, inserting the round bar of the same diameter into the circular shape hole and applying the load. CONSTITUTION:A testpiece is placed on a supporting stand 4 by putting down the surface provided with a groove hole 2. The hole larger than the outer diameter of the groove hole 2 is opened beforehand at the supporting stand 4, the hole axis of the mutual hole is made coincident and the part of the groove 2 is constituted so as not to contact with the surface of the supporting stand 4. A round bar 3 is inserted into a circular shape hole 1, the load is applied to the round bar 3, and thereby, at the part shown in an A part, the tensile force occurs in the interlayer direction of a laminated plate 5. Until the tensile destruction occurs at the interlayer, the load is applied to the round bar 3, the breaking load is divided by the area of a B part and then, the interlayer tensile strength of the laminated plate 5 can be obtained.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for interlaminar tensile testing of laminates.

[Conventional technology]

Since the laminate is an anisotropic plate, it has three-dimensional mechanical properties, and various tests are required to measure the properties. Examples of measurement methods include in-plane tensile tests, bending tests, and interlaminar shear tests, which are already compliant with the Japanese Industrial Standards (J
IS).

However, an appropriate test method for interlaminar tensile testing has not been established because the thickness of the laminate is thin. This is because, in order to perform a tensile test, gripping parts must be provided at both ends of the test piece in order to attach it to the gripping jig of the testing machine, and the test piece needs to have a certain length.

Possible methods for creating such a test piece include press-forming the laminate into a test piece much thicker than the original thickness, and using a laminate with the normal thickness to create a test piece. There is also a method of stacking the sheets and gluing them together with adhesive.

[Problem that the invention seeks to solve]

However, in the former method, in order to make the wall thick, the laminate has heat distribution during press forming, the curing conditions differ in each part of the laminate, and residual stress occurs, even if the laminate is made of the same material. This is not preferable since there is a possibility that the mechanical properties will differ due to the difference in plate thickness. Furthermore, in the latter method, it is difficult to increase the adhesive strength between the laminates beyond the interlaminar tensile strength, making it difficult to achieve the desired measurement.

The present invention provides a method by which an interlaminar tensile test can be performed on a laminate even when the original thickness remains unchanged.

[Means for solving problems]

The present invention involves drilling a non-penetrating straight circular hole in a laminate from the top surface, and drilling a non-penetrating circular slot hole from the bottom surface where the circular hole and the hole axis are connected to each other, and whose inner diameter is larger than the diameter of the circular hole. The holes were processed so that the total depth of each hole was greater than the thickness of the laminate, and this was used as a test piece. It is characterized in that it is placed with the side provided with it facing down so that the hole axes of the slot and the hole in the support stand are aligned, and a round rod of the same diameter is inserted into the circular hole to apply a load.

The present invention will be explained in detail with reference to the drawings.

FIG. 1 is a longitudinal sectional view illustrating the principle of an interlaminar tensile test method for a laminate. A straight circular hole 1 is provided on one side of the laminated plate 5, and a circular slot hole is provided on the other side so as to surround the straight circular hole 1. The two holes do not pass through each other, and their hole axes coincide with each other. The depth of the holes is machined so that there is a part where two holes overlap in the direction of the large ring, as shown in part A.

That is, the total depth of both holes is greater than the thickness of the laminate.

Next, the test method will be explained. The test piece is placed on the support stand 4 with the side with the slot 2 facing down. A hole larger than the outer diameter of the slot 2 is previously drilled in the support 4, and the axes of the holes are aligned to prevent the part of the slot 2 from contacting the surface of the support 4. A round rod 3 is inserted into the circular hole 1, and a load is applied to this round rod 3.

By doing so, a tensile force is generated in the interlayer direction of the laminate 5 at the portion indicated by A section. Round bar 3 until tensile failure occurs between this layer.
The interlaminar tensile strength of the laminate 5 can be determined by applying a load to the laminate 5 and dividing the breaking load by the area of section B in FIG.

Furthermore, since stress concentration is likely to be applied to portion a of the bottom of the circular hole 1 and portion b of the bottom of the slotted hole 2 when a load is applied, it is preferable to chamfer or round the edges. Further, it is preferable that the distance between the outer wall of the circular hole 1 and the inner wall of the slot hole 2 is in the range of 0.5 to 2 fl. If it is less than 0.5 fl, processing accuracy will deteriorate and dimension measurement will become difficult, and if it exceeds 2 fl, bending force will be applied to the part A rather than glabellar tensile force, which is not preferable.

〔Example〕

Hereinafter, the present invention will be explained in detail based on examples.

The laminate used was a phenolic resin laminate with a paper base. The plate thickness is 1.541 m. Figure 3 shows the tools used to process the test piece. (Al is a helical condom mill used for machining circular holes.The diameter is 1 dragon and the tip edge is 0,1
A chamfer of approximately 5 tm was chamfered. (b) is a two-blade parallel end mill that has been modified for slotting. The overall diameter is 3 mm, and the cutting edge has been processed to have a groove cutting blade with a blade width of 0.5 mm. The inner edge of the cutting edge of the groove cutting blade was chamfered to a depth of about 0.1'5 mm. The test piece was processed using a drilling machine, and both holes had a depth of 1 fl.

The test conditions are shown in Figure 4. A laminate plate, which is a test piece, is placed on a support stand, and a round bar 3 is inserted into the circular hole.

The tip of the round bar on the side to be inserted into the circular hole was chamfered to 0.150. A guide 6 is provided to prevent the round bar 3 from falling. A motor-driven tensile testing machine is used as the testing machine, and a compressive load is applied to the round bar 3. The test speed is 1 mm/min.

The test results are shown in Figure 5. This represents the change in interlaminar tensile strength with temperature.

〔Effect of the invention〕

According to the present invention, it has become possible to measure the interlaminar tensile strength of a laminate without changing its original thickness.

[Brief explanation of drawings]

Figure 1 is a longitudinal cross-sectional view explaining the principle of interlaminar tensile testing of laminated plates, Figure 2 is a plan view of processed N-laminated plates, and Figure 3 (a
l (b) is a front view of the tool used to process the specimen;
FIG. 4 is an explanatory longitudinal cross-sectional view during the test, and FIG. 5 is a graph showing the temperature change of the measurement results of the interlaminar tensile strength of the phenolic resin laminate using paper as the base material. 1 Circular hole 2 Slot 3 Round bar 4 Support stand 5 Laminated plate 6 Guide 771
．． 61. . Agent Patent Attorney Kunihiko Wakabayashi 1.゛、、"Pa□.!-・51' Figure 4 3L Degree ('C) Figure 5 Procedural Amendment (Spontaneous) 11th and 1st Tomoe, 1985, 1985 Patent Application No. No. 217299 2, Name of the invention Interlaminar tensile test method for laminates 3, Relationship with the case of the person making the amendment Patent applicant name +445) Hitachi Chemical Co., Ltd. 4, Agent
Person 6, Contents of amendment (1) The scope of the % claim is corrected as shown in the attached sheet. (2) In the 5th line of page 6 of the specification, the phrase "...to prepare test pieces..." is corrected to "...to tabulate test pieces..." . (5) Clarification: In the 7th line of page 4 of iF, the phrase "...larger than the outer diameter of the slot" is corrected to "...larger than the outer diameter of the slot." (4) “(a) is helicalco” on page 6, line 7 of the specification.
Correct the statement to read, ``(a) is King Helical.'' (5) In the 6th line from the bottom of the 7th page of the clear page ``Figure 6 (a)
(bJ Haha...”) [Figure 3 (a) (b)!!
"..." I corrected myself. (Attachment) Claim 1: A straight circular hole that does not penetrate from the top surface of the laminate, and a circular hole that does not penetrate from the bottom surface, whose thick axis coincides with the circular hole, and whose inner diameter is larger than the diameter of the circular hole. Drill a slotted hole, process the holes so that the total depth of each hole is greater than the thickness of the laminate, and use this as a test specimen to drill a hole larger than the outer diameter of the slotted hole. t Place the slotted side on the support base so that the thick axes of the slots and the holes in the support base are aligned, insert a round bar with the same diameter into the circular hole, and apply the load. An interlaminar tensile test method for a laminate, characterized in that the edge of the bottom of the straight circular hole of the test specimen and the inner edge of the bottom of the circular slot are rounded or rounded. Interlaminar tensile testing method for laminates according to paragraph 1. 5. A patent in which the distance between the outer wall of the straight circular hole of the test piece and the inner wall of the circular slot is in the range of 0.5 to 2.0111ffl (1). An interlaminar tensile test method for a laminate according to claim 1 or 2.

Claims (1)

[Scope of Claims] 1. A straight circular hole that does not penetrate from the top surface of the laminate, and a circular groove that does not penetrate from the bottom surface and whose hole axis coincides with the circular hole and whose inner diameter is larger than the diameter of the circular hole. Holes were drilled and processed so that the total depth of each hole was greater than the thickness of the laminate, and this was used as a test piece and placed on a support stand with a hole larger than the outer diameter of the slot. , with the side with the slotted hole facing down, the hole axes of the slotted hole and the hole of the support stand are aligned, and a round rod of the same diameter is inserted into the circular hole to apply a load. Interlaminar tensile test method for laminates. 2. The interlaminar tensile test method for a laminate according to claim 1, wherein the edge of the bottom of the straight circular hole of the test piece and the inner edge of the bottom of the circular slot are chamfered or rounded. 3. The laminate according to claim 1 or 2, wherein the distance between the outer wall of the straight circular hole and the inner wall of the circular slot of the test piece is in the range of 0.5 to 2.0 mm. Interlaminar tensile test method.