JP2009257885A - Test piece holding apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test piece holding apparatus simplified in its constitution and capable of precisely performing the tensile test and compression test of a thin plate. <P>SOLUTION: A base member 1 includes an one end holding part 20 for holding one end of a test piece P, an another end holding part 10 for holding another end of the test piece P and a compression deformation preventing part 30 for preventing the compression deformation of the test piece P. The one end holding part 20 is slidably arranged on the base member 1 and the another end holding part 10 is slidably arranged on the base member 1. The compression deformation preventing part 30 contains the receiving part 31 slidably arranged on the base member and receiving the intermediate part of the test piece P and a test piece biasing part 32 supported on the receiving part 31 to bias the intermediate part of the test piece P. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a specimen holding device. More specifically, the present invention relates to a test piece holding device that holds a test piece in a tension / compression test for grasping the tensile / compression characteristics of a thin metal plate.

  When the metal material is subjected to tensile plastic deformation and then compressed by reversing the load direction, as shown in FIG. 4, after the elastic deformation, the yield starts again with a considerably smaller stress than the initial tension, and then rapidly hardens. The phenomenon of doing is seen. This phenomenon is called the Bausinger effect.

  Moreover, when tension and compression are repeated on the metal material, as shown in FIG. 5, the stress-strain curve draws hysteresis, and the phenomenon that the deformation stress increases with the number of repetitions and the metal material becomes hard is observed. This phenomenon is called repeated plastic hardening. The degree of hardening in this repeated plastic hardening differs depending on the type of metal material and the repeated plastic strain width.

  As described above, metal materials generally are plastic-cured when repeated tension and compression are repeated, but some of them are softened without being cured when repeated tension and compression are repeated. In other words, there are those that repeatedly plastically soften.

  However, the Bauschinger effect and cyclic plastic hardening / softening properties (hereinafter collectively referred to as cyclic plastic properties) are closely related to the press formability of the plate material, especially the size of the springback, so that these properties are accurate. Need to figure out.

  These characteristics are generally grasped by a tensile / compression test.

  However, since the plate material used for the sheet metal press has a very thin thickness of about 1 mm, even if a tensile test can be performed, the compression test cannot be performed because the test piece is bent in the compression test.

  Therefore, conventionally, several plates to be tested are bonded to form a test piece, and apparently, the thickness of the plate is increased to perform a test while avoiding bending of the test piece during compression.

  However, the conventional test method has a problem that the production of the test piece is complicated.

  In order to solve such a conventional problem, Non-Patent Document 1 proposes a test piece holding device having a comb-teeth engaging portion as shown in FIG.

However, the test piece holding device according to the proposal of Non-Patent Document 1 not only has a complicated structure, but also cannot be attached to a general-purpose material testing machine and requires a dedicated testing machine. There's a problem.
2005 Plastic Working Spring Proceedings (pp.129-130) (2005.5.55-27)

  The present invention has been made in view of the problems of the prior art, and an object of the present invention is to provide a test piece holding device that has a simplified structure and that can accurately perform a tensile / compression test of a thin plate material.

  The test piece holding device of the present invention is a test piece holding device that holds a test piece during a tensile compression test of a thin plate material, and includes an end holding portion that holds one end of the test piece, and a test piece The base member includes a second end holding portion that holds the other end portion and a compression deformation preventing portion that prevents compressive deformation of the test piece, and the one end holding portion is slidably disposed on the base member. The other end holding portion is slidably disposed on the base member, and the compression deformation preventing portion is slidably disposed on the base member and receives a middle portion of a test piece, And a test piece urging portion that is supported by the receiving portion and urges the test piece intermediate portion to the receiving portion.

  In the test strip holding device of the present invention, the test strip urging section includes, for example, a biasing member that biases the test strip and a spring biasing mechanism that biases the biasing member. The

  In the test piece holding device of the present invention, the spring urging mechanism includes, for example, a bolt and a coil spring fitted to the bolt.

  Moreover, in the test piece holding apparatus of this invention, it is preferable that an urging | biasing member has a window or the hole penetrated and formed toward the test piece, for example.

  Since the test piece holding device of the present invention is configured as described above, it is possible to prevent the test piece from being bent during the compression test and to obtain an excellent effect that an accurate test can be performed.

  Hereinafter, although the present invention is explained based on an embodiment, referring to an accompanying drawing, the present invention is not limited only to this embodiment.

  A test piece holding device (hereinafter simply referred to as “device”) according to an embodiment of the present invention is schematically shown in FIG. 1, and a test piece held by the test piece holding device is shown in FIG. In the following description, the one set on the upper side of the tensile / compression tester (hereinafter simply referred to as “tester”) is referred to as “upper” or “upper”, and the one set on the lower side is “lower”. Alternatively, it will be referred to as “lower side”.

  The apparatus A includes a base plate 1, an upper holding portion 10 that holds the upper PU of the test piece P so as to be slidable in the vertical direction, and a lower holding portion that holds the lower side PL of the test piece P so that it cannot slide in the vertical direction. 20 and a slidable compressive deformation preventing portion 30 that supports the intermediate portion of the test piece P and prevents compressive deformation as main components.

  The base plate 1 is a rectangular thick plate, on which an upper holding portion 10, a lower holding portion 20, and a compression deformation preventing portion 30 are disposed.

  More specifically, the upper holding part 10 and the compression deformation preventing part 30 are slidably disposed on a slide rail 1 a laid on the base plate 1.

  The upper holding part 10 includes a holding body 11 that holds the upper PU of the test piece P provided at one side end, and an attachment part 12 to the testing machine provided at the other side end. A base 11 a of the holding body 11 is slidably engaged with a slide rail 1 a of the base plate 1.

  Further, the holding body 11 includes a U-shaped test piece holding member 11 b that holds the upper PU of the test piece P so as to face the compression deformation preventing unit 30.

  The lower holding part 20 includes a holding body 21 that holds and holds the lower side PL of the test piece P provided at one side end, and an attachment part 22 to the testing machine provided at the other side end. And disposed below the base plate 1.

  The holding main body 21 includes a U-shaped test piece holding member 21 a that sandwiches and holds the lower side PL of the test piece P toward the compression deformation preventing unit 30.

  As shown in FIGS. 1 and 3, the compression deformation preventing part 30 includes a receiving part 31 that receives an intermediate part of the test piece P and a test piece urging part 32 that urges the test piece P to the receiving part 31. It is supposed to be.

  The receiving portion 31 includes a base portion 31a that is slidably engaged with the slide rail 1a of the base plate 1, and a test piece mounting portion 31b disposed on the base portion 31a.

  The test piece urging unit 32 includes an urging member 33 and a spring urging mechanism 34 that urges the urging member 33 with a spring. The urging force of the spring urging mechanism 34 is prepared so as to prevent compression bending of the test piece P in the compression test, while not giving unnecessary restraint to the test piece P. It is determined by a test or the like according to the material of the piece P.

  As shown in FIG. 3, the spring urging mechanism 34 includes a bolt 34a and a coil spring 34b fitted on the bolt 34a.

  As shown in FIG. 3, the urging member 33 is a cross-shaped member in which an insertion portion 33 a for inserting the bolt 34 a of the spring urging mechanism 34 protrudes from the center of both sides of the block-shaped member. In the center of the urging member 33, a window 33b for penetrating and observing and taking out a strain gauge signal line affixed to the test piece P or mounting a displacement type is formed. In addition, it may replace with a window and may just be a through-hole. Further, the urging member 33 may be simply a rod-shaped member.

  The bolt 34a of the spring urging mechanism 34 passes through a bolt hole formed through the insertion portion 33a and is screwed into a female screw formed on the test piece placement portion 31b. Thereby, the spring urging mechanism 34 is supported by the test piece mounting portion 31b.

  The urging mechanism is not limited to the spring urging mechanism 34, and may be, for example, an air cylinder urging mechanism.

  Thus, the intermediate portion of the test piece P is set in the apparatus A in a state where it is placed on the test piece placement portion 31 b and is urged by the urging member 33.

  Since the apparatus A has such a configuration, when the test piece P is set in the apparatus A and the compression test is performed by the tester, the test is not performed in a state where the bending of the test piece is prevented by the biasing member 33. obtain. Therefore, the compression characteristic of the test piece P can be measured with high accuracy.

  Further, the test piece P is placed on the test piece placing portion 31b that is slidable in the vertical direction, that is, in the tension / compression direction, and an urging mechanism 34 that urges the test piece P is supported by the test piece placing portion 31b. Therefore, the resultant shear force is zero on the front and back sides of the test piece P. Therefore, measurement accuracy is further improved.

  Further, since the shearing force is not generated on the front and back of the test piece P, the urging member 33 is fixed at the center position of the test piece P, so that the test piece P observation, strain measurement and the like can be easily performed from the window 33b.

  The present invention can be applied to a tensile / compression test of a thin plate.

It is the schematic of the test piece holding | maintenance apparatus which concerns on one Embodiment of this invention. It is the schematic of the test piece hold | maintained at the same apparatus. It is the schematic of the compression deformation prevention part of the apparatus. It is a graph for demonstrating work hardening. It is a figure which shows an example of a stress-strain curve. It is the schematic of the test piece holding | maintenance apparatus based on the proposal of a nonpatent literature 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base plate 1a Slide rail 10 Upper holding part 11 Holding main body 11b Test piece holding member 12 Attaching part 20 Lower holding part 21 Holding main body 21a Test piece holding member 22 Attaching part 30 Compression deformation preventing part 31 Receiving part 31a Base 31b Test piece mounting Placement portion 32 Biasing portion 33 Biasing member 33b Window 34 Spring biasing mechanism 34a Bolt 34b Coil spring A Test piece holding device P Test piece

Claims (4)

A test piece holding device for holding a test piece during a tensile compression test of a thin plate material,
One end holding part for holding one end of the test piece, the other end holding part for holding the other end of the test piece, and a compression deformation preventing part for preventing compressive deformation of the test piece are used as a base member. Prepared,
The one end holding portion is disposed on the base member so as not to slide,
The other end holding portion is slidably disposed on the base member,
The compression deformation preventing portion includes a receiving portion that is slidably disposed on the base member and receives an intermediate portion of a test piece, and a test piece biasing portion that is supported by the receiving portion and biases the receiving portion of the test piece to the receiving portion. And a test piece holding device.   2. The test piece holding device according to claim 1, wherein the test piece urging unit includes an urging member that urges the test piece and a spring urging mechanism that urges the urging member.   The test piece holding apparatus according to claim 2, wherein the spring biasing mechanism includes a bolt and a coil spring fitted to the bolt.   The test piece holding apparatus according to claim 2, wherein the biasing member has a window or a hole penetratingly formed toward the test piece.