Ultrasonic fatigue testing machine and ultrasonic fatigue testing method

Abstract

To provide an ultrasonic fatigue testing machine capable of imparting appropriate stress in a twisting direction to a test piece.SOLUTION: An ultrasonic fatigue testing machine has: an ultrasonic wave generation part for generating ultrasonic waves; a first horn in which one end is fixed and the other end holds one end of a test piece while amplifying the amplitude of ultrasonic waves inputted to one end and outputting them from the other end; a second horn that is disposed opposite to the first horn while one end in a side opposite to the first horn is fixed and the other end holds the other end of a test piece; a measurement part for measuring a moment imparted to a test piece; a rotary stage capable of adjusting average torsional stress imparted to a test piece according to a moment; and a first XY stage that is positioned between the second horn and the rotary stage and can adjust axis deviation between the center axis of the second horn and the rotation center axis of the rotary stage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an ultrasonic fatigue testing machine and an ultrasonic fatigue testing method. [Background technology]

[0002] 2. Description of the Related Art Conventionally, ultrasonic fatigue testing machines are known for performing ultrasonic fatigue testing by resonating a test piece with ultrasonic waves having a torsional amplitude.

[0003] Patent Document 1 describes an ultrasonic fatigue testing method in which ultrasonic waves are input from one end of a test piece via a horn without fixing the other end of the test piece.

[0004] Patent Document 2 describes an ultrasonic fatigue testing method in which ultrasonic waves are input from one end of a test piece via a horn while the other end of the test piece is fixed via the horn.

[0005] Recently, an ultrasonic fatigue testing method has become known in which an average torsional stress is applied to a test piece by a rotating stage. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-271248 [Patent Document 2] Japanese Patent Application Publication No. 2019-53009 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when applying an average torsional stress to a test specimen, if the central axis of the test specimen is misaligned with the central axis of rotation of the rotation stage, it is not possible to apply an appropriate stress to the test specimen in the torsional direction, and stress will also be generated in other directions, which is a problem.

[0008] The present invention has been made in view of the above, and aims to provide an ultrasonic fatigue testing machine and an ultrasonic fatigue testing method that can apply an appropriate stress in the torsional direction to a test piece. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems and achieve the object, one embodiment of the ultrasonic fatigue testing machine of the present invention is an ultrasonic fatigue testing machine for performing ultrasonic fatigue testing by resonating a test piece with ultrasonic waves having a torsional amplitude, and is characterized by comprising: an ultrasonic generator that generates the ultrasonic waves; a first horn that is fixed at one end and holds one end of the test piece at the other end, and that amplifies the amplitude of the ultrasonic waves input to the one end and outputs it from the other end; a second horn that is arranged opposite the first horn, has one end opposite the first horn fixed, and the other end holds the other end of the test piece; a measurement unit that measures the moment applied to the test piece; a rotation stage that can adjust the average torsional stress applied to the test piece in accordance with the moment; and a first XY stage that is positioned between the second horn and the rotation stage and can adjust the axial misalignment between the central axis of the second horn and the rotation central axis of the rotation stage.

[0010] Furthermore, an ultrasonic fatigue testing machine according to one embodiment of the present invention is characterized in that the first XY stage is capable of adjusting the axial misalignment between the central axis of the second horn and the central axis of rotation of the rotation stage to be below a threshold value.

[0011] Furthermore, an ultrasonic fatigue testing machine according to one embodiment of the present invention is characterized in that it includes a fixing jig that fixes the one end of the second horn by pressing a portion of the second horn toward the opposite side of the test piece.

[0012] Furthermore, an ultrasonic fatigue testing machine according to one embodiment of the present invention is characterized in that it includes a second XY stage on which the rotating stage is placed and which is capable of adjusting the axial misalignment between the central axis of the first horn and the central axis of the second horn.

[0013] Furthermore, an ultrasonic fatigue testing method according to one embodiment of the present invention is an ultrasonic fatigue testing method in which a test piece is resonated with ultrasonic waves having a torsional amplitude, the method comprising: holding one end of the test piece at the other end of a first horn that is fixed at one end and amplifies the amplitude of the ultrasonic waves input to the one end and outputs it from the other end; holding the other end of the test piece at the other end of a second horn that is arranged opposite the first horn and has one end opposite the first horn that is fixed; adjusting the axial misalignment between the central axis of the second horn and the rotational central axis of the rotational stage by operating a first XY stage located between the second horn and a rotational stage that can adjust the average torsional stress applied to the test piece; measuring the moment applied to the test piece; and adjusting the average torsional stress applied to the test piece in accordance with the moment by operating the rotational stage.

[0014] Furthermore, an ultrasonic fatigue testing method according to one embodiment of the present invention is characterized in that the axial misalignment between the central axis of the second horn and the central axis of rotation of the rotation stage is adjusted to be below a threshold value by operating the first XY stage.

[0015] Furthermore, an ultrasonic fatigue testing method according to one embodiment of the present invention is characterized in that the one end of the second horn is fixed by pressing a portion of the second horn toward the opposite side of the test piece using a fixing jig.

[0016] Furthermore, an ultrasonic fatigue testing method according to one embodiment of the present invention is characterized in that, before adjusting the average torsional stress applied to the test piece according to the moment by operating the rotating stage, the axial misalignment between the central axis of the first horn and the central axis of the second horn is adjusted by operating a second XY stage on which the rotating stage is mounted. [Effects of the Invention]

[0017] According to the present invention, it is possible to realize an ultrasonic fatigue testing machine and an ultrasonic fatigue testing method that can apply an appropriate stress to a test piece in the torsional direction. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of an ultrasonic fatigue testing machine according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the direction of the moment on the test specimen. [Figure 3] FIG. 3 is a flowchart of an ultrasonic fatigue testing method using the ultrasonic fatigue testing machine shown in FIG. [Figure 4] FIG. 4 is a diagram showing the state in which the rod-shaped portion of the amplifier horn and the rod-shaped portion of the horn are connected to the test piece. [Figure 5] FIG. 5 is a diagram showing how the axis misalignment is adjusted by the first XY stage and the second XY stage. [Figure 6] FIG. 6 is a diagram showing how the first fixing jig is fixed to the second fixing jig. [Figure 7] FIG. 7 is a diagram showing how the torsional stress on the test piece is adjusted by the rotation stage. [Figure 8] FIG. 8 is a diagram showing how the moment changes when the rotary stage is rotated. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as "embodiments") will be described with reference to the accompanying drawings. Note that the drawings are schematic, and the relationship between the thickness and width of each part, the thickness ratio of each part, etc. may differ from the actual ones, and the drawings may also include parts with different dimensional relationships and ratios.

[0020] (Embodiment) Fig. 1 is a schematic diagram showing the configuration of an ultrasonic fatigue testing machine according to an embodiment. As shown in Fig. 1, the ultrasonic fatigue testing machine 1 according to this embodiment includes a control device 2, an ultrasonic generator 3, an amplifier horn 4 serving as a first horn, a test piece 5, a horn 6 serving as a second horn, a fixture 7, a first XY stage 8, a six-component force meter 9 serving as a measurement unit, a rotation stage 10, and a second XY stage 11.

[0021] The control device 2 supplies driving power to the ultrasonic wave generating unit 3 and controls the ultrasonic wave generating unit 3 .

[0022] The ultrasonic wave generating unit 3 generates ultrasonic waves having a torsional amplitude in response to an input from the ultrasonic wave generating unit 3. The ultrasonic wave generating unit 3 includes an ultrasonic oscillator 31 and a torsional converter 32. However, as long as the ultrasonic oscillator can generate ultrasonic waves having a torsional amplitude, the configuration may not include a torsional converter.

[0023] The ultrasonic oscillator 31 generates ultrasonic waves having a predetermined amplitude and frequency in the lateral direction, for example, in response to the input from the ultrasonic wave generating unit 3. The frequency of the ultrasonic waves generated by the ultrasonic oscillator 31 is, for example, 20 kHz, but an appropriate frequency can be selected within the range of, for example, 15 to 30 kHz.

[0024] The torsional converter 32 converts the ultrasonic waves having a lateral amplitude from the ultrasonic generator 3 into ultrasonic waves having a torsional amplitude.

[0025] The amplifier horn 4 has a rod-shaped portion 4a and an expanded diameter portion 4b whose central axis coincides with that of the rod-shaped portion 4a. The amplifier horn 4 is fixed at one end (upper end) opposite the rod-shaped portion 4a, and the other end (lower end) holds one end (upper end) of the test piece 5. The amplifier horn 4 amplifies the amplitude of ultrasonic waves input from the ultrasonic generator 3 to one end (upper end) and outputs them from the other end (lower end) to the test piece 5. However, the amplifier horn 4 may have a shape without a rod-shaped portion, and may have a tapered shape in which the diameter decreases toward the lower end, for example.

[0026] The test piece 5 has both ends (upper and lower ends) fixed to the rod-shaped portion 4a of the amplifier horn 4 and the rod-shaped portion 6a of the horn 6, respectively, and resonates with ultrasonic waves having an amplitude in the torsional direction. The test piece 5 is not particularly limited, but may be, for example, a metal piece, and may be a processed material in the shape of a so-called test piece, or the material may be used in its unprocessed form (for example, a wire rod in its linear form).

[0027] Horn 6 is disposed opposite amplifier horn 4 and has a rod-shaped portion 6a and an expanded diameter portion 6b whose central axis coincides with that of rod-shaped portion 6a. Horn 6 is fixed at one end (lower end) opposite amplifier horn 4, and the other end (upper end) holds the other end (lower end) of test piece 5. However, horn 6 may have a shape without a rod-shaped portion, and may have, for example, a tapered shape in which the diameter decreases toward the upper end.

[0028] The amplifying horn 4, test piece 5, and horn 6 resonate with each other due to ultrasonic waves having a torsional amplitude from the ultrasonic generator 3, and their mass and rigidity are adjusted so that the node is located at the center of the test piece 5 and the antinode is located at the end of the amplifying horn 4 and horn 6 opposite the test piece 5.

[0029] Fixing jig 7 presses a part of horn 6 toward the opposite side to test piece 5, thereby fixing expanded diameter portion 6b of horn 6 to first XY stage 8. However, the direction in which fixing jig 7 presses horn 6 is not particularly limited. Fixing jig 7 has a first fixing jig 71 and a second fixing jig 72.

[0030] First fixing jig 71 fixes the end of expanded diameter portion 6b of horn 6 by pressing a part of horn 6 (for example, a flange portion formed at the end opposite test piece 5) from the side opposite test piece 5. First fixing jig 71 is fixed to second fixing jig 72, for example, with screws.

[0031] The second fixing jig 72 is fixed to the first XY stage 8 .

[0032] The first XY stage 8 is located between the horn 6 and the rotation stage 10, and is capable of adjusting the axial misalignment between the central axis of the horn 6 and the central axis of rotation of the rotation stage 10.

[0033] The six-component force meter 9 measures the moment applied to the test piece 5. Specifically, the six-component force meter 9 measures the forces applied along three orthogonal axial directions and the moments around each axis. Figure 2 is a diagram showing the direction of the moments applied to the test piece. As shown in Figure 2, the six-component force meter 9 measures the forces Fx, Fy, and Fz applied along the x-, y-, and z-axis directions, and the moments Mx, My, and Mz around each axis. The six-component force meter 9 may be placed in a position where it can measure the forces and moments applied to the test piece 5.

[0034] The rotation stage 10 is capable of adjusting the average torsional stress applied to the test piece 5 .

[0035] The second XY stage 11 has the rotary stage 10 mounted thereon, and can adjust the axial misalignment between the central axis of the amplification horn 4 and the central axis of the horn 6 to, for example, a threshold value or less. The threshold value is, for example, 0.05 mm, but is not particularly limited.

[0036] Next, an ultrasonic fatigue testing method using the ultrasonic fatigue testing machine 1 will be described. FIG. 3 is a flowchart of the ultrasonic fatigue testing method using the ultrasonic fatigue testing machine shown in FIG. 1. As shown in FIG. 3, first, the rod-shaped portion 4a of the amplifier horn 4 and the rod-shaped portion 6a of the horn 6 are connected to the test piece 5 (step S1). FIG. 4 is a diagram showing the state in which the rod-shaped portions of the amplifier horn and the horn are connected to the test piece. As shown in FIG. 4, a screw formed on one end (upper end) of the test piece 5 is threaded into a threaded hole formed on one end (lower end) of the amplifier horn 4, thereby holding the test piece 5 on the rod-shaped portion 4a of the amplifier horn 4. Furthermore, a screw formed on the other end (lower end) of the test piece 5 is threaded into a threaded hole formed on the other end (upper end) of the horn 6, thereby holding the test piece 5 on the rod-shaped portion 6a of the horn 6.

[0037] Next, the first XY stage 8 is operated to adjust the axial misalignment between the central axis of the horn 6 and the central axis of rotation of the rotation stage 10 (step S2). Figure 5 is a diagram showing how the axial misalignment is adjusted using the first XY stage and the second XY stage. As shown in Figure 5, with the upper end of the amplification horn 4 fixed, the first XY stage 8 is operated to adjust the axial misalignment between the central axis A1 of the horn 6 and the central axis A2 of the rotation stage 10 to be below a threshold.

[0038] Furthermore, horn 6 is fixed by first fixing jig 71 and second fixing jig 72 (step S3). FIG. 6 is a diagram showing how the first fixing jig is fixed to the second fixing jig. As shown in FIG. 6, first fixing jig 71 presses the flange portion of horn 6 toward the opposite side (upper side) from test piece 5, thereby fixing the end of enlarged diameter portion 6b of horn 6 to second fixing jig 72, which is pre-fixed to first XY stage 8. First fixing jig 71 is fixed to second fixing jig 72 with screws. Because first fixing jig 71 and second fixing jig 72 sandwich and fix horn 6 along the z-axis direction, the amount of deviation of the central axis of horn 6 during fixation can be made smaller than when horn 6 is pressed from other directions.

[0039] Thereafter, the second XY stage 11 is operated to adjust the axial misalignment between the central axis of the amplification horn 4 and the central axis of the horn 6, for example, to a threshold value or less (step S4). Specifically, the second XY stage 11 is operated so that the amount of change in the bending moment Mx or My when the rotation stage 10 is rotated is reduced.

[0040] Then, the rotation stage 10 is rotated counterclockwise to adjust the average torsional stress applied to the test piece 5 (step S5). Fig. 7 is a diagram showing how the rotation stage is used to adjust the torsional stress applied to the test piece. As shown in Fig. 7, by rotating the rotation stage 10 counterclockwise, the average torsional stress applied to the test piece 5 can be adjusted to be, for example, equal to or less than a threshold value.

[0041] Fig. 8 is a diagram showing how the moments change when the rotation stage is rotated. As shown in Fig. 8, when rotation stage 10 is rotated counterclockwise, torsional moment Mz changes, but the changes in bending moments Mx and My are below thresholds, which indicates that the misalignment between the central axis of horn 6 and the rotation central axis of rotation stage 10, and the misalignment between the central axis of amplifying horn 4 and the central axis of horn 6 are sufficiently small.

[0042] According to the embodiment described above, by operating the first XY stage 8 and the second XY stage 11, it is possible to adjust the axial misalignment between the central axis of the horn 6 and the central axis of rotation of the rotating stage 10, and the axial misalignment between the central axis of the amplifying horn 4 and the central axis of the horn 6, and then apply an appropriate stress in the torsional direction to the test piece 5 using the rotating stage 10 to perform an ultrasonic fatigue test.

[0043] Furthermore, with this ultrasonic fatigue testing machine 1, ultrasonic fatigue testing can be performed in a state where the average torsional stress applied to the test piece 5 is approximately zero, or in a state where an average torsional stress of a predetermined magnitude is applied to the test piece 5.

[0044] In addition, by using the ultrasonic fatigue testing machine 1 and operating the first XY stage 8 and the second XY stage 11 in any direction in advance, ultrasonic fatigue testing can be performed while applying stress in other directions in addition to the average torsional stress. [Explanation of symbols]

[0045] 1. Ultrasonic fatigue testing machine 2. Control device 3 Ultrasonic generator 4. Amplified Horn 4a, 6a Rod-shaped part 4b, 6b expansion section 5 Test pieces 6 Horn 7 Fixture 8. 1st XY Stage 9 Six component force meter 10 Rotation Stage 11 2nd XY Stage 31 Ultrasonic oscillator 32 Torsion converter 71 First Fixture 72 Second Fixture

Claims

1. An ultrasonic fatigue testing machine for performing an ultrasonic fatigue test by resonating a test piece with ultrasonic waves having a torsional amplitude, an ultrasonic wave generating unit that generates the ultrasonic waves; a first horn having one end fixed and the other end holding one end of the test piece, the first horn amplifying the amplitude of the ultrasonic wave input to the one end and outputting the amplified ultrasonic wave from the other end; a second horn disposed opposite the first horn, one end of which is fixed opposite the first horn, and the other end of which holds the other end of the test piece; a measuring unit that measures a moment applied to the test piece; a rotation stage capable of adjusting the average torsional stress applied to the test piece in accordance with the moment; a first XY stage positioned between the second horn and the rotary stage, capable of adjusting an axial misalignment between a central axis of the second horn and a central axis of rotation of the rotary stage; An ultrasonic fatigue testing machine comprising:

2. 2. The ultrasonic fatigue testing machine according to claim 1, wherein the first XY stage is capable of adjusting an axial misalignment between the central axis of the second horn and the central axis of rotation of the rotary stage to be equal to or less than a threshold value.

3. 3. The ultrasonic fatigue testing machine according to claim 1, further comprising a fixing jig that fixes the one end of the second horn by pressing a part of the second horn on the side opposite to the test piece.

4. 4. The ultrasonic fatigue testing machine according to claim 1, further comprising a second XY stage on which the rotary stage is mounted and which is capable of adjusting the axial misalignment between the central axis of the first horn and the central axis of the second horn.

5. An ultrasonic fatigue testing method in which a test piece is resonated with ultrasonic waves having a torsional amplitude, One end of the test piece is held at the other end of a first horn, which has one end fixed and amplifies the amplitude of the ultrasonic wave input to the one end and outputs it from the other end, while the other end of the test piece is held at the other end of a second horn, which is disposed opposite to the first horn and has one end opposite to the first horn fixed; adjusting an axial misalignment between a central axis of the second horn and a central axis of rotation of the rotation stage by operating a first XY stage located between the second horn and a rotation stage capable of adjusting an average torsional stress applied to the test piece; a fixing jig is used to press a portion of the second horn toward an opposite side to the test piece, thereby fixing the one end of the second horn; adjusting the axial misalignment between the central axis of the first horn and the central axis of the second horn by operating a second XY stage on which the rotation stage is placed; measuring a moment applied to the test piece; An ultrasonic fatigue testing method, characterized in that the average torsional stress applied to the test piece is adjusted according to the moment by operating the rotation stage.

6. The ultrasonic fatigue testing method according to claim 5, characterized in that the axial misalignment between the central axis of the second horn and the central axis of rotation of the rotation stage is adjusted to be equal to or less than a threshold value by operating the first XY stage.

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