CN1281938C - High frequency responding high temperature drawing-twisting fatigue extender - Google Patents

Abstract

The invention discloses a high-frequency response high-temperature pull-torsion fatigue extensometer, which belongs to the improvement technology of a material pull-torsion fatigue tester. The fatigue extensometer consists of a two-way two-lever mechanism and a displacement sensor. The two-way two-lever mechanism includes two symmetrically arranged upper and lower right-angled force plates with non-equal thickness sections. The vertical thick-wall plate section of the two force plates A quartz thimble is connected to each of the opposite ends of the two force plates, and the pull-torsion force tester, the torque tester and the tensile tester are connected sequentially from the inside to the outside on the two thin-walled plate sections of the two force plates. The tension-torsion tester consists of two rotating shafts, a spring leaf and a support rod connected to the spring leaf; the torque tester includes a rotating reflector and a torsional displacement sensor; the tensile tester includes an axial reflector Plate and axial displacement sensor constitute. The invention has the advantages of convenient installation, quick measurement dynamic response, small temperature drift, wide measurement range, long service life and high precision.

Description

High Frequency Response High Temperature Tension-Torsion Fatigue Extensometer

Technical field:

The invention relates to a high-frequency response high-temperature pull-torsion fatigue extensometer, which belongs to the improvement technology of the pull-torsion fatigue tester for materials.

Background technique:

At present, there are only uniaxial fatigue extensometers in China, and there is no manufacturing technology for multiaxial fatigue extensometers, and the testing principle of uniaxial extensometers is still based on the strain gauge method, which has not fundamentally overcome the inherent shortcomings of the strain gauge method. For example, the test accuracy is greatly affected by the quality of the patch, temperature drift, slow dynamic response, small measurement range, short service life, etc. At the same time, the existing extensometer cannot be used for high temperature material testing, so its applicability is poor.

Invention content:

The object of the present invention is to provide a high-frequency response high-temperature tension-torsion fatigue extensometer. The fatigue extensometer has fast measurement dynamic response, high precision and long service life.

The present invention is achieved through the following technical solutions. The fatigue extensometer includes a two-way two-lever mechanism and a displacement sensor, and is characterized in that: the two-way two-lever mechanism includes two symmetrically arranged upper and lower right-angled force plates 1, 11 of non-equal-thickness wall sections, and the vertical force plates between the two force plates The opposite end of the thick-walled plate section is connected to a quartz thimble 15 through a pressure plate 14 and a bolt 13, and a tension-torsion force receiver is sequentially connected on the two thin-walled plate sections of the two force-bearing plates from inside to outside. , a torque tester and a tensile tester, the pull-torsion force receiver includes two rotating shafts 3, the rotating shaft is connected to the spring leaf 2 and the support rod 10 connected to the spring leaf; the described torque tester includes a rotational reflection plate 8 and the torsional displacement sensor 9 connected to the supporting vertical plate 4; the tensile tester includes an axial displacement sensor 7 and an axial reflection plate 6 supported on the connecting vertical plate 5.

The invention has the advantages of simple structure, convenient installation, flexible adjustment of test range, good dynamic response characteristics, test frequency up to 5 times per minute, maximum tensile strain up to 5%, and maximum shear strain up to 5%. The test temperature can reach 600 ~ 800 ℃, the temperature drift is small, the measurement range is wide, the service life is long, and the precision is high.

Description of drawings:

Fig. 1 is a structural schematic diagram of the present invention.

In the figure: 1 upper force plate, 2 spring leaf, 3 rotating shaft, 4 supporting vertical plate, 5 connecting vertical plate, 6 axial reflective plate, 7 axial displacement sensor, 8 rotating reflective plate, 9 torsional displacement sensor, 10 support rod, 11 lower force plates, 12 screws, 13 bolts, 14 pressure plates, 15 quartz thimbles, and 16 test pieces.

Detailed ways:

In the preparation of the present invention, the upper force plate 1, the rotating shaft 3, the support vertical plate 4, the connection vertical plate 5, the support rod 10, the lower force transmission plate 11, etc. are all made of aluminum alloy materials, and the axial reflection plate 6 and the rotation reflection plate 8. No. 45 steel is used, and the spring leaf is made of 20mm wide and 0.3mm thick 304 stainless steel sheet. Design the height of the spring leaf according to the gauge length of the required extensometer. When assembling, first use the bolts to fix the quartz thimble, then connect the spring piece 2 with the rotating shaft 3 and the support rod 10, respectively connect the supporting vertical plate 4, the connecting vertical plate 5 and the rotating reflection plate 8 with the upper force plate 1 and the lower receiving plate. The force plate 11 is connected, and finally the rotating shaft of the leaf spring and the force plate are fixed with nuts. After calculation, if the rigidity and strength requirements are met, M4 threads, M4 stainless steel screws or bolts are uniformly used for connection.

In addition, in order to ensure the convenient installation of the extensometer test, the extensometer frame should be designed according to the structural size of the testing machine chuck. The height of the frame is generally 1.5 times to 2 times the height of the extensometer, and the frame should be ensured to have sufficient rigidity.

The structural design of the present invention is mainly based on the principle of leverage. The test principle is that through the elastic deformation of the rotating shaft and the spring sheet in the direction of tension and compression, the rotational deformation and axial relative deformation of the thimble measurement specimen can be converted into rotational reflection plate and torsional displacement. The relative displacement output between the sensors, and the relative displacement output between the axial reflector and the axial displacement sensor. Adjusting the length of the rotating shaft, vertical plate, and thimble can change the measurement range of the extensometer in the direction of rotation; adjusting the position of the support rod, the length of the thin-walled section on the lower side, or changing the length of the thimble and spring can change the axial measurement range of the extensometer. The support rod is the fulcrum of the entire extensometer, connecting it with the external bracket can fix the extensometer at any position in space, and it is convenient to install and clamp on the tested object.

Using the present invention to test the pull-twist process of the test piece: the extensometer should be calibrated for strain when it is used for the first time, so that the measurement accuracy can be improved. When the quartz thimble touches the test piece, the test piece produces axial deformation or rotational deformation under the action of force, and the quartz thimble converts the rotational deformation and axial relative deformation of the test piece into relative displacement output through the rotating shaft and spring plate, and passes through two A non-contact eddy current displacement sensor measures the change value, and the measured displacement value is linearly related to the electrical signal output of the sensor. The millivolt level voltage signals output by the two eddy current sensors are respectively amplified by the DC amplifier, and the positive and negative 5V (or 10V, depending on the range of the AD board) voltage is input to the multi-channel AD board for AD conversion. Finally, the AD board can convert the axial and torsional strain values of the tested piece into digital signals for output, display or storage on the computer for subsequent processing. The extensometer thimble adopts quartz rod, which can be used for the measurement and control of high temperature strain.

Claims (1)

1. A high-frequency response high-temperature tension-torsion fatigue extensometer, the fatigue extensometer includes a two-way two-lever mechanism and a displacement sensor, characterized in that: the two-way two-lever mechanism includes two symmetrically arranged upper and lower non-equal-thickness wall sections at right angles Stress plate (1), (11), respectively connect a quartz thimble (15) by pressing plate (14) and bolt (13) at the counterpart end of the vertical thick-walled plate section of two stress plates, Two thin-walled plate sections of a force plate are sequentially connected with a pull-torsion loader, a torque tester and a tensile tester from the inside to the outside, and the pull-torsion loader includes two rotating shafts (3 ), the rotating shaft is connected to the spring leaf (2) and the support rod (10) that is connected on the spring leaf; the described torque tester includes a rotating reflector (8) and a torsional displacement sensor (9) connected to the support vertical plate (4) ); The tensile tester includes an axial displacement sensor (7) and an axial reflection plate (6) supported on the connection riser (5).

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