CN202330188U - Micro-torsion mechanical property testing device - Google Patents

Abstract

A device for testing micro-torsion mechanical properties of low-dimensional materials, including a frame, force sensors, micro-torque sensors, twisted wire rotation angle measurement components, upper and lower chucks, stepping motors, three-dimensional translation stages, screw nut components, and servo control device, A/D acquisition card and computer system. The two ends of the torsion wire of the micro-torque sensor are tensioned and fixed on the bracket, which has good rigidity and stability, and the measurement range can also be adjusted by replacing the torsion wire. In addition, a force sensor is installed on the upper end of the micro-torque sensor, which can detect the axial force during the torsion test in real time. The utility model adopts the method of combining the light target and the photoelectric displacement sensor to measure the rotation angle of the twisted wire. Compared with the traditional light lever method, the utility model has the advantages of compact structure, high degree of automation and good stability. The centering of the upper and lower clamping points is realized by adjusting the three-dimensional translation platform. The computer system can obtain the torque-rotation angle curve of the sample in real time. This device is suitable for testing the micro-torsion mechanical properties of various low-dimensional materials.

Description

A micro-torsion mechanical performance testing device

technical field

The utility model relates to a device for testing the micro-torsion mechanical properties of low-dimensional materials such as fibers and films, and belongs to the field of precise measurement of mechanical properties of micro-scale materials.

Background technique

Micro-electromechanical systems (MEMS) are integrated microsystems that integrate sensing, information processing and execution, and have been widely used in acceleration sensors, inertial, pressure sensors, micro jet engines, large-scale data storage systems and Miniature biochemical analysis equipment, etc., the application field is still expanding. The design and material selection of MEMS systems use a large number of low-dimensional materials such as silicon films, metal films, and various fibers with geometric feature sizes on the order of microns or submicrons. Therefore, accurate and reliable testing of the mechanical behavior of such materials is not only crucial for the safety and reliability of MEMS, but also has important academic and application value for the research of micro-nano mechanics and materials science. In particular, a large number of experiments in recent years have shown that when the characteristic length of non-uniform plastic deformation of metal materials is on the order of microns or submicrons, it shows a strong scale effect. In order to test the mechanical properties of micro-nano materials, researchers designed various micro-tension, micro-indentation and micro-bending experimental devices. However, for the micro-torsion experiment of low-dimensional materials, due to problems such as the sensitivity and stability of the torque sensor, the measurement of the rotation angle, the clamping and centering of the sample, the work in this area has been stagnant, and the corresponding experimental devices have also been delayed. Rarely reported.

The measurement of microtorsion mechanical properties of low-dimensional materials is a new problem, and there is no relatively perfect measurement method at present. Sail et al. (M.T.A Saif and N.C MacDonald, Journal of Materials Research 13, 3353 (1998).) used micromachining technology to couple torsion specimens, actuators, and calibration rods in a MEMS system, with a size of 1 μm × 1 μm and The 1.5μm×1.5μm rectangular cross-section monocrystalline silicon material was tested for micro-torsion mechanical properties. The problems of this method are that it is difficult to calibrate the driving force, the small size of the sample affects the test results, and the measuring range of the device is small. In the torsion device developed by Schiltges et al. (G.Schiltges, D.Gsell, and J.Dual, Microsystem technologies 5, 22 (1998).), the sample is glued to the fixture and kept consistent with the axis of the torque sensor. The measurement adopts the light lever principle, and the tensile stress of the sample is measured by a precision balance. Through micro-torsion experiments on silicon and nickel samples, it is found that the main defects of the device are: inconvenient clamping and centering of samples, poor structural stability, complex twisted wire rotation angle measurement components, and large errors in measurement results. Fleck et al. (N.A.Fleck et al., Acta Metallurgica et Materialia 42, 475 (1994).) In order to study the scale effect in the micro-twisting process of fine copper wires, a fine wire micro-twisting experimental device was built, which used glass wire as The torsion elastic element, the two ends of the glass filament are connected with the sample and the driving device respectively, and the torsion angle of the sample is obtained by two pointers and an angle ruler. The device still has disadvantages such as inconvenient clamping and centering of the sample, poor structural stability, and low efficiency in reading angle data.

To sum up, the micro-torsion experiment is the most direct and effective means to observe the scale effect and torsional mechanical properties of low-dimensional materials, and its testing method is still far from perfect. Therefore, it is of great scientific significance and practical value to develop a device for testing the micro-torsion mechanical properties of low-dimensional materials, and it will also make a great contribution to the development of micro-nano mechanics and MEMS.

Utility model content

The purpose of this utility model is to provide a device for testing the micro-torsion mechanical properties of low-dimensional materials. The parameter value of the torsional mechanical properties of the dimension material; the device has the advantages of wide application range, high sensitivity, stable structure and reliable measurement results.

The utility model provides a low-dimensional material micro-torsion mechanical performance testing device, which is characterized in that the device includes a frame, a force sensor, a micro-torque sensor, a twisted wire rotation angle measurement component, an upper chuck, a lower chuck, a stepper Motor, three-dimensional translation stage, lead screw nut assembly, servo controller, A/D acquisition card and computer system; micro torque sensor includes torsion wire, bracket, rectangular frame, upper torsion wire fixed block and lower torsion wire fixed block; torsion wire Tensioned and fixed on the support, the two ends are respectively pressed by the upper twisted wire fixing block and the lower twisted wire fixing block, and the rectangular frame is suspended and fixed in the middle of the twisted wire.

The bracket of the micro-torque sensor is suspended and fixed on the upper end of the frame through the force sensor. The upper chuck is connected to the lower end of the rectangular frame by means of fasteners. The lower chuck is installed on the main shaft of the stepping motor. The upper chuck and the lower chuck For clamping the sample, the stepper motor is placed on the three-dimensional translation platform, the three-dimensional translation platform is installed on the lead screw nut assembly, and the lead screw nut assembly is fixed at the bottom of the frame.

The servo controller is electrically connected with the stepping motor; the A/D acquisition card is used for data acquisition of the twisted wire rotation angle and axial tension, and the servo controller and the A/D acquisition card are electrically connected with the computer system;

The twisted wire rotation angle measurement component consists of a one-dimensional translation stage, a photoelectric displacement sensor and a light target. The one-dimensional translation stage is installed on the side support plate of the frame, the photoelectric displacement sensor is placed on the one-dimensional translation stage, and the light target is fixed on the rectangular frame and The joint of the twisted wire is kept on the same plane as the twisted wire, and the light target faces the light outlet of the photoelectric displacement sensor, and the emitted beam A of the photoelectric displacement sensor hits the light target.

Compared with the prior art, the utility model has the following advantages and prominent effects: (1) twisted wire is used as the torsion elastic element, and the twisted wire is tensioned and fixed on the bracket, which greatly improves the rigidity and stability of the system, and provides The realization of automatic and intelligent measurement of micro-torque of low-dimensional materials has laid the foundation; the torque acting on the sample is directly transmitted to the torsion wire through the upper chuck and the rectangular frame, without frictional resistance torque interference, and the test results are more stable and accurate; through By replacing the torsion wires of different specifications, micro-torque sensors with different ranges can be produced, so as to realize the wide-range measurement of the micro-torsion mechanical properties of low-dimensional materials. (2) The utility model uses a non-contact photoelectric displacement sensor to measure the displacement δ of the light spot on the target surface, and then converts the displacement into the twisted wire rotation angle, and the resolution can be as high as 10 ^-6 rad. Compared with the traditional optical lever principle to measure the rotation angle, the structure is more compact, the degree of automation is higher, and the stability is better. (3) The chuck assembly adopts a special four-head cable nozzle cylindrical chuck, and the alignment of the upper and lower chucks is ensured by adjusting the three-dimensional translation platform. (4) The upper chuck and the rectangular frame are connected by fasteners, which is convenient for sample clamping. (5) The upper end of the micro-torque sensor is fixed with a force sensor, which can detect the pre-tension of the sample and the Z-direction tension during the micro-torsion process in real time. The entire measurement has the characteristics of automation, real-time, intelligence, high precision, high sensitivity and wide range, and the device is compact in structure, stable in performance, easy to operate, reliable in measurement results, and suitable for micro-torsion mechanical performance tests of various low-dimensional materials. .

Description of drawings

Fig. 1 is the structural representation of the utility model.

Fig. 2 is a schematic diagram of a twisted wire rotation angle measuring assembly.

Fig. 3 is a torque-angle curve diagram of copper wire (38 μm).

In the figure: 1-frame; 2-three-dimensional translation stage; 3-screw nut assembly; 4-stepper motor; 5-lower chuck; 6-sample; 7-upper chuck; 8-bracket; 9- Lower twisted wire fixed block; 10-rectangular frame; 11-one-dimensional translation stage; 12-photoelectric displacement sensor; 13-light target; 14-twisted wire; 15-upper twisted wire fixed block; 16-force sensor; Controller; 18-A/D acquisition card; 19-computer system; A-laser beam; B-initial position of light target; B'-current position of light target; C-light spot.

Detailed ways

The embodiment of the present utility model is described in further detail in conjunction with accompanying drawing now.

The utility model is based on the static working principle of the torsion balance, but the form is improved to increase the rigidity of the structure and ensure good stability.

As shown in Figure 1, the utility model device includes a frame 1, a force sensor 16, a micro torque sensor, a twisted wire rotation angle measurement assembly, an upper chuck 7, a lower chuck 5, a stepper motor 4, a three-dimensional translation platform 2, a wire Bar nut assembly 3, servo controller 17, A/D acquisition card 18 and computer system 19.

Micro-torque sensor is made up of torsion wire 14, support 8, rectangular frame 10 and upper and lower torsion wire fixing blocks 15,9; Tight, the rectangular frame 10 is hung and fixed on the middle part of the twisted wire 14.

The twisted wire rotation angle measurement assembly consists of a one-dimensional translation stage 11 , a photoelectric displacement sensor 12 and a light target 13 . The one-dimensional translation platform 11 is installed on the side support plate of the frame 1, the photoelectric displacement sensor 12 is placed on the one-dimensional translation platform 11, the light target 13 is fixed on the junction of the rectangular frame 10 and the twisted wire 14, and is connected with the twisted wire 14 Keep on the same plane, and the light target 13 faces the light outlet of the photoelectric displacement sensor 12 , and the emitted light beam A of the photoelectric displacement sensor 12 hits the light target 13 .

The bracket 8 of the micro-torque sensor is suspended and fixed on the upper end of the frame 1 through the force sensor 16, the upper chuck 7 is connected to the lower end of the rectangular frame 10, the lower chuck 5 is installed on the main shaft of the stepping motor 4, and the upper and lower chucks The sample 6 is clamped between 7 and 5, the stepper motor 4 is placed on the three-dimensional translation platform 2, the three-dimensional translation platform 2 is installed on the lead screw nut assembly 3, and the lead screw nut assembly 3 is fixed on the bottom of the frame 1.

The micro-torque sensor is characterized in that the two ends of the elastic element torsion wire 14 are tensioned and fixed on the support 8, which greatly improves the rigidity of the system, and the torque acting on the sample 6 passes through the upper chuck 7 and the rectangular frame 10 directly. Passed to the twisted wire 14, there is no interference of frictional resistance torque, and the test result is stable and accurate; the twisted wire rotation angle measurement assembly is characterized in that it uses an optical non-contact method to measure the rotation angle of the twisted wire, and has a simple structure and high resolution. The distance between the light point C on the target surface 13 and the twisted wire 14 is obtained by adjusting the one-dimensional translation table 11; the upper and lower chucks 7, 5 are characterized in that they all adopt four-headed cable nozzle type cylindrical chucks , good neutrality, wherein the upper chuck 7 and the rectangular frame 10 are connected by fasteners, and the sample is conveniently clamped; the servo controller 17 is used to control the motion of the stepping motor 4; the A/D acquisition card 18 is used for data acquisition of twisted wire 14 rotation angle and axial tension; computer system 19 is used for completing parameter setting of the test system, data analysis and processing, and real-time display of the torque-rotation angle curve.

Its steps:

(1) According to the measurement requirements, cut a certain length of undamaged material sample, use soft base material as a pad to paste the two ends of the sample, and complete the production of sample 6. Clamp the sample between the upper chuck 7 and the lower chuck 5 with tweezers, and make it in a relaxed state. Then, the X and Y directions of the three-dimensional translation table 2 are adjusted so that the upper and lower clamping points and the torsion wire 14 are kept on the same axis.

(2) Apply a certain pretension to the sample to keep the sample 6 straight. Firstly adjust the screw nut assembly 3 roughly, then finely adjust the three-dimensional translation stage 2 along the Z direction, drive the stepper motor 4 and the lower chuck 5 to move downward, and apply a pre-tension to the sample 6, the size of the pre-tension is determined by Force sensor 16 detects.

(3) The sample 6 is torsionally loaded. When the sample 6 is twisted at a certain angle, the torque T in the sample 6 is transmitted to the micro-torque sensor through the upper clamp 7, and the equilibrium position of the micro-torque sensor under the action of T is A deflection will occur, and at this time, the torsion wire 14 as a torsion elastic element will provide a counter torque T _w , so that the system can be balanced again. The corresponding rotation angle θ of the twisted wire 14 is detected by the twisted wire rotation angle measuring component, and the torque of the sample is obtained according to the torque balance

T＝ _Tw ＝Kθ ①

In the formula, K is the torsional elastic coefficient of the twisted wire 14, and θ is the torsion angle of the twisted wire 14. Since the rectangular frame 10 divides the twisted wire 14 into two sections l ₁ and l ₂ , according to the knowledge of material mechanics,

$K=\frac{\mathrm{G\π}{d}^4}{32}(\frac{1}{l_1}+\frac{1}{l_2})$ ②

In the formula, G is the shear modulus of the twisted wire 14, and d is the diameter of the twisted wire 14.

The twisted wire rotation angle measurement assembly is shown in Figure 2, the initial position B (reference plane) of the light target 13 is perpendicular to the laser beam A of the photoelectric displacement sensor 12, when the twisted wire 14 drives the light target 13 to rotate to B' , the photoelectric displacement sensor 12 measures its displacement δ from the reference plane B, then the rotation angle of the twisted wire 14 is

$\mathrm{\θ}=\arctan \left(\frac{\mathrm{\δ}}{L}\right)$ ③

In the formula, L is the distance between the light spot C on the light target 13 and the twisted wire.

At this time, the torsion angle of sample 6 is

④

为步进电机4对试样6施加的转角。In the formula,

is the rotation angle applied by the stepping motor 4 to the sample 6.

(4) The angle of rotation θ of the twisted wire 14 and the angle of rotation applied by the stepper motor 4 to the sample 6 The A/D acquisition card 18 and the servo controller 17 respectively transmit to the computer system 19, and then according to formulas ① to ④, the computer system 19 can obtain the torque-rotation angle curve in real time when the sample is slightly torsion. After the test, save the relevant data, as shown in Figure 3.

Example:

The twisted wire of the micro-torque sensor in the device is pure tungsten wire with a diameter of 80 μm. The length of the upper and lower twisted wires is 20 cm, the resolution is 0.5 μN.cm, and the measuring range is ±6000 μN.cm. The force sensor has a resolution of 0.1mN and a measuring range of ±5N. The selected photoelectric displacement sensor has a resolution of 1 μm and a measuring range of ±15 mm, and uses triangulation to measure the rotational distance of the target surface. The selected stepper motor has a minimum step angle of 0.0072°. The stroke of the screw nut assembly is 200mm, the stroke of the one-dimensional translation stage is 20mm, and the strokes of the three-dimensional translation stage X, Y, and Z are all 10mm.

The utility model is not limited to the above-mentioned specific implementation methods, and those skilled in the art can implement the utility model by adopting other various specific implementation modes according to the disclosed content of the utility model. Do some simple changes or modified designs, all fall into the protection scope of the present utility model.

Claims (1)

1. A low-dimensional material micro-torsion mechanical performance testing device is characterized in that the device comprises a frame (1), a force sensor (16), a micro-torque sensor, a twisted wire rotation angle measurement assembly, an upper chuck (7), Lower chuck (5), stepping motor (4), three-dimensional translation stage (2), screw nut assembly (3), servo controller (17), A/D acquisition card (18) and computer system (19) The micro torque sensor comprises twisted wire (14), support (8), rectangular frame (10), upper twisted wire fixed block (15) and lower twisted wire fixed block (9); twisted wire (14) is tensioned and fixed on the bracket (8) On, the two ends are compressed with the upper twisted wire fixing block (15) and the lower twisted wire fixing block (9) respectively, and the rectangular frame (10) is suspended and fixed in the middle part of the twisted wire (14); The support (8) of the micro torque sensor is suspended and fixed on the upper end of the frame (1) by the force sensor (16). 5) Installed on the spindle of the stepping motor (4), the upper chuck (7) and the lower chuck (5) are used to clamp the sample (6), and the stepping motor (4) is placed on the three-dimensional translation stage (2 ), the three-dimensional translation platform (2) is installed on the lead screw nut assembly (3), and the lead screw nut assembly (3) is fixed on the bottom of the frame (1); Described servo controller (17) is electrically connected with stepper motor (4); A/D acquisition card (18) is used for the data acquisition of torsion wire (14) angle of rotation and axial tension, and servo controller (17) and A/D acquisition card (18) are all electrically connected with computer system (19); The twisted wire rotation angle measurement assembly consists of a one-dimensional translation stage (11), a photoelectric displacement sensor (12) and a light target (13). The one-dimensional translation stage (11) is installed on the side support plate of the frame (1), and the photoelectric displacement sensor (12) placed on the one-dimensional translation platform (11), the light target (13) is fixed on the junction of the rectangular frame (10) and the twisted wire (14), and remains on the same plane with the twisted wire (14), and the light The target (13) faces the light outlet of the photoelectric displacement sensor (12), and the emission beam A of the photoelectric displacement sensor (12) hits the light target (13). the

Images