JP2016105057A - Tensile test device and tensile test method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tensile test device which can measure a superelasticity property and a viscoelasticity property simultaneously.SOLUTION: A tensile test device 100 comprises: an upper side chuck 21/a lower side chuck 22 by which both ends of a test piece T is held; a rod 41 which can be connected with the lower side chuck 22; an approach mechanism 30 which is interposed between the rod 41 and the lower side chuck 22; and a linear motor 42 which moves the rod 41 in a prescribed direction. The approach mechanism 30 comprises: a guide 35 which is connected with the lower side chuck 22 and can move in a direction of movement of the rod 41; a hook part 37 which is arranged in the guide 35; and a part 43 to be hooked which is arranged in the rod 41 capable of being hooked to the hook part 37. The guide 35 is relatively movable with respect to the rod 41. The part 43 to be hooked is hooked to the hook part 37 so that the guide 35 and the rod 41 are integrally movable. A stop auxiliary mechanism 60 is installed at a terminal end of a moving range in a tension direction of the lower side chuck 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technique of a tensile test apparatus and a tensile test method.

  A tensile test apparatus is known as an apparatus for performing a tensile test (for example, Patent Document 1). A tensile test is a material test in which a tensile load is applied to a test piece, the relationship between stress and strain is measured, and the elastic modulus, elastic limit, proportional limit, yield point, tensile strength, etc. of the test piece are obtained.

  In a conventional tensile test apparatus as disclosed in Patent Document 1, the superelastic characteristics and viscoelastic characteristics of a test piece are measured by individual test apparatuses. For example, the superelastic property of a test piece has been measured by an autograph or a universal testing machine that generates a large strain at a slow speed in the test piece. On the other hand, the viscoelastic properties of the test piece have been measured by a dynamic viscoelasticity measuring device or the like that applies a small amplitude with a large excitation speed to the test piece.

  However, from the viewpoint of the test efficiency of the tensile test, it is desired to simultaneously measure the superelastic property and the viscoelastic property of the test piece. Here, in order to measure the superelastic property and viscoelastic property of the test piece at the same time, the test piece is pulled to a predetermined position at a high speed and then stopped, and the test piece is held in a state where a predetermined strain is generated. Stress relaxation must be measured.

JP 2006-170959 A

  The problem to be solved by the present invention is to provide a tensile test apparatus and a tensile test method capable of simultaneously measuring superelastic characteristics and viscoelastic characteristics.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, in claim 1, a pair of gripping tools for gripping both ends of the test piece, a rod connectable to one of the gripping tools, and a running mechanism interposed between the rod and the one gripping tool, A linear motor that moves the rod in a predetermined direction, and the one gripping tool is moved in the pulling direction of the test piece by the rod. A guide connected to a gripping tool and movable in the moving direction of the rod; a hooking portion provided on the guide; a hooking portion provided on the rod and hookable on the hooking portion; The guide is movable relative to the rod, and the hooked portion is hooked on the hooking portion, whereby the guide and the rod are relatively moved. Limited, the guide and the rod The tensile test apparatus is provided with a stop assist mechanism that absorbs an impact generated when the gripping tool is stopped at the end of the range of movement of the one gripping tool in the pulling direction. It is.

  According to a second aspect of the present invention, the tensile test apparatus according to the first aspect includes a photographing mechanism for photographing an image of the test piece.

  In claim 3, a pair of gripping tools gripping both ends of the test piece, a rod connectable to one of the gripping tools, a running mechanism interposed between the rod and the one gripping tool, A linear motor that moves the rod in a predetermined direction, and a tensile test method of a tensile test apparatus in which the one gripping tool is moved in the tensile direction of the test piece by the rod, wherein the running mechanism includes A guide connected to one gripping tool and movable in the moving direction of the rod, a latching portion provided in the guide, and a latched portion provided in the rod and latchable on the latching portion And by driving the linear motor, the rod is accelerated in the moving direction, the hooked portion is hooked on the hooked portion, and the linear motor is driven to drive the test piece. , Said one The test piece, the one gripping tool, the guide and the rod are moved at a constant speed in the moving direction by accelerating the gripping tool, the guide and the rod in the moving direction and driving the linear motor. Then, by stopping the linear motor, the test piece, the one gripping tool, the guide, and the rod are stopped.

  According to a fourth aspect of the present invention, in the tensile test method according to the third aspect, an image of the test piece is taken.

  According to the tensile test apparatus and the tensile test method of the present invention, superelastic characteristics and viscoelastic characteristics can be measured simultaneously.

The schematic diagram which shows the whole structure of a tension test apparatus. The schematic diagram which shows the effect | action of a tension test apparatus. The graph which shows an example of the measuring method by a tension test apparatus.

The configuration of the tensile test apparatus 100 will be described with reference to FIG.
In addition, in FIG. 1, the structure of the tensile test apparatus 100 is typically represented by the side view. In the following, description will be made according to the vertical direction shown in FIG.

  The tensile test apparatus 100 is an embodiment according to the tensile test apparatus of the present invention. The tensile test apparatus 100 is an apparatus that performs a tensile test. The tensile test is a material test in which a tensile load is applied to the test piece T, the relationship between stress and strain is measured, and the elastic modulus, elastic limit, proportional limit, yield point, tensile strength, etc. of the test piece T are obtained. .

  The tensile test apparatus 100 includes a main body 10, an upper chuck 21 and a lower chuck 22 as a pair of gripping tools that grip a test piece T, a running mechanism 30, a moving mechanism 40, a controller 50, and a stop assisting mechanism 60. And.

  The main body 10 supports the running mechanism 30, the moving mechanism 40, and the like. The main body 10 includes a base 11, a lower plate 12, a rail 13, and an upper plate 14.

  The lower plate 12 is placed on the base 11. A linear motor 42 is provided on the lower surface side of the lower plate 12. On the upper surface side of the lower plate 12, a stop assist mechanism 60 is provided, and rails 13 and 13 are erected. A rod 41 is passed through the central portion of the lower plate 12.

  The rails 13 and 13 support a guide 35, which will be described later, so as to be slidable in the vertical direction that is the moving direction of the rod 41. An upper plate 14 is fixed to the upper end side of the rails 13 and 13. An upper chuck 21 to be described later is fixed on the lower surface side of the upper plate 14.

  The upper chuck 21 and the lower chuck 22 grip the both ends of the test piece T in the vertical direction. The upper chuck 21 and the lower chuck 22 are arranged to face each other in the vertical direction. The lower chuck 22 is fixed to a frame 36 of a running mechanism 30 described later.

  The running mechanism 30 applies a tensile load generated by the lower chuck 22 moving at a predetermined speed to the test piece T. Therefore, before the hooked portion 43 comes into contact with the guide 35, the rod 41 is moved in a predetermined manner. It is a mechanism that accelerates (runs up) to speed. The run-up mechanism 30 includes a guide 35, a hooking portion 37, and a hooked portion 43.

  The guide 35 is connected to the lower end portion of the lower chuck 22 through the frame 36 so as to interlock with the lower chuck 22. A rod 41, which will be described later, penetrates the guide 35 so as to be relatively movable in the vertical direction (moving direction of the rod 41). The guide 35 is supported by the rail 13 so as to be slidable in the vertical direction.

  A frame 36 is formed on the upper side of the guide 35 and a latching portion 37 is attached. The hooked portion 43 is fixed to the upper end portion of the rod 41.

  The frame 36 has a space in which the latching portion 37 and the latching portion 43 can be accommodated, and the latching portion 43 can move in the vertical direction in the space. The hooked portion 43 is separated from the guide 35 when moved upward, and abuts against the guide 35 when moved downward.

  The lower chuck 22 is connected to the upper surface of the frame 36. The latching portion 37 is configured to be latched with the latched portion 43. When the latching portion 37 moves upward and is separated from the guide 35, the latching portion 37 is released from the latching portion 43, and moves downward and the latched portion 43 comes into contact with the guide 35. In this state, it is configured to be hooked with the hooked portion 43.

  In a state in which the latching portion 37 is latched by the latched portion 43, the relative movement between the guide 35 and the rod 41 is restricted, and the guide 35 and the rod 41 move integrally.

  The moving mechanism 40 includes a rod 41 and a linear motor 42.

  The rod 41 is moved in the vertical direction by driving the linear motor 42. The rod 41 is disposed through the guide 35 and the lower plate 12. A hooked portion 43 is connected to the upper end side of the rod 41.

  The linear motor 42 moves the rod 41 in the vertical direction. The linear motor 42 is a linear motor of the moving magnet type, and the rod 41 is obtained by the cooperation of a moving magnet (not shown) provided on the rod 41 and a linear motor coil arranged with a moving magnet and a clearance. Is moved up and down. The linear motor 42 is connected to the controller 50.

  The stop assist mechanism 60 is a mechanism that assists the stop of the guide 35. The stop assist mechanism 60 is disposed so as to come into contact with the guide 35 slightly before (above) the stop position of the guide 35 that moves downward. The stop assist mechanism 60 is constituted by an absorber and absorbs an impact when the guide 35 is stopped.

  In other words, in the tensile test apparatus 100, a stop assist mechanism 60 that absorbs an impact generated when the lower chuck 22 is stopped at the end of the movement range in the pulling direction of the lower chuck 22 that moves integrally with the guide 35. Is provided.

  The controller 50 controls the driving of the linear motor 42. The controller 50 has a function of driving and controlling the linear motor 42 to move the rod 41 in the vertical direction. The linear motor 42 is connected to the measurement controller 55.

  The measurement controller 55 processes measurement information acquired by a measurement device such as the load cell 59. The measurement controller 55 is connected to the controller 50, a high-speed camera 56 as an imaging mechanism, a thermography 57, a displacement sensor 58, and a load cell 59.

  The high-speed camera 56 acquires an image of the test piece T. The thermography 57 measures the temperature distribution of the test piece T. The displacement sensor 58 measures the displacement of the test piece T. The load cell 59 measures a load acting on the test piece T.

  The measurement controller 55 has a function of changing the shooting timing of the high-speed camera 56. In addition, the measurement controller 55 synchronizes with the photographing timing of the high-speed camera 56, the temperature distribution of the test piece T by the thermography 57, the displacement of the test piece T by the displacement sensor 58, and the load acting on the test piece T by the load cell 59. It has a function to acquire.

The operation of the tensile test apparatus 100 will be described with reference to FIG.
In addition, in FIG. 2, the effect | action of the tension test apparatus 100 is typically represented by the side view. Moreover, in FIG. 2, the effect | action of the tensile test apparatus 100 is represented in order of (A), (B), (C), (D) in steps.

  As shown in FIG. 2A, in the tensile test apparatus 100 at the start of the tensile test, both ends of the test piece T are held by the upper chuck 21 and the lower chuck 22. At this time, the rod 41 is held at a position where the hooked portion 43 is separated from the guide 35.

  From this state, the linear motor 42 is driven by the controller 50 and the rod 41 is moved downward. The moving speed of the rod 41 increases from the start of movement and is accelerated to a predetermined speed.

  As shown in FIG. 2B, in the tensile test apparatus 100, when the rod 41 reaches the predetermined speed, the hooked portion 43 comes into contact with the guide 35, and the hooked portion 43 becomes the hooking portion 37. Be hooked on. Here, a section in which the rod 41 is accelerated to the predetermined speed is defined as a running section.

  As shown in FIG. 2C, in the tensile test apparatus 100, the linear motor 42 is driven by the controller 50, and the rod 41 is moved further downward.

  At this time, the lower chuck 22 and the guide 35 and the rod 41 are integrated with each other because the lower chuck 22 and the guide 35 are connected to the rod 41 by the hooked portion 43 being hooked on the hook portion 37. Accordingly, the test piece T is pulled downward by the lower chuck 22. That is, after the hooked portion 43 is hooked on the hooking portion 37, the lower chuck 22 is moved in the pulling direction of the test piece T by the rod 41.

  Furthermore, the rod 41 moving speed after the hooked portion 43 comes into contact with the guide 35 is further accelerated from the predetermined speed when the hooked portion 43 comes into contact with the guide 35 and reaches the maximum speed, Thereafter, the rod 41 moves at a constant speed.

  As shown in FIG. 2D, in the tensile test apparatus 100, the rod 41 is stopped when the controller 50 stops the linear motor. At this time, the guide 35 tries to move further downward due to the inertial force, but stops with the rod 41 because the hooked portion 43 is hooked on the hooking portion 37.

  In addition, since the stop assist mechanism 60 is disposed slightly before the stop position of the guide 35, the guide 35 comes into contact with the stop assist mechanism 60 immediately before the rod 41 stops, and the impact when the guide 35 stops is absorbed. Will be.

The effect of the tensile test apparatus 100 will be described.
According to the tensile test apparatus 100, it is possible to simultaneously measure superelastic characteristics and viscoelastic characteristics.

  That is, according to the tensile test apparatus 100, high-speed tensile performance can be improved by using the moving magnet type linear motor 42 to reduce the weight of the rod 41 that is the motor drive unit. Further, at the time of acceleration, the acceleration mechanism 30 can reduce the acceleration time from the start of the pulling of the test piece T by the lower chuck 22 until the rod 41 moving speed reaches the maximum speed, and the lower chuck 22 is fixed. The high-speed tensile performance of the tensile test apparatus 100 can be improved by increasing the section moving at the maximum speed.

  Further, according to the tensile test apparatus 100, the overshoot at the stop position due to the inertia force of the guide 35 and the like can be reduced by the hooking portion 37, and the lower chuck 22 can be stopped at an arbitrary position. Furthermore, according to the tensile test apparatus 100, the stop assist mechanism 60 can absorb the impact at the time of stop, and the overshoot at the stop position of the guide 35 and the like can be reduced.

  Therefore, compared to a configuration in which the lower chuck 22 is stopped at the stop position by the linear motor 42 alone, in the configuration in which the lower chuck 22 is stopped using the latching portion 37, the stop auxiliary mechanism 60, and the linear motor 42, the lower chuck 22 is stopped. The time until the side chuck 22 is stopped can be shortened.

  Thus, according to the tensile test apparatus 100, the test piece T is pulled at a high speed by pulling the test piece T at a high speed and stopped at an arbitrary position, and a predetermined strain is generated in the test piece T. Thus, the relaxation of stress can be measured while holding the test piece T. Therefore, the superelastic property and viscoelastic property of the test piece T can be measured simultaneously.

An example of a measurement method using the tensile test apparatus 100 will be described with reference to FIG.
In FIG. 3, an example of a measurement method using the tensile test apparatus 100 is represented by a graph of stress change of the test piece T.

  As shown in FIG. 3, in the test piece T, the stress generated in the test piece T increases while being pulled by the tensile test apparatus 100, and then the test piece T is pulled by the tensile test apparatus 100 to a predetermined amount. The stress generated in the test piece T is relaxed while being held at.

  At this time, in the tensile test apparatus 100, the measurement controller 55 changes the shooting timing of the high-speed camera 56 to acquire the image of the test piece T. In the tensile test apparatus 100, while the test piece T is pulled and the stress is increased, the image is taken at a high speed (5000 frames / s), and thereafter, the test piece T is held and the stress is relaxed. The shooting speed is gradually reduced (from 500 frames / s to 100 frames / s).

  In this way, according to the tensile test apparatus 100, it is possible to significantly reduce the amount of image data in the entire tensile test without reducing the photographing speed during tension.

  In addition, the tensile test apparatus 100 synchronizes with the photographing timing of the high-speed camera 56 by the measurement controller 55, acquires the temperature distribution of the test piece T by the thermography 57, acquires the displacement of the test piece T by the displacement sensor 58, A load acting on the test piece T is acquired by the load cell 59.

21 Upper Chuck 22 Lower Chuck 30 Running Mechanism 35 Guide 36 Frame 37 Hook 40 Moving Mechanism 41 Rod 42 Linear Motor 43 Hook 50 Controller 55 Measurement Controller 60 Stop Auxiliary Mechanism 100 Tensile Test Device

Claims (4)

A pair of gripping tools for gripping both ends of the test piece, a rod connectable to one gripping tool, a running mechanism interposed between the rod and the one gripping tool, and moving the rod in a predetermined direction A tensile motor that includes the linear motor, wherein the one gripping tool is moved in the pulling direction of the test piece by the rod,
The running mechanism is
A guide connected to the one gripping tool and movable in the moving direction of the rod;
A latch provided on the guide;
A hooked portion provided on the rod and capable of being hooked on the hooking portion;
The guide is movable relative to the rod;
The relative movement between the guide and the rod is restricted by the hooked portion being hooked on the hooking portion, and the guide and the rod can move integrally,
In the tensile test apparatus,
A stop assist mechanism that absorbs an impact generated when the gripping tool is stopped is provided at the end of the moving range in the pulling direction of the one gripping tool.
Tensile test device. The tensile test device according to claim 1,
A photographing mechanism for photographing an image of the test piece;
Tensile test device. A pair of gripping tools for gripping both ends of the test piece, a rod connectable to one gripping tool, a running mechanism interposed between the rod and the one gripping tool, and moving the rod in a predetermined direction A tension motor test method, wherein the one gripping tool is moved in the pulling direction of the test piece by the rod,
The running mechanism is
A guide connected to the one gripping tool and movable in the moving direction of the rod;
A latch provided on the guide;
A hooked portion provided on the rod and capable of being hooked on the hooking portion;
By driving the linear motor, the rod is accelerated in the moving direction,
The hooked portion is hooked on the hooking portion,
By driving the linear motor, the test piece, the one gripping tool, the guide and the rod are accelerated in the moving direction,
By driving the linear motor, the test piece, the one gripping tool, the guide, and the rod are moved in a moving direction at a constant speed,
By stopping the linear motor, the test piece, the one gripping tool, the guide and the rod are stopped.
Tensile test method. A tensile test method according to claim 3,
Taking an image of the specimen,
Tensile test method.

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