JPH01244333A - Apparatus for detecting composite displacement of pulling pressure and torsion - Google Patents

Abstract

PURPOSE:To detect displacement accurately, by providing a pair of annular fixing tools at a specified interval in the axial direction of a body under test, and providing a displacement detecting means in the torsional direction which detects the deflecting amount of a plate spring corresponding to the relative angle displacement of both annular fixing tools. CONSTITUTION:When a load in the axial direction and a load in the torsional direction are applied in a body under test TP, only the displacement in the axial direction is detected with a non-contact type optical displacement gage 4. Since the gage is a non-contact type, its measuring range can be made large. In a displacement detecting mechanism 6 in the torsional direction, the axial displacement is absorbed with flexible wire 10 and a groove 12. The amount of strain of a plate spring 9 corresponding to the relative rotary angles of annular fixing tools 1 and 2 is outputted as an electric signal from a strain gage 11. Only the torsional displacement is detected. The measuring range is made large by the wire 10 and the long plate spring 9.

Description

[Detailed Description of the Invention] A. Industrial Field of Application The present invention is directed to a suction pressure tester used in a test in which tension and torsion, or compression and torsion are simultaneously applied to a specimen (hereinafter referred to as a combined suction/torsion test).・Related to torsional compound displacement detector.

B. Conventional technology The combined tension/torsion test is a test in which the test specimen is subjected to an axial load such as a retro-tensile load, and at the same time a load in the torsional direction is applied to measure the combined stress strength. , it is necessary to extract the axial displacement amount and torsional direction displacement amount between the gauge points of the specimen with high precision.

Conventionally, a pair of upper and lower fixing rings were attached to the gauge points of the specimen, and one leaf spring was placed on one side in a plane perpendicular to the axis of the specimen, and the other was placed in a plane parallel to the axis of the specimen. By providing strain gauges on both leaf springs, the former can be used as an axial displacement detection means, and the latter can be used as a torsional displacement detection means. It has been proposed that the tip of the spring and the other ring are connected by sliding contact so that axial displacement and torsional displacement can be taken out independently (Utility Model Application No. 59-120407).

Also, there are some that use a differential transformer instead of strain gauges and leaf springs.

C0 Problems to be Solved by the Invention However, conventional detection methods directly deform a short leaf spring or detect using a differential transformer with a limited stroke, which limits the measurement range, such as axial displacement. is 1 to 2 mm, the twist angle is 1 to 3 degrees, and F R
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There was a problem in that it could not be applied to specimens with large axial displacements and torsional displacements, such as those in the case of tic). In addition, the mechanism is complicated, the detector is large and heavy, and handling is complicated.

The present invention has been made to solve these problems, and its purpose is to provide a suction/torsion combined displacement detector with a wide measurement range and high accuracy.

Means for Solving the D0 Problem The combined suction/torsion displacement detector according to the present invention includes a pair of annular fixtures that are mounted at a predetermined interval in the axial direction of a specimen and are arranged opposite to each other, and a pair of axial displacement detection means provided on each of the annular fixtures to detect relative axial displacement of both annular fixtures; a leaf spring whose plane is perpendicular to the tangential direction of the other annular fixture, and whose one end is wound around the other annular fixture and whose other end is orthogonally connected to the plane at the other end of the leaf spring; It has a striatum of
The above problem is solved by providing a torsional displacement detection means for detecting the amount of deflection of the leaf spring in accordance with the relative angular displacement of both annular fixtures.

When the E1 effect specimen is displaced in the axial direction, the annular fixture is relatively displaced in the axial direction, and this displacement is detected by the axial displacement detection means. The axial displacement detection means is a non-contact type, and can be measured without any problem even if the two annular fixtures are relatively angularly displaced due to twisting of the specimen, and even if the amount of axial displacement is large. Measurable. On the other hand, when the specimen is photographed at the same time, both annular fixtures undergo a relative angular displacement in the torsional direction, causing the leaf spring to bend. Due to the axial displacement of the specimen, the filament is axially displaced at the winding portion of the annular fixture, and the relative displacement of both annular fixtures in the axial direction is absorbed. By measuring this amount of deflection with a strain gauge or the like, the twist angle and twist direction of the specimen can be detected.

It is also possible to detect the deflection of the leaf spring using an optical sensor.

F. Example The present invention will be described below based on an illustrative example.

As shown in FIG. 1, a pair of upper and lower annular fixtures 1 and 2 are arranged facing each other at a predetermined interval in the axial direction of the specimen TP,
An optical displacement meter 4 is provided below the upper annular fixture 1 via an annular mounting flat plate 3, and an axial displacement detection annular flat plate 5 is provided above the lower annular fixture 2 to detect the optical displacement meter 4 and axial displacement. An annular flat plate 5 detects axial displacement. In addition, the annular fixture 1
and 2 are connected by a torsional displacement detection mechanism 6 to detect displacement in the torsional direction.

The annular fixtures 1 and 2 have locking pieces IA and 2A that protrude in the axial direction of the specimen TP, and the locking pieces IA.

It is attached to the gage point by a mounting screw 7 screwed into 2A.

The annular mounting flat plate 3 and the axial displacement detection annular flat plate 5 are attached in parallel to the annular fixtures 1 and 2 via the connecting member 21.

A plurality of optical displacement meters 4 (for example, 180
The upper surface of the axial displacement detecting annular flat plate 5 is polished to a mirror finish to improve reflection. The optical displacement meter 4 has a light emitting element and a light receiving element, the light from the light emitting element is reflected by an annular flat plate 5, the reflected light is detected by the light receiving element, and the axial displacement is detected based on the change in the light receiving position. By providing a plurality of these and taking the average value, even if the parallelism between the flat plates 3 and 5 deviates, it can be corrected.

Note that the flat plates 3 and 5 may be omitted, the optical displacement meter 4 may be attached to the annular fixture 1, and the annular fixture 2 may be an annular flat plate for detecting axial displacement. Furthermore, the displacement meter is not limited to an optical displacement meter, and may be a non-contact type displacement meter such as a capacitance type.

The torsional displacement detection mechanism 6 includes a mounting arm 8, a torsion sensing plate spring 9, a wire (flexible filament) 10, and a strain gauge 11, and has a flexible structure capable of absorbing axial displacement by a wire 1o. It becomes.

The mounting arm 8 is horizontally projecting from the annular fixture 1, and has a leaf spring 9 hanging from its tip. The leaf spring 9 is long enough to extend to the annular fixture 2, and a strain gauge 11 is attached to the center of the leaf spring. The base end of the wire 10 is fixed to the annular fixture 2, and the wire 10 is slightly wound around the annular fixture 2, and the tip end is fixed to the lower end of the leaf spring 9. Further, the leaf spring 9 is attached to the attachment arm 8 so that its plane is perpendicular to the tangential direction of the annular fixture 1, that is, the straight line portion of the wire 10.

The winding portion of the wire 10 provided on the annular fixture 2 includes:
A groove 12 having a width corresponding to the axial displacement of the specimen TP is provided, the wire 10 moves in the axial direction in response to the axial displacement, and the wire 10 and the leaf spring 9 are always perpendicular to each other to improve detection accuracy. Do it like this.

Furthermore, the leaf spring 9 is bent in the set state before starting the test so that torsion in the forward and reverse directions can be detected.

The output of the strain gauge 11 at this time is calibrated with the twist angle being zero, and the twist angle and twist direction are detected by increasing or decreasing the output of the strain gauge 11.

When an axial load and a torsional load are applied to the specimen TP in the above state, only the axial displacement is detected by the non-contact optical displacement meter 4. Since it is a non-contact type, the measurement range can be expanded. In the torsional displacement detection mechanism 6, the axial displacement is absorbed by the flexible wire 10 and the groove 12, and the amount of strain in the leaf spring 9 corresponding to the relative rotation angle of the annular fixtures 1 and 2 is detected as an electrical signal by the strain gauge 11. and only the displacement in the torsional direction is detected. The measurement range can be increased by using the wire 10 and the long leaf spring 9. Other flexible filaments may be used instead of wires.

Note that the torsional displacement is not limited to the above-mentioned structure.

Optical non-contact detection may be performed using moiré interference fringes using two gratings. Alternatively, an encoder method may be used in which a small pitch code is printed on the surface of the flat plate 5 and counted by an optical detector. Furthermore, a potentiometer system that detects resistance changes due to resistance wires and contacts may be used. In this case, the contact extends between the upper and lower parallel flat plates 3 and 5 and becomes long in the axial direction.

G0 Effects of the Invention Since the present invention is configured as described above, it is possible to accurately detect axial displacement and torsional displacement, which have a large amount of displacement, such as in FRP. Furthermore, the mechanism is simplified, contributing to the reduction in size and weight of the detector, and it is also easy to handle.

[Brief explanation of the drawing]

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are a longitudinal sectional view, a front view, a transverse sectional view, and a perspective view, respectively, showing an embodiment of the present invention. 1.2: Annular fixture 4: Optical displacement meter 5: Axial displacement detection annular flat plate 6: Torsional displacement detection mechanism 9: Leaf spring 10: Wire 11: Strain gauge Patent applicant Shimadzu Corporation Patent attorney Eiji Fuyuki I

Claims (1)

[Scope of Claims] A pair of annular fixtures installed at a predetermined interval in the axial direction of the specimen and arranged to face each other; axial displacement detection means for detecting displacement; one end fixed to the one annular fixture, the other end extending to the other annular fixture, the plane of which is perpendicular to the tangential direction of the other annular fixture; a leaf spring; and a flexible filament whose one end is wound around the other annular fixture and whose other end is orthogonally connected to the plane at the other end of the leaf spring;
A combined suction/torsion displacement detector comprising: torsional displacement detection means for detecting the amount of deflection of the leaf spring according to the relative angular displacement of both the annular fixtures.