CN114527196A - Fractal structure input solitary wave metamaterial nondestructive testing device and application - Google Patents

Abstract

The invention discloses a fractal structure input solitary wave metamaterial nondestructive testing device and application thereof, wherein the device comprises a fractal bending cavity track, a vertical cavity track, discrete particle groups, impact particles and signal acquisition particles; the fractal bending cavity track consists of a plurality of sub bending cavity tracks and a plurality of mother bending cavity tracks, the bottoms of the plurality of mother bending cavity tracks are communicated with the top of the vertical cavity track, and the top of each mother bending cavity track is communicated with the bottoms of the plurality of sub bending cavity tracks; two openings are oppositely formed in the lower portion of the vertical cavity track, the track wall of each secondary bent cavity track and the track wall of each primary bent cavity track; all pack in crooked cavity track and the vertical cavity track and have scattered solid particle group, the orbital bottom of vertical cavity is equipped with the signal acquisition granule, is equipped with the piezoelectric patches in the signal acquisition granule, and the piezoelectric patches passes through wire and trompil and external circuit connection, and the orbital top trompil of every sub-crooked cavity is used for assaulting the granule and freely gets into.

Description

A fractal structure input solitary wave metamaterial nondestructive testing device and its application

technical field

The invention relates to the technical field of artificial elastic wave metamaterials, in particular to a nondestructive testing device for solitary wave metamaterials with fractal structure input.

Background technique

In recent years, phononic crystals have aroused extensive interest of scholars in many fields. They are artificial periodic structures whose material constants change periodically. Granular phononic crystals and elastic wave metamaterials are one of the most studied forms. The elastic particles in contact with each other in particle-phononic crystals satisfy the Hertzian contact law, and the nonlinearity mainly comes from the contact deformation between adjacent particles. The nonlinear wave propagation of granular phononic crystals exhibits rich wave properties and exhibits broad application prospects. Among them, a highly nonlinear solitary wave can be formed in the one-dimensional particle chain composed of the same particles, which can maintain stable propagation in a long distance, and the reflection and transmission of the wave are related to the properties of the materials in contact. It is these special propagation characteristics that make one-dimensional particle chains a good carrier for highly nonlinear solitary waves. With the development of non-destructive testing technology and the improvement of non-destructive testing instruments, people have higher requirements for non-destructive testing technology, etc., so that the one-dimensional particle chain solitary wave non-destructive testing method has received extensive attention. The solitary wave flaw detection based on particle chains has the advantages of small size and high portability. Such solitary wave metamaterials can be used in many engineering applications, including vibration absorbers, impurity detectors, acoustic diodes, and nondestructive testing.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies in the prior art, and to provide a solitary wave metamaterial nondestructive testing device with fractal structure input. By adopting the structure form of fractal multi-curved cavity track propagation, the present invention can excite nonlinear solitary wave signals at multiple positions, and realize multiple non-destructive testing of the same substance to be tested. The effect of multiple nonlinear solitary wave signals for non-destructive testing of the same substance under test is achieved by the convergence of multiple curved cavity tracks with the same vertical track characteristics, the purpose of multi-nonlinear solitary wave signal detection is achieved, and the non-destructive testing of the substance to be tested is improved. The efficiency and accuracy of detection are of great significance to the study of nonlinear solitary wave propagation characteristics.

The purpose of this invention is to realize through the following technical solutions:

A fractal structure input solitary wave metamaterial nondestructive testing device, including fractal curved cavity orbit, vertical cavity orbit, scattered particle group, impact particle, signal acquisition particle; the fractal curved cavity orbit and vertical cavity The body rails are all tubular structures composed of white resin; the fractal curved cavity rails are composed of several sub-curved cavity rails and several parent curved cavity rails, and the bottoms of the several parent curved cavity rails are in common with the vertical. The tops of the straight cavity rails are connected, and the top of each parent curved cavity rail is connected with the bottoms of several sub curved cavity rails; the inner parts of the sub curved cavity rails, the parent curved cavity rails and the vertical cavity rails are mutually connected. Connected; two openings are oppositely arranged on the lower part of the vertical cavity track, each sub-bending cavity track and the track wall of each parent bending cavity track; the curved cavity track and the vertical cavity track The inside is filled with scattered particle groups, the bottom of the vertical cavity track is provided with signal acquisition particles, and the signal acquisition particles are provided with piezoelectric sheets. The piezoelectric sheets are connected to the external circuit through wires and openings. The top opening of the sub-bending cavity track is used for free entry of impact particles.

Further, the elastic modulus of the fractal curved cavity track and the vertical cavity track is E=2.65GPa, the Poisson's ratio ν is 0.41, and the density ρ is 0.5kg/m ³ .

Further, the dispersed particle group is composed of several Q235 stainless steel particle balls with a diameter of 19 mm, and the material and size of the impact particles are the same as the particle balls in the dispersed particle group.

Further, the signal acquisition particle is composed of a disc-shaped piezoelectric sheet and two hemispherical particles. The disc-shaped piezoelectric sheet is made of DM-5H, with a diameter of 19 mm and a thickness of 0.3 mm. The diameter of the two hemispherical particles is 18.7 mm. mm of Q235 stainless steel; polyimide films are pasted on the butt surfaces of the two hemispherical particles, and the piezoelectric sheet is pasted between the polyimide films.

Further, the outer diameter of the fractal curved cavity track and the vertical cavity track is 21 mm, and the inner diameter is 19 mm.

Further, the diameter of the opening is smaller than the outer diameter of each particle sphere in the dispersed particle group.

Further, there are altogether three parent curved cavity orbits and nine sub curved cavity orbits in the fractal curved cavity orbits.

The invention also provides an application of a solitary wave metamaterial nondestructive testing device inputted by a fractal structure, which is used to excite nonlinear solitary wave signals at several positions to realize several nondestructive testing of the same tested substance.

Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

1. The device of the present invention achieves the effect of non-destructive testing of the same substance under test by multiple nonlinear solitary wave signals by converging the same vertical track characteristics of several curved cavity tracks, thus achieving the purpose of detecting multiple nonlinear solitary wave signals and improving The efficiency and accuracy of non-destructive testing of the substance to be tested are analyzed.

2. Since there are multiple propagation tracks in the device of the present invention, under the excitation of multiple nonlinear solitary wave signals, the device can realize the effect of detecting the same substance to be tested by multiple signals. Compared with the previous elastic wave metamaterial device, it has the advantage of multi-signal detection, and can be used in situations where multiple non-destructive testing of the same substance to be tested is required.

3. Different from the conventional nonlinear solitary wave signal detection device, the present invention utilizes a multi-track structure, so that multiple detections of the same tested substance can be realized under multiple excited nonlinear solitary wave signals.

4. Due to the large number of input signal tracks in the present invention, if one of the input signals fails, detection can also be performed, thus enhancing the anti-interference ability of the detection device.

5. When multiple signals are excited at the same time, the disadvantage of weak signal in the case of a single input can be avoided, so that the strength of the detection signal aggregated by the device is significantly enhanced, so the strength of the detection signal can be greatly improved, and it is more suitable for small and medium-sized defects to be detected. Outstanding discernment.

6. The non-destructive testing device for non-linear solitary wave signals of the present invention is simple in structure, flexible in size, convenient in installation, and applicable to various environments.

Description of drawings

FIG. 1 is a schematic structural diagram of a metamaterial device according to an embodiment of the present invention.

FIG. 2 is a schematic top-view structural diagram of an apparatus provided by an embodiment of the present invention.

FIG. 3 is a half cross-sectional view of one of the channels of the device containing bulk particles according to an embodiment of the present invention.

FIG. 4 is a schematic diagram of the dispersion of multiple tracks of a device provided by an embodiment of the present invention.

FIG. 5 is a schematic structural diagram of a signal collection particle provided by an embodiment of the present invention

FIG. 6 is a schematic diagram of a homogeneous particle chain composed of a dispersed particle group provided in an embodiment of the present invention.

FIG. 7 is a signal response diagram recorded by the signal collecting particles at the bottom of the vertical cavity track 1 during the experiment when the impact particle of 0.313 m/s is excited at the top of the sub-curved cavity track 5 according to the embodiment of the present invention.

FIG. 8 is a signal response diagram recorded by the signal collecting particles at the bottom of the vertical cavity track 1 during the experiment when the impact particles of 0.313 m/s are excited at the top of the sub-curved cavity track 6 according to the embodiment of the present invention.

FIG. 9 is a signal response diagram recorded by the signal collecting particles at the bottom of the vertical cavity track 1 during the experiment when the impact particles of 0.313 m/s are excited at the top of the sub-curved cavity track 7 according to the embodiment of the present invention.

FIG. 10 is a signal response diagram recorded by the signal collecting particles at the bottom of the vertical cavity track 1 during the experiment when the impact particles of 0.313 m/s are excited at the top of the sub-curved cavity track 8 according to the embodiment of the present invention.

11 is a signal response diagram recorded by the signal collecting particles at the bottom of the vertical cavity track 1 during the experiment when the impact particle of 0.313 m/s is excited at the top of the sub-curved cavity track 9 according to the embodiment of the present invention.

FIG. 12 is a signal response diagram recorded by the signal collecting particles at the bottom of the vertical cavity track 1 during the experiment when the impact particle of 0.313 m/s is excited at the top of the sub-curved cavity track 10 according to the embodiment of the present invention.

13 is a signal response diagram recorded by the signal collecting particles at the bottom of the vertical cavity track 1 during the experiment when the impact particles of 0.313 m/s are excited at the top of the sub-curved cavity track 11 according to the embodiment of the present invention.

14 is a signal response diagram recorded by a signal collecting particle at the bottom of the vertical cavity track 1 during the experiment when the impact particle of 0.313 m/s is excited at the top of the sub-curved cavity track 12 according to the embodiment of the present invention.

FIG. 15 is a signal response diagram recorded by the signal collecting particles at the bottom of the vertical cavity track 1 during the experiment when the impact particles of 0.313 m/s are excited at the top of the sub-curved cavity track 13 according to the embodiment of the present invention.

Detailed ways

Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but not to be construed as a limitation of the present invention.

As shown in FIG. 1 to FIG. 5 , an embodiment of the present invention provides a nondestructive testing device for solitary wave metamaterials with fractal structure input, including a fractal curved cavity track, a vertical cavity track 1, a group of scattered particles, and an impact particle , signal acquisition particles; both the fractal curved cavity track and the vertical cavity track are cylindrical structures composed of white resin; in this embodiment, the fractal curved cavity track consists of nine sub-curved cavity tracks 5, 6, 7, 8, 9, 10, 11, 12, 13 and three female curved cavity rails 2, 3, and 4. The bottoms of the female curved cavity rails 2, 3, and 4 are in communication with the top of the vertical cavity rail 1. , the top of the parent bending cavity track 2 is communicated with the bottom of the child bending cavity tracks 10, 12 and 13; the top of the parent bending cavity track 3 is communicated with the bottom of the child bending cavity tracks 7, 9 and 11; The top of the curved cavity track 4 is communicated with the bottom of the sub-curved cavity tracks 5, 6, and 8; each sub-curved cavity track and each parent curved cavity track are communicated with the interior of the vertical cavity track 1; The lower part of the straight cavity rail 1, the rail walls of each sub-curved cavity rail and each parent curved cavity rail are oppositely provided with two narrow and elongated openings; the curved cavity rail and the vertical cavity rail The inside is filled with scattered particle groups, the bottom of the vertical cavity track is provided with signal acquisition particles, the signal acquisition particles are provided with piezoelectric sheets, and the piezoelectric sheets are connected to the external circuit through wires and openings, and each sub-bend cavity is The top opening of the track allows free entry of impact particles.

The embodiment of the present invention proposes a nondestructive testing device for solitary wave metamaterial input with fractal structure. Since nonlinear solitary wave signals can be stably propagated in homogeneous small spherical particles, multiple nonlinear solitary wave signals can be detected on the same measured object. The effect of non-destructive testing of substances. The invention provides a through track structure so that the elastic wave metamaterial achieves the effect of multi-track propagation of multiple excitation signals.

The solution adopted by the solitary wave metamaterial nondestructive testing device inputted by the fractal structure in the embodiment of the present invention is: in the sub-curved cavity tracks 5, 6, 7, 8, 9, 10, 11, 12, 13 of the nondestructive testing device Shock pellets with a height of 5 mm are respectively released above the top, and instantaneous shock excitation is applied, and the signal collection particles at the bottom of the vertical cavity track 1 receive and detect the excitation signal. Test the response signal of the same receiver under the impact of the same impact velocity excited by the ball at multiple locations, to achieve the purpose of multiple non-destructive testing of the same substance to be tested, and improve the efficiency and accuracy of non-destructive testing of the substance to be tested. .

In this embodiment, the bottom of the vertical cavity track 1 is not closed. When the object to be measured is detected, the signal collecting particles are brought into contact with the surface of the object to be measured. Particle detection of nonlinear solitary wave signals by signal acquisition at the bottom of the volume track.

In the embodiment of the present invention, the fractal curved cavity track and the vertical cavity track are both cylindrical structures composed of white resin, the elastic modulus is E=2.65GPa, the Poisson’s ratio ν is 0.41, and the density ρ is 0.5kg/ m ³ , FIG. 2 is a schematic top view of the structure of the device according to the present embodiment, the outer diameter of each sub-bending cavity track, parent bending cavity track and vertical track cavity is 21 mm, and the inner diameter is 19 mm.

FIG. 3 is a half cross-sectional view of one of the channels of the device containing bulk particles according to an embodiment of the present invention. The device is equipped with Q235 stainless steel particles with a diameter of 19mm; many stainless steel particles form a dispersed particle group.

FIG. 4 is a schematic diagram of a dispersed state of a plurality of tracks in a device provided by an embodiment of the present invention. Each section of curved cavity track and vertical cavity track has two narrow and elongated openings symmetrically along the length of the track. The width of the openings is 10mm, which is convenient to lead out the wire and adjust the particle ball .

As shown in Figure 5, the signal acquisition particle consists of a circular piezoelectric sheet and two hemispherical particles. The piezoelectric sheet is 19 mm in diameter and 3 mm in thickness, embedded between the two hemispheres, and a polyimide film is used to isolate the piezoelectric sheet from the hemispherical particles. The diameter of the hemispherical particles is 18.7mm, and the material is Q235 stainless steel. The hemispherical particles, the polyimide film and the piezoelectric sheet are all connected to each other by sticking, and a groove is provided on the butting surface of one of the hemispherical particles in each signal collecting particle for accommodating wires.

FIG. 6 is a schematic diagram of a homogeneous particle chain composed of a static pre-pressed dispersed particle group provided in an embodiment of the present invention, which is a typical one-dimensional homogeneous spherical particle chain composed of the same solid particle spheres. The material of the particle ball is Q235 stainless steel ball. The deformation process of the contact area between two adjacent particle spheres satisfies Hertz's contact law:

F=kδ ^3/2

In the formula, F represents the dynamic contact force, k represents the contact stiffness between particles, and δ represents the displacement difference between the spherical centers of two adjacent particles.

Among them, the contact stiffness k is related to the elastic modulus and geometric parameters of the particles, and its expression is:

In the formula, E represents the elastic modulus of the particle, υ represents the Poisson's ratio of the moving particle, and R represents the radius of the particle.

When there is no external impact load, the motion equation of the nth pellet can be described as:

In the formula, m represents the mass of the pellet; u _n represents the displacement of the nth pellet relative to the initial position.

The working principle of the solitary wave metamaterial nondestructive testing device input by the fractal structure involved in the above embodiment is as follows:

The discrete particle model is a commonly used numerical model of particle dynamics and is widely used in the study of the mechanical behavior of granular materials. In dynamic analysis, particles can be simplified as mass points, and nonlinear spring connections are used between particles. Analyze the wave behavior of granular materials by calculating the equation of motion for particle-particle interactions. When the impact particle hits the particle chain and introduces energy, an incident nonlinear solitary wave propagating at a stable speed can be formed. The nonlinear solitary wave signal recorded by the signal acquisition particle is the center of the piezoelectric sheet deformation force is generated.

Figure 7 is a graph of the transient excitation signal for particle detection in the signal collection at the bottom of the vertical cavity track 1. The impact particle ball with a height of 5mm is released at the top of the sub-curved cavity track 5 of the device, and an instantaneous impact excitation is applied to the particle chain. A nonlinear solitary wave signal is generated, and the nonlinear solitary wave signal propagating in the system is detected at the vertical cavity track 1, and the time to arrive at the signal acquisition particle is about 0.97ms. In the above model, when the impact particle is the same size as the particle material in the particle chain, the impact particle hits the particle chain and introduces an incident nonlinear solitary wave, and the propagation velocity v of the incident nonlinear solitary wave can be expressed as:

v=(16/25) ^1/5 (2R)(0.682Vk ² /m ² ) ^1/5

≈1.694R(Vk ² /m ² ) ^1/5

where v represents the incident velocity of the nonlinear solitary wave, and V represents the impact velocity of the impact particle.

Figures 8 to 15 are respectively the nonlinear isolation propagating in the system for particle detection by signal acquisition at the bottom of vertical cavity track 1 when the impact particle ball with a height of 5 mm is released at the top of the sub-curved cavity track 6 to 13 of the device. Wave signal response graph. The impact particle ball exerts instantaneous impact excitation on the particle chain to generate nonlinear solitary wave signal. At the same impact velocity, the nonlinear solitary wave signal propagating in the vertical cavity orbit 1 detection system, at this time, reaches each point of the nonlinear solitary wave signal. The time is about 0.97ms.

To sum up, compared with the conventional nonlinear solitary wave signal detection device, the present invention adopts multiple orbits to excite the propagation of nonlinear solitary waves in the particle ball chain, and adopts the structure of multiple fractal and multi-curved orbits to propagate. In this way, the nonlinear solitary wave signal can be excited at multiple positions, so as to achieve the purpose of multiple non-destructive testing of the same substance to be tested and enhance the detection of the solitary wave signal, and improve the efficiency and accuracy of non-destructive testing of the substance to be tested. sex.

The device of the present invention only tests a certain transient impact excitation, but by adjusting the impact particle ball, the nonlinear solitary wave detection generated by impact particles with different initial velocities can be realized.

The whole of the device is composed of white resin through 3D printing. The device has a simple structure design, is easy to purchase and assemble, and is very easy to operate after the design is completed.

Those of ordinary skill in the art can understand that the accompanying drawing is only a schematic diagram of an embodiment, and the modules or processes in the accompanying drawing are not necessarily necessary to implement the present invention.

The apparatus and system embodiments described above are only illustrative, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, It can be located in one place, or it can be distributed over multiple network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution in this embodiment. Those of ordinary skill in the art can understand and implement it without creative effort.

It will be understood by those skilled in the art that the singular forms "a", "an", "the" and "the" as used herein can include the plural forms as well, unless expressly stated otherwise. It should be further understood that the word "comprising" used in the description of the present invention refers to the presence of stated features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features, Integers, steps, operations, elements, components and/or groups thereof. It will be understood that when we refer to an element as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Furthermore, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Claims (8)

1. A fractal structure input solitary wave metamaterial nondestructive testing device is characterized by comprising a fractal bending cavity track, a vertical cavity track, discrete particle groups, impact particles and signal acquisition particles; the fractal bending cavity track and the vertical cavity track are both of circular tube-shaped structures consisting of white resin; the fractal bending cavity track consists of a plurality of sub bending cavity tracks and a plurality of mother bending cavity tracks, the bottoms of the plurality of mother bending cavity tracks are communicated with the top of the vertical cavity track, and the top of each mother bending cavity track is communicated with the bottoms of the plurality of sub bending cavity tracks; the interiors of the secondary bent cavity track, the primary bent cavity track and the vertical cavity track are communicated with each other; two openings are oppositely formed in the lower portion of the vertical cavity track, the track wall of each secondary bent cavity track and the track wall of each primary bent cavity track; bulk particle groups are filled in the bending cavity track and the vertical cavity track, signal acquisition particles are arranged at the bottom of the vertical cavity track, piezoelectric patches are arranged in the signal acquisition particles and are connected with an external circuit through leads and openings, and the openings at the top of each sub-bending cavity track are used for allowing impact particles to freely enter.

2. The fractal-structure-input solitary wave metamaterial nondestructive testing device as claimed in claim 1, wherein the fractal bending cavity rail and the vertical cavity rail have elastic modulus of E-2.65 GPa, poisson ratio v of 0.41, and density p of 0.5kg/m³。

3. The solitary wave metamaterial nondestructive testing device as claimed in claim 1, wherein the discrete particle group is composed of a plurality of Q235 stainless steel particle balls with a diameter of 19mm, and the impact particles are the same in material and size as the particle balls in the discrete particle group.

4. The solitary wave metamaterial nondestructive testing device with fractal structure input as claimed in claim 1 wherein the signal collection particles are composed of a disc-shaped piezoelectric plate and two hemispherical particles, the disc-shaped piezoelectric plate is DM-5H, the diameter is 19mm, the thickness is 0.3mm, and the two hemispherical particles are both Q235 stainless steel with the diameter of 18.7 mm; polyimide films are pasted on the butt joint surfaces of the two hemispherical particles, and the piezoelectric sheets are pasted between the polyimide films.

5. The fractal-structure-input soliton wave metamaterial nondestructive testing device as claimed in claim 1 or 2, wherein the fractal bending cavity track and the vertical cavity track have an outer diameter of 21mm and an inner diameter of 19 mm.

6. The fractal-structure-input soliton metamaterial nondestructive testing device as claimed in claim 1, wherein the diameter of the opening is smaller than the outer diameter of each particle sphere in the discrete particle group.

7. The fractal-structure-input solitary wave metamaterial nondestructive testing device as claimed in claim 1, wherein the fractal bending cavity rails comprise three mother bending cavity rails and nine daughter bending cavity rails.

8. The application of the fractal structure input solitary wave metamaterial nondestructive testing device is characterized by being used for exciting nonlinear solitary wave signals at a plurality of positions to realize nondestructive testing on the same tested substance for a plurality of times.

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