JP2017201258A - Fatigue test method, and fatigue test device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fatigue test method capable of applying a high speed and stable vibration load to a test piece, and a fatigue test device capable of carrying out a fatigue test according to the fatigue test method.SOLUTION: According to the fatigue test method: a motor is driven to rotate and to transfer a rotational motion of the motor to a body of rotation; plural rotation side permanent magnets or a rotation side coil which is disposed in a rotation direction of the body of rotation rotates along a rotation axis of the motor; on a fix side permanent magnet or a fix side coil, which is disposed at a position separated a predetermined distance away from the rotation side permanent magnet or the rotation side coil, a magnetic force is generated to thereby transmit the force to a test piece which is connected to the fix side permanent magnet or the fix side coil. With this, a fatigue test in which a vibration load is stably given at a high speed to the test piece is carried out.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fatigue test apparatus, and more particularly to a fatigue strength evaluation apparatus that applies a variable load to a material at high speed.

  In many cases, a complex vibration load whose amplitude and frequency fluctuate is applied to an operating mechanical structure. In general, it is known that the fatigue strength of a material is greatly different from that in a case where a vibration load whose amplitude or frequency changes is applied to the material. Further, in the fatigue design of a structure, it is important to accurately grasp the variation in the fatigue life of the material. Therefore, it is necessary to efficiently perform a fatigue test on many specimens. Therefore, it is desired to realize a test method and a test apparatus that can efficiently perform a fatigue test that simulates a complex load generated during actual machine operation.

  One method for efficiently conducting a fatigue test on a material is to apply a vibration load at high speed. As a test apparatus for applying a vibration load to a material at high speed, there is a fatigue tester using ultrasonic waves. This test apparatus can perform a fatigue test at a high speed at a frequency of several tens of kHz using ultrasonic vibration. However, since this apparatus uses a resonance phenomenon, it is difficult to perform a fatigue test that simulates a complicated vibration load whose amplitude and frequency change.

  As a test device that applies a vibration load to a material at high speed without using a resonance phenomenon, for example, a magnet is attached to one end of a test body, and a movable magnet is disposed at a position away from the magnet by a predetermined distance. There has been proposed a test apparatus capable of applying a vibration load to a test body by a magnetic force (Patent Document 1).

JP 2014-74598

  In the technique according to Patent Document 1, since a mechanism for controlling the direction in which the specimen is deformed is not provided, it is difficult to stably deform the specimen along one direction. Moreover, since the vibrator used for the oscillation part of patent document 1 has the same direction of magnetic force as the moving direction of the magnet, the movement of the magnet is obstructed by the magnetic force as the magnetic force increases, and a high load is applied at high speed. Is difficult.

  Therefore, there is a problem to be solved in terms of improving the reliability related to the fatigue strength of a material in a fatigue test method and a fatigue test apparatus for applying a vibration load to the material.

  An object of the present invention has been made in view of the circumstances of the prior art, and a fatigue test method capable of stably and rapidly giving a complex variable load generated during actual machine operation to a specimen. And a fatigue test apparatus capable of performing a fatigue test according to such a fatigue test method.

  The purpose is to rotate the motor, transmit the rotational motion of the motor to the rotating body, and a plurality of rotating permanent magnets or rotating coils provided in the rotating direction of the rotating body rotate along the rotation axis of the motor. , A test in which a magnetic force is generated in the fixed-side permanent magnet or the fixed-side coil arranged at a predetermined distance from the rotating-side permanent magnet or the rotating-side coil and connected to the fixed-side permanent magnet or the fixed-side coil. This can be solved by a fatigue test method that transmits force to the body.

  In addition, an operation jig connected to one end side of the test body, a moving means for moving the operation jig in one direction of the test body, and a load means for applying a variable load to the operation jig in a non-contact manner, The load means includes a motor, a rotating body connected to the motor, and a plurality of rotation-side permanent magnets or rotation-side coils provided in the rotation direction of the rotation body, and operates with the operation jig or the operation jig. Can be solved by a fatigue test apparatus including a fixed permanent magnet or a fixed coil facing the rotating permanent magnet or the rotating coil.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to implement | achieve the fatigue test which simulated the complicated fluctuating load assumed at the time of actual operation and use of a machine or a building at high speed and stably.

External view of Example 1 Side view of Example 1 External view of Example 2 Side view of Example 2 Schematic diagram showing a decrease in fatigue strength due to an average load. External view of Example 3 Side view of Example 4 Side view of Example 5 Side view of Example 6 External view of a linear specimen External view of specimen with notch in the center Side view of a magnet with convex or concave portions

  Hereinafter, an example of a fatigue test apparatus capable of performing a fatigue test according to the fatigue test method of the present invention will be described with reference to the drawings.

  The fatigue test apparatus 1 shown as Example 1 in FIG. 1 and FIG. 2 arrange | positions the motor 2 on the fixing stand 100, and fixes the rotating plate 3 to the motor 2, as shown in the external appearance shape and a side surface shape, A plurality of rotating side magnets 5 are arranged along the periphery of the rotating plate 3, a fixed side magnet 6 is arranged at a position away from the rotating side magnet 5 by a predetermined distance, and the fixed side magnet 6 is connected to the test body via the jig 7. 8 is connected to an operation jig 14 that can move smoothly in one direction regulated along a linear guide 13 (moving means), and the other end of the test body is connected to the load measuring device 11 and linear via the jig 9. It is connected to an operation jig 15 that can move smoothly in one direction regulated along a guide 13, and a load measuring device 11 is connected to a fixed wall 12 arranged on a fixed base 100. This is an embodiment in which the rotational motion 4 is given to the.

  As a result, a magnetic force acts intermittently on the fixed side magnet 6 as the rotary side magnet 5 rotates, so that a vibration load is applied to the test body 8. At this time, since the direction of the magnetic force and the rotational motion 4 of the rotation-side magnet 5 are orthogonal, the influence of the magnetic force on the rotational motion 4 is small, and the motor 2 can be rotated at a high speed with a low torque. Therefore, a vibration load having a large amplitude can be applied to the test body 8 at a high speed. Further, since the motion jigs 14 and 15 are moved only in a predetermined direction by the linear guide 13, it is possible to stably apply a vibration load without causing bending or torsional deformation of the test body. As described above, the fatigue test apparatus 1 according to the present embodiment can perform a fatigue test with a wide range of frequencies by adjusting the number of magnets arranged on the periphery of the rotating plate and the rotational speed of the motor.

  In the present embodiment, a configuration in which the rotating side magnet 5 and the fixed side magnet 6 are used in combination has been shown, but permanent magnets may be used as these magnets, or electromagnets using coils may be used. When a permanent magnet is employed, the fatigue test apparatus of the present embodiment can be realized with a simple configuration, and the cost can be reduced. In addition, when an electromagnet is used, the magnitude of the vibration load can be controlled during the test. For example, a smoother vibration load (vibration load closer to a sine curve) or a vibration load than when a permanent magnet is used. It is possible to easily realize control suitable for the test contents, such as giving a complex fluctuating load generated during actual machine operation.

  In the present embodiment, the test body 8 is fixed to the jig 7 and the jig 9 via bolts 10, but as shown in FIGS. 10 and 11, the test body 8 is provided with gripping portions 31A and 31B, These grips may be clamped with a jig and fixed. Here, as shown in FIG. 11, when the notches 30 are provided on both sides of the approximate center of the test body 8, deformation at a higher strain rate is applied to the approximate center of the test body 8 than the fluctuating load applied by the rotating magnet 5. Therefore, compared to the case of using the test body 8 of FIG. 10, a fatigue test can be performed over a wider range of materials having a high strain rate dependency.

  1 and 2, the shape of the rotating side magnet 5 and the fixed side magnet 6 is a rectangular parallelepiped. However, for example, as shown in FIG. Even if it is installed at a slight angle, the positional relationship between the rotating side magnet 5 and the stationary side magnet 6 can be made equal to that in the normal case, so that the magnetic force is generated more stably and the vibration load applied to the test body is stabilized. It is also possible to do.

  Furthermore, although the magnets are arranged at equal intervals along the periphery of the rotating plate, by placing the magnets at different intervals, the vibration load that changes the frequency that occurs during actual operation of the test specimen Can also be given.

  Next, the fatigue test apparatus of Example 2 will be described. Description of points common to the first embodiment is omitted.

  The fatigue test apparatus 1 shown as Example 2 in FIG. 3 and FIG. 4 connects the member 17 to the jig 7 and the operation jig 14 in the fatigue test apparatus of Example 1, as shown in the external appearance shape and the side shape, The member 18 is arranged at a position away from the member 17 by a predetermined distance, the spring 19 is arranged between the members 17 and 18, the member 18 is fixed to the fixing member 20 by the bolt 21, and the bolt 21 is fixed by the nut 22 to the predetermined position. This is an embodiment fixed by.

  As a result, the load generated in the spring 19 is adjusted depending on the position of the member 18, and as shown in the left diagram of FIG. 5, a fatigue test in which a vibration load is applied in a state where a constant load is applied to the test body 8 is possible. Become. Further, as shown in the right diagram of FIG. 5, it is known that the fatigue strength of the material is reduced by applying a constant load. In this example, it is possible to easily evaluate the fatigue strength reduction. Become. At this time, by setting the stiffness of the spring sufficiently lower than the stiffness of the test specimen, the influence of the deformation of the test specimen due to the vibration load on the constant load generated in the spring can be reduced as much as possible. A vibration load can be applied in a state where a constant load is stably applied.

  Next, a fatigue test apparatus of Example 3 will be described. Description of points common to the above-described embodiment is omitted.

  The fatigue test apparatus 1 shown in FIG. 6 as Example 3 is the same as that of the fatigue test apparatus of Example 1 or 2, as shown in its external shape. In this embodiment, 5C and 5D are arranged along the periphery of the rotating plate 3.

  Thereby, it becomes possible to give the test body 8 a vibration load whose amplitude changes as generated during actual operation.

  Next, a fatigue test apparatus of Example 4 will be described. Description of points common to the above-described embodiment is omitted.

  The fatigue test apparatus 1 shown as Example 4 in FIG. 7 is a displacement measuring device 23 at a position where the state of the gap 16 can be measured in any one of the fatigue test apparatuses of Examples 1 to 3 as shown in the side surface shape thereof. Is an embodiment in which

  Thereby, it is possible to continuously measure a change in the state of the test body 8 such as a decrease in rigidity by continuously measuring the temporal change in the distance of the gap 16 that is reduced by the progress of fatigue of the test body 8. . Further, by detecting a sudden change in the gap 16, it is possible to detect the breakage of the test body 8, and it is also possible to safely stop the fatigue test apparatus using the breakage of the test body 8 as a trigger. In FIG. 7, the displacement measuring device 23 is arranged on the upper part of the rotating plate 3, but it can also be arranged on the side surface of the jig 7 or the linear guide 13.

  If the distance of the gap 16 can be measured as in the present embodiment, the magnetic force of the electromagnet used as the rotation-side magnet 5 can be adjusted, and a constant variable load can be applied to the test body 8 regardless of the distance of the gap 16. it can.

  Next, a fatigue test apparatus of Example 5 will be described. Description of points common to the above-described embodiment is omitted.

  The fatigue test apparatus 1 shown in FIG. 8 as Example 5 is electrically connected to the displacement measuring device 23 and the control apparatus 27 in the fatigue test apparatus of Example 4 as shown in the side shape thereof. The recording device 28 and the motor 24 are electrically connected, and the motor 24 is connected to the fixed wall 12 via a conversion mechanism 25 that converts the rotational motion of the motor 24 into a translational motion along one direction of the test body 8. In this embodiment, the fixed wall 12 and the linear guide 13 are fixed to an operation jig 26 that can move smoothly on the fixed base 100 along one direction of the test body 8.

  As a result, even when the distance of the gap 16 changes due to a change in the state of the specimen such as a decrease in rigidity, a predetermined rotational motion is generated in the motor 24 by the control device 27 based on the measurement result of the displacement measuring device 23, and the motor By converting the rotational movement of 24 into a translational movement along one direction of the test body 8 by the conversion mechanism 25, the distance of the gap 16 can be kept constant and a vibration load can be stably applied to the test body 8. It becomes.

  Next, a fatigue test apparatus of Example 6 will be described. Description of points common to the above-described embodiment is omitted.

  The fatigue test apparatus 1 shown as Example 6 in FIG. 9 is the fatigue test apparatus of any one of Examples 1 to 5, as shown in the side shape thereof, and includes an environmental tank 29 surrounding a part or the whole of the fatigue test apparatus. It is the arranged embodiment.

  This enables a fatigue test in which environmental influences such as temperature, humidity, and corrosion are superimposed. In addition, since a vibration load can be applied to the test body in a non-contact manner, as shown in FIG. 9, even when the vibration load is applied from the outside of the environmental tank or when the entire fatigue test apparatus is placed in the environment. There is an advantage that the time change of the load due to the environment hardly occurs.

DESCRIPTION OF SYMBOLS 1 ... Fatigue testing apparatus 2 ... Motor 3 ... Rotating plate 4 ... Rotary motion 5, 5A, 5B, 5C, 5D ... Rotation side magnet 6 ... Fixed side magnet 7 ... Jig 8 ... Test body 9 ... Jig 10 ... Bolt 11 ... Load Measuring instrument 12 ... fixed wall 13 ... linear guide 14 ... operating jig 15 ... operating jig 16 ... gap 17 ... member 18 ... member 19 ... spring 20 ... fixing member 21 ... bolt 22 ... nut 23 ... displacement measuring instrument 24 ... motor 25 ... Conversion mechanism 26 ... Operation jig 27 ... Control device 28 ... Recording device 29 ... Environmental tank 30 ... Notches 31A, 31B ... Grab portion 100 ... Fixing base

Claims (9)

  Rotating the motor, transmitting the rotational motion of the motor to the rotating body, and rotating side permanent magnets or rotating side coils provided in the rotating direction of the rotating body rotate along the rotation axis of the motor, A magnetic force is generated in the permanent magnet or the stationary coil arranged at a predetermined distance from the permanent magnet or the rotating coil, and the force is applied to the stationary permanent magnet or the test body connected to the stationary coil. A fatigue test method characterized by transmitting. An operation jig connected to one end of the test body, a moving means for moving the operation jig in one direction of the test body, and a load means for applying a variable load to the operation jig in a non-contact manner,
The load means includes a motor, a rotating body connected to the motor, and a plurality of rotating-side permanent magnets or rotating-side coils provided in the rotating direction of the rotating body,
The fatigue testing apparatus characterized in that the operating jig or a member operating together with the operating jig includes a fixed permanent magnet or a fixed coil facing the rotating permanent magnet or the rotating coil. The fatigue test apparatus according to claim 2,
A second load means that applies a constant load to the motion jig or a member that operates together with the motion jig; the second load means includes a spring, a member connected to the spring, and a predetermined member; A fatigue testing apparatus comprising fixing means for fixing to a position. In the fatigue testing apparatus according to claim 2 or 3,
A fatigue test apparatus comprising a plurality of rotating-side permanent magnets or rotating-side coils having different shapes and / or magnetic flux densities in the rotating direction of the rotating body. In the fatigue test apparatus according to any one of claims 2 to 4,
A fatigue test apparatus comprising a measuring means for measuring a gap provided between the rotating side permanent magnet or the rotating side coil and the fixed side permanent magnet or the fixed side coil. In the fatigue test apparatus according to claim 5,
A control unit electrically connected to the measurement unit; and a recording unit electrically connected to the measurement unit and the control unit. The control unit is electrically connected to the control unit and the control unit. And a mechanism for converting the rotational motion of the motor into a translational motion along one direction of the test body, the mechanism being connected to a member that fixes one end of the test body, A fatigue testing apparatus comprising moving means for moving in a direction. In the fatigue test apparatus according to any one of claims 2 to 6,
A fatigue test apparatus characterized in that an environmental tank for sealing an inclusion is disposed in a manner surrounding a part or the whole of the fatigue test apparatus. A first jig connected to one end of the test body;
A second jig connected to the other end of the test body;
Load means for applying a variable load to the first jig in a non-contact manner;
A linear guide that regulates the moving direction of the first jig in one direction;
A fatigue test apparatus comprising: The fatigue test apparatus according to claim 8,
The load means includes a motor, a rotating body connected to the motor, and a plurality of rotating side magnets provided in the rotating direction of the rotating body,
The fatigue test apparatus according to claim 1, wherein the first jig includes a fixed side magnet facing the rotation side magnet.

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