JP2014074655A - Tensile strength testing method of filament-reinforced metal matrix composite material and tensile test piece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tensile strength testing method of a filament-reinforced metal matrix composite material capable of stably and precisely performing a tensile strength test.SOLUTION: The tensile strength testing method is a method to test on a filament-reinforced metal matrix composite material in the longitudinal direction, in which plural high strength continuous filaments (12) are disposed adjacent to the central axis thereof along a longitudinal direction of a rod-like matrix metal (11). The rod-like matrix metal (11) has a parallel portion (13) where a part in the longitudinal direction is reduced in thickness and a pair of grip portions (14) formed at both outer end portions interposed by the parallel portion (13) therebetween. After gripping the grip portions (14) with chucks of the test machine, the parallel portion (13) is pulled by separating the chucks away from each other. The high strength continuous filaments (12) are extended from both outer ends of the grip portions (14) being fixed thereto.

Description

  The present invention relates to a tensile strength test method and a tensile test piece of a long fiber reinforced composite material, and in particular, a plurality of high-strength continuous long fibers are arranged in the vicinity of the central axis along the longitudinal direction of a rod-like matrix metal. The present invention relates to a tensile strength test method in the longitudinal direction of a long fiber reinforced metal matrix composite material and a tensile test piece.

  The gripping portions at both ends of the tensile test piece made from the member to be measured (or the material to be measured) whose tensile strength is to be measured are respectively held by a pair of opposing chucks of the tensile tester, and the chuck is relatively A tensile strength test is performed in which the tensile strength of the object to be measured is measured after being separated. When the object to be measured is a composite material containing long fibers (long fiber reinforced composite material) and the tensile strength in the direction in which the long fibers extend is measured, a tensile test piece is prepared along the direction and a tensile strength test is performed. Is done.

  For example, in Patent Document 1, a long-fiber reinforced composite material embedded in concrete as an alternative to a reinforcing bar as a building material, which is a rod-shaped body in which a plurality of continuous aramid fibers are bundled and the peripheral surface thereof is hardened with a resin. A method for testing the tensile strength of long fiber reinforced composite materials is disclosed. When trying to compress the rod-shaped body so that it can resist the proof strength of aramid continuous long fiber with high tensile strength and hold it by the chuck of the tensile tester, the rod-shaped body will be compressed and buckled, causing chuck slip, The tensile strength could not be measured. In view of this, the gripping portion of the chuck in the rod-shaped body is molded with resin to increase the buckling resistance, so that it can be strongly compressed and gripped by the chuck of the tensile tester without damaging the long fibers.

  Patent Document 2 also discloses a tensile strength test method for a long fiber reinforced composite material of a rod-like body in which a bundle of continuous long fibers having high tensile strength such as glass fibers is impregnated with a thermosetting resin such as an epoxy resin. ing. Here, a bundle of continuous long fibers is impregnated with a thermosetting resin, and both ends thereof are wound around a cylindrical jig, and then the thermosetting resin is cured and fixed to the cylindrical jig. The tensile strength is measured by separating them.

  By the way, in the tensile strength test of JIS K7162 and JIS Z2241, the both ends are gripped with a chuck using a tensile test piece provided with a stress concentration part in which the cross-sectional area of the central part of the rod-like body is reduced to reduce the proof stress. By separating them relatively, only the central part is deformed and the tensile strength is measured. Even when such a test method is used, the tensile strength of a long fiber reinforced composite material of a rod-like body in which long fibers are dispersed can be measured. Further, the long fiber reinforced composite material of the rod-like body in which continuous long fibers having a very high tensile strength compared with the resin as a matrix as in Patent Documents 1 and 2 are also used as the stress concentration part. The tensile strength can be measured by greatly reducing the cross-sectional area of the portion and greatly reducing the yield strength.

  Furthermore, in Patent Document 3, polymer continuous long fibers bundled with a plurality of strands are inserted into a cylindrical metal tube and swaged, and in the vicinity of the central axis along the longitudinal direction of the matrix metal of the round bar. A method for producing a long fiber reinforced metal matrix composite in which a plurality of continuous long fibers are arranged is disclosed. Even with such a composite material, the cross-sectional area of the central portion of the rod-shaped body can be reduced, and the tensile test piece as described above can be produced.

Japanese Patent Laid-Open No. 04-274730 JP-A-11-183340 JP 2008-235259 A

  In the long fiber reinforced metal matrix composite material of Patent Document 3, continuous long fibers having high tensile strength are concentrated and arranged in the vicinity of the central axis of the rod-shaped body, so that even if the cross-sectional area is reduced from the outer periphery of the rod-shaped body, The decrease in the yield strength of the part is small, and even if the gripping parts on both sides are gripped by the chuck and are relatively separated from each other, only the part cannot be deformed. In addition, when gripping the rod-shaped body from the outer periphery, even if the chuck and the matrix metal can be fixed, the matrix metal and the continuous long fiber slip before the continuous long fiber breaks, so-called “fiber loss” occurs. Sometimes it ends up. That is, the tensile strength cannot be measured stably and accurately.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a tensile strength test method and tensile strength of a long fiber reinforced metal matrix composite that can stably and accurately measure tensile strength. It is to provide a test piece.

  The tensile strength test method for long fiber reinforced metal matrix composites according to the present invention is a long fiber reinforced metal matrix in which a plurality of high strength continuous long fibers are arranged in the vicinity of the central axis along the longitudinal direction of the matrix metal of the rod-shaped body. A method for testing the tensile strength of a composite material in the longitudinal direction, in which a parallel portion with a reduced thickness is provided in a part of the longitudinal direction, and gripping portions are provided on both outer side portions sandwiching the parallel portion. In the test method in which the grip portion is gripped by the chuck and the parallel portion is pulled by separating the chuck, the high-strength continuous long fiber is further extended to both outer portions of the grip portion, and this is applied to the grip portion. It is made to adhere.

  According to such an invention, the end portion of the high-strength continuous long fiber is fixed to the grip portion gripped by the chuck, and the high-strength continuous long fiber and the matrix metal are prevented from relatively sliding due to the movement of the chuck, It is possible to perform a tensile strength test stably and accurately for a long fiber reinforced metal matrix composite.

  In the above-described invention, an extension portion obtained by cutting the matrix metal may be provided on the outer side portion of the grip portion so as to reduce the thickness of the rod-shaped body. According to this invention, the contact area between the high-strength continuous long fibers and the matrix metal is relatively increased in the grip portion and the outer portion with respect to the parallel portion, and the end portion of the high-strength continuous long fibers is gripped by the chuck. The high strength continuous long fiber and the matrix metal are prevented from slipping relatively by the movement of the chuck, and the tensile strength test is performed stably and accurately on the long fiber reinforced metal matrix composite. Can do.

  In the above-described invention, the high-strength continuous long fiber may be penetrated from the extension portion to the outer side portion, and a locking piece for fixing the high-strength continuous long fiber to the end portion of the extension portion may be provided. According to such an invention, the high-strength continuous long fiber is further fixed to the end of the extension portion by the locking piece, and the end of the high-strength continuous long fiber is more securely fixed to the grip portion gripped by the chuck, It is possible to suppress the relative slip of the high-strength continuous long fibers and the matrix metal due to the movement of the chuck, and to perform the tensile strength test stably and accurately for the long fiber reinforced metal matrix composite material.

  In the above-mentioned invention, the high-strength continuous long fiber may be further penetrated from the grip portion to the outer side portion, and a locking piece for fixing the high-strength continuous long fiber to the end portion of the grip portion may be provided. According to this invention, the high-strength continuous long fiber is fixed to the end of the grip portion by the locking piece, and the end of the high-strength continuous long fiber is more securely fixed to the grip portion gripped by the chuck. It is possible to suppress the relative slip of the high-strength continuous long fibers and the matrix metal by the movement of the long-strength, and to perform the tensile strength test stably and accurately with respect to the long-fiber reinforced metal matrix composite material.

  In the above-described invention, the high-strength continuous long fiber penetrating from the grip portion may be folded back to give the locking piece. According to this invention, the high-strength continuous long fiber is more securely fixed to the end of the grip portion, and the end of the high-strength continuous long fiber is more securely fixed to the grip portion gripped by the chuck. It is possible to suppress the relative slip of the high-strength continuous long fibers and the matrix metal by the movement of the long-strength, and to perform the tensile strength test stably and accurately for the long-fiber reinforced metal matrix composite.

  In the above-described invention, the locking piece may be provided so as to caulk the high-strength continuous long fibers. According to this invention, the high-strength continuous long fiber can be firmly fixed by the locking piece, and the end of the high-strength continuous long fiber can be more firmly fixed to the grip portion gripped by the chuck, and the high-strength continuous long fiber can be increased by moving the chuck. It is possible to suppress the relative slip of the continuous long fiber and the matrix metal, and to perform the tensile strength test stably and accurately for the long fiber reinforced metal matrix composite.

  Moreover, the tensile test piece of the long fiber reinforced metal matrix composite material according to the present invention is used for the above-described tensile strength test method.

  According to this invention, the end of the high-strength continuous long fiber is fixed to the grip portion, and the high-strength continuous long fiber and the matrix metal are prevented from relatively sliding in the tensile strength test, and the long-fiber reinforced metal base The tensile strength test can be performed stably and accurately on the composite material.

It is a perspective view which shows the external appearance of a long fiber reinforced composite bar. It is sectional drawing of the tensile test piece used with the method by this invention. It is a figure which shows the method of the tensile strength test by this invention. It is sectional drawing of the other tensile test piece used with the method by this invention. It is sectional drawing of the other tensile test piece used with the method by this invention. It is sectional drawing of the other tensile test piece used with the method by this invention.

  A long fiber reinforced metal matrix composite material to be measured for tensile strength according to the present invention will be described with reference to FIG.

  As shown in FIG. 1, a long fiber reinforced composite rod (composite wire) 100, which is a long fiber reinforced metal matrix composite material, is a long linear body, for example, suspended in the air along a track in a railway. Used for power lines that are supported to conduct power. The long fiber reinforced composite rod 100 is composed of a matrix metal 11 which is a round rod-shaped linear body, and high-strength continuous long fibers 12 which are given as a reinforcing material in order to increase the tensile strength of the linear body. In particular, the long fiber reinforced composite rod 100 used as a power line is made of conductive copper, a copper-based alloy, aluminum, an aluminum-based alloy, or the like as the matrix metal 11, but as appropriate for other applications, Different metal materials can be used. Furthermore, the high-strength continuous long fibers 12 have a tensile strength higher than that of the matrix metal 11 as a reinforcing material, and are continuous long high-strength fibers such as carbon fibers and aramid fibers. As the tensile strength of the high-strength continuous long fibers 12 is higher, the amount of the high-strength continuous long fibers 12 inserted to give the same tensile strength to the long-fiber reinforced composite rod 100 can be reduced, and the cost can be reduced. For example, in the case of being used for a power line or the like, the composition ratio of the matrix metal 11 responsible for the transportation of electric power can be increased, and a larger current can flow.

  In the long fiber reinforced composite rod 100, the high-strength continuous long fibers 12 are arranged in the vicinity of the central axis along the longitudinal direction of the matrix metal 11. In such a long fiber reinforced composite rod 100, for example, a bundle of high-strength continuous long fibers 12 is separated once and opened, and each of the fibers is plated with substantially the same material as the matrix metal 11. It is obtained by bundling again and inserting it into a metal tube to be the matrix metal 11 and swaging. By this method, in the long fiber assembly region 16, which is a region where the high-strength continuous long fibers 12 are aggregated and arranged, the plating metal made of substantially the same material as the matrix metal 11 is formed between the single fibers of the high-strength continuous long fibers 12. The high-strength continuous long fibers 12 are gathered and arranged independently in the vicinity of the central axis along the longitudinal direction of the matrix metal 11.

[Example 1]
Next, a tensile test piece used in a tensile strength test method according to one embodiment of the present invention will be described with reference to FIG. 2, and the test method will be described with reference to FIG.

  As shown in FIG. 2, the tensile test piece 10 is obtained by cutting a long fiber reinforced composite rod 100 (see FIG. 1) into a predetermined length, and the diameter of the matrix metal 11 from the outer periphery in the vicinity of the center in the longitudinal direction. It is given by cutting to reduce. That is, it comprises a parallel portion 13 having a circular cross section at the central portion in the longitudinal direction, an R portion 13a having a diameter gradually increased from the parallel portion 13 toward both outer sides in the longitudinal direction, and a gripping portion 14 continuous therewith. In the cutting of the parallel portion 13, only the matrix metal 11 is cut and the long fiber assembly region 16 is not cut, so that the high-strength continuous long fibers 12 are not cut. Further, the gripping part 14 has a male threaded part 14a formed on its peripheral surface. On the outer side of the gripping part 14, an extension part 15 in which the matrix metal 11 is cut and the diameter is reduced from the gripping part 14 is processed. That is, the tensile test piece 10 has a shape in which a substantially cylindrical extension portion 15 is provided outside a grip portion of a rod-like test piece having a circular cross section defined by JIS Z2241. In addition, the grip part 14 should just be a shape which can be attached to the test piece attachment part of the tensile testing machine to be used, for example, can be made into other shapes, such as a flange shape and a wedge shape.

  In the tensile test piece 10 having the extension portion 15, the length of the long fiber assembly region 16 before and after the grip portion 14 with respect to the length of the long fiber assembly region 16 of the parallel portion 13 which is a stress concentration portion in a tensile test described later. The length is extended by the extension 15. As a result, the frictional force between the matrix metal 11 and the high-strength continuous long fibers 12 when the grip portion 14 is pulled outward in the longitudinal direction is relatively increased before and after the grip portion 14, and the high-strength continuous long fibers are applied to the grip portion 14. 12 is fixed. That is, the length of the extension 15 may be determined according to the strength of the bundle of high-strength continuous long fibers 12.

  As shown in FIG. 3, the test piece mounting portion 90 of the tensile tester includes a grip 93 having an internal thread portion 93 a that is screwed with the grip portion 14 of the tensile test piece 10, and a chuck frame that supports the grip 93 in a suspended manner. 92 and a rod 91 connected to the chuck frame 92 are arranged so as to face each other vertically. The lower rod 91 is fixed, and the upper rod 91 connected to a servo motor (not shown) moves upward, so that the pair of grips 93 moves apart on one axis. A load cell (not shown) is appropriately incorporated in the upper rod 91. Note that if the female threaded portion 93a of the grip 93 is a bag hole, it is difficult for air to escape when the tensile test piece 10 is screwed and attached, and for the purpose of preventing this, the through-hole 93b uniaxially with the female threaded portion 93a. Is provided.

  The tensile strength test is carried out by attaching the gripping portion 14 of the tensile test piece 10 to the test piece mounting portion 90 from the outer periphery. The tensile test piece 10 screws the male screw portion 14a into the female screw portion 93a while inserting the extension portion 15 into the through hole 93b provided in the grip 93. Accordingly, the grip portions 14 on both sides of the tensile test piece 10 are fixed to the upper and lower grips 93 and attached to the test piece attachment portion 90. In the tensile strength test, the upper grip 93 is raised via the upper rod 91 by a servo motor, and a tensile load in the longitudinal direction is applied to the tensile test piece 10. The tensile load applied to the tensile test piece 10 can be measured by a load cell (not shown) connected to the upper rod 91.

  By the way, in the tensile test piece 10, the proof stress of the parallel portion 13 having a small diameter with respect to the grip portion 14 is relatively low with respect to the grip portion 14. However, if the difference in tensile strength between the matrix metal 11 and the high-strength continuous long fibers 12 is large, even if only the diameter of the matrix metal 11 is reduced, the decrease in the relative proof strength of the parallel portion 13 is small.

  As described above, in this embodiment, the length of the long fiber assembly region 16 before and after the grip portion 14 is extended by the extension portion 15 with respect to the length of the long fiber assembly region 16 of the parallel portion 13, The frictional force between the matrix metal 11 and the high-strength continuous long fibers 12 is relatively increased, and the high-strength continuous long fibers 12 are fixed to the grip portion 14. That is, when a tensile load is applied via the grip 93, the matrix metal 11 and the high-strength continuous long fibers 12 are prevented from slipping relatively, so even if the tensile load is increased, the matrix metal 11 Thus, the metal linear body and the high-strength continuous long fibers 12 are integrated and carry this load without separation. As a result, even if the relative yield strength of the parallel portion 13 relative to the grip portion 14 is small, stress can be concentrated on the parallel portion 13, and the tensile test piece 10 can be pulled at the parallel portion 13 to be stably broken. Thus, the tensile strength test can be performed stably and accurately.

  In addition, as long as the extension part 15 can attach the tensile test piece 10 to the test piece attachment part 90 without interfering with the through-hole 93b, it is sufficient to reduce the diameter from the grip part 14 or slightly.

[Example 2]
Next, a tensile test piece used in a tensile strength test method according to another embodiment of the present invention will be described with reference to FIG. 4, and the test method will be described with reference to FIG. 3 as appropriate.

  As shown in FIG. 4, the tensile test piece 20 is a high-strength continuous long fiber 12 (or a long fiber containing the matrix metal 11 at both ends of the extension 15 on both sides, compared to the tensile test piece 10 in Example 1. A cylindrical locking piece 21 is provided so as to extend the gathering region 16) and to fix the extension to the side end of the extension 15. Specifically, the locking piece 21 is compressed in the radial direction by a crimping tool or the like so that the high-strength continuous long fiber 12 is inserted into the locking piece 21 and is brought into contact with the side end surface of the extension portion 15. That is, the locking piece 21 is fixed to the high-strength continuous long fiber 12 by caulking. The locking piece 21 restricts the high-strength continuous long fiber 12 from sliding in the direction toward the parallel portion 13 relative to the grip portion 14 and the extension portion 15 during the tensile strength test. That is, the end portion of the high-strength continuous long fiber 12 is more securely fixed to the grip portion 14. Further, the length of the extension 15 can be made shorter than that of the tensile test piece 10 of Example 1.

  Also in the tensile test piece 20, when a tensile load is applied via the grip 93 (see FIG. 3), the matrix metal 11 and the high-strength continuous long fibers 12 are prevented from slipping relatively. Even if the tensile load is increased, the metal linear body made of the matrix metal 11 and the high-strength continuous long fibers 12 are integrated and carry this load without being separated. As a result, even if the relative yield strength of the parallel portion 13 relative to the grip portion 14 is small, stress can be concentrated on the parallel portion 13, and the tensile test piece 10 can be pulled at the parallel portion 13 to be stably broken. Thus, the tensile strength test can be performed stably and accurately.

  Note that the locking piece 21 may be fastened to the high-strength continuous continuous fiber 12 by an adhesive, for example, or may be fixed by other methods without using caulking.

[Example 3]
Further, a tensile test piece used in a tensile strength test method according to another embodiment of the present invention will be described with reference to FIG. 5, and the test method will be described with reference to FIG. 3 as appropriate.

  As shown in FIG. 5, the tensile test piece 30 is different from the tensile test piece 10 in Example 1 in that the high-strength continuous long fibers 12 (or A cylindrical locking piece 21 is provided so as to extend the long fiber assembly region 16) including the matrix metal 11 and to fix the extended portion to the side end of the grip portion 14. Also in this case, the locking piece 21 is compressed in the radial direction by a crimping tool or the like so that the high-strength continuous long fiber 12 is inserted into the locking piece 21 and is brought into contact with the side end surface of the grip portion 14. The locking piece 21 restricts the high-strength continuous long fiber 12 from sliding in the direction toward the parallel portion 13 relative to the grip portion 14 during the tensile strength test. The end is firmly fixed to the grip 14.

  Also in the tensile test piece 30, when a tensile load is applied via the grip 93 (see FIG. 3), the matrix metal 11 and the high-strength continuous long fiber 12 are prevented from slipping relatively. Even if the tensile load is increased, the metal linear body made of the matrix metal 11 and the high-strength continuous long fibers 12 are integrated and carry this load without being separated. As a result, even if the relative yield strength of the parallel portion 13 relative to the grip portion 14 is small, stress can be concentrated on the parallel portion 13, and the tensile test piece 10 can be pulled at the parallel portion 13 to be stably broken. Thus, the tensile strength test can be performed stably and accurately.

[Example 4]
Further, a tensile test piece used in a tensile strength test method according to another embodiment of the present invention will be described with reference to FIG. 6, and the test method will be described with reference to FIG. 3 as appropriate.

  As shown in FIG. 6, the tensile test piece 40 is provided with a folded-type locking piece 41 instead of the locking piece 21 with respect to the tensile test piece 30 in the third embodiment. The folding type locking piece 41 includes a cylindrical cylindrical body 42 and a cylindrical fitting body 43 whose one end is fitted so as to cover the outside thereof. The cylindrical body 42 extends the high-strength continuous long fibers 12 (or the long fiber assembly region 16 containing the matrix metal 11) to both ends of the grip portion 14, and the extension portion is inserted into the cylindrical body 42 so that the grip portion 14 side is extended. It is given so as to contact the end face. Furthermore, the high-strength continuous long fibers 12 extended from the side end of the cylindrical body 42 are folded back to the outer peripheral side at the end face of the cylindrical body 42. Here, the high-strength continuous long fibers 12 may be divided into a plurality of bundles and folded back. The fitting body 43 is fitted into the cylindrical body 42 so that the folded high-strength continuous long fiber 12 is crimped to the outer peripheral surface of the cylindrical body 42.

  By the cylindrical body 42 and the fitting body 43, the high-strength continuous long fibers 12 are pressure-bonded and fixed to the folding-type locking pieces 41. In the folding type locking piece 41, the high-strength continuous long fiber 12 is restricted from sliding and moving in the direction toward the parallel portion 13 relative to the grip portion 14. 12 can be fixed. That is, the end portion of the high-strength continuous long fiber 12 is more securely fixed to the grip portion 14.

  Also in the tensile test piece 40, when a tensile load is applied via the grip 93 (see FIG. 3), the matrix metal 11 and the high-strength continuous long fiber 12 are restrained from sliding relatively. Even if the tensile load is increased, the metal linear body made of the matrix metal 11 and the high-strength continuous long fibers 12 are integrated and carry this load without being separated. As a result, even if the relative yield strength of the parallel portion 13 relative to the grip portion 14 is small, stress can be concentrated on the parallel portion 13, and the tensile test piece 10 can be pulled at the parallel portion 13 to be stably broken. Thus, the tensile strength test can be performed stably and accurately.

  The folding-type locking piece 41 does not press the high-strength continuous long fibers 12 to the outer peripheral surface of the cylindrical body 42. For example, the high-strength continuous long fibers 12 are bonded to the outer peripheral surface of the cylindrical body 42 by an adhesive. It may be glued.

  In each of the embodiments described above, the long fiber reinforced metal matrix composite material to be measured for tensile strength is a linear body in which no matrix metal is arranged between single fibers of high-strength continuous long fibers, that is, a metal material. A linear body obtained by inserting a long fiber bundle as it is into a tubular body made by swaging and a linear body obtained by similarly inserting a prepreg impregnated with an adhesive into the long fiber bundle. There may be. The long fiber reinforced metal matrix composite material may be a linear body other than a round bar shape such as a square cross-sectional shape.

  Up to this point, representative embodiments and modifications based thereon have been described. However, the present invention is not necessarily limited thereto, and those skilled in the art will understand the gist of the present invention or the appended claims. Various alternative embodiments and modifications may be found without departing from the invention.

DESCRIPTION OF SYMBOLS 10 Tensile test piece 11 Matrix metal 12 High-strength continuous long fiber 13 Parallel part 14 Grasp part 100 Long fiber reinforced composite rod

Claims (7)

A method for testing the tensile strength in the longitudinal direction of a long fiber reinforced metal matrix composite in which a plurality of high-strength continuous fibers are arranged in the vicinity of the central axis along the longitudinal direction of a matrix metal of a rod-shaped body,
Provide a parallel part with reduced thickness in a part of the longitudinal direction and provide gripping parts on both outer sides sandwiching the parallel part, and make the chuck of the testing machine grip the gripping part and separate the chuck. In the test method for pulling the parallel part, the high-strength continuous long fiber is extended to both outer parts of the grip part and fixed to the grip part. Strength test method.   2. The tension of the long fiber reinforced metal matrix composite material according to claim 1, wherein an extension portion obtained by cutting the matrix metal is provided on the outer side portion of the grip portion so as to reduce the thickness of the rod-shaped body. Strength test method.   3. The long fiber reinforced metal matrix composite material according to claim 2, wherein the high strength continuous long fiber penetrates from the extension part to the outer side part, and a locking piece for fixing the high strength continuous long fiber to the end part of the extension part is provided. Tensile strength test method.   2. The long fiber reinforced metal matrix composite material according to claim 1, wherein the high strength continuous long fibers are further penetrated from the grip portion to the outer side portion, and a locking piece is provided to fix the high strength continuous long fiber to the end portion of the grip portion. Tensile strength test method.   5. The tensile strength test method for a long fiber reinforced metal matrix composite material according to claim 4, wherein the high-strength continuous long fiber penetrating from the gripping portion is folded and then the locking piece is provided.   6. The method for testing the tensile strength of a long fiber reinforced metal matrix composite according to claim 3, wherein the locking piece is applied so as to caulk the high-strength continuous long fibers. A tensile test piece comprising a long fiber reinforced metal matrix composite used in the tensile strength test method according to claim 1.