Test piece set, test piece forming jig, and tensile test preparation method

Abstract

A test piece set, a test piece forming jig, and a preparation method for a tensile test, which enable a test piece to be easily and accurately attached to a tensile test device during a tensile test, are provided. [Solution] The test piece set Ts used in a tensile test includes a test piece T extending in a membrane-like shape, and a frame-shaped test piece holder H that holds both ends of the longitudinal direction of the test piece T and exposes the test piece T to an inner space S, and both ends of the frame length direction that coincides with the longitudinal direction of the test piece T are held by a tensile testing device.

Description

[Technical field]

[0001] The present invention relates to a test piece set used in a tensile test, a test piece forming tool used when forming the test piece set, and a method for preparing a tensile test using the test piece set 2. [Background technology]

[0002] A tensile testing device used to obtain the tensile properties of, for example, a resin film or sheet is known (for example, Patent Document 1). In a tensile test using this type of device, one end of a test piece is attached to a load measuring device and the other end is held by a holder, and the other end is pulled against the one end of the test piece, and the load applied to the test piece at this time is measured. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-148057 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of film-like test pieces, the thickness is often very thin, and therefore when attaching one end of the test piece to a load measuring device and setting the other end in a holder in a tensile test, it is difficult to set the test piece in a predetermined position without bending in the tensile direction, which causes a problem of requiring a lot of work for test preparation.

[0005] Therefore, the present invention provides a test piece set that enables a test piece to be easily and accurately attached to a tensile testing device during a tensile test, a test piece forming jig for forming the test piece set, and a preparation method for a tensile test. [Means for solving the problem]

[0006] A test piece set according to one embodiment of the present invention is a test piece set used for tensile testing, and comprises a test piece extending in a membrane-like shape, and a test piece holder that holds both longitudinal ends of the test piece and is frame-shaped to expose the test piece to an internal space, and whose both ends in the frame length direction that coincides with the longitudinal direction of the test piece are held by a tensile testing device.

[0007] In the above test strip set, the test strip holder may have a slit formed on one side of the frame width direction, which coincides with the membrane width direction of the test strip, connecting the inner space with the outside of the test strip holder.

[0008] In the above test piece set, a slit width dimension, which is a dimension of the slit in the frame length direction, may be larger than a time integral value of the tensile speed in an acceleration region in the tensile test from zero to a constant speed.

[0009] In the above test piece set, the test piece holder has a first side region and a second side region that overlap in the film thickness direction of the test piece, and in the test piece holder, the inner surface of the first side region (hereinafter, first side inner surface) and the inner surface of the second side region (hereinafter, second side inner surface) are opposed to each other, an adhesive is interposed between the first side inner surface and the second side inner surface, and both ends of the test piece may be clamped between the first side inner surface and the second side inner surface, respectively.

[0010] A test formation jig according to one embodiment of the present invention is a test piece formation jig for forming the above-mentioned test piece set, and comprises a jig body having a reference line on its upper surface indicating the position for placing the test piece, and a positioning surface protruding from the upper surface of the jig body and positioning the first side region in the test piece holder when the first side inner surface of the first side region is placed facing the upper surface.

[0011] A tensile test preparation method according to one embodiment of the present invention is a tensile test preparation method for performing a tensile test using the above-mentioned test piece set, and includes the steps of holding the test piece in the test piece holder, holding both ends of the test piece holder in the frame length direction in the tensile testing apparatus, and cutting the test piece holder to divide it into two in the frame length direction. Effect of the Invention

[0012] According to the above-mentioned test piece set, test piece forming jig, and tensile test preparation method, it becomes possible to easily and accurately attach the test piece to the tensile tester during the tensile test. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an overall plan view of a tensile testing device using a test piece set according to an embodiment of the present invention, in which (a) shows the state before the start of testing, and (b) shows the state after the start of testing in which the test piece has been elongated. [Diagram 2] FIG. 2 is a diagram showing how a test piece elongates when a tensile test is performed in the tensile test apparatus. [Diagram 3] FIG. 2 is an enlarged front view showing a state in which a test piece set is installed in the tensile testing apparatus. [Figure 4] 4 is a graph showing the relationship between test time and tensile speed when a tensile test is performed in the tensile tester. [Diagram 5] FIG. 2 is a diagram showing the test piece set, in which (a) is a front view and (b) is a cross-sectional view taken along the line IV-IV in (a). [Figure 6] FIG. 2 is a diagram showing a test piece forming jig for forming the test piece set, in which (a) is a plan view and (b) is a front view taken along the line VI in (a). [Figure 7] 1A, 1B, and 1C are diagrams showing the procedure for forming the test piece set in chronological order. [Figure 8]FIG. 1 shows the test preparation when conducting a tensile test using the above test piece set, where (a) shows the state immediately after the test piece set is attached to the tensile test device, and (b) shows the state in which the test piece is bent. [Figure 9] 13A and 13B are diagrams showing modified examples of the test piece forming jig for forming the test piece set. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. (Overall composition) As shown in Figures 1(a) and (b), the tensile testing device 100 is a device for performing a tensile test in which a membrane-like (film-like, sheet-like) test piece T is pulled such that one end Tb of the test piece T is separated from one end of the test piece T. The test piece T is formed, for example, from a resin or the like, and has a shape in which the dimension in the membrane length direction is longer than the membrane width direction. In this embodiment, the test piece T constitutes a test piece set Ts together with a test piece holder H, which will be described in detail later.

[0015] Specifically, the tensile testing apparatus 100 comprises a plate-shaped main base 10, a one-end holder 1, an other-end holder 2, a holder support base 3, an observation base 4, a main drive unit 5, an imaging unit 6, a moving link mechanism 7, and a load measuring device 8, which are provided on the main base 10.

[0016] The main base 10 is, for example, a plate-like member placed on a horizontal surface. The main base 10 is provided with a control unit 9 that controls the operation of the main drive unit 5, which will be described in detail later. The control unit 9 is composed of a computer including a processor and the like.

[0017] The one-end holder 1 holds one end Ta of the test piece T in the longitudinal direction via a test piece holder H described later. The one-end holder 1 is, for example, a chuck that holds the test piece T in the thickness direction (hereinafter, film thickness direction) of the test piece, and is connected to a load measuring device 8 described in detail later.

[0018] The other end holder 2 is disposed with a gap in the longitudinal direction of the test piece T relative to the one end holder 1, and holds the other end Tb of the test piece T via a test piece holder H, which will be described later. Similar to the one end holder 1, the other end holder 2 is, for example, a chuck that clamps the test piece T in the thickness direction (hereinafter, film thickness direction) of the test piece.

[0019] The holder support base 3 supports the other end holder 2 from below, and is capable of moving horizontally together with the other end holder 2 relative to the main base 10 on the main base 10, and linearly in the device length direction that coincides with the longitudinal direction of the test piece T. The holder support base 3 is capable of reciprocating in the device length direction so as to move the one end holder 1 and the other end holder 2 closer to and away from each other.

[0020] The observation base 4 is provided between the main base 10 and the holder support base 3, and is capable of linear reciprocating movement on the main base 10 in the apparatus length direction relative to the main base 10, and is also capable of linear reciprocating movement in the apparatus length direction relative to the holder support base 3. Specifically, for example, a slide rail 40 is provided between the observation base 4 and the holder support base 3, and the observation base 4 moves linearly while being guided by this slide rail 40 in the apparatus length direction, but the guide structure of the observation base 4 is not particularly limited.

[0021] The main drive unit 5 moves the observation base 4 reciprocally in a straight line in the device length direction on the main base 10 relative to the one-end holder 1. Although detailed illustration is omitted, the main drive unit 5 includes, for example, a stepping motor and a ball screw driven by the stepping motor. The main drive unit 5 is driven and controlled by a control unit 150 provided on the main base 10, and is capable of moving the observation base 4 at any speed and stopping it at any position. The configuration of the main drive unit 5 is not particularly limited, and may be configured by other known methods such as a linear motor.

[0022] The imaging unit 6 is fixed on the observation base 4 and is configured with a camera or the like capable of observing an observation position, which is a predetermined position in the longitudinal direction of the test piece T. In this embodiment, this observation position is the central part Tc of the test piece T in the longitudinal direction.

[0023] The moving link mechanism 7 is a mechanical mechanism that moves the holder support base 3 and the observation base 4 relative to each other. The moving link mechanism 7 is configured so that a first movement amount (which may be a movement speed) L1, which is the linear movement amount (movement distance) of the holder support base 3 toward the separation side (the side where the holder support base 3 separates from the one-end side holder 1) relative to the one-end side holder 1, is a predetermined multiple of a second movement amount (which may be a movement speed) L2, which is the linear movement amount (movement distance) of the observation base 4 toward the separation side relative to the one-end side holder 1. Specifically, the ratio of the first movement amount L1 to the second movement amount L2 is defined as N, and the initial length of the test piece T before the tensile test is defined as L T The initial length of the test piece T is the length from one end Ta to the observation position, and L K (see FIG. 2), the moving link mechanism 7 is configured so as to satisfy the following formula (1).

[0024] N=L T / L K (1) In this embodiment, in the above formula (1), N = 2. That is, the first movement amount L1 which is the movement amount of the holder support base 3 is twice the second movement amount L2 which is the movement amount of the observation base 4.

[0025] The configuration of the moving link mechanism 7 is not particularly limited, but as an example, it has a first rack 70 provided on the holder support base 3, a first rotating body 71 which is a gear provided on the observation base 4, a second rack 72, and a second rotating body 73 which is also a gear, and a belt 74 as a power transmission part interposed between the first rotating body 71 and the second rotating body 73.

[0026] The first rotating body 71 meshes with the first rack 70 and is rotated as the observation base 4 moves linearly toward the separating side.

[0027] The rotational force of the first rotor 71 is transmitted to the second rotor 73 by a belt 74, and the second rotor 73 is rotated by the rotational force of the first rotor 71. The second rotor 73 is engaged with a second rack 72, and transmits its own rotational force as a linear movement force of the holder support base 3 through the second rack 72.

[0028] As described above, the gear ratios among the first rack 70, the first rotor 71, the second rack 72, and the second rotor 73 are set to values ​​such that the first movement amount L1 of the holder support base 3 is twice the second movement amount L2 of the observation base 4. Note that the first rotor 71 and the second rotor 73 may be pulleys instead of gears.

[0029] The load measuring device 8 measures the load (tensile force) applied to the test piece T when the test piece T is pulled in a tensile test, and is configured by a load cell in this embodiment. The load measuring device 8 is supported by a stand 11 on a main base 10 and is fixed to the main base 10. The load measuring device 8 is also electrically connected to a control unit 9, and its output is transmitted to the control unit 9. The method of detecting the load in the load measuring device 8 is not particularly limited, and may be any of a strain gauge type, a piezoelectric type, a capacitive type, an electromagnetic type, a tuning fork type, or the like.

[0030] (Test piece set) Next, a detailed description will be given of the test piece set Ts of this embodiment used in the tensile testing apparatus 100. As shown in Fig. 3, the test piece set Ts has the test piece T extending in a film shape and a thin frame-shaped test piece holder H that holds both ends of the test piece T in the longitudinal direction.

[0031] The test piece holder H is provided so as to surround the outer periphery of the test piece T, and both ends in the frame length direction, which coincides with the longitudinal direction of the test piece T, are clamped and held by one end holder 1 and the other end holder 2 of the tensile testing device 100. The material of the test piece holder H is not particularly limited, but it is preferably made of thick paper, which has greater strength in the frame length direction than the strength of the test piece T in the longitudinal direction.

[0032] The test piece holder H also has an inner space S in which the test piece T is placed and which serves as a through hole penetrating in the thickness direction (frame thickness direction) of the test piece holder H. The test piece T is arranged so as to block a part of the inner space S, and a part of the longitudinal direction of the test piece T is exposed to the inner space S. Furthermore, the test piece holder H has a slit Ha formed on one side in the frame width direction, which coincides with the membrane width direction of the test piece T, which connects the inner space S to the outside of the test piece holder H. In other words, the test piece holder H is in a state in which one region and the other region in the frame length direction are separated only on one side in the frame width direction, and the test piece holder H is approximately C-shaped when viewed from the frame thickness direction.

[0033] Here, the width dimension of the slit Ha in the frame length direction, i.e., the slit width dimension W, is the width of the slit Ha when the tensile speed u changes from zero to a constant speed u c In other words, the slit width W is larger than the area of ​​the shaded triangular region (acceleration region) R in the function graph showing the relationship between the test time t and the tensile speed u shown in Figure 4.

[0034] 5(a) and 5(b), the test piece holder H has a first side region Hx and a second side region Hy that overlap in the frame thickness direction. The first side region Hx and the second side region Hy are connected to each other across a folding line PL on one side of the frame width direction (or may be on one side of the frame length direction) of the test piece holder H. In addition, in the test piece holder H, a first side inner surface Hxa that is the inner surface of the first side region Hx and a second side inner surface Hya that is the inner surface of the second side region Hy are opposed to each other, and an adhesive P is interposed between the first side inner surface Hxa and the second side inner surface Hya, so that the first side region Hx and the second side region Hy are bonded to each other. In addition, both ends of the test piece T are sandwiched between the first side inner surface Hxa and the second side inner surface Hya, respectively, and thus the test piece T and the test piece holder H are integrated.

[0035] Next, a test piece forming jig 200 for forming the test piece set Ts and a method for forming (manufacturing) the test piece set Ts using the test piece forming jig 200 will be described. 6(a) and 6(b), the test piece forming jig 200 has a plate-shaped jig body 210 having a reference line LX on an upper surface 210a, the reference line LX indicating the position for placing the test piece T, and a protrusion 220 provided so as to protrude from the upper surface 210a of the jig body 210. The upper surface 210a is coated with, for example, a fluororesin coating.

[0036] The jig body 210 has two reference lines LX arranged in parallel, and an area A between the two reference lines has a shape that substantially matches the test piece T.

[0037] The protrusion 220 forms a positioning surface 220a that aligns the position of the test piece holder H when a first-side inner surface Hxa of the first side region Hx of the test piece holder H is placed facing the upper surface 210a. In this embodiment, when the first side region Hx of the test piece holder H is placed facing the upper surface 210a, the edge of the positioning surface 220a is L-shaped when viewed from above in the thickness direction of the test piece forming jig 200 so that the test piece holder H faces the positioning surface 220a from one side in the frame width direction and one side in the frame length direction of the first side region Hx.

[0038] In the test preparation method for preparing for a tensile test using the test piece set Ts, first, the test piece set Ts is formed. That is, as shown in FIG. 7(a), the test piece T is placed along the reference line LX provided on the upper surface 210a of the test piece forming jig 200. Then, as shown in FIG. 7(b), the first side inner surface Hxa of the first side region Hx of the test piece holder H provided with the adhesive P is placed facing the upper surface 210a. In this way, both sides of the test piece T in the longitudinal direction are attached to the first side inner surface Hxa. At this time, the second side region Hy of the test piece holder H is placed so as to protrude outside the test piece forming jig 200 on the other side in the frame width direction of the test piece holder H, which is the side on which the positioning surface 220a does not exist.

[0039] Then, with the test piece T attached, the first side region Hx of the test piece holder H is removed from the upper surface 210a, and the second side region Hy of the test piece holder H is folded back along the fold line LP as shown in Fig. 7(c) and attached so that the first side inner surface Hxa of the first side region Hx and the second side inner surface Hya of the second side region Hy overlap each other. This completes the test piece set Ts in which the test piece T is sandwiched between the first side region Hx and the second side region Hy of the test piece holder H (see Figs. 5(a) and 5(b)).

[0040] Next, in the above test preparation method, the test piece set Ts is attached to a tensile test apparatus. That is, one side of the test piece holder H in the frame length direction is clamped by the one end holder 1 of the tensile test apparatus 100, and the other side of the test piece holder H in the frame length direction is clamped by the other end holder 2. At this time, it is preferable that one end Ta and the other end Tb of the test piece T are also clamped by the one end holder 1 and the other end holder 2 together with the test piece holder H. Then, as shown in FIG. 8(a), on the other side of the frame width direction, which is the side on which the slit Ha is not formed with respect to the test piece T, the test piece holder H is cut along the extension direction of the slit Ha, i.e., along the frame width direction, at a position between the one end holder 1 and the other end holder 2, and divided into two in the frame length direction. When cutting the test piece holder H, it is preferable to cut the test piece holder H at two imaginary cutting lines VL spaced apart in the frame length direction by approximately the same distance as the slit width dimension W. Thereafter, as shown in FIG. 8(b), the one-end holder 1 and the other-end holder 2 of the tensile test device 100 are brought close to each other (so-called "setback" is performed), thereby bending the test piece T in the longitudinal direction. The tensile test is started from this state, and the tensile speed is gradually increased while the test piece is run up to the predetermined speed u. c After reaching the specified speed u, constant speed tensile testing begins (see Figure 4). The tensile speed u increases from zero to a specified speed u c When this occurs, it is desirable that the test piece T is neither bent nor stretched to its natural length.

[0041] By using the above-described test piece set Ts in the tensile testing apparatus 100, the risk of the test piece T being attached to the apparatus 100 in a bent state can be reduced compared to when the test piece T is attached to the tensile testing apparatus 100 by itself. That is, during a tensile test, the test piece T can be easily and accurately attached to the tensile testing apparatus 100. This improves the accuracy of the tensile test.

[0042] In particular, in the test piece set Ts of this embodiment, the slit Ha is formed only on one side in the frame width direction of the test piece holder H. Therefore, the test piece T and the test piece holder H are in an integrated state without being separated, and the relative positions of the test piece T and the test piece holder H do not shift when the test piece set Ts is attached to the tensile test apparatus 100 or when it is carried, reducing the risk that the test piece T is attached to the tensile test apparatus 100 in a bent state. Furthermore, after the test piece set Ts is attached to the tensile test apparatus 100, the test piece holder H can be cut only on the side where the slit Ha is not formed, allowing the tensile test to start immediately, which is very convenient.

[0043] In addition, by making the slit width dimension W of the slit Ha larger than the area of ​​the acceleration region R (see FIG. 4), the setback can be secured in a state where one side and the other side in the frame length direction of the test piece holder H are not in contact with each other as shown in FIG. 8(b), which makes it easy to set the setback (secure the acceleration region R).

[0044] Furthermore, the test piece holder H is configured with a first side region Hx and a second side region Hy opposed to each other, and the test piece T is sandwiched between the first side region Hx and the second side region Hy, so that the test piece T can be firmly fixed by the test piece holder H, thereby reducing the risk that the test piece T will fall off the test piece holder H during testing.

[0045] Furthermore, by using the test piece forming jig 200, the test piece T can be easily clamped in the test piece holder H at a desired position, and the formation of the test piece set Ts can be facilitated. As shown in Fig. 9, in the test piece forming jig 200, three or more reference lines LX can be provided at intervals, that is, multiple areas A sandwiched between a pair of reference lines LX can be arranged at intervals in the membrane width direction of the test piece T, thereby forming a test piece set Ts in which multiple test pieces T are arranged in the membrane width direction.

[0046] Here, it is not necessary to form a slit Ha in the test piece set Ts. If there is no slit Ha, the test can be started by cutting the test piece holder H on both sides of the test piece T in the frame width direction.

[0047] Furthermore, when a tensile test is performed on the test piece T using the above-mentioned tensile test apparatus 100, the test piece T elongates, and the elongation amount ΔLb of the other end Tb becomes twice the elongation amount ΔLc of the central portion Tc (see FIG. 2). In this embodiment, the moving link mechanism 7 is configured so that the first movement amount L1, which is the linear movement amount of the holder support base 3 that holds the other end Tb of the test piece T, is twice the second movement amount L2, which is the linear movement amount of the observation base 4 on which the imaging unit 6 is provided. Therefore, the imaging unit 6 can move in conjunction with the movement of the central portion Tc accompanying the elongation of the test piece T, and the central portion Tc, which is the predetermined position of the test piece T, can be constantly observed.

[0048] In this way, with a very simple structure using the mechanical moving link mechanism 7, it is possible to continuously observe the observation position, which is a predetermined position on the test piece T.

[0049] Furthermore, only the observation base 4 is operated by the main drive unit 5, and the holder support base 3 is moved by the mechanical moving link mechanism 7. Compared to a case in which the holder support base 3 and the observation base 4 are moved by separate drive units, the relative movement amount between the holder support base 3 and the observation base 4 can be kept constant more reliably.

[0050] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention. For example, the tensile testing apparatus in which the above-mentioned test piece set Ts is used is not limited to the tensile testing apparatus 100 having the above-mentioned configuration, and the test piece set Ts may be used in a conventional tensile testing apparatus that does not have, for example, an observation base 4 or a movable link mechanism 7.

[0051] Furthermore, in the case of the above-mentioned tensile testing apparatus 100, the observation base 4 was moved linearly by the main drive unit 5, but it is also possible to move the holder support base 3 linearly by the main drive unit 5 and move the observation base 4 relative to the holder support base 3 by the moving link mechanism 7.

[0052] Furthermore, the position of the test piece T observed by the imaging unit 6 does not necessarily have to be the center Tc of the test piece T, but may be any other position in the longitudinal direction of the test piece T. [Industrial Applicability]

[0053] According to the test piece set, test piece forming jig, and tensile test preparation method of the present invention, it becomes possible to easily and accurately attach a test piece to a tensile tester during a tensile test. [Explanation of symbols]

[0054] 1...One end holding body 2...Other end side holding body 3...Base for supporting the holding body 4…Observation base 5…Main drive unit 6…Imaging unit 7...Moving link mechanism 8...Load measuring device 9...Control section 70…First rack 71...First rotating body 72…Second rack 73...Second rotating body 100...Tensile testing device 200...Test piece forming jig 210...Jig body 210a…Top surface 220a...positioning surface H: Test piece holder Ha…Slit Hx…first side area Hxa...first side inner surface Hy…Second side area Hya…Second side inner surface LX: Reference line S…Inner space T: Test piece Ta…One end Tb: other end Tc…Central part Ts: Test piece set L1…First movement amount L2…Second movement amount W…Slit width dimension

Claims

1. A test piece set used in a tensile test, comprising: A test piece extending in a film shape; a test piece holder that holds both ends of the test piece in the longitudinal direction and exposes the test piece to an internal space, and that has a frame shape, and both ends of the frame length direction that coincides with the longitudinal direction of the test piece are held by a tensile testing device; A test specimen set for tensile testing comprising:

2. 2. A test piece set for tensile testing as described in claim 1, wherein the test piece holder has a slit formed on one side of the frame width direction that coincides with the membrane width direction of the test piece, the slit connecting the inner space with the outside of the test piece holder.

3. 3. The test piece set for a tensile test according to claim 2, wherein a slit width dimension, which is a dimension of the slit in the frame length direction, is larger than a value of a time integral of the tensile speed in an acceleration region in the tensile test from zero to a constant speed.

4. the test strip holder has a first side region and a second side region overlapping in a thickness direction of the test strip, In the test strip holder, an inner surface of the first side region (hereinafter, a first-side inner surface) and an inner surface of the second side region (hereinafter, a second-side inner surface) face each other, An adhesive is interposed between the first inner surface and the second inner surface, 4. The test piece set for a tensile test according to claim 1, wherein both ends of the test piece are clamped between the first inner surface and the second inner surface.

5. A test strip forming tool for forming the test strip set according to claim 4, comprising: A jig body having a reference line on its upper surface indicating a position where the test piece is to be placed; a positioning surface that protrudes from an upper surface of the jig body and positions the first side region of the test piece holder when the first side inner surface of the first side region of the test piece holder is disposed opposite the upper surface; A test specimen forming fixture comprising:

6. A preparation method for a tensile test when performing a tensile test using the test piece set according to any one of claims 1 to 3, comprising the steps of: holding the test strip in the test strip holder; a step of holding both ends of the test piece holder in the frame length direction by the tensile testing device; cutting the test strip holder into two in the frame length direction; A method for preparing a tensile test comprising:

Images