Young modulus measuring device

Abstract

The invention provides an experimental device for measuring the Young modulus of a material. The experimental device comprises a supporting flat plate, a supporting column with a knife edge, a to-be-tested piece, a force applying frame with a knife edge, a mechanical sensor, a frame with a coil, a current source, a permanent magnet, a fixing frame, a cantilever beam supporting column, a cantilever beam fixing plate, a four-dimensional adjusting platform, an industrial CCD and a computer. According to the device, the magnitude of current is controlled to enable the coil to generate different Ampere forces to load a test piece, the magnitude of the force is obtained through the mechanical sensor, the industrial CCD obtains images of the force application frame with the knife edge under the different Ampere forces, and the displacement of a force application point of the test piece in the vertical direction is calculated based on a digital image correlation technology; the Young modulus of the material is measured through the relation between the force and deformation of a three-point bending or cantilever beam structure, and the device has the advantages of being simple, high in precision, convenient to adjust and the like.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical parameter measurement, and in particular to a material Young's modulus measurement method and a measurement device. Background Art

[0002] Young's modulus is an important mechanical parameter of materials, and the key to its measurement lies in accurately measuring the relationship between stress and strain. Common measurement methods include weight loading, motor-controlled beam movement loading, and electric cylinder telescopic movement loading. Strain measurement methods include optical levers, interferometry, extensometers, strain gauges, etc. These methods are complex, occupy large space, and are costly, which have certain shortcomings in daily teaching. Summary of the invention

[0003] In view of this, the purpose of the present invention is to provide a material Young's modulus measuring device with a simple structure and high precision, taking the Ampere force received by the coil in the magnetic field as the stress, using digital image correlation technology to calculate the downward movement distance of the force-applying frame with a knife edge, and calculating the Young's modulus of the material through two stress states of three-point bending or cantilever beam, which has simple operation and high measurement accuracy.

[0004] The invention provides an experimental device for measuring the Young's modulus of a material, comprising: a supporting plate, a supporting column with a knife edge, a test piece, a force-applying frame with a knife edge, a mechanical sensor, a frame with a coil, a current source, a permanent magnet and a fixing frame, a cantilever beam supporting column, a cantilever beam fixing plate, a four-dimensional adjustment platform, an industrial CCD and a computer; the supporting plate is used for fixing the supporting column with a knife edge, the permanent magnet fixing frame, the four-dimensional adjustment platform and the cantilever beam supporting column; the force-applying frame with a knife edge in the device is located in the middle of two supporting columns with a knife edge, so that the test piece forms a three-point bending stress state or is located at a non-clamping part of a cantilever beam structure to form a cantilever beam stress state; the frame with a coil is located between two permanent magnets, and the current source controls the coil current so that the coil is stressed in a vertical direction; the upper end of the mechanical sensor is connected to the force-applying frame with a knife edge, and the lower end is adjacent to the frame with a coil, so as to display the magnitude of the force applied by the force-applying frame with a knife edge; the industrial CCD is installed on the four-dimensional adjustment platform, and an image of the force-applying frame with a knife edge is collected through a computer connected to the industrial CCD.

[0005] Specifically, a plurality of turns of coils are wound around the lower end of the coil frame, the lower end coil is placed between two permanent magnets, and the upper end coil is located outside the magnetic field formed by the two permanent magnets.

[0006] Specifically, the digital image correlation technology is used to process the image of the blade force applying frame to calculate the downward movement distance of the blade force applying frame under different loading forces.

[0007] Specifically, the force applied by the force-applying frame with a knife edge and the downward movement distance thereof are combined with the stress state to calculate the Young's modulus of the material.

[0008] Specifically, the materials to be measured include, but are not limited to, metal materials, polymer materials, ceramic materials and composite materials.

[0009] It can be seen from the above description of the present invention that, compared with the existing method, the present invention has the following beneficial effects:

[0010] (1) The device provided by the present invention adopts a three-point bending or cantilever beam structure, uses the Ampere force exerted on the coil in the magnetic field as the loading force, calculates the displacement of the force application point based on the image processing of the knife-edge force application frame with digital image correlation technology, obtains the relationship between the material force and deformation, and thus obtains the Young's modulus of the material. It has a simple structure, low cost, and high measurement accuracy.

[0011] (2) The device provided by the present invention has the advantages of being controllable, easy to adjust, stable and continuous in the Ampere force controlled by the current source, which can avoid external deflection caused by weight loading and reduce the discreteness of the data;

[0012] (3) The device provided by the present invention adopts a non-contact optical deformation measurement method to avoid the additional deformation introduced by contact measurement, and has the advantage of high measurement accuracy;

[0013] (4) The device provided by the present invention integrates force, electricity, light and magnetism, and can better meet the needs of scientific research and teaching practice.

[0014] In order to make the objects, features and advantages of the present invention more clearly understood, preferred embodiments are given below with reference to the accompanying drawings for detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A device for measuring Young's modulus is provided in Embodiment 1 of the present invention.

[0016] Figure 2 A device for measuring Young's modulus provided in the second embodiment of the present invention.

[0017] Among them: 1 supporting plate; 2 supporting column with knife edge; 3 test piece; 4 force application frame with knife edge; 5 mechanical sensor; 6 frame with coil; 7 current source; 8 permanent magnet and fixing frame; 9 cantilever beam supporting column; 10 cantilever beam fixing plate; 11 four-dimensional adjustment platform; 12 industrial CCD; 13 computer. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] Embodiment 1:

[0020] like Figure 1 The Young's modulus measuring device of the material involved in the three-point bending mechanical state in this embodiment includes: a supporting plate 1, a support column with a knife edge 2, a test piece 3, a force-applying frame with a knife edge 4, a mechanical sensor 5, a frame with a coil 6, a current source 7, a permanent magnet and a fixing frame 8, a four-dimensional adjustment platform 11, an industrial CCD 12 and a computer 13; the supporting plate 1 is used to fix the support column with a knife edge 2, the permanent magnet fixing frame 8, and the four-dimensional adjustment platform 11; the force-applying frame with a knife edge 4 in the device is located in the middle of the two support columns with a knife edge 2, so that the test piece forms a three-point bending stress state; the frame with a coil 6 is located between the two permanent magnets, and the current source 7 controls the coil current so that the coil is stressed in the vertical direction; the upper end of the mechanical sensor 5 is connected to the force-applying frame with a knife edge 4, and the lower end is adjacent to the frame with a coil 6, so as to display the magnitude of the force applied by the force-applying frame with a knife edge; the industrial CCD 12 is installed on the four-dimensional adjustment platform 11, and the image of the force-applying frame with a knife edge is collected through the computer 13 connected thereto.

[0021] Specifically, a plurality of turns of coil are wound around the lower end of the coil frame 6 , the lower end coil is placed between two permanent magnets, and the upper end coil is located outside the magnetic field formed by the two permanent magnets.

[0022] The method for using the Young's modulus measuring device provided in the embodiment of the present invention is now described as follows:

[0023] 1) Measure the initial axial length l0, width b, thickness h, and the distance l between the two support columns with knife edges of the specimen, where l0 should be between 1.2 and 1.5l;

[0024] 2) Place the material to be tested on the measuring device to form a three-point bending force form. The force-applying frame 4 with a knife edge should be located in the middle of the two support columns 2 with a knife edge. The force-applying frame 4 with a knife edge, the mechanical sensor 5 and the frame 6 with a coil should all be in a vertical downward force state;

[0025] 3) Adjust the four-dimensional adjustment platform so that the industrial CCD can capture a clear image of the frame with the knife edge force;

[0026] 4) Adjust the current of the current source, apply different forces, and collect force values ​​and force-applying frame images with knife edges under different current loadings;

[0027] 5) Based on the digital image correlation method (DIC) program, the image of the force frame with the blade is processed to calculate different loading forces F i The lower blade force application frame 4 moves downward by a distance V i ;

[0028] 6) With the loading force F i The blade force frame 4 moves downward by a distance V i It may deviate from the linear increase state, when the material enters the plastic deformation state, so the effective data point should be the loading force F i The increase in the amount of force applied by the blade 4 is related to the downward movement distance V i The increase is within the linear range;

[0029] 7) Measure at least 5 sets of data and calculate the loading force F based on the difference method i The increase ΔF and the downward movement distance V of the blade force application frame 4 i Increase ΔV;

[0030] 8) The width b, thickness h, and distance l between the two blade support columns of the specimen are used to calculate the loading force F based on the difference method. i The increase ΔF and the downward movement distance V of the blade force application frame 4 i Substitute the increase ΔV into the following formula to calculate the Young's modulus E of the material.

[0031]

[0032] Embodiment 2:

[0033] like Figure 2 The difference between the device of this embodiment and the first embodiment is that the Young's modulus of the material is measured in a cantilever beam stress state, including: a support plate 1, a cantilever beam support column 9, a cantilever beam fixing plate 10, a test piece 3, a knife-edge force frame 4, a mechanical sensor 5, a coil frame 6, a current source 7, a permanent magnet and a fixing frame 8, a four-dimensional adjustment platform 11, an industrial CCD 12 and a computer 13; the support plate 1 is used to fix the knife-edge support column 2, the permanent magnet fixing frame 8, and the four-dimensional adjustment platform 11; the knife-edge force frame 4 in the device is located at a certain position on the right side of the cantilever beam support column fixing part, so that the test piece forms a cantilever beam stress state; the coil frame 6 is located between two permanent magnets, and the current source 7 controls the coil current so that the coil is stressed in the vertical direction; the upper end of the mechanical sensor 5 is connected to the knife-edge force frame 4, and the lower end is adjacent to the coil frame 6, which displays the magnitude of the force applied by the knife-edge force frame; the industrial CCD 12 is installed on the four-dimensional adjustment platform 11, and the image of the force-applying frame with a knife edge is collected through a computer 13 connected thereto.

[0034] Specifically, a plurality of turns of coil are wound around the lower end of the coil frame 6 , the lower end coil is placed between two permanent magnets, and the upper end coil is located outside the magnetic field formed by the two permanent magnets.

[0035] The method for using the Young's modulus measuring device provided in the embodiment of the present invention is now described as follows:

[0036] 1) Measure the initial axial length l0, width b, and thickness h of the specimen. The initial axial length l0 of the specimen should ensure sufficient clamping length and the length from the blade of the blade force frame to the rightmost end of the specimen should not be less than 0.1l0 to prevent the blade from slipping;

[0037] 2) Place the material to be tested on the measuring device to form a cantilever beam force form. The force application frame 4 with a knife edge, the mechanical sensor 5 and the frame 6 with a coil should all be in a vertical downward force state;

[0038] 3) Measure the shortest distance l from the blade of the blade force application frame to the clamping position of the cantilever beam;

[0039] 4) Adjust the four-dimensional adjustment platform so that the industrial CCD can capture a clear image of the frame with the blade force;

[0040] 5) Adjust the current source current, apply different forces, and collect force values ​​and force-applying frame images with knife edges under different current loadings;

[0041] 6) Based on the program of digital image correlation technology, the image of the force frame with the knife edge is processed to calculate different loading forces F i The lower blade force application frame 4 moves downward by a distance V i ;

[0042] 7) With the loading force F i The blade force frame 4 moves downward by a distance V i It may deviate from the linear increase state, when the material enters the plastic deformation state, so the effective data point should be the loading force F i The increase in the amount of force applied by the blade 4 is related to the downward movement distance V i The increase is within the linear range;

[0043] 8) Measure at least 5 sets of data and calculate the loading force F based on the difference method i The increase ΔF and the downward movement distance V of the blade force application frame 4 i Increase ΔV;

[0044] 9) The width b, thickness h, and the shortest distance l from the blade of the force-applying frame with a blade to the clamping position of the cantilever beam are used to calculate the loading force F based on the difference method. i The increase ΔF and the downward movement distance V of the blade force application frame 4 i Substitute the increase ΔV into the following formula to calculate the Young's modulus E of the material.

[0045]

[0046] In the description of the above embodiments of the invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the terms in the present invention can be understood according to specific circumstances.

[0047] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0048] Finally, it should be noted that the above-described embodiments are only specific implementations of the present invention, which are used to illustrate the technical solutions of the present invention, rather than to limit them. The protection scope of the present invention is not limited thereto. Although the present invention is described in detail with reference to the above-described embodiments, ordinary technicians in the field should understand that any technician familiar with the technical field can still modify the technical solutions recorded in the above-described embodiments within the technical scope disclosed by the present invention, or can easily think of changes, or make equivalent replacements for some of the technical features therein; and these modifications, changes or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A Young's modulus measuring device, characterized in that: include: Support plate, support column with knife edge, test piece, force application frame with knife edge, mechanical sensor, frame with coil, current source, permanent magnet and fixing frame, cantilever beam support column, cantilever beam fixing plate, four-dimensional adjustment platform, industrial CCD and computer; The support plate is used to fix the support column with a knife edge, the permanent magnet fixing frame, the four-dimensional adjustment platform and the cantilever beam support column; The force-applying frame with a knife edge in the device is located in the middle of two support columns with knife edges, so that the test piece forms a three-point bending stress state or is located in a non-clamping part of the cantilever beam structure to form a cantilever beam stress state; The frame with coils is located between two permanent magnets, and the current source controls the current of the coils so that the coils are subjected to force in the vertical direction; The upper end of the mechanical sensor is connected to the blade force application frame, and the lower end is adjacent to the coil frame, and displays the magnitude of the force applied by the blade force application frame; The industrial CCD is installed on a four-dimensional adjustment platform, and the image of the force-applying frame with a knife edge is collected through a computer connected thereto.

2. The device according to claim 1, characterized in that The measurement steps include: 1) Measure the initial axial length, width, thickness, the distance between the two blade support columns, and the shortest distance from the blade of the blade force application frame to the cantilever beam clamping position of the specimen; 2) Place the material to be tested on the measuring device to form a three-point bending or cantilever beam stress form; 3) Adjust the four-dimensional adjustment platform so that the industrial CCD can capture a clear image of the frame with the knife edge force; 4) Adjust the current of the current source, apply different forces, and collect force values ​​and force-applying frame images with knife edges under different current loadings; 5) Using digital image correlation technology to process the image of the force-applying frame with a knife edge and calculate the downward movement distance of the force-applying frame with a knife edge under different loading forces; 6) The force applied by the force-applying frame with a knife edge and its downward movement distance are combined with the stress state to calculate the Young's modulus of the material.

3. The device according to claim 2, characterized in that The lower end of the coil frame is wound with a plurality of turns of coil, the lower end coil is placed between two permanent magnets, and the upper end coil is located outside the magnetic field formed by the two permanent magnets.

4. The device according to claim 2, characterized in that The materials to be measured include, but are not limited to, metal materials, polymer materials, ceramic materials and composite materials.

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