Device for measuring shear modulus of linear material based on optical detection technology

Abstract

The utility model discloses a device for measuring the shear modulus of a linear material based on an optical detection technology. The device comprises an optical interferometer, a tension meter and a display screen, the light interferometer comprises a bottom plate, high polymerization nylon, a track device, a left end fixing clamp, a movable reflective mirror, a laser pen, a light and beam splitter, a fixed reflective mirror, an observation screen and a right end fixing frame. The display screen is connected with the tension meter through a wire; the high-polymerization nylon is fixed on the left-end fixing clamp; one end of the high-polymerization nylon is connected to the tension meter, and the tension meter is used for measuring force applied to the high-polymerization nylon; the track device comprises a toothless nut, a toothless screw rod and a movable device; the toothless screw rod is connected with the toothless nut in a rotating or moving mode, the toothless screw rod is fixed to the right end fixing frame, the movable device moves on the toothless screw rod, the toothless nut is installed in the movable device, and the movable reflective mirror is installed above the movable device. And the other end of the high-polymerization nylon is connected with the movable reflective mirror.

Description

TECHNICAL FIELD

[0001] The utility model belongs to nondestructive testing field especially relates to a device based on optical detection technique measurement linear material shear modulus. BACKGROUND

[0002] Optical detection is an important nondestructive testing technique, through the detection light's reflection or transmission, interference, diffraction etc. information, can evaluate material's performance change and defect etc. With the rapid development of optical detection technique, optical detection, laser imaging, singular light's micro - control etc. technology has shown the unique excellent characteristic in communication, medical treatment, material analysis detection etc. But also there are some problems, for example: surface irregularity problem, deformation uniformity problem, dynamic measurement stability problem. Shear modulus is the important physical quantity of describing solid material's resistance shear deformation ability, is one of the basis of selecting mechanical component.

[0003] Shear modulus's measurement has the important significance to the research material's mechanical property, the state and life. Shear modulus measurement's key technology is that material produces the measurement of small strain when receiving stress. How to measure shear modulus is the problem that urgently needs to be solved. UTILITY MODEL CONTENT

[0004] The utility model aims at providing a kind of device based on optical detection technique measurement linear material shear modulus, the device with the advantages such as phenomenon stable and result is more accurate, structure is easy to operate and observe to solve the technical problem of the deficiency of existing optical detection technique.

[0005] To solve the above technical problems, the specific technical scheme of the utility model is as follows:

[0006] A kind of device based on optical detection technique measurement linear material shear modulus, including optical interferometer, tension meter and display screen;Optical interferometer includes bottom plate, high polymer nylon, track device, left end fixed clamp, movable mirror, laser pen, beam splitter, fixed mirror, observation screen and right end fixed frame;

[0007] Bottom plate is installed tension meter, left end fixed clamp, right end fixed frame, beam splitter, fixed mirror, laser pen and observation screen in order from left to right;

[0008] Display screen is connected tension meter by wire;

[0009] High polymer nylon is fixed on left end fixed clamp;

[0010] One end of high polymer nylon is connected on tension meter, and tension meter is used to measure the force exerted on high polymer nylon;

[0011] The track device comprises a toothless nut, a toothless screw rod and a movable device; the toothless screw rod is connected with the toothless nut through rotation or movement, the toothless screw rod is fixed on a right end fixed frame, the movable device moves on the toothless screw rod, the toothless nut is installed in the movable device, and a movable mirror is installed above the movable device.

[0012] The other end of the high polymer nylon is connected with the movable mirror, and is used for measuring the shear modulus of the high polymer nylon.

[0013] Further, the optical interferometer further comprises a coarse adjustment hand wheel and a fine adjustment hand wheel.

[0014] The fine adjustment hand wheel is fixed on the bottom plate and connected with the toothless screw rod to control the movable mirror, and is used for moving the movable mirror in the horizontal direction when the moving distance of the movable mirror is less than or equal to a preset moving distance; and the coarse adjustment hand wheel is fixed on the bottom plate and connected with the toothless screw rod to control the movable mirror, and is used for moving the movable mirror in the horizontal direction when the moving distance of the movable mirror is greater than the preset moving distance.

[0015] Further, the fixed clamp, the movable mirror, the beam splitter and the observation screen are arranged on the same straight line.

[0016] The device for measuring the shear modulus of linear materials based on optical detection technology has the following advantages:

[0017] 1. High-precision force measurement and uniform force application

[0018] Through the combination of the tension meter and the track device, the experiment can accurately monitor the force applied on the material and ensure uniform force application, avoiding uneven distribution of force and ensuring the accuracy and reliability of the experimental results.

[0019] 2. Perfect combination of optics and mechanics

[0020] The optical interference technology combined with the precise force application system can accurately measure the deformation of the material without contacting the sample, reduce the error and sample damage in the traditional method, and improve the measurement accuracy.

[0021] 3. Non-contact measurement

[0022] The optical interference technology avoids direct contact with the sample, reduces friction and error, improves measurement accuracy and protects the sample.

[0023] 4. Real-time data feedback and accurate control

[0024] Through the real-time data feedback of the observation screen and the display screen, the operator can monitor the deformation and the applied force at any time, ensure accurate control of the experimental conditions, adjust the experimental parameters in time, and avoid experimental errors. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 This is a block diagram of the design of the shear modulus measuring device of this utility model;

[0026] Figure 2 This is a schematic diagram of the shear modulus measuring device of this utility model;

[0027] Figure 3 This is a schematic diagram of the minute deformation caused by shearing of the object under test in this utility model;

[0028] Figure 4 This is the optical path diagram of the optical interferometer of this utility model;

[0029] Figure 5 This is a schematic diagram of the toothless nut of this utility model;

[0030] Figure 6 This is a schematic diagram of the toothless screw of this utility model.

[0031] The markings in the diagram are as follows: 1. Observation screen; 2. Coarse adjustment handwheel; 3. Beam splitter; 4. Laser pointer; 5. Fixed reflector; 6. Fine adjustment handwheel; 7. Movable reflector; 8. Fixing clamp; 9. High-polymer nylon; 10. Tensile gauge; 11. Base plate; 12. Display screen; 13. Track device; 14. Right end fixing bracket. Detailed Implementation

[0032] To better understand the purpose, structure, and function of this utility model, the following description, in conjunction with the accompanying drawings, provides a more detailed account of a device for measuring the shear modulus of linear materials based on optical detection technology.

[0033] A device for measuring the shear modulus of linear materials based on optical detection technology, such as Figure 1 As shown: Includes an optical interferometer, a force gauge 10, and a display screen 12; as Figure 2 As shown, the optical interferometer includes a base plate 11, a high-polymer nylon 9, a track device 13, a left end fixing clamp 8, a movable reflector 7, a laser pointer 4, a beam splitter 3, a fixed reflector 5, an observation screen 1, and a right end fixing bracket 14.

[0034] The base plate 11 is installed from left to right as follows: tension gauge 10, left end fixing clip 8, right end fixing bracket 14, beam splitter 3, fixed reflector 5, laser pointer 4 and observation screen 1.

[0035] The display screen 12 is connected to the force gauge 10 via a data acquisition system. The display screen 12 displays the acquired interference fringe images or mechanical data (such as the force applied by the force gauge) in real time to help analyze the mechanical behavior of the high-polymer nylon 9.

[0036] The display screen 12 is used to display the experimental data in real time, including the applied force, the degree of deformation of the material, the change of interference fringes of the optical interferometer, and other information. Through the display screen 12, the operator can monitor the experimental process in real time, adjust the force application method, and obtain the required data.

[0037] The base plate 11 provides a stable support platform to ensure the fixation and accurate positioning of various components of the experimental device.

[0038] The high polymer nylon 9 is fixed on the left end fixed clamp 8.

[0039] One end of the high polymer nylon 9 is connected to the tensile meter 10, which is used to measure the force applied to the high polymer nylon 9. As the force changes, the high polymer nylon 9 deforms under the action of tension, and the optical interferometer monitors these deformations.

[0040] The tensile meter 10 is used to transmit the applied force and ensure the stability of the applied force.

[0041] The main function of the tensile meter 10 is to change the deformation of the high polymer nylon 9 by applying precise tension, thereby causing changes in the optical path of the interferometer and affecting the interference pattern. The tensile meter ensures that the applied force is uniform and controllable, providing a basis for subsequent optical interference measurement.

[0042] The beam splitter 3 is used to divide the laser beam into two parts, one part is used to measure the deformation of the high polymer nylon 9, and the other part is used to feedback the tensile meter 10. The beam splitter 3 is connected to the laser pen 4 and distributes the laser beam to the observation screen 1, the fixed mirror 5, the movable mirror 7, and the tensile meter 10 through optical fibers or mirrors.

[0043] The laser pen 4 provides a laser light source that irradiates the high polymer nylon 9.

[0044] The fixed mirror 5 is used to reflect the laser beam and guide its path to the material sample, ensuring that the laser beam accurately irradiates the target position.

[0045] The movable mirror 7 accurately adjusts the angle of the laser beam, ensuring that the laser beam accurately irradiates the high polymer nylon 9.

[0046] The left end fixed clamp 8 ensures that the high polymer nylon 9 does not displace during the experiment. The left end fixed clamp 8 is connected to the base plate 11 by screws or clamps, ensuring that the high polymer nylon 9 is stably fixed.

[0047] The track device 13 is used to adjust the applied force during the experiment, ensuring the uniformity of the force application process.

[0048] The right end fixed frame 14 is fixed above the toothless screw rod. The right end fixed frame 14 is connected to the base plate 11 by screws or clamps, ensuring that the track device is suspended.

[0049] The track device 13 includes a toothless nut, a toothless screw, and a movable device; the toothless screw is connected with the toothless nut through rotation or movement, the toothless screw is fixed on the right end fixed frame 14, the movable device moves on the toothless screw, the toothless nut is installed inside the movable device, and the movable mirror 7 is installed above the movable device; the toothless screw and the toothless nut are connected through the structure of mutual engagement. When the toothless screw is connected with the toothless nut in rotation, the special spiral convex or groove on the surface of the toothless screw cooperates with the matching spiral structure in the toothless nut, the screw rotation can drive the nut to move linearly along the axial direction, and rotation-linear motion conversion is realized; when the toothless screw is connected with the toothless nut in movement, the special linear guide structure of the toothless screw is closely attached to the toothless nut, and when the screw moves linearly, the nut moves synchronously with the screw by relying on friction or a constraint mechanism.

[0050] The toothless nut adjusts the linear movement of the toothless nut through the rotation of the screw, and then changes the tension applied to the high polymer nylon 9.

[0051] The main function of the toothless nut and the toothless screw is to provide precise and uniform force application. By rotating the toothless screw, the operator can accurately adjust the force, ensuring that the force is evenly distributed on the high polymer nylon 9, which helps to obtain accurate optical interference data and experimental results.

[0052] The main function of the high polymer nylon 9 is to serve as a material sample in the experiment, which is deformed under the influence of the applied external force, and the optical interferometer monitors the deformation of the material in real time through the optical system. By measuring the deformation, the shear modulus and other physical properties of the material can be further calculated.

[0053] In this optical interferometer experiment, the toothless screw and the toothless nut provide a precise force adjustment mechanism for the experiment. By rotating the toothless nut, the tension meter 10 moves smoothly and applies force to the high polymer nylon 9. The tension meter 10 applies external force through the toothless screw and the toothless nut, causing the high polymer nylon 9 to deform, and the optical interferometer captures the deformation of the material in real time by monitoring the interference fringes generated by the deformation. The display screen 12 is connected with the optical interferometer and the tension meter, and displays the applied force and the deformation degree of the high polymer nylon 9 in real time, helping the operator to monitor the experimental process and obtain data. Through the cooperation of these components, the experiment can accurately measure the shear modulus and other mechanical properties of the high polymer nylon 9, ensuring the accuracy and reliability of the experimental data.

[0054] The observation screen 1 is used to display the path of the laser beam passing through the beam splitter 3 and to observe the deformation of the material sample (such as the high polymer nylon 9).

[0055] The observation screen 1 is usually fixed at a proper position of the experimental device, so that the operator can clearly see the optical signal and the deformation of the material sample.

[0056] The optical interferometer also includes a coarse adjustment wheel 2 and a fine adjustment wheel 6. The coarse adjustment wheel 2 is used to roughly adjust the position of the movable reflector in the device to roughly align it with the path of the laser beam. The coarse adjustment wheel is mechanically connected to either the fixed reflector 5 or the movable reflector 7, helping the operator quickly adjust the optical path. The fine adjustment wheel 6 is used to finely adjust the position of the reflector to precisely align it with the laser beam and ensure accurate illumination of the material surface. The fine adjustment wheel 6 is connected to the movable reflector 7 and is used to finely adjust the position of the reflector to ensure the beam accurately illuminates the material.

[0057] The fine-tuning handwheel 6 is fixed to the base plate 11 and connected to a toothless screw to control the movable reflector 7. It is used to move the movable reflector 7 horizontally when its movement distance is less than or equal to a preset movement distance. The coarse-tuning handwheel 2 is fixed to the base plate 11 at the left end of the observation screen 1 and connected to a toothless screw to control the movable reflector 7. It is used to move the movable reflector 7 horizontally when its movement distance is greater than a preset movement distance. The fixing clamp 8, the movable reflector 7, the beam splitter 3, and the observation screen 1 are arranged on the same straight line.

[0058] During the shear modulus measurement experiment, the deformation of the material is monitored in real time by observation screen 1. The coarse adjustment handwheel 2 and beam splitter 3 split the light emitted by the laser pointer 4. The beam splitter 3, utilizing its semi-transparent and semi-reflective properties, divides the light emitted by the laser pointer 4 into two beams: one transmitted and one reflected, which propagate along different optical paths. The coarse adjustment handwheel 2, by rotating, moves or rotates the movable reflector 7, changing the propagation path and optical path difference of the two beams, thus adjusting the split optical path. The fixed reflector 5 reflects the light, while the fine adjustment handwheel 6 finely adjusts the optical path. The fine adjustment handwheel 6 is connected to a toothless screw; rotating it causes a slight angular change in the movable reflector 7, thereby adjusting the direction of the reflected light. The movable reflector 7, in conjunction with the track device 13, changes the optical path. High-polymer nylon 9 is used to apply and measure tensile force. The display screen 12 records the applied force and material deformation data. Finally, based on the relationship between the force value and the deformation, the shear modulus is calculated using a formula.

[0059] The derivation of the formula will be explained below.

[0060] After installing the instrument according to the above procedure, place the high-polymer nylon 9 between the left-end fixing clamp 8 and the tensioner 10. When the left-end fixing clamp 8 is subjected to an external force along its length, it will elongate or shorten, i.e., deform. Let the cross-sectional area of ​​the high-polymer nylon 9 be S. If... Figure 3 As shown, with a length of L, an external force F is applied along the length direction, causing the high polymer nylon 9 to elongate by ΔL. The ratio F / S is the force per unit cross section, called stress; the ratio ΔL / L is the relative elongation of the high polymer nylon 9, called strain, which represents the magnitude of the deformation of the high polymer nylon 9.

[0061] According to Hooke's law, the stress of high polymer nylon 9 is proportional to the strain within the elastic limit, and the formula is as follows:

[0062]

[0063] In the formula, the proportional coefficient E is the elastic modulus (or Young's modulus) of the material, which is only related to the nature of the material itself, and is independent of the external force F, the original length L and the cross-sectional area S of the material. Rewrite the formula as follows:

[0064]

[0065] Therefore, the elastic modulus E is equal to the stress caused by the relative change per unit length. The formula can be used to calculate the elastic modulus, where:

[0066] • L can be measured by a general measuring tool,

[0067] • F can be calculated by the mass m of the digital force meter in the experiment, F = mg, where g is the acceleration of gravity,

[0068] • S can be obtained by measuring the diameter d of the material,

[0069] After substituting S, the formula becomes:

[0070]

[0071] The elastic modulus of high polymer nylon 9 can be measured using the principle of light interference and the tensioner 10. Then:

[0072]

[0073] Since the movement of the movable mirror 7 causes a small deformation of the high polymer nylon 9, the change in the corresponding distance Δd is equal to the elongation ΔL of the high polymer nylon 9, i.e. Δd = ΔL, then formula (4) can be substituted into formula (3), and then:

[0074]

[0075] The elastic modulus of high polymer nylon 9 can be calculated by formula (5).

[0076] The shear modulus and the elastic modulus are related to each other, and their relationship is also affected by the Poisson's ratio of the material, which is defined as the ratio of the strain in the tensile or compressive direction to the strain perpendicular to the direction. That is, the formula is:

[0077]

[0078] Where:

[0079] • Transverse strain refers to the degree of deformation (usually shrinkage) of the material in the perpendicular direction.

[0080] • Axial strain refers to the degree of deformation of the material in the direction of tension.

[0081] The formula for calculating strain is usually:

[0082]

[0083] Where:

[0084] ΔL is the change in length of the material after being stressed.

[0085] L0 is the original length of the material.

[0086] To this end, the track device 13 is introduced, as shown in Figure 5 and Figure 6 The track device 13 in the track device 13 is composed of a box with a reversing lever, and there are three iron blocks (the middle iron block and the two side iron blocks) inside the box, each iron block is equipped with a ball bearing inside, the inner ring of the bearing is in contact with the iron rod, which can drive the iron block to rotate around the vertical axis. When the lever is pushed, the middle iron block deflects and drives the adjacent two iron blocks to move in the opposite direction through the protruding column on it. When the inner ring of the bearing of these iron blocks is in contact with the iron rod, friction will occur, which will generate a component force in the axial direction, pushing the box to move on the iron rod. Through the operation of the lever, the deflection direction of the three iron blocks will change instantaneously, changing the contact point of the bearing and the direction of the friction force, so as to change the moving direction of the box. By adjusting the installation position of the bearing in the iron block, the position of the bearing contact point with the iron rod is changed. Therefore, the direction conversion and stepless speed regulation function can be realized, so as to change the size of the push-pull force.

[0087] In summary, the elastic modulus E and Poisson's ratio v are known, so the relationship between the elastic modulus E, the shear modulus G and Poisson's ratio v is used. The formula is:

[0088]

[0089] Then formula (5) can be brought into formula (8), and formula (9) can be obtained:

[0090]

[0091] The shear modulus of high polymer nylon 9 can be calculated by formula (9).

[0092] Assemble the instrument, put the high polymer nylon 9 on the fixed knobs at both ends, put one end into the groove of the tensile meter 10 and the other end into the groove of the movable mirror 7, and adjust appropriately to keep the line in a horizontal state. Then, adjust the coarse adjustment hand wheel 2, start the optical interferometer, the track device 13 starts to deflect and changes the bearing contact mode, the movable mirror 7 moves, thereby causing the high polymer nylon 9 to be slightly deformed, and force is generated. At this time, the display screen 12 directly displays the size of the applied force.

[0093] As shown in Figure 4 , first, adjust the optical interferometer to be approximately horizontal, turn on the helium-neon laser light source (λ = 632.8 nm), and make the laser light enter along the vertical direction of the mirror surface of the movable mirror 7. Then, adjust the fixed mirror 5 and the movable mirror 7 through the coarse adjustment hand wheel 2 to make them approximately parallel. Adjust the screws at the back of the fixed mirror 5 and the tension spring screw below the movable mirror 7 to make the fixed mirror 5 approximately parallel, and avoid that the screws are too tight or too loose. Put down the observation screen 1, adjust the position of the fixed mirror 5 until the brightest points in the two rows of light spots coincide, and ensure that the fixed mirror 5 is parallel. After observing the interference fringes, adjust the position of the movable mirror 7 to make the center of the ring fringes align with the screen. Turn the coarse adjustment hand wheel 2, record the change in the number of ring fringes Δk under different tensions, and draw a graph of the relationship between the tension and the change in the number of ring fringes. Finally, calculate the ratio of the tension F to the change in the number of ring fringes Δk , and substitute the known length L and diameter d of the high polymer nylon into the formula to obtain the elastic modulus E:

[0094]

[0095] The shear modulus and the elastic modulus are related to each other, and their relationship is affected by the Poisson's ratio of the material. In summary, the relationship formula among the elastic modulus E, the shear modulus G, and the Poisson's ratio v is:

[0096]

[0097] The shear modulus of the high polymer nylon 9 can be calculated by using the elastic modulus E:

[0098]

[0099] It can be understood that the utility model is described through some embodiments, and those skilled in the art know that various changes or equivalent replacements can be made to these features and embodiments without departing from the spirit and scope of the utility model. In addition, under the guidance of the utility model, these features and embodiments can be modified to adapt to specific conditions and materials without departing from the spirit and scope of the utility model. Therefore, the utility model is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application belong to the scope protected by the utility model.

Claims

1. An apparatus for measuring the shear modulus of a linear material based on optical detection techniques, characterized in that, The light interferometer, the tension gauge (10) and the display screen (12); the light interferometer comprises a base plate (11), a high polymer nylon (9), a track device (13), a left end fixed clamp (8), a movable mirror (7), a laser pen (4), a light splitting beam splitter (3), a fixed mirror (5), an observation screen (1) and a right end fixed frame (14); The base plate (11) is sequentially installed with the tension gauge (10), the left end fixed clamp (8), the right end fixed frame (14), the light splitting beam splitter (3), the fixed mirror (5), the laser pen (4) and the observation screen (1) from left to right; The display screen (12) is connected with the tension gauge (10) through a wire; The high polymer nylon (9) is fixed on the left end fixed clamp (8); One end of the high polymer nylon (9) is connected with the tension gauge (10), and the tension gauge (10) is used for measuring the force applied on the high polymer nylon (9); The track device (13) comprises a toothless nut, a toothless screw rod and a movable device; the toothless screw rod is connected with the toothless nut through rotation or movement, the toothless screw rod is fixed on the right end fixed frame (14), the movable device moves on the toothless screw rod, the toothless nut is installed in the movable device, and the movable mirror (7) is installed above the movable device; The other end of the high polymer nylon (9) is connected with the movable mirror (7) and used for measuring the shear modulus of the high polymer nylon (9).

2. The apparatus for measuring the shear modulus of a linear material based on optical detection technology according to claim 1, wherein, The light interferometer further comprises a coarse adjustment hand wheel (2) and a fine adjustment hand wheel (6); The fine adjustment hand wheel (6) is fixed on the base plate (11) and connected with the toothless screw rod to control the movable mirror (7) and move the movable mirror (7) in the horizontal direction when the moving distance of the movable mirror (7) is less than or equal to a preset moving distance; the coarse adjustment hand wheel (2) is fixed on the base plate (11) and connected with the toothless screw rod to control the movable mirror (7) and move the movable mirror (7) in the horizontal direction when the moving distance of the movable mirror (7) is greater than the preset moving distance.

3. The apparatus for measuring the shear modulus of a linear material based on optical detection technology according to claim 1, wherein, The fixed clamp (8), the movable mirror (7), the light splitting beam splitter (3) and the observation screen (1) are arranged on the same straight line.

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