Leakage detection method of composite material component based on air coupling ultrasonic technology

Abstract

The invention discloses a leakage detection method for a composite material component with a cavity based on an air coupling ultrasonic technology, and the method comprises the steps: scanning a to-be-detected component in an atmospheric environment through employing the air coupling ultrasonic technology, so as to obtain a first ultrasonic scanning image; placing the to-be-tested component in an atmosphere filled with inert high-density gas; taking out the to-be-detected component from the atmosphere, and scanning the to-be-detected component again in the atmospheric environment by using the air coupling ultrasonic technology so as to acquire a second ultrasonic scanning image; and comparing the second ultrasonic scanning image with the first ultrasonic scanning image to check whether the second ultrasonic scanning image presents an additional high-attenuation area or not. According to the invention, defect detection and leakage detection of the composite material component with the cavity can be realized in a completely lossless manner in a dry environment, and the leakage detection efficiency is remarkably improved.

Description

Technical Field

[0001] This disclosure relates to the technical field of nondestructive testing of composite materials, and in particular to a leak detection method for composite material components based on air-coupled ultrasonic technology. Background Technology

[0002] Composite material components with cavities are widely used in areas such as wings, control surfaces, and cabin doors of civil aircraft due to their advantages such as light weight and high bending rigidity. Typical forms of these composite material components include, for example, foam composite sandwich structures and honeycomb sandwich structures, and they share some common characteristics.

[0003] Taking honeycomb sandwich structures as an example, but not limited to this, the structural strength of the honeycomb core is generally slightly weaker. When used in the civil aviation industry, this can lead to problems such as relatively thin skins, delamination, debonding, and honeycomb core collapse and deformation. Furthermore, during the manufacturing and service of honeycomb sandwich structures, there is a possibility of localized failure in the edge seals, and penetrating pinholes may appear on the skin surface. These gap-type and pinhole-type opening defects can easily allow liquids or moisture to penetrate the honeycomb sandwich structure, adversely affecting its strength. Therefore, macroscopic defect detection and leakage detection of honeycomb sandwich structures are necessary.

[0004] For leak detection in honeycomb sandwich structures, these defects are often hidden and have small openings, making direct detection with conventional ultrasonic testing impossible. Traditional methods for this type of structure often use water as a medium, fully exposing the components to a liquid environment to locate leaks during immersion. This method suffers from complex cleaning procedures after inspection: if a leak is found, the component must be thoroughly dried before repair to remove any seeping moisture, which is time-consuming and labor-intensive. Furthermore, this detection method also has some negative impacts on composite material components, and therefore, strictly speaking, it cannot guarantee completely non-destructive testing and maintenance throughout the long-term service life (the entire lifespan of the component).

[0005] Therefore, there is an urgent need to provide a new method for leak detection of composite material components, so as to at least partially alleviate or solve the above-mentioned problems and defects of existing solutions. Summary of the Invention

[0006] One objective of this disclosure is to propose a leakage detection method for composite material components based on air-coupled ultrasonic technology, in order to overcome the lack of existing technologies for accurate and completely non-destructive defect detection of composite material components with cavities.

[0007] This disclosure provides a leakage detection method for composite material components based on air-coupled ultrasonic technology, wherein the composite material component is a component under test with a cavity, and the leakage detection method includes:

[0008] Step 1: Scan the component under test using air-coupled ultrasound technology in an atmospheric environment to acquire a first ultrasound scan image;

[0009] Step 2: Place the component under test in an atmosphere filled with an inert high-density gas, so that the inert high-density gas can displace the air contained in the component under test, wherein the density of the inert high-density gas is greater than the density of air.

[0010] Step 3: Remove the component under test from the atmosphere and scan it again in the atmospheric environment using air-coupled ultrasound technology to acquire a second ultrasound scan image.

[0011] Step 4: Compare the second ultrasound scan image with the first ultrasound scan image to check whether the second ultrasound scan image shows additional high attenuation areas, which indicate additional areas where there are sealing problems.

[0012] The detection method provided in this disclosure is generally based on the following insights. For macroscopic defects in cavity composite material components such as honeycomb sandwich structures, a relatively advanced non-destructive testing technique, air-coupled ultrasound, can be used for non-contact detection and evaluation of defects in honeycomb cores, foam cores, and corresponding sandwich structures. However, because this technique uses air as the ultrasonic coupling transmission medium, and it is currently difficult to produce piezoelectric materials with acoustic impedance close to that of air (and even if such progress is made in the future, high material costs may remain an obstacle), the transmission efficiency of air-coupled ultrasound is relatively low, and the ultrasonic signal amplitude is greatly affected by the characteristics of the coupling transmission medium. This makes this relatively advanced non-destructive testing technique slightly insufficient in terms of sensitivity and accuracy when applied to defect detection in cavity composite material components. To this end, this disclosure proposes placing the component under test (DUT) in an atmosphere filled with an inert high-density gas. This allows the inert high-density gas to fully replace any air that may be contained within the DUT. Consequently, a considerable amount of the replaced inert high-density gas will be present in areas of the DUT where sealing defects or leakage problems exist. The introduction of this inert high-density gas will significantly alter the acoustic coupling characteristics of these areas, thereby allowing additional high-attenuation areas to be more clearly presented in the second ultrasonic scan image, indicating local defects in the DUT.

[0013] In this way, the leak detection method provided in this disclosure is completely non-destructive, has sufficient detection sensitivity and accuracy, is easy to implement, and helps reduce related maintenance and detection costs.

[0014] According to some embodiments of this disclosure, step two includes:

[0015] The component to be tested is immersed in an open container or tank filled with inert high-density gas and left to stand for a predetermined time or longer.

[0016] According to some embodiments of this disclosure, in step two, the component to be tested is placed at the bottom of the open container or trough for a predetermined time or longer.

[0017] According to some embodiments of this disclosure, the density of the inert high-density gas is more than three times the density of air.

[0018] According to some embodiments of this disclosure, the inert high-density gas includes one or more of sulfur hexafluoride, carbon tetrafluoride, perfluoropropane, and octafluorocyclobutane.

[0019] According to some embodiments of this disclosure, during the two scans of the component under test using air-coupled ultrasound technology, the ultrasonic transmitting probe and the ultrasonic receiving probe maintain the same relative position to the component under test, and the component under test maintains the same orientation.

[0020] According to some embodiments of this disclosure, the two scans of the component under test using air-coupled ultrasonic technology are performed using either the penetration method or the reflection method.

[0021] According to some embodiments of this disclosure, in step four, the comparison check is performed to determine whether the second ultrasound scan image contains additional high-attenuation areas that are shaded.

[0022] According to some embodiments of this disclosure, the component to be tested is a sandwich component, which includes a foam core or a honeycomb core.

[0023] Based on common knowledge in the field, the above-mentioned preferred conditions can be combined arbitrarily to obtain various preferred embodiments of the present disclosure.

[0024] The positive and progressive effects of this disclosure are as follows:

[0025] The leakage detection method for composite material components based on air-coupled ultrasonic technology disclosed herein can detect defects and leaks in composite material components with cavities in a completely non-destructive manner in a dry environment, significantly improving leakage detection efficiency and having sufficient detection sensitivity and accuracy. At the same time, it is easy to implement and helps to reduce related maintenance and detection costs. Attached Figure Description

[0026] Figure 1 The diagram illustrates a preferred embodiment of the leakage detection method according to the present disclosure, showing a state in which ultrasonic scanning of the component under test is performed using the penetration method.

[0027] Figure 2A-2B The diagram illustrates a state in which the component to be tested is immersed in an open container or tank filled with inert high-density gas and left to stand according to a preferred embodiment of the leakage detection method of the present disclosure.

[0028] Figure 3 An example of a second ultrasonic scan image obtained using a leak detection method according to a preferred embodiment of the present disclosure is shown schematically, the example image including additional high-attenuation areas that are shaded. Detailed Implementation

[0029] The preferred embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The following description is exemplary and not intended to limit the present invention. Any other similar situations also fall within the protection scope of the present invention.

[0030] In the following detailed description, directional terms such as "left," "right," "up," "down," "front," and "back" are used with reference to the directions described in the accompanying drawings. Components of embodiments of the invention may be positioned in a variety of different orientations; the directional terms are for illustrative purposes and not limiting.

[0031] The leakage detection method for composite material components based on air-coupled ultrasonic technology according to a preferred embodiment of the present disclosure is applicable to non-destructive testing of composite material components with cavities (hereinafter referred to as the component under test 1). The leakage detection method includes:

[0032] Step 1: Scan the component under test 1 using air-coupled ultrasound technology in an atmospheric environment to acquire the first ultrasonic scan image, referencing... Figure 1 As shown;

[0033] Step 2: Place the component to be tested 1 in an atmosphere filled with an inert high-density gas, so that the inert high-density gas can displace the air contained in the component to be tested 1. The density of the inert high-density gas is greater than the density of air. (Refer to...) Figure 2A As shown;

[0034] Step 3: Remove the component 1 from the atmosphere and scan it again in the atmospheric environment using air-coupled ultrasound technology to acquire a second ultrasonic scan image. (Refer to...) Figure 1 As shown;

[0035] Step 4: Compare the second ultrasound scan image with the first ultrasound scan image to check whether the second ultrasound scan image shows additional high attenuation areas, which indicate additional areas with sealing problems.

[0036] It should be understood that the term "inert high-density gas" in this article does not refer to an elemental gas, but rather to compounds that are gaseous at room temperature and pressure. It is intended to indicate that such a gas has a higher density than air, while also possessing better stability and being less likely to react with common components in the air, such as oxygen, and is non-flammable and does not support combustion. It is also less likely to react with other common materials, such as some metals and composite materials widely used in civil aircraft, and possesses high chemical stability.

[0037] The above method involves placing the component under test (DUT) in an atmosphere filled with an inert high-density gas. This inert high-density gas effectively replaces any air that might be contained within the DUT. Taking advantage of the substantial amount of replaced inert high-density gas present in areas of the DUT with sealing defects or leaks, a second ultrasonic scan is performed. Since the introduction of this inert high-density gas significantly alters the acoustic coupling characteristics of this area, it allows additional high-attenuation regions to be more clearly presented in the second ultrasonic scan image, indicating localized defects in the DUT. In this way, the leak detection method provided in this disclosure is completely non-destructive, possesses sufficient detection sensitivity and accuracy, is easy to implement, and helps reduce related maintenance and inspection costs.

[0038] The area of ​​the transverse plane or a certain vertical plane along the groove should not be less than the projected area of ​​the component to be measured 1 during scanning.

[0039] According to some preferred embodiments, step two includes:

[0040] The component to be tested 1 is immersed in an open container or tank 4 filled with inert high-density gas and left to stand for a predetermined time or longer. More preferably, the component to be tested 1 is placed at the bottom of the open container or tank 4 for a predetermined time or longer, for example, as shown in the example below. Figure 2B As shown.

[0041] In this way, the inert high-density gas will be able to displace the air in the component under test 1 more quickly due to gravity, especially in areas with sealing defects or leakage problems, thereby improving the efficiency of the test.

[0042] According to some preferred embodiments, the density of the inert high-density gas is more than three times that of air, and one preferred inert high-density gas is sulfur hexafluoride. Alternatively, other preferred inert high-density gases can be carbon tetrafluoride, perfluoropropane, or octafluorocyclobutane. Wherein, if the density difference between the selected inert high-density gas and air is relatively small, the immersion depth of the component under test in the inert high-density gas needs to be set relatively deeper. Therefore, using an inert high-density gas with a density more than three times that of air allows the use of relatively small-sized open containers or tanks for immersing the component under test in an atmosphere filled with inert high-density gas, thereby implementing the leakage detection method for composite material components based on air-coupled ultrasonic technology according to the preferred embodiments of this disclosure.

[0043] According to some preferred embodiments, during the two scans of the component 1 under test using air-coupled ultrasound technology, the ultrasonic transmitting probe 2 and the ultrasonic receiving probe 3 maintain the same relative position to the component 1, and the component 1 maintains the same orientation. This makes it easier to identify or confirm whether the second ultrasonic scan image exhibits additional high-attenuation areas when comparing the second and first ultrasonic scan images in step four. For example,

[0044] More preferably, the component 1 under test is scanned twice using air-coupled ultrasonic technology, both times employing either the penetration method or the reflection method. In step four, the second ultrasonic scan image is compared to check for any additional high-attenuation areas that appear as shadowed regions. For example, in... Figure 3 In the example of the secondary scan image shown, in addition to the well-sealed, shadowless area, there are two blue shadowed areas, which are additional high-attenuation areas, indicating "leakage areas" in the component under test.

[0045] The above method is particularly suitable for non-destructive testing of composite material components in the form of sandwich structures, which may specifically include foam cores or honeycomb cores that are prone to difficult-to-detect or detect sealing defects.

[0046] The leakage detection method for composite material components based on air-coupled ultrasonic technology disclosed herein can perform defect and leakage detection on composite material components with cavities in a completely non-destructive manner in a dry environment, significantly improving leakage detection efficiency and possessing sufficient detection sensitivity and accuracy. Furthermore, it is easy to implement and helps reduce related maintenance and inspection costs.

[0047] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and the scope of protection of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but all such changes and modifications fall within the scope of protection of the present invention.

Claims

1. A method for leak detection of composite material components based on air-coupled ultrasonic technology, wherein the composite material component is a component under test with a cavity, characterized in that, The leakage detection method includes: Step 1: Scan the component under test using air-coupled ultrasound technology in an atmospheric environment to acquire a first ultrasound scan image; Step 2: Place the component under test in an atmosphere filled with an inert high-density gas, so that the inert high-density gas can displace the air contained in the component under test, wherein the density of the inert high-density gas is greater than the density of air. Step 3: Remove the component under test from the atmosphere and scan it again in the atmospheric environment using air-coupled ultrasound technology to acquire a second ultrasound scan image. Step 4: Compare the second ultrasound scan image with the first ultrasound scan image to check whether the second ultrasound scan image shows additional high attenuation areas, which indicate additional areas where there are sealing problems.

2. The leakage detection method for composite material components based on air-coupled ultrasonic technology as described in claim 1, characterized in that, Step two includes: The component to be tested is immersed in an open container or tank filled with inert high-density gas and left to stand for a predetermined time or longer.

3. The leakage detection method for composite material components based on air-coupled ultrasonic technology as described in claim 2, characterized in that, In step two, the component to be tested is placed at the bottom of the open container or trough for a predetermined time or longer.

4. The leakage detection method for composite material components based on air-coupled ultrasonic technology as described in claim 1, characterized in that, The density of the inert high-density gas is more than three times that of air.

5. The leakage detection method for composite material components based on air-coupled ultrasonic technology as described in claim 1, characterized in that, The inert high-density gas includes one or more of sulfur hexafluoride, carbon tetrafluoride, perfluoropropane, and octafluorocyclobutane.

6. The leakage detection method for composite material components based on air-coupled ultrasonic technology as described in claim 1, characterized in that, During the two scans of the component under test using air-coupled ultrasound technology, the ultrasonic transmitting probe and the ultrasonic receiving probe maintain the same relative position to the component under test, and the component under test maintains the same orientation.

7. The leakage detection method for composite material components based on air-coupled ultrasonic technology as described in claim 6, characterized in that, The two scans of the component under test using air-coupled ultrasonic technology were performed either by the penetration method or by the reflection method.

8. The leakage detection method for composite material components based on air-coupled ultrasonic technology as described in claim 1, characterized in that, In step four, the comparison is used to check whether the second ultrasound scan image contains additional high-attenuation areas that are shaded.

9. The leakage detection method for composite material components based on air-coupled ultrasonic technology as described in claim 1, characterized in that, The component to be tested is a sandwich component, which includes a foam core or a honeycomb core.

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