Test fixture for tensile properties of ring-shaped samples, and method for testing the tensile properties of ring-shaped samples.

Abstract

To provide a tensile property test jig for measuring tensile properties when an internal pressure is applied to a ring-shaped sample, and a test method using the test jig.SOLUTION: An extension part in a substantially columnar shape formed by arranging a pair of top members opposite to each other on a side plane is placed on a pedestal in a state where a projection and / or a recess [Afb] formed on a bottom face of the extension part and a guide or a rail of the pedestal are fitted to each other. A ring-shaped sample is fitted to a side peripheral surface of the extension part. A material universal testing machine is used to lower a tapered rod with its leading end directed downward and inserted into a tapered groove [Am] formed by arranging two notch portions formed in the side peripheral surface of the extension part so that the notch portions face each other, thereby bringing the leading end of the rod between the top members. Pressing force is applied to increase an interval between the top members of the extension part as a tapered surface of the rod is lowered. Force is applied in an extending direction along the guide or the rail and outward force is applied to the ring-shaped sample to measure tensile force at break.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tensile property test jig for measuring the tensile properties when an internal pressure is applied to a ring-shaped sample, and a test method using this jig.

Background Art

[0002] In recent years, fiber-reinforced composite materials have been increasingly applied not only to the field of transportation equipment such as aircraft structural members and automobile structural members, but also to general industrial fields such as pressure vessel members and building materials, and the shapes of the members to which they are applied have become more diverse. In the general industrial field, these materials are often applied to members to which an internal pressure is applied. In various members including such fiber-reinforced composite materials, the properties of the material with respect to the internal pressure, that is, the tensile properties when an internal pressure is applied to a ring-shaped material, are important.

[0003] As a method for evaluating the tensile properties when an internal pressure is applied to such a ring-shaped sample, there is a method known in ASTM D2290 in which a ring-shaped sample is fitted onto the side circumferential surface of a jig having a substantially cylindrical shape formed by combining two split semi-cylindrical jigs, these jigs are clamped, and a tensile force is applied in the circumferential direction by pulling outward.

[0004] In addition, Patent Document 1 discloses a method for evaluating the circumferential tensile force of a cylindrical material by applying an internal pressure with a liquid, and Patent Document 2 discloses a method for applying an internal pressure to a cylindrical tube by expanding an internal pressure element with another pressure element from above and below to evaluate the circumferential tensile force of the material of the cylindrical tube.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

[0006] The method described in ASTM D2290 involves drilling a hole in the jig, inserting a pin, and then gripping the pin and pulling it outwards. However, this method has the problem of insufficient jig strength when the diameter of the ring-shaped sample being evaluated is reduced.

[0007] The test method described in Patent Document 1 uses a liquid to apply internal pressure to a cylindrical body, which has the drawback of being a complicated test.

[0008] The test method described in Patent Document 2 involves expanding an internal indenter with indenters from above and below to apply internal pressure to a cylindrical tube. However, there is no way to uniformly control the pressure from above and below, and therefore, it is not possible to apply uniform internal pressure in the vertical direction of the cylindrical tube.

[0009] The present invention aims to improve upon the shortcomings of the prior art and provide a test fixture for easily and accurately evaluating the tensile properties of a ring-shaped sample, as well as a test method using this fixture. [Means for solving the problem]

[0010] As a result of diligent research to solve the aforementioned problems, the inventors have discovered a test fixture having the following configuration and have completed the present invention. That is, the test fixture of the present invention is as follows. 1. A test fixture for the mechanical properties of a ring-shaped sample, having the following components [A] to [C].

[0011] [A]: Extension consisting of a pair of saddle members [B]: A base for placing [A], the base having a linear guide or rail that fits into part [Afb] of [A]. A tapered rod that can be inserted into a tapered groove [Am] in [C]:[A], wherein the tapered surface of the rod makes surface contact with the tapered surface in the groove [Am] when inserted into the groove [Am]. And, Each component of [A] is based on a semi-cylindrical shape and has a top surface, bottom surface, side circumferential surface and side plane. moreover, [Ac]: Notches formed in a pair of spinning top members, extending from the top surface of the spinning top member to a position lower than 1 / 4 of the height in the side plane, and having substantially the same shape. [Afb]: Convex and / or concave parts formed on the bottom surface [Afs]: A total of two or more recesses and / or protrusions formed on each saddle member in the range of 1 / 3 to 2 / 3 of the height direction on the side plane, wherein the recesses are formed extending inward from the side plane into the saddle member, and the protrusions are formed extending perpendicularly from the side plane. The part is formed, When the pair of spinning top members are placed facing each other on their side planes, the recess of one spinning top member at part [Afs] fits into the protrusion of the other spinning top member, forming a substantially cylindrical shape with a base formed by the two bases. Both notches [Ac] form tapered grooves [Am] which are roughly triangular prism, roughly gable top, roughly polygonal pyramidal, roughly frustum-shaped, roughly conical, or roughly frustum-shaped spaces that taper from the top to the bottom of the roughly cylindrical column. When the substantially cylindrical object is placed on [B] with the two side planes facing each other oriented perpendicular to the guide or rail of [B], part [Afb] fits into the guide or rail and slides along its longitudinal direction in a direction that separates a pair of saddle members. 2. A mechanical properties test fixture for the ring-shaped sample described in 1 above, wherein the angle of the tip of the groove [Am] is less than 120°. 3. A mechanical properties test fixture for a ring-shaped sample according to 1 or 2 above, wherein the diameter of the approximately cylindrical shape formed with respect to [A] is 5 cm or less. 4. A method for evaluating the mechanical properties of a ring-shaped sample using a jig described in any of items 1 to 3 above. [Effects of the Invention]

[0012] According to the present invention, the tensile properties of a ring-shaped sample can be evaluated simply and accurately.

Brief Description of the Drawings

[0013] [Figure 1] It is a view of the extension part A-1 according to a specific embodiment of the present invention, a cross-sectional view (upper left) of a substantially cylindrical shape formed by a pair of koma members as seen from above, a view (lower left) of the side plane of the koma member as seen from the front, and a cross-sectional view (right) of the substantially cylindrical shape as seen from a direction perpendicular to the surface where the side planes face each other on the side surface. [Figure 2] It is a view of the extension part A-2 according to an embodiment that does not meet the requirements of the present invention, a cross-sectional view (upper left) of a substantially cylindrical shape formed by a pair of koma members as seen from above, a view (lower left) of the side plane of the koma member as seen from the front, and a cross-sectional view (right) of the substantially cylindrical shape as seen from a direction perpendicular to the surface where the side planes face each other on the side surface. [Figure 3] It is a view of the extension part A-3 according to an embodiment that does not meet the requirements of the present invention, a cross-sectional view (upper left) of a substantially cylindrical shape formed by a pair of koma members as seen from above, a view (lower left) of the side plane of the koma member as seen from the front, and a cross-sectional view (right) of the substantially cylindrical shape as seen from a direction perpendicular to the surface where the side planes face each other on the side surface. [Figure 4] It is a view of the pedestal B-1 according to a specific embodiment of the present invention, a view (upper left) of the pedestal as seen from above, a cross-sectional view (lower left) of the pedestal as seen from the front in the sliding direction of the koma member, and a cross-sectional view (right) of the pedestal as seen from the side in the sliding direction of the koma member. [Figure 5] It is a view of the rod C-1 according to a specific embodiment of the present invention, a view (upper left) of the rod as seen from above, a view (lower left) of the rod as seen from the direction corresponding to the front of the side plane of the koma member when inserting the rod into the groove, and a view (right) of the rod as seen from the vertical direction of the surface where the side planes of the koma member face each other when inserting the rod into the groove.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, the components and conditions of the test jig of the present invention described above will be described.

[0015] The jig of the present invention has the members [A] to [C] described above.

[0016] The tensile property evaluation of the ring-shaped sample using the jig of the present invention is generally as follows. The member [A], which is a substantially cylindrical expansion part formed by facing a pair of plate members on the side plane, is placed on [B] in a state where the convex part and / or concave part [Afb] formed on the bottom surface of [A] is fitted with the guide or rail of the pedestal [B], and a ring-shaped sample is fitted on the side peripheral surface of [A].

[0017] More specifically, by facing a pair of plate members on the side plane, a tapered rod [C] is inserted into a tapered groove [Am] formed by facing two notch portions [Ac] formed on the side plane of [A], using a universal material testing machine or the like, with its tip facing downward and descending. The tapered surface of the rod [C] is brought into contact with the tapered surface in [Am], and by further lowering the rod [C], the tip of the rod enters between the plate members, and by applying pressure, as the tapered surface of the rod [C] descends, the space between the plate members of [A] is expanded, a force is applied in the direction of expansion along the guide or rail, an outward force is applied to the ring-shaped sample, and the breaking tensile force can be measured. Here, when the rod [C] is inserted into the groove [Am], the portions other than the tapered surface may be in contact with the groove [Am], and although the effect of stabilizing the rod may be obtained in some cases, it is not necessarily in contact.

[0018] When forming the substantially cylindrical expansion part [A] by facing a pair of plate members on the side plane, the side planes of the plate members do not necessarily have to be in contact with each other, and there may be a gap as long as the substantially cylindrical shape is maintained. Depending on the tip shape of the rod [C], due to the above-mentioned gap, the tapered surface of the rod [C] may enter the gap between the plate members, and in some cases, the plate members can be expanded more smoothly along the guide or rail.

[0019] Furthermore, the breaking tension of a ring-shaped sample can be obtained, for example, as the compressive force of the rod when the ring-shaped sample breaks, using a universal material testing machine. This compressive force can be converted to the breaking tension of the ring-shaped sample from the correlation between the rod compressive force and the strain of the metal ring, for example, by using a metal calibration ring with a known modulus of elasticity.

[0020] In the present invention, the notches [Ac] are formed on each of the spinning top members and extend from the top surface to a position lower than 1 / 4 of the height of the side plane, or they may extend from the top surface through the side plane to the bottom surface. Preferably, they are formed from 1 / 3 to 2 / 3 of the height. Note that the height of the side plane does not include the height of the fitting portion [Afb] on the bottom surface. The notches are formed in substantially the same shape on a pair of spinning top members, and when the spinning top members are placed facing each other with their side planes facing each other to form a substantially cylindrical shape, the notches [Ac] face each other to form a groove [Am], and this groove is a space that tapers from the top surface to the bottom surface of the substantially cylindrical shape, and is a space selected from a substantially triangular prism shape, a substantially gable top shape, a substantially polygonal pyramidal shape, a substantially frustoconical shape, a substantially conical shape, or a substantially frustoconical shape.

[0021] As described above, the notched portion [Ac] is a roughly cylindrical shape formed by joining the top members at their side planes, extending from the top surface to the depth described above. By forming the notched portion within the above range, when the top members expand under pressure from the rod [C], the top members become less likely to tilt, and the internal pressure applied to the ring-shaped sample becomes more uniform.

[0022] If the groove [Am] is a roughly triangular prism-shaped space, the deepest part of the groove must be formed by one of the sides of the roughly triangular prism, and the two sides including this side are formed by notches formed in the side plane of the roughly cylindrical, forming the tapering portion of the groove [Am]. Also, the top and bottom surfaces are perpendicular to the side plane of the roughly cylindrical. Note that if there is a gap between the side planes of the top members, the side is a shape close to a plane. Furthermore, both the top and bottom surfaces of the roughly triangular prism must be isosceles triangles, and the side including the base of the isosceles triangle is formed parallel to the top surface of the top member at the same height.

[0023] If the groove [Am] is a space with a roughly gable top shape, the deepest part of the groove must be formed at the top edge of the roof portion of the roughly gable top. The two surfaces including this top edge are formed by a notch formed in the side plane of the roughly cylindrical shape, forming the tapering portion of the groove [Am]. Also, when the cross section is viewed from the side of the roughly cylindrical shape in a direction perpendicular to the side plane, the groove [Am] appears to tapere. Note that if there is a gap between the side planes of the saddle members, the top edge will have a shape close to a surface. Furthermore, the bottom surface of the roughly gable top will be formed parallel to the top surface of the saddle member at the same height.

[0024] If the tapering groove [Am] is roughly pyramidal or conical, the apex of the cone must be positioned at the deepest part of the conical groove. Furthermore, the bottom surface of the cone is formed parallel to the top surface of the top component at the same height.

[0025] If the groove [Am] is roughly frustum-shaped, such as a roughly polygonal frustum or a roughly cone frustum, the bottom surface of the frustum will be formed parallel to the top surface of the top component at the same height.

[0026] The groove [Am] preferably has a tip angle of less than 120°. More preferably, it is in the range of 30 to 100°. Having a tip angle within this range allows for smooth movement when the core member expands under pressure from the rod [C], enabling uniform expansion of the ring-shaped sample. The tip angle of the groove [Am] referred to here is the angle of the tapered groove [Am] when a pair of core members forming a roughly cylindrical shape are placed facing each other on their side planes, and the cross-section is observed from a direction perpendicular to the side plane of the core members. If the tip has a curved shape, the angle can be determined by extending the two sides that form the tip angle and using the angle at their intersection.

[0027] In this invention, member [A] has a convex or concave portion as a fitting portion [Afb] on its bottom surface, and member [B] has a linear guide or rail. These fit together when a pair of spool members are placed on the base of [B] such that they form a substantially cylindrical shape and the faces of their two side planes facing each other are oriented perpendicular to the guide or rail of [B]. That is, when the two are fitted together, the faces of the side planes of [A] facing each other stand upright perpendicular to the longitudinal direction of the guide or rail. Furthermore, portion [Afb] is slidable along the longitudinal direction of the guide or rail in a direction that separates the pair of spool members. With this fitting, when the spool members are pressed by the rod [C] and expand, they slide along the guide or rail without tilting, and the internal pressure applied to the ring-shaped sample becomes uniform. In addition, although this is a different embodiment from the present invention, there may be an embodiment in which the protrusion or recess of member [A] that provides this fitting is not present on the bottom surface of member [A], but is set at any other location. For example, it may be set on the boundary between the side plane and the side circumferential surface of the roller member [A], and fit with a guide or rail provided on the side of [A], so that the roller member slides along the direction of the guide or rail without tilting, thereby fulfilling the above role.

[0028] Each spinning top member has two or more recesses or protrusions extending perpendicularly to the side plane, positioned in the range of 1 / 3 to 2 / 3 of the height direction of the semi-cylindrical shape on the side plane, as side plane fitting portions [Afs]. Note that the height of the semi-cylindrical shape on the side plane does not include the height of the bottom fitting portion [Afb]. All of the fitting portions [Afs] on a single spinning top member may be recesses, all may be protrusions, or a combination of recesses and protrusions. However, when a pair of spinning top members are placed facing each other on the side plane to form a roughly cylindrical shape, the recesses of one spinning top member must fit into the protrusions of the other spinning top member. In other words, within the height range on the side plane as described above, the positions of the fitting portions [Afs] on a pair of spinning top members are the same in both the height and width directions. If one spinning top member has a protrusion, the fitting portion [Afs] on the other spinning top member at the same height and width direction must be a recess. One of the spinning top members may have a recess on its side surface that does not function as a fitting portion [Afs], but if a protrusion is provided, the other spinning top member must have a recess at the same position, and when the two spinning top members are placed facing each other on their side surfaces, a substantially cylindrical shape must be formed with the circle formed by the two bottom surfaces as its base.

[0029] On the side surface, the recessed portion [Afs] and the convex portion, which constitute the fitting area, fit together as described above. This makes it less likely for the compost member to tilt when it expands under pressure from the rod [C], and ensures that the internal pressure applied to the ring-shaped sample becomes uniform.

[0030] Furthermore, the fitting portion [Afs] in the case of a recess is provided inside the spinning top member from the side plane, that is, it does not reach the outer circumferential surface of the spinning top member. If the recess extends to the outer circumferential surface, when the substantially cylindrical object is viewed from above, the portion where the recess is formed will not be circular in shape and will not come into contact with the ring-shaped sample. Moreover, the convex portion must be provided so as to fit into the recess, meaning that in a substantially cylindrical object formed by joining the spinning top members at their side planes, the convex portion must not form the side circumferential surface. And therefore, the recess must be provided inside the spinning top member from the side plane and must not be exposed on the side circumferential surface. If the recess is exposed on the side circumferential surface and the convex portion to which it fits forms part of the side circumferential surface, it may come into contact with and interfere with the ring-shaped sample fitted to the side circumferential surface when the spinning top member is expanded.

[0031] Regarding the formation position of the fitting portions [Afs], it is preferable that they exist in pairs on the side plane, as shown in Figures 1-3, at positions that straddle the center line of the spinning top member. This is because when the spinning top member expands under pressure from the rod [C], the stability of the spinning top member increases, and the internal pressure applied to the ring-shaped sample becomes more uniform. While two fitting portions [Afs] on a single spinning top member are often sufficient for proper function, three or more, or even four, are also acceptable. A pattern in which two fitting portions [Afs] exist in pairs at positions that straddle the center line of the spinning top member, as described above, is also conceivable. However, having too many, for example, more than 10, may affect the productivity of the spinning top member, and may also prevent the formation of a roughly cylindrical shape as intended when a pair of spinning top members are placed facing each other due to damage or other reasons. Therefore, this is not necessarily preferable. However, this may not apply if the spinning top member itself is enormous.

[0032] The shape of the recess and / or protrusion in the fitting portion [Afb] is not particularly limited, but cylindrical, elliptical, or prismatic shapes can be preferably used.

[0033] There are no restrictions on the diameter of the ring-shaped sample evaluated by the jig of the present invention, but the jig of the present invention can be preferably used to evaluate ring-shaped samples with a diameter of 5 cm or less. More preferably, it can be used for ring-shaped samples with a diameter of 2 cm or less, and preferably for ring-shaped samples with a diameter of 0.5 cm or more.

[0034] The three components constituting the test fixture of the present invention are not limited to any particular material as long as they can withstand the load during testing, but stainless steel is preferable from the viewpoint of handling and strength. Furthermore, the manufacturing method of the three components constituting the test fixture of the present invention is not particularly limited, but they can be manufactured by methods such as casting or machining. From the viewpoint of dimensional accuracy, machining is preferred.

[0035] The material of the ring-shaped sample to be measured for fracture strength using the test fixture of the present invention is not particularly limited, but preferred evaluation targets include ring-shaped samples made of fiber-reinforced composite materials or metal. In particular, ring-shaped samples made of fiber-reinforced composite materials can be preferably evaluated. The fibers and resins used in the fiber-reinforced composite material are not particularly limited, but carbon fibers and epoxy resins can be preferably used as the fibers and resins, respectively.

[0036] The tensile properties of a ring-shaped sample using the test fixture of the present invention can be evaluated, for example, using a universal material testing machine (Instron Japan Co., Ltd., "Instron" (registered trademark) Model 5565 P8564) in the procedure described above. [Examples]

[0037] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the descriptions in these examples. (Material used: [A] extension) • Extension A-1: ​​A stainless steel spindle component was manufactured by machining, with the dimensions and shape shown in Figure 1. Figure 1 is a cross-sectional view from the top and side of a roughly cylindrical shape formed by bringing the spindle components related to extension A-1 together and abutting them on their side surfaces. The diameter of the circle formed on the top and bottom surfaces was 11 mm, and the height of the roughly cylindrical shape excluding part [Afb] was 10 mm. As shown in the figure, part [Afb] was formed in the shape of a rectangular parallelepiped on the bottom surface of the roughly cylindrical shape, in the lateral center when viewed from the front of the side surface. Furthermore, each spinning top member has a cylindrical protrusion and a cylindrical recess extending perpendicularly to the side surface as part [Afs]. The center of the bottom surface of the recess and protrusion is located at approximately half the height of the cylinder (5 mm vertically from the top surface). The recess is formed inside the spinning top member, and is shaped and positioned so that when the cylinder is formed, the recess of one spinning top member fits into the protrusion of the other spinning top member. Part Ac is formed from the top surface of the spinning top member to 3 / 4 of the height of the cylinder on the side surface, and is shaped so that a gable-top groove [Am] is formed when the cylinder is formed. The vertical distance from the top surface of the groove [Am] to its ridge is 5 mm, and as shown in the right diagram of Figure 1, the angle of the tip of the groove [Am] when viewed from the side of the cylinder in a direction perpendicular to the opposing side surfaces is 90°. • Extension A-2: Figure 2 is a cross-sectional view from the top and side of the extension A-2, which is formed by facing the top members of the extension A-2 on the side planes to form a roughly cylindrical shape. Part Ac is formed from the top surface of the top member to 1 / 4 of the height of the roughly cylindrical shape on the side plane. When the roughly cylindrical shape is formed, a triangular prism-shaped groove [Am] is formed so that one of its sides faces the top surface of the roughly cylindrical shape, and the remaining side faces downwards. The other dimensions, shape, and material are the same as those of extension A-1, and a stainless steel top member was manufactured. • Extension A-3: Figure 3 is a top and side cross-sectional view of the extension A-3, where the spool members are facing each other on the side plane to form a roughly cylindrical shape. The part [Afs] is located at a position where its vertical center is half the height of the roughly cylindrical shape (5 mm vertically from the top surface). Each spool member has one recess and one protrusion, extending perpendicularly from near the boundary between the side plane and the side circumferential surface in the shape shown in Figure 3. The protrusion forms part of the shape of the side circumferential surface, and the recess is not inside the spool member but is exposed on the side circumferential surface and fits with the protrusion on the other spool member. The other dimensions, shape, and material are the same as those of extension A-1, and stainless steel spool members were manufactured. (Materials used: Base [B]) • Base B-1: Base B-1 was manufactured from stainless steel with the dimensions shown in Figure 4. As shown in Figure 4, a rectangular guide with a width of 3 mm was provided in the center of the base, and when a roughly cylindrical object was placed on the base with its side planes perpendicular to the opposing surfaces, the guide and part [Afb] would fit together. Furthermore, the pair of swivel members were slidable in a direction perpendicular to the width of the guide. (Materials used: [C] Rod) • Rod C-1: Figure 5 shows cross-sectional views of the top and side of Rod C-1. Rod C-1 was designed with a cross-sectional shape and size that would allow it to be inserted into the groove [Am]. As shown in Figure 5, it has a tapered gable-top shape, and when inserted into the groove [Am], the tapered surface contacts the tapered surface of the groove [Am]. (Ring-shaped sample used) • Sample 1: Stainless steel ring with a thickness of 1.0 mm, an inner diameter of 11 mm, and a height of 8 mm. (Equipment used) • Universal material testing machine (manufactured by Instron Japan Co., Ltd., "Instron" (registered trademark) Model 5565 P8564) (Example 1) The two spool members of the expansion section A-1 were placed facing each other on their side planes to form a roughly cylindrical shape, and the convex portion of the bottom surface was fitted with the guide on the base B-1. The expansion section A-1 was then placed on the base B-1 so that the facing side planes were oriented perpendicular to the longitudinal direction of the guide, and sample 1 was fitted onto the side surface of the expansion section A-1. After applying grease to the jig and the ring to be evaluated, the rod C-1 was lowered from above the expansion section A-1 at a speed of 0.5 mm / min using the universal material testing machine "Instron" (registered trademark), and inserted into the groove [Am] formed by the notch. The rod C-1 was lowered further after the tapered surface of the rod C-1 came into contact with the tapered surface of the groove [Am], thereby expanding the spool member in the longitudinal direction of the guide, and a tensile test was performed by applying internal pressure to sample 1.

[0038] During the test, the spinning top did not fall over, the upper surface of the spinning top moved parallel to the longitudinal direction of the base guide, and sample 1 received uniform internal pressure in the height direction. When the shape of sample 1 was visually observed after the test, it was found that the height expansion of sample 1 was the same at the top and bottom, and sample 1 was uniformly expanded.

[0039] (Comparative Example 1) A tensile test was performed in the same manner as in Example 1, except that the expansion part [A] was changed from expansion part A-1 to expansion part A-2. Because the depth from the top surface of the notch of expansion part A-2 was 1 / 4 of the height of the side plane, the compost member tilted during the test, and sample 1 was subjected to non-uniform internal pressure in the height direction. When the shape of sample 1 was visually observed after the test, it was found that sample 1 had a larger spread at the top than at the bottom, and the expansion in the height direction was non-uniform.

[0040] (Comparative Example 2) A tensile test was performed in the same manner as in Example 1, except that the expansion part [A] was changed from expansion part A-1 to expansion part A-3. The recess formed on the side surface of the spindle member constituting expansion part A-3 is not inside the spindle member, and the protrusion that fits into the recess becomes part of the side surface when a roughly cylindrical shape is formed. As a result, the protrusion interfered with sample 1 during the test, and when the shape of sample 1 was visually observed after the test, it was found that sample 1 had depressions near the recess and protrusion extending from the side surface of the spindle member, indicating that the expansion was heterogeneous. [Industrial applicability]

[0041] The tensile properties testing fixture and the testing method using this fixture of the present invention enable the simple and accurate measurement of the tensile properties of a ring-shaped sample, and can be suitably used for material evaluation in general industrial fields. [Explanation of Symbols]

[0042] [Afs] Side plane fitting part [Afb] Bottom fitting part [Am] Tapered groove 1 Guide 2. The part that contacts the tapered portion of the groove [Am] 3. Sliding direction of the 3-piece member 4. Direction of rod insertion

Claims

1. A test fixture for the mechanical properties of a ring-shaped sample, having the following components [A] to [C]. [A]: Extension consisting of a pair of saddle members [B]: A base for placing [A], the base having a linear guide or rail that fits into part [Afb] of [A]. [C]: A tapered rod that can be inserted into a tapered groove [Am] in [A], wherein the tapered surface of the rod makes surface contact with the tapered surface in the groove [Am] when inserted into the groove [Am]. And, Each component of [A] is based on a semi-cylindrical shape and has a top surface, bottom surface, side circumferential surface and side surface. moreover, [Ac]: A notch formed in a pair of spinning top members, extending from the top surface of the spinning top member to a position lower than 1 / 4 of the height in the side plane, and having substantially the same shape. [Afb]: Convex and / or concave parts formed on the bottom surface [Afs]: A total of two or more recesses and / or protrusions formed on each saddle member in the range of 1 / 3 to 2 / 3 of the height direction on the side plane, wherein the recesses are formed extending inward from the side plane into the saddle member, and the protrusions are formed extending perpendicularly from the side plane. The part is formed, When the pair of spinning top members are placed facing each other on their side planes, the recess of one spinning top member at part [Afs] fits into the protrusion of the other spinning top member, forming a substantially cylindrical shape with a base formed by the two bases. Both notches [Ac] form tapered grooves [Am] which are roughly triangular prism, roughly gable top, roughly polygonal pyramidal, roughly frustum-shaped, roughly conical, or roughly frustum-shaped spaces that taper from the top to the bottom of the roughly cylindrical column. When the substantially cylindrical object is placed on [B] with the two side planes facing each other oriented perpendicular to the guide or rail of [B], part [Afb] fits into the guide or rail and slides along its longitudinal direction in a direction that separates a pair of saddle members.

2. The mechanical properties testing fixture for a ring-shaped sample according to claim 1, wherein the angle of the tip of the groove [Am] is less than 120°.

3. The mechanical properties testing fixture for a ring-shaped sample according to claim 1, wherein the diameter of the substantially cylindrical part formed with respect to [A] is 5 cm or less.

4. A method for evaluating the mechanical properties of a ring-shaped sample using the jig described in any one of claims 1 to 3.

Images