Flexible connection mechanism and method for inhibiting attenuation of acoustic emission signals in in-situ scratches

Abstract

The invention discloses a flexible connection mechanism and method for inhibiting attenuation of acoustic emission signals in in-situ scratches. The flexible connecting mechanism is composed of a counterbore, an acoustic emission signal detection surface, a flexible beam, an acoustic emission sensor assembly connecting hole and a pressure head mounting hole, and is used for integrally fixing an acoustic emission sensor assembly and a pressure head at the loading output end of the scratch tester. The method for inhibiting the attenuation of the acoustic emission signal in the in-situ scratch comprises the following steps: mounting an acoustic emission sensor assembly and a pressure head on a flexible connecting mechanism, and ensuring that a sensor detection surface is tightly attached to an acoustic emission signal detection surface of the flexible connecting mechanism; the testing pressure head is mounted at the bottom of the connecting part; the flexible connection mechanism integrating the acoustic emission sensor and the pressure head is fixed to the loading output end of the scratch tester, and attenuation of acoustic emission signals is inhibited by means of microscopic deformation of the flexible connection mechanism. According to the method adopted by the invention, the attenuation of the acoustic emission signal in the transmission process is effectively reduced, and the capability of capturing a weak signal is improved.

Description

Technical Field

[0001] The present invention belongs to the field of acoustic emission signal detection, and particularly relates to a flexible connection mechanism and method for suppressing the attenuation of acoustic emission signals in in-situ scratching. Background Art

[0002] As an important non-destructive testing method, acoustic emission detection technology has been widely used in the evaluation of the bonding strength between coating materials and substrate materials and the real-time monitoring of failure behaviors in in-situ scratching tests. This technology captures the stress wave signals released by the test material under the action of the indenter load due to micro-damage mechanisms such as plastic deformation, crack initiation and propagation, and coating fragmentation through acoustic emission sensors, and can realize the dynamic characterization and quantitative analysis of the material failure process, which makes acoustic emission technology an important means for evaluating the interface performance of coatings.

[0003] However, the acoustic emission signal detection system in the existing scratching test technology still has significant technical defects, mainly manifested in the serious signal attenuation. In the scratching tester with a traditional rigid structure, during the process of the acoustic emission signal transmitting from the material surface to the sensor detection surface, due to factors such as acoustic impedance mismatch and structural damping, the stress wave signal undergoes rapid attenuation, seriously affecting the accurate evaluation of material properties.

[0004] With the wide application of new coating materials in fields such as aerospace and new energy, higher requirements are put forward for the detection accuracy of scratching tests. Especially when evaluating advanced materials such as functional coatings and nano-composite coatings, the traditional detection methods are difficult to meet the monitoring requirements of micron-scale damage. Therefore, developing a new signal transmission mechanism to effectively suppress the energy attenuation of acoustic emission signals during propagation has important engineering application value for improving the signal detection intensity and realizing the accurate evaluation of material properties. Summary of the Invention

[0005] In order to solve the problems existing in the background art, the present invention proposes a flexible connection mechanism and method for suppressing the attenuation of acoustic emission signals in in-situ scratching. This method changes the rigid connection mechanism between the acoustic emission sensor and the loading output end of the scratching tester into a flexible connection structure with a specific stiffness range, optimizes the transmission path of the acoustic emission signal, and effectively suppresses the energy attenuation of the acoustic emission signal through the microscopic deformation of the acoustic emission sensor connection part in the flexible connection mechanism, enhancing the acoustic emission signal detection intensity in in-situ scratching tests and providing more reliable technical support for the mechanical evaluation of material properties.

[0006] To achieve the above object, the present invention is realized through the following technical solutions:

[0007] The flexible connection mechanism adopts an integrated design and is composed of a countersunk hole, an acoustic emission signal detection surface, a flexible beam, an acoustic emission sensor assembly connection hole, and a indenter mounting hole. This mechanism fixes the integrated acoustic emission sensor assembly and the indenter to the loading output end of the scratch tester by using the cooperation of bolts and countersunk holes, suppresses the attenuation of acoustic emission signals during in-situ scratch testing, and improves the detection ability of micro-damage signals of materials.

[0008] Preferably, the flexible beam adopts a flat thin plate structure design and is respectively arranged at the top and bottom of the acoustic emission signal detection surface. On the one hand, this design provides appropriate flexibility in the direction perpendicular to the scratch, enabling the acoustic emission signal detection surface to generate controllable microscopic deformation during the test, thereby enhancing the signal detection ability of the acoustic emission sensor. On the other hand, it maintains sufficient stiffness in the scratch direction to ensure the movement stability of the indenter during the test. This specific structure realizes the optimal combination of flexibility and rigidity, meeting both the requirements of signal detection sensitivity and ensuring the mechanical stability of the test system.

[0009] Preferably, the indenter mounting hole adopts a cylindrical structure design and is arranged at the lower position of the acoustic emission signal detection surface. There are threaded holes on the back of the acoustic emission signal detection surface, and the indenter is reliably fixed by configuring set screws. This structural design not only ensures the installation accuracy of the indenter but also guarantees the integrity of the acoustic emission signal detection surface.

[0010] Preferably, acoustic emission sensor assembly connection holes are provided on both sides of the acoustic emission signal detection surface, and the acoustic emission sensor assembly can be fixed to the flexible connection mechanism by bolt connection.

[0011] Preferably, the acoustic emission sensor assembly consists of an acoustic emission sensor, a semi-cylindrical sleeve, an arc-shaped pressing plate, and two fixing bolts. The acoustic emission sensor is installed inside the semi-cylindrical sleeve, and the arc-shaped pressing plate fastens the acoustic emission sensor in the semi-cylindrical sleeve through two fixing bolts.

[0012] Another object of the present invention is to provide a method for suppressing the attenuation of acoustic emission signals in in-situ scratching, including the following steps:

[0013] a) Design the connection method between the acoustic emission sensor and the loading platform of the scratch tester, changing the rigid structure to a flexible structure. The flexible structure connection method can effectively suppress the energy transmission of the acoustic emission signals generated by the indenter on the surface of the test sample during in-situ scratch testing.

[0014] The stress wave generated from the material surface will propagate to the acoustic emission sensor through the flexible connection mechanism. The energy attenuation of the stress wave during propagation can be expressed by the following formula:

[0015] E(x)=E0e -αx

[0016] Among them, E(x) is the energy at the propagation distance x, that is, the energy detected when the stress wave propagates to the acoustic emission sensor, E0 is the initial energy, and α is the attenuation coefficient, whose value is closely related to the internal damping characteristics and geometric structure of the connecting mechanism; due to its low stiffness and small damping characteristics, the flexible connecting mechanism can effectively reduce the energy loss during the propagation of the stress wave; according to the stress wave energy attenuation formula, the attenuation coefficient α of the flexible connecting mechanism is small, so that the stress wave energy can be better maintained during propagation;

[0017] b) Fix the acoustic emission sensor assembly and the indenter on the flexible connecting mechanism;

[0018] c) Fasten the flexible connecting mechanism integrating the acoustic emission sensor assembly and the indenter to the loading platform of the scratch tester with bolts, and ensure that the indenter is perpendicular to the surface of the stage;

[0019] d) After debugging the scratch tester, the in-situ scratch test can be started.

[0020] The present invention has achieved the following technical results compared with the prior art:

[0021] A flexible connecting mechanism and method for suppressing the attenuation of acoustic emission signals in in-situ scratching disclosed by the present invention effectively solve the technical defect of the traditional acoustic emission sensor using rigid connection. The innovative design of the flexible connecting mechanism optimizes the transmission path of the acoustic emission signal, realizes the effective suppression of the energy attenuation of the acoustic emission signal, significantly improves the detection ability of the acoustic emission signal, enhances the intensity of the acoustic emission signal detection in the in-situ scratch test, provides more detailed signals of micro-damage for the study of the mechanical properties of materials, and realizes a more accurate characterization of the material failure behavior;

[0022] The flexible connecting mechanism of the present invention adopts an integrated design, has the characteristics of simple structure, stable performance, convenient processing, and not easy to be damaged, and can meet the requirements of long-term stable testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The schematic examples of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention.

[0024] Figure 1 Schematic diagram of the flexible connecting mechanism integrating the acoustic emission sensor assembly and the indenter according to the present invention;

[0025] Figure 2 Schematic diagram of the flexible connecting mechanism according to the present invention;

[0026] Figure 3Schematic diagram of the acoustic emission sensor assembly according to the present invention;

[0027] Figure 4 Data comparison curve graph for in-situ linear load scratch test provided by the embodiments of the present invention and comparative experiments;

[0028] In the figure: 1. Flexible connection mechanism; 2. Acoustic emission sensor assembly; 3. Indenter; 101. Countersunk hole; 102. Acoustic emission signal detection surface; 103. Flexible beam; 104. Acoustic emission sensor assembly connection hole; 105; Indenter mounting hole; 201. Fixing bolt; 202. Arc-shaped pressing plate; 203. Acoustic emission sensor; 204. Semi-cylindrical sleeve. Detailed implementation manners

[0029] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0030] The flexible connection mechanism 1 adopts an integrated design and is composed of a countersunk hole 101, an acoustic emission signal detection surface 102, a flexible beam 103, an acoustic emission sensor assembly connection hole 104 and an indenter mounting hole 105, as Figure 2 shown; this mechanism fixes the integrated acoustic emission sensor assembly 2 and the indenter 3, as Figure 1 shown, to the loading output end of the scratch tester by using the cooperation of bolts and the countersunk hole 101, and suppresses the attenuation of acoustic emission signals during the in-situ scratch test, improving the detection ability for tiny damage signals of materials;

[0031] Specifically, the flexible beam 103 adopts a flat thin plate structure design and is respectively arranged at the top and bottom of the acoustic emission signal detection surface 102; on the one hand, this design provides appropriate flexibility in the direction perpendicular to the scratch, enabling the acoustic emission signal detection surface 102 to generate controllable microscopic deformation during the test, thereby enhancing the signal detection ability of the acoustic emission sensor 203; on the other hand, it maintains sufficient stiffness in the scratch direction to ensure the movement stability of the indenter 3 during the test; this specific structure realizes the optimal combination of flexibility and rigidity, meeting both the requirements of signal detection sensitivity and ensuring the mechanical stability of the test system;

[0032] Specifically, the indenter mounting hole 105 is designed with a cylindrical structure and is arranged below the acoustic emission signal detection surface 102. There are threaded holes on the back of the acoustic emission signal detection surface 102, and the reliable fixation of the indenter 3 is achieved by configuring set screws; this structural design not only ensures the installation accuracy of the indenter 3 but also guarantees the integrity of the acoustic emission signal detection surface 102;

[0033] Specifically, acoustic emission sensor assembly connection holes 104 are provided on both sides of the acoustic emission signal detection surface 102, and the acoustic emission sensor assembly 2 can be fixed to the flexible connection mechanism 1 through bolt connection;

[0034] Specifically, the acoustic emission sensor assembly 2 is composed of an acoustic emission sensor 203, a semi-cylindrical sleeve 204, an arc-shaped pressing plate 202, and two fixing bolts 201, as Figure 3 shown; among them, the acoustic emission sensor 203 is installed inside the semi-cylindrical sleeve 204, and the arc-shaped pressing plate 202 fastens the acoustic emission sensor 203 in the semi-cylindrical sleeve 204 through two fixing bolts 201.

[0035] Example: Using the flexible connection method of the acoustic emission sensor and the scratch tester of the present invention, an in-situ linear load scratch test is carried out on the surface of a modified silicon coating - single crystal silicon substrate material, including the following steps:

[0036] a) Design the connection method between the acoustic emission sensor 203 and the loading platform of the scratch tester, change the rigid connection structure to a flexible connection structure 1, and the flexible connection method can effectively suppress the energy transmission of the acoustic emission signal generated by the indenter 3 on the surface of the test sample during the in-situ scratch test;

[0037] In this embodiment, the flexible connection mechanism 1 between the acoustic emission sensor 203 and the scratch tester adopts an anisotropic stiffness design, maintaining appropriate flexibility in the direction perpendicular to the scratch, enabling the acoustic emission signal detection surface 102 to generate controllable minute deformations, thereby enhancing the intensity of signal reception; at the same time, maintaining a high stiffness in the scratch direction to ensure the movement stability of the indenter 3 during the test;

[0038] The stress wave generated from the material surface will propagate through the flexible connection mechanism 1 to the acoustic emission sensor 203, and the energy attenuation of the stress wave during propagation can be expressed by the following formula:

[0039] E(x) = E0e -αx

[0040] Among them, E(x) is the energy at the propagation distance x, that is, the energy detected when the stress wave propagates to the acoustic emission sensor 203. E0 is the initial energy, and α is the attenuation coefficient, whose value is closely related to the internal damping characteristics and geometric structure of the connection mechanism. Due to its low stiffness and small damping characteristics, the flexible connection mechanism 1 can effectively reduce the energy loss during the propagation of the stress wave. According to the stress wave energy attenuation formula, the attenuation coefficient α of the flexible connection mechanism 1 is small, enabling the stress wave energy to be better maintained during propagation.

[0041] b) Fix the acoustic emission sensor assembly 2 and the indenter 3 on the flexible connection mechanism 1.

[0042] In this embodiment, the acoustic emission sensor 203 is fixedly installed through a semi-cylindrical sleeve 204, and its detection surface is set as a protruding structure higher than the edge of the sleeve. This assembly method ensures that when the acoustic emission sensor assembly 2 is integrally installed on the flexible connection mechanism 1, the detection surface of the acoustic emission sensor 203 can form a tight fit with the acoustic emission signal detection surface 102 of the flexible connection mechanism 1, thereby realizing the efficient conduction of the stress wave signal.

[0043] c) Fasten the flexible connection mechanism 1 integrating the acoustic emission sensor assembly 2 and the indenter 3 to the loading platform of the scratch tester with bolts, and ensure that the indenter 3 is perpendicular to the surface of the stage.

[0044] In this embodiment, when installing the flexible connection mechanism 1, the loading platform of the scratch tester needs to be adjusted to a safe distance away from the stage in advance to provide sufficient installation space for the flexible connection mechanism 1 and ensure that it can be firmly and reliably fixed on the loading platform.

[0045] d) After debugging the scratch tester, the in-situ scratch test can be started.

[0046] In this embodiment, an in-situ linear load scratch test is performed on the surface of the modified silicon coating - single crystal silicon substrate material using the debugged scratch tester. The loading load is set to increase from 0 N to 5 N, the scratch speed is set to 10 μm / s, and the loading speed is set to 0.1 N / s. The test results are as Figure 4 shown in (b).

[0047] Comparative experiment: An in-situ scratch test with the same parameters is performed on the same sample block using a traditional scratch tester without integrating the flexible connection mechanism 1. The test results are as Figure 4 shown in (a).

[0048] As can be seen from the above experimental data results, the flexible connection method proposed by the present invention effectively inhibits the energy attenuation of acoustic emission signals during propagation. The in-situ scratch test implemented by this method can significantly improve the ability to capture signals of minor material damage. Compared with the traditional rigid connection method, more acoustic emission signals characterizing the failure characteristics of the material can be detected, providing a more accurate detection means for the mechanical property evaluation of coating materials.

[0049] The above are only the preferred examples of the present invention and are not intended to limit the present invention. For those skilled in the art, various modifications and changes can be made to the present invention. Any modifications, substitutions, improvements, etc. made to the present invention shall be included within the protection scope of the present invention.

Claims

1. A flexible connection mechanism for suppressing the attenuation of acoustic emission signals in in-situ scratching, characterized in that: The flexible connection mechanism (1) adopts an integrated design and is composed of a countersunk hole (101), an acoustic emission signal detection surface (102), a flexible beam (103), an acoustic emission sensor assembly connection hole (104), and a indenter mounting hole (105). This mechanism fixes the integrated acoustic emission sensor assembly (2) and the indenter (3) to the loading output end of the scratch tester by using the cooperation of bolts and the countersunk hole (101), and suppresses the attenuation of acoustic emission signals during in-situ scratch testing, improving the detection ability of micro-damage signals of materials.

2. The flexible connection mechanism for suppressing the attenuation of acoustic emission signals in in-situ scratching according to claim 1, wherein: The flexible beam (103) mentioned above adopts a flat thin plate structure design and is respectively arranged at the top and bottom of the acoustic emission signal detection surface (102). On the one hand, this design provides appropriate flexibility in the direction perpendicular to the scratch, enabling the acoustic emission signal detection surface (102) to generate controllable microscopic deformation during the test, thereby enhancing the signal detection ability of the acoustic emission sensor (203). On the other hand, it maintains sufficient stiffness in the scratch direction to ensure the movement stability of the indenter (3) during the test. This specific structure realizes the optimal combination of flexibility and rigidity, meeting both the requirements of signal detection sensitivity and ensuring the mechanical stability of the test system.

3. The flexible connection mechanism for suppressing the attenuation of acoustic emission signals in in-situ scratching according to claim 1, characterized in that: The indenter mounting hole (105) mentioned above adopts a cylindrical structure design and is arranged at the lower position of the acoustic emission signal detection surface (102). There are threaded holes on the back of the acoustic emission signal detection surface (102), and the indenter (3) is reliably fixed by configuring set screws. This structural design not only ensures the installation accuracy of the indenter (3) but also guarantees the integrity of the acoustic emission signal detection surface (102).

4. The flexible connection mechanism for suppressing the attenuation of acoustic emission signals in in-situ scratching according to claim 1, wherein: Acoustic emission sensor assembly connection holes (104) are provided on both sides of the acoustic emission signal detection surface (102) mentioned above, and the acoustic emission sensor assembly (2) can be fixed to the flexible connection mechanism (1) through bolt connection.

5. The flexible connection mechanism for suppressing the attenuation of acoustic emission signals in in-situ scratching according to claim 4, characterized in that: The acoustic emission sensor assembly (2) mentioned above is composed of an acoustic emission sensor (203), a semi-cylindrical sleeve (204), an arc-shaped pressing plate (202), and two fixing bolts (201). Among them, the acoustic emission sensor (203) is installed inside the semi-cylindrical sleeve (204), and the arc-shaped pressing plate (202) fastens the acoustic emission sensor (203) in the semi-cylindrical sleeve (204) through two fixing bolts (201).

6. Method for suppressing attenuation of acoustic emission signal in in-situ scratch, characterized in that, Using the flexible connection mechanism for suppressing the attenuation of acoustic emission signals in in-situ scratches described in any one of claims 1-5, includes the following steps: a) Design the connection method between the acoustic emission sensor (203) and the loading platform of the scratch tester, changing the rigid connection structure to a flexible connection structure (1). The flexible connection method can effectively suppress the energy transmission of the acoustic emission signals generated by the indenter (3) on the surface of the test sample during in-situ scratch testing. The stress wave generated from the material surface will propagate to the acoustic emission sensor (203) through the flexible connection mechanism (1). The energy attenuation of the stress wave during propagation can be expressed by the following formula: E(x) = E0e -αx Among them, E(x) is the energy at the propagation distance x, that is, the energy detected when the stress wave propagates to the acoustic emission sensor (203), E0 is the initial energy, and α is the attenuation coefficient, whose value is closely related to the internal damping characteristics and geometric structure of the connecting mechanism; due to its low stiffness and small damping characteristics, the flexible connecting mechanism (1) can effectively reduce the energy loss during the propagation of the stress wave; according to the stress wave energy attenuation formula, the attenuation coefficient α of the flexible connecting mechanism (1) is small, enabling the stress wave energy to be better maintained during propagation; b) Fix the acoustic emission sensor assembly (2) and the indenter (3) on the flexible connecting mechanism (1); c) Fasten the flexible connecting mechanism (1) integrating the acoustic emission sensor assembly (2) and the indenter (3) to the loading platform of the scratch tester with bolts, and ensure that the indenter (3) is perpendicular to the surface of the stage; d) After debugging the scratch tester, the in-situ scratch test can be started.

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