Test specimen set, test specimen forming fixture, and tensile test preparation method

Abstract

The present invention provides a specimen set, a specimen forming jig, and a method for preparing for tensile testing, all of which enable easy and accurate attachment of specimens to a tensile testing apparatus during tensile testing. [Solution] A set of test specimens Ts used for tensile testing, comprising a test specimen T that extends in a film-like manner, and a test specimen holder H that is frame-shaped, holding both longitudinal ends of the test specimen T and exposing the test specimen T to an inner space S, with both ends in the frame length direction, which coincides with the longitudinal direction of the test specimen T, being 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 jig used when forming the test piece set, and a method for preparing a tensile test using the test piece set 2.

Background Art

[0002] Conventionally, for example, a tensile test apparatus used to obtain the tensile properties of a resin film or sheet is known (for example, Patent Document 1). In a tensile test using this type of apparatus, one end of the test piece is attached to a load measuring instrument and the other end is held by a holding portion, and the other end is pulled with respect to one end of the test piece, and the load applied to the test piece is measured at that time.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the case of a film-shaped test piece, since the thickness is often very thin, it is difficult to set it at a predetermined position and without bending in the tensile direction when attaching one end of the test piece to a load measuring instrument and setting the other end to a holding portion in a tensile test, and there is a problem that test preparation takes time.

[0005] Therefore, the present invention provides a test piece set that can easily and accurately attach a test piece to a tensile test apparatus, a test piece forming jig for forming the test piece set, and a method for preparing a tensile test.

Means for Solving the Problems

[0006] A specimen set according to one aspect of the present invention is a specimen set used for tensile testing, comprising a specimen extending in a film-like manner, and a specimen holder that holds both longitudinal ends of the specimen and exposes the specimen to an inner space, with both ends in the frame length direction, which coincides with the longitudinal direction of the specimen, being held by a tensile testing device.

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

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

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

[0010] A test forming jig according to one aspect of the present invention is a test piece forming jig for forming the above-mentioned set of test pieces, comprising: a jig body having a reference line on its upper surface indicating the position for arranging the test pieces; and a positioning surface protruding from the upper surface of the jig body, which positions the first side region when the inner surface of the first side region of the test piece holder is positioned opposite the upper surface.

[0011] A method for preparing for a tensile test according to one aspect of the present invention is a method for preparing for a tensile test when performing a tensile test using the above-described set of test specimens, comprising the steps of: holding the test specimens in the test specimen holder; holding both ends of the test specimen holder in the frame length direction in the tensile test device; and cutting the test specimen holder and dividing it into two parts in the frame length direction. [Effects of the Invention]

[0012] According to the above-described test specimen set, test specimen forming jig, and tensile test preparation method, it becomes possible to easily and accurately attach the test specimen to the tensile testing apparatus during a tensile test. [Brief explanation of the drawing]

[0013] [Figure 1] This is an overall plan view of a tensile testing apparatus using a set of test specimens according to an embodiment of the present invention, where (a) shows the state before the start of the test, and (b) shows the state after the start of the test when the test specimen has been stretched. [Figure 2] This figure shows how the test specimen stretches when a tensile test is performed using the tensile testing apparatus described above. [Figure 3] This is an enlarged front view showing the tensile testing apparatus with the test specimen set installed. [Figure 4] This graph shows the relationship between the test time and the tensile speed when performing a tensile test using the tensile testing apparatus described above. [Figure 5] The above diagram shows the set of test specimens, where (a) is a front view and (b) is a cross-sectional view of (a) along the line IV-IV. [Figure 6] The figure shows a specimen forming jig for forming the above-mentioned set of test specimens, where (a) is a plan view and (b) is a front view taken along arrow VI in (a). [Figure 7] The procedure for forming the above test specimen set is shown in chronological order in (a), (b), and (c). [Figure 8]The figure shows the test preparation when performing a tensile test using the above test piece set. (a) shows the state immediately after attaching the test piece set to the tensile test apparatus, and (b) shows the state where the test piece is bent. [Figure 9] The figure shows a modified example of a test piece forming jig for forming the above test piece set.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (Overall Configuration) As shown in FIGS. 1(a) and (b), the tensile test apparatus 100 is an apparatus that performs a tensile test for pulling a test piece T so that the other end Tb of the test piece T moves away from one end of the test piece T formed in a film shape (film shape, sheet shape). The test piece T is formed of, for example, resin or the like, and has a shape in which the dimension in the film length direction is longer than the dimension in the film width direction. In the present 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 test apparatus 100 includes a plate-shaped main base 10, a one-end-side holder 1 provided on the main base 10, an other-end-side 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.

[0016] The main base 10 is, for example, a plate-shaped member installed on a horizontal plane. 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 configured by a computer including a processor or the like.

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

[0018] The other-end holder 2 is positioned at a distance from the one-end holder 1 in the longitudinal direction of the test piece T, and holds the other end Tb of the test piece T via the test piece holder H, which will be described later. The other-end holder 2 is a chuck that, like the one-end holder 1, clamps the test piece T from, for example, the thickness direction of the test piece (hereinafter referred to as the film thickness direction).

[0019] The support base 3 for the holder supports the other end holder 2 from below and is able to move linearly in the device length direction, which coincides with the longitudinal direction of the test piece T, in the horizontal direction relative to the main base 10, together with the other end holder 2. The support base 3 for the holder is able to reciprocate in the device length direction so as to bring the one end holder 1 and the other end holder 2 closer together and further apart.

[0020] The observation base 4 is provided between the main base 10 and the holder support base 3, and is capable of reciprocating linearly in the device length direction relative to the main base 10 on the main base 10, and is also capable of reciprocating linearly in the device 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 in the device length direction by this slide rail 40, but the guide structure of the observation base 4 is not particularly limited.

[0021] The main drive unit 5 moves the observation base 4 back and forth linearly in the direction of the device length relative to the one-end holder 1 on the main base 10. The main drive unit 5, although not shown in detail in the illustration, 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, making it possible to move the observation base 4 at any speed and stop 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 fixedly mounted on the observation base 4 and consists of a camera or the like capable of observing the 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 in the longitudinal direction of the test piece T.

[0023] The moving link mechanism 7 is a mechanical mechanism that moves the support base 3 and the observation base 4 relative to each other. The moving link mechanism 7 is configured such that the first movement amount (which may also be a speed) L1, which is the linear movement amount (distance) of the support base 3 toward the side away from the support base 3 relative to the support base 1, is a predetermined multiple of the second movement amount (which may also be a speed) L2, which is the linear movement amount (distance) of the observation base 4 toward the side away from the support base 1. Specifically, let N be the ratio of the first movement amount L1 to the second movement amount L2, and let L be the initial length of the test piece T before the tensile test. T Let L be the length from one end Ta of the test specimen T, which is the initial length, to the position to be observed. K When this is the case (see Figure 2), the moving link mechanism 7 is configured to satisfy the following equation (1).

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

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

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

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

[0028] The gear ratios of the first rack 70, the first rotating body 71, the second rack 72, and the second rotating body 73 are set to such a value that the first movement L1 of the support base 3 is twice the second movement L2 of the observation base 4, as described above. Note that the first rotating body 71 and the second rotating body 73 may be replaced with pulleys instead of gears.

[0029] The load measuring device 8 measures the load (tensile force) applied to the test specimen T when it is pulled during a tensile test, and in this embodiment, it is composed of a load cell. The load measuring device 8 is supported by a frame 11 on the main base 10 and is fixed to the main base 10. The load measuring device 8 is also electrically connected to the 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 the following: strain gauge type, piezoelectric type, capacitive type, electromagnetic type, or tuning fork type.

[0030] (Test piece set) Next, the specimen set Ts of this embodiment used in the tensile testing apparatus 100 will be described in detail. As shown in Figure 3, the specimen set Ts comprises the specimen T which extends in a film-like manner, and specimen holders H which are thin plate frames that hold both ends of the specimen T in the longitudinal direction.

[0031] The specimen holder H is provided so as to surround the specimen T from the outer circumference, and both ends of the specimen T in the frame length direction, which coincides with the longitudinal direction of the specimen T, are held by the one-end holder 1 and the other-end holder 2 of the tensile testing apparatus 100, respectively. The material of the specimen holder H is not particularly limited, but it is preferable that it be made of thick paper, which has greater strength in the frame length direction than the strength of the specimen T in the longitudinal direction.

[0032] Furthermore, the specimen holder H has an inner space S formed therein, which is a through-hole that penetrates the specimen holder H in the thickness direction (frame thickness direction) and where the specimen T is placed. The specimen T is positioned so as to occupy a portion of the inner space S, and a portion of the specimen T in the longitudinal direction is exposed to the inner space S. In addition, the specimen holder H has a slit Ha formed on one side in the frame width direction, which coincides with the film width direction of the specimen T, connecting this inner space S to the outside of the specimen holder H. In other words, the specimen holder H is separated into one region in the frame length direction and the other region only on one side in the frame width direction, and when viewed from the frame thickness direction, the specimen holder H has a roughly C shape.

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

[0034] Furthermore, as shown in Figures 5(a) and 5(b), the specimen holder H has a first side region Hx and a second side region Hy that overlap in the frame thickness direction. These first side region Hx and second side region Hy are connected to each other across a broken line PL on one side in the frame width direction (or one side in the frame length direction) of the specimen holder H. In the specimen holder H, the first side inner surface Hxa, which is the inner surface of the first side region Hx, and the second side inner surface Hya, which is the inner surface of the second side region Hy, are facing each other, and an adhesive P is interposed between these first side inner surface Hxa and 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 specimen T are sandwiched between the first side inner surface Hxa and the second side inner surface Hya, respectively, thereby integrating the specimen T and the specimen holder H.

[0035] Next, we will describe a specimen forming jig 200 for forming a specimen set Ts, and a method for forming (manufacturing) the specimen set Ts using the specimen forming jig 200. As shown in Figures 6(a) and 6(b), the specimen forming jig 200 has a plate-shaped jig body 210 with a reference line LX on its upper surface 210a indicating the position for placing the specimen T, and a protrusion 220 that protrudes 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 the region A between these two reference lines has a shape that approximately coincides with the test piece T.

[0037] The protrusion 220 forms a positioning surface 220a for aligning the position of the specimen holder H when the first inner surface Hxa of the first side region Hx of the specimen holder H is positioned opposite the upper surface 210a. In this embodiment, when the first side region Hx of the specimen holder H is positioned opposite the upper surface 210a, the edge of the positioning surface 220a is L-shaped when viewed from above in the thickness direction of the specimen forming jig 200, so that the specimen 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 when preparing for a tensile test using the test specimen set Ts, the test specimen set Ts is first formed. That is, as shown in Figure 7(a), the test specimen T is placed along the reference line LX provided on the upper surface 210a of the test specimen forming jig 200. Then, as shown in Figure 7(b), the first inner surface Hxa of the first side region Hx of the test specimen holder H, to which adhesive P has been applied, is positioned opposite the upper surface 210a. This adheres both sides of the longitudinal direction of the test specimen T to the first inner surface Hxa. At this time, on the other side in the frame width direction of the test specimen holder H, which is the side without the positioning surface 220a, the second side region Hy of the test specimen holder H is positioned to protrude to the outside of the test specimen forming jig 200.

[0039] Then, with the specimen T attached, the first side region Hx of the specimen holder H is removed from the upper surface 210a, and as shown in Figure 7(c), the second side region Hy of the specimen holder H is folded back along the broken line LP 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. This completes the specimen set Ts in which the specimen T is sandwiched between the first side region Hx and the second side region Hy of the specimen holder H (see Figures 5(a) and 5(b)).

[0040] Next, in the above test preparation method, the test specimen set Ts is attached to the tensile testing apparatus. That is, one side of the test specimen holder H in the frame length direction is clamped by the one-end holder 1 of the tensile testing apparatus 100, and the other side of the test specimen 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 specimen T are also clamped by the one-end holder 1 and the other-end holder 2 together with the test specimen holder H. Then, as shown in Figure 8(a), on the other side in the frame width direction where the slit Ha is not formed on the test specimen T, the test specimen holder H is cut along the direction in which the slit Ha extends, i.e., in the frame width direction, at a position between the one-end holder 1 and the other-end holder 2, dividing it into two parts in the frame length direction. When cutting the test specimen holder H, it is preferable to cut the test specimen holder H at two virtual cutting lines VL that are spaced approximately the same distance as the slit width dimension W in the frame length direction. Subsequently, as shown in Figure 8(b), the test specimen T is deflected in the longitudinal direction by bringing the one-end holder 1 and the other-end holder 2 of the tensile testing apparatus 100 closer together (a so-called "setback" is performed). The tensile test is started from this state, and the specimen is gradually accelerated while increasing the tensile speed, reaching the predetermined speed u described above. c Constant-speed tensioning is initiated after reaching a certain point (see Figure 4). The tensioning speed u increases from zero to a predetermined speed u c In this case, it would be ideal if the test piece T is neither bent nor stretched, but at its natural length.

[0041] By using the specimen set Ts described above with the tensile testing apparatus 100, the risk of the specimen T being attached to the apparatus 100 in a deformed state can be reduced compared to when the specimen T is attached to the apparatus 100 individually. In other words, during tensile testing, the specimen T can be attached to the tensile testing apparatus 100 easily and accurately. Therefore, the accuracy of the tensile test can be improved.

[0042] In particular, in the specimen set Ts of this embodiment, the slit Ha is formed only on one side in the frame width direction of the specimen holder H. Therefore, the specimen T and the specimen holder H remain as one unit without separation, and the relative positions of the specimen T and the specimen holder H do not shift when attaching the specimen set Ts to the tensile testing device 100 or when transporting it, thereby reducing the risk of the specimen T being attached to the tensile testing device 100 in a bent state. Furthermore, after attaching the specimen set Ts to the tensile testing device 100, the tensile test can be started immediately by cutting the specimen holder H only on the side where the slit Ha is not formed, making it very easy to use.

[0043] Furthermore, because the slit width W in slit Ha is larger than the area of ​​the acceleration region R (see Figure 4), the setback can be secured when one side of the specimen holder H in the frame length direction does not come into contact with the other side, as shown in Figure 8(b). Therefore, setting the setback (securing the acceleration region R) becomes easier.

[0044] Furthermore, by configuring the specimen holder H with a first side region Hx and a second side region Hy facing each other, and sandwiching the specimen T between the first side region Hx and the second side region Hy, the specimen T can be firmly fixed by the specimen holder H, reducing the risk of the specimen T falling out of the specimen holder H during testing.

[0045] Furthermore, by using the specimen forming jig 200, the specimen T can be easily and precisely held in the specimen holder H at the desired position, thereby facilitating the formation of the specimen set Ts. As shown in Figure 9, in the specimen forming jig 200, three or more reference lines LX are provided at intervals, that is, multiple regions A sandwiched between a pair of reference lines LX are arranged at intervals in the film width direction of the specimen T, thereby forming a specimen set Ts in which multiple specimens T are arranged in the film width direction.

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

[0047] Furthermore, when a tensile test is performed on the test piece T using the tensile testing apparatus 100 described above, the test piece T elongates, and the elongation amount ΔLb at the other end Tb becomes twice the elongation amount ΔLc at the central part Tc (see Figure 2). In this embodiment, the movement link mechanism 7 is configured such that the first movement amount L1, which is the linear movement amount of the 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. As a result, the imaging unit 6 can move in conjunction with the movement of the central part Tc accompanying the elongation of the test piece T, and can continuously observe the central part Tc, which is at a predetermined position on the test piece T.

[0048] And with such a simple structure, using a mechanical moving link mechanism 7, it becomes possible to continuously observe the position to be observed, which is a predetermined position on the test specimen T.

[0049] Furthermore, the main drive unit 5 operates only the observation base 4, while the mechanical moving link mechanism 7 moves the support base 3 for the holder. Compared to the case where the support base 3 for the holder and the observation base 4 are moved by separate drive units, this allows for a more reliable maintenance of a constant relative movement between the support base 3 for the holder and the observation base 4.

[0050] Herein, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the tensile testing apparatus in which the above-described specimen set Ts is used is not limited to the tensile testing apparatus 100 with the above configuration, and the specimen set Ts may also 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] In the case of the tensile testing apparatus 100 described above, the observation base 4 was moved linearly by the main drive unit 5. However, the support base 3 for the holder body may be moved linearly by the main drive unit 5, and the observation base 4 may be moved relative to the support base 3 by the moving link mechanism 7.

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

[0053] According to the present invention, the test specimen set, test specimen forming jig, and tensile test preparation method make it possible to easily and accurately attach the test specimen to the tensile testing apparatus during a tensile test. [Explanation of Symbols]

[0054] 1...One end holding body 2...Other end side holding body 3...Base for supporting the holder 4… Observation base 5…Main drive unit 6… Imaging Department 7…Moving link mechanism 8…Load measuring device 9... Control Unit 70...First rack 71…First rotating body 72... Second rack 73…Second Rotating Body 100...Tensile testing device 200... Test specimen forming jig 210... Jig body 210a…Top surface 220a... Positioning surface H... Test specimen holder Ha... Slit Hx…first side area Hxa...first side inner surface Hy…Second side area Hya... Second inner side 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 set of test specimens used for tensile testing, A test specimen that extends in a film-like manner, A specimen holder is provided, which holds both ends of the specimen in the longitudinal direction and exposes the specimen to an inner space, with both ends of the frame in the longitudinal direction, which coincides with the longitudinal direction of the specimen, being held by a tensile testing device. A set of test specimens for tensile testing, equipped with the necessary components.

2. The specimen holder has a slit formed on one side in the frame width direction, which coincides with the film width direction of the specimen, that connects the inner space with the outside of the specimen holder, as described in claim 1.

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

4. The specimen holder has a first side region and a second side region that overlap in the thickness direction of the specimen, In the specimen holder, the inner surface of the first side region (hereinafter referred to as the first side inner surface) and the inner surface of the second side region (hereinafter referred to as the second side inner surface) are facing each other. An adhesive is interposed between the first inner surface and the second inner surface. A test specimen set for tensile testing according to any one of claims 1 to 3, wherein both ends of the test specimen are sandwiched between the first inner surface and the second inner surface.

5. A test specimen forming jig for forming the test specimen set described in claim 4, A jig body having a reference line on its upper surface indicating the position where the test piece is placed, A positioning surface that protrudes from the upper surface of the jig body and positions the first side inner surface of the first side region of the test piece holder when the first side inner surface is positioned opposite the upper surface, A test specimen forming jig equipped with the following features.

6. A method for preparing for a tensile test when performing a tensile test using a set of test specimens described in any one of claims 1 to 3, The steps include: holding the test specimen in the test specimen holder, The steps include: holding both ends of the specimen holder in the length direction of the frame to the tensile testing device; The steps include cutting the specimen holder and dividing it into two parts in the length direction of the frame, A method for preparing for a tensile test, comprising the following components.

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