Material elasticity modulus measuring device based on optical detection technology

Abstract

The utility model provides a material elasticity modulus measuring device based on an optical detection technology, and belongs to the field of nondestructive testing, a light source, a light and beam splitter, a fixed reflective mirror and a movable reflective mirror form a light interferometer, laser passes through the light and beam splitter and then is reflected along the vertical direction of the mirror surface of the movable reflective mirror and the mirror surface of the fixed reflective mirror; an equal-inclination interference ring is displayed on the observation screen, the movable reflective mirror is adjusted in the horizontal direction, so that the sample to be tested is stretched to generate tension on the digital tension meter, and the stage number of the equal-inclination interference ring in the interferometer is changed; and calculating the elastic modulus of the to-be-measured sample according to the tension variation, the series variation of the isotropic interference ring, the length of the to-be-measured sample, the diameter of the to-be-measured sample and the wavelength of the light source. The elastic modulus measuring instrument has the advantages that the structure is easy to operate and observe, the phenomenon is stable, the result is accurate and the like, and the problems that a traditional elastic modulus measuring instrument is not high in measuring accuracy, and only limited types of materials can be measured are solved.

Description

Technical Field

[0001] This application relates to the field of non-destructive testing technology, and particularly to a device for measuring the elastic modulus of materials based on optical detection technology. Background Art

[0002] Optical detection is an important non-destructive testing technology. By detecting information such as light reflection or transmission, interference, and diffraction, the performance changes and defects of materials can be evaluated. With the rapid development of optical detection technology, technologies such as optical detection, laser imaging, and micro-manipulation of singular light have shown unique and excellent characteristics in communication, medical treatment, material analysis and detection, etc. The elastic modulus is an important physical quantity that describes the ability of solid materials to resist deformation and is one of the bases for selecting mechanical components.

[0003] The measurement of the elastic modulus is of great significance for studying the mechanical properties, state, and lifespan of materials. The key technology for measuring the elastic modulus is the measurement of the tiny strain generated when the material is stressed, which is an urgent problem to be solved when measuring the elastic modulus. Utility Model Content

[0004] This application provides a device for measuring the elastic modulus of materials based on optical detection technology. The measuring device has the advantages of easy operation and observation of the structure, stable phenomena, and relatively accurate results, and solves the problems of low measurement accuracy of existing traditional instruments for detecting elastic modulus and the ability to measure only a limited variety of materials.

[0005] This application provides a device for measuring the elastic modulus of materials based on optical detection technology, including: an observation screen, an adjustment handwheel, a beam splitter, a light source, a fixed reflector, a movable reflector, a precision lead screw, a tensile track, a digital tensiometer, and a lifting platform;

[0006] Wherein, one end of the tensile track is fixed on the lifting platform, and the other end is fixed on the precision lead screw;

[0007] The digital tensiometer is fixed at one end of the tensile track close to the lifting platform;

[0008] One end of the sample to be measured is connected to the digital tensiometer, and the other end is connected to the movable reflector. By adjusting the height of the lifting platform to drive the tensile track to rise and fall, the digital tensiometer and the round hole in front of the movable reflector are in the same horizontal plane;

[0009] The precision lead screw, the movable mirror, the beam splitter, and the observation screen are sequentially arranged on the same straight line. By adjusting the light source, the fixed mirror, and the movable mirror, the laser is reflected along the vertical direction of the mirror surfaces of the movable mirror and the fixed mirror after passing through the beam splitter, and equal inclination interference fringes are displayed on the observation screen;

[0010] The adjustment handwheel is used to move the movable mirror in the horizontal direction. While stretching the sample to be measured, it causes the equal inclination interference fringes to emerge or sink, resulting in a change in the order, so as to calculate the elastic modulus of the sample to be measured according to the change amount of the tensile force of the sample to be measured, the change amount of the order of the equal inclination interference fringes, the length of the sample to be measured, the diameter of the sample to be measured, and the wavelength of the light source.

[0011] Optionally, in the present application, the device further includes:

[0012] A digital tensiometer display screen, which is connected to the digital tensiometer and is used to display the reading of the digital tensiometer.

[0013] Optionally, in the present application, the adjustment handwheel further includes:

[0014] A coarse adjustment handwheel, which is used to move the movable mirror in the horizontal direction when the moving distance of the movable mirror is greater than a preset moving distance;

[0015] A fine adjustment handwheel, which is used to move the movable mirror in the horizontal direction when the moving distance of the movable mirror is less than or equal to the preset moving distance.

[0016] The material elastic modulus measuring device based on optical detection technology in the present application uses the interference method of light. The stretching length of the sample to be measured is characterized by the emergence or sinking of the equal inclination interference fringes, and then the elastic modulus of the sample to be measured is calculated, avoiding the direct measurement of the tiny deformation when the sample to be measured is stretched. The structure of the device for measuring the elastic modulus is easy to operate and observe, the phenomenon is stable and the result is relatively accurate.

[0017] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. Description of the Drawings

[0018] The above and / or additional aspects and advantages of the present application will become apparent and easy to understand from the following description of the embodiments in conjunction with the drawings, where:

[0019] Figure 1 It is a schematic structural diagram of a material elastic modulus measuring device based on optical detection technology according to an embodiment of the present application;

[0020] Figure 2 Schematic diagram of the tiny deformation generated by stretching the sample to be measured;

[0021] Figure 3 Optical path diagram at the optical interferometer;

[0022] Figure 4 Schematic diagram of the aperture change when the aperture swallows one level.

[0023] Explanation of reference numerals in the drawings: 1 - observation screen; 2 - coarse adjustment handwheel; 3 - beam splitter; 4 - light source; 5 - fixed reflector; 6 - fine adjustment handwheel; 7 - movable reflector; 8 - precision lead screw; 9 - sample to be measured; 10 - tension track; 11 - digital tensiometer; 12 - digital tensiometer display screen; 13 - lifting platform. Detailed implementation manners

[0024] The embodiments of the present application will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and should not be construed as a limitation to the present application.

[0025] Figure 1 Schematic structural diagram of a material elastic modulus measurement device based on optical detection technology provided according to an embodiment of the present application.

[0026] As Figure 1 shown, the material elastic modulus measurement device based on optical detection technology includes: an observation screen 1, an adjustment handwheel, a beam splitter 3, a light source 4, a fixed reflector 5, a movable reflector 7, a precision lead screw 8, a tension track 10, a digital tensiometer 11, and a lifting table 13.

[0027] Wherein, one end of the tension track 10 is fixed on the lifting platform 13, and the other end is fixed on the precision lead screw 8;

[0028] The digital tensiometer 11 is fixed at one end of the tension track 10 close to the lifting platform 13.

[0029] One end of the sample to be measured 9 is connected to the digital tensiometer 11, and the other end is connected to the movable reflector 7. By adjusting the height of the lifting platform 13, the tension track 10 is driven to rise and fall, so that the digital tensiometer 11 and the round hole in front of the movable reflector 7 are on the same horizontal plane.

[0030] The precision lead screw 8, the movable mirror 7, the beam splitter 3, and the observation screen 1 are arranged in sequence on the same straight line. By adjusting the light source 4, the fixed mirror 5, and the movable mirror 7, the laser is reflected along the vertical direction of the mirror surfaces of the movable mirror 7 and the fixed mirror 5 after passing through the beam splitter 3, and equal inclination interference fringes are displayed on the observation screen 1.

[0031] The adjusting handwheel is used to move the movable mirror in the horizontal direction. While stretching the sample to be measured, the equal inclination interference fringes gush out or sink in, resulting in a change in the order, so as to calculate the elastic modulus of the sample to be measured according to the change amount of the tensile force of the sample to be measured, the change amount of the order of the equal inclination interference fringes, the length of the sample to be measured, the diameter of the sample to be measured, and the wavelength of the light source.

[0032] In an embodiment of the present application, the measuring device further includes:

[0033] The digital dynamometer display screen 12 is connected to the digital dynamometer 11 and is used to display the reading of the digital dynamometer 11.

[0034] In an embodiment of the present application, the adjusting handwheel further includes:

[0035] The coarse adjustment handwheel 2 is used to 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;

[0036] The fine adjustment handwheel 6 is used to move the movable mirror 7 in the horizontal direction when the moving distance of the movable mirror 7 is less than or equal to the preset moving distance.

[0037] In a specific embodiment of the present application, one end of the tension rail 10 is placed on the lifting platform 13, and the other end is placed at the precision lead screw 8. Then the digital dynamometer 11 is fixed on the tension rail 10, and the height of the lifting platform 13 is adjusted so that the digital dynamometer 11 and the front round hole of the movable mirror 7 are in the same horizontal plane. Fixing knobs are installed at both ends of the sample to be measured 9, one end is placed in the groove of the digital dynamometer 11, and the other end is placed in the appropriate groove of the movable mirror 7 in the interferometer, and the wire is appropriately adjusted to be horizontal. When the fine adjustment handwheel 6 is adjusted, the movable mirror 7 moves forward, stretching the sample to be measured 9, generating a tensile force at the digital dynamometer 11 end, and the generated tensile force can be read on the digital dynamometer display screen 12.

[0038] In the embodiment of the present application, the measurement of the elastic force mainly relies on Hooke's law of the digital dynamometer to measure the magnitude of the tensile force and the principle of optical interference to measure the magnitude of the wavelength.

[0039] After installing the measuring device, place the sample to be measured between the material clamp and the digital tensiometer. When an external force is applied to the object to be measured along its length direction, it will elongate or shorten, that is, deformation occurs. As Figure 2 shown, let the cross-sectional area of the object to be measured be S and the length be L. Apply an external force F along the length direction to make the object to be measured elongate by ΔL. Then the ratio F / S is the force per unit cross-section, called stress; the ratio ΔL / L is the relative elongation of the object, called strain, which represents the magnitude of the object's deformation.

[0040] According to Hooke's law, within the elastic limit of an object, stress is proportional to strain, that is:

[0041]

[0042] In the formula, the proportionality coefficient E is the elastic modulus (or Young's modulus) of the sample to be measured. Its magnitude only depends on the nature of the sample itself and is independent of the external force F, the original length L of the sample, and the cross-sectional area S. Rewrite the above formula as:

[0043]

[0044] It can be seen that the elastic modulus E is numerically equal to the stress F / S when causing a unit relative change in the length of the material. According to this formula, the elastic modulus can be calculated. Among them, L can be measured by a general measuring tool, F can be obtained from the mass m displayed on the digital tensiometer in the experiment, that is, F = mg, where g is the acceleration due to gravity. The cross-sectional area of the material to be measured can be obtained by measuring its diameter d. Substitute into it, and the equation becomes:

[0045]

[0046] Based on the principle of optical interference and the digital tensiometer to measure the elastic modulus of the object to be measured, the measurement of the elastic modulus of the object to be measured can be realized. The specific device and measurement method are as follows: Fix one end of the sample to be measured on the material clamp and the other end on the digital tensiometer 11. The movable mirror 7 is stably placed on the tension track 10. By adjusting the fine adjustment handwheel 6, the mirror 7 can be moved to change the stretching amount of the object to be measured. The sample to be measured has a slight movement driven by the mirror, and the optical path difference of the interferometer will also change accordingly, causing the equal inclination interference fringes to emerge or sink. Whenever the spacing d changes by λ / 2, that is, one fringe emerges or is swallowed, the optical path difference of the coherent light changes by one wavelength λ; when Δk fringes emerge or are swallowed, if the change amount of the corresponding spacing is Δd, then there is:

[0047]

[0048] Since the movement of the movable mirror causes a slight deformation of the item to be measured, the change in the corresponding spacing Δd is equal in magnitude to the elongation ΔL of the item to be measured, that is, Δd = ΔL. Then the calculation formula for the elastic modulus of the sample to be measured is:

[0049]

[0050] The elastic modulus of the item to be measured can be calculated through the above formula.

[0051] In the embodiment of the present application, as Figure 3 shown, the interferometer is preliminarily adjusted. First, adjust the interferometer to make the guide rail approximately horizontal. Turn on the helium-neon laser light source (laser wavelength λ = 632.8 cm), and adjust the fiber head so that the laser can be incident along the vertical direction of the mirror surface of the movable mirror 7. Then adjust the coarse adjustment handwheel 2 to make the distances from the fixed mirror 5 and the movable mirror 7 to the beam splitter 3 approximately equal. Adjust the screws on the back of the fixed mirror 5 and the movable mirror 7 and the two tension spring screws below the movable mirror 7 so that the fixed mirror 5 and the movable mirror 7 are approximately perpendicular. It is required that the screws are not too loose or too tight, so as to leave room for subsequent adjustment to be flexible. Lower the observation screen 1. At this time, looking from the observation screen 1 towards the plane mirror direction, two rows of light spots can be seen, which are the light spot images reflected by the fixed mirror 5 and the movable mirror 7 respectively. There are four light spots in each row, the middle one is brighter, and the two on both sides are darker. Carefully adjust the screws behind the fixed mirror 5 and the movable mirror 7 so that the two brightest points in the two rows of light spots coincide. In this way, the fixed mirror 5 and the movable mirror 7 are basically perpendicular, that is, the images of the fixed mirror 5 and the movable mirror 7 are perpendicular to each other (when adjusting, if the light intensity is too strong and the light spots are too bright, a piece of paper can be placed at the fiber head to appropriately weaken the light intensity). Lift the observation screen 1, and non-localized interference fringes can be seen. At this time, if the center of the circle is not in the center of the observation screen, the fine adjustment screw near the movable mirror 7 can be gently adjusted to move the center of the ring pattern to the center of the screen. If it is not a concentric circle, it may be that the fixed mirror 5 and the movable mirror 7 are not strictly perpendicular. The screws behind the fixed mirror 5 and the movable mirror 7 can be alternately and slowly adjusted until circular ring patterns are seen. If no ring patterns can be observed, it may be because the distances between the fixed mirror 5 and the movable mirror 7 are too large so that the ring patterns are too fine to be seen. At this time, the position of the fixed mirror 5 needs to be readjusted. After the fringes appear, it is also necessary to observe up, down, left, and right to see if there is parallax, and use the horizontal and vertical tension spring screws below the movable mirror 7 to reduce or eliminate the phenomenon of expansion and contraction.

[0052] As Figure 4As shown, after observing the annular fringes, rotate the adjusting handwheel until the reading on the digital tensiometer display 12 reaches F = 0.10 kg (i.e., 1 N), and record the number of fringes Δk1 when the annular fringes "swallow" or "spit out" at this time. Then continue to rotate the adjusting handwheel in the same direction until the reading on the digital tensiometer display 12 reaches F = 0.20 kg (i.e., 2 N), and record the number of fringes Δk2 when the annular fringes "swallow" or "spit out" at this time... Continuously record 10 data. According to the data, obtain the relationship graph between the tensile force ΔF and the number of fringes Δk. It can be seen that the tensile force ΔF and the number of fringes Δk are in a proportional relationship, that is is a fixed value, so the slope of this straight line is the value of. (Note that the instrument readings need to be calibrated before measurement).

[0053] Calculate the ratio After that, use a meter ruler to measure the original length L of the sample to be measured 9, and then use a micrometer to measure the diameter d of the sample to be measured 9. Substitute the above values into the calculation formula of the elastic modulus to calculate the elastic modulus.

[0054] It can be understood that in this application, each device used is a conventional device, and the functions achieved are those that the device itself or the combination of devices can achieve.

[0055] According to the material elastic modulus measurement device based on optical detection technology proposed in the embodiment of the present application, an optical interferometer is composed of a light source, a beam splitter, a fixed mirror, and a movable mirror. The laser is reflected along the vertical direction of the mirror surface of the movable mirror and the mirror surface of the fixed mirror after passing through the beam splitter, and equal-inclination interference fringes are displayed on the observation screen. The movable mirror is adjusted horizontally so that a tensile force is generated on the digital tensiometer after the sample to be measured is stretched, and the number of equal-inclination interference fringes in the interferometer changes. The elastic modulus of the sample to be measured is calculated according to the change in tensile force, the change in the number of equal-inclination interference fringes, the length of the sample to be measured, the diameter of the sample to be measured, and the wavelength of the light source, avoiding direct measurement of the small deformation when the sample to be measured is stretched. The structure of the device for measuring the elastic modulus is easy to operate and observe, the phenomenon is stable, and the result is relatively accurate.

[0056] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0057] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "N" is at least two, such as two, three, etc., unless otherwise specifically defined.

Claims

1. A material elastic modulus measuring device based on optical detection technology, characterized in that: include: Observation screen, adjustment hand wheel, beam splitter, light source, fixed reflector, movable reflector, precision screw, tension track, digital dynamometer, lifting platform; Wherein, one end of the tension rail is fixed on the lifting platform, and the other end is fixed on the precision screw rod; The digital dynamometer is fixed on one end of the traction track close to the lifting platform; One end of the sample to be tested is connected to the digital tensile gauge, and the other end is connected to the movable reflector. The tensile track can be raised and lowered by adjusting the height of the lifting platform, so that the digital tensile gauge and the circular hole in front of the movable reflector are in the same horizontal plane; The precision screw, the movable reflector, the beam splitter and the observation screen are sequentially arranged on the same straight line, and by adjusting the light source, the fixed reflector and the movable reflector, the laser light is reflected along the vertical direction of the movable reflector surface and the fixed reflector surface after passing through the beam splitter, and an equi-inclined interference ring is displayed on the observation screen; The adjusting hand wheel is used to move the movable reflector in the horizontal direction, so that the equal-inclined interference rings surge out or sink in while stretching the sample to be tested, resulting in a series change, so that the elastic modulus of the sample to be tested is calculated according to the change in the tension of the sample to be tested, the series change of the equal-inclined interference rings, the length of the sample to be tested, the diameter of the sample to be tested and the wavelength of the light source.

2. The device according to claim 1, characterized in that The device also includes: A digital tensile gauge display screen is connected to the digital tensile gauge and is used to display the reading of the digital tensile gauge.

3. The device according to claim 1, characterized in that The adjusting hand wheel also includes: A coarse adjustment hand wheel, used to move the movable reflector in the horizontal direction when the moving distance of the movable reflector is greater than a preset moving distance; The fine-tuning hand wheel is used to move the movable reflector in the horizontal direction when the moving distance of the movable reflector is less than or equal to the preset moving distance.

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