阅读说明：本技术 一种铝基隐身涂层损伤的超声波检测方法 (Ultrasonic detection method for damage of aluminum-based stealth coating ) 是由 郭孝欢 韩亮 孙法亮 秦宇飞 陈垚君 刘媛媛 石钰琳 卢彬彬 于 2021-08-26 设计创作，主要内容包括：本发明公开了一种铝基隐身涂层损伤的超声波检测方法,准备一台含有相控阵超声成像检测系统的相控阵超声成像检测设备,将声学轮上的水舱装满水并去除水泡,随后将装满水的声学轮水舱与所述相控阵超声成像检测系统连接；准备待检测的试块,用浸湿的抹布擦拭试块表面,保证试块处于表面湿润状态；开启相控阵超声成像检测设备,对相控阵超声成像检测系统进行系统参数设置；对相控阵超声成像检测系统进行检测参数设置,选择进入A+L+C检测模式；参数设置好之后,缓慢移动探头扫查,通过检测底波的方式对所述试块进行检测,观察C扫图像；对比C扫图像和试块实际缺陷情况,得出检测结论。本发明能够解决常规超声检测时各界面反射信号因互相重叠而无法区分的问题。(The invention discloses an ultrasonic detection method for damage of an aluminum-based stealth coating, which comprises the steps of preparing phased array ultrasonic imaging detection equipment containing a phased array ultrasonic imaging detection system, filling a water tank on an acoustic wheel with water and removing bubbles, and then connecting the water tank of the acoustic wheel filled with water with the phased array ultrasonic imaging detection system; preparing a test block to be detected, and wiping the surface of the test block by using a soaked rag to ensure that the test block is in a surface wet state; starting the phased array ultrasonic imaging detection equipment, and carrying out system parameter setting on a phased array ultrasonic imaging detection system; setting detection parameters of a phased array ultrasonic imaging detection system, and selecting to enter an A + L + C detection mode; after the parameters are set, slowly moving a probe to scan, detecting the test block in a bottom wave detection mode, and observing a C-scanning image; and comparing the C-scan image with the actual defect condition of the test block to obtain a detection conclusion. The invention can solve the problem that the reflected signals of all interfaces cannot be distinguished because of mutual overlapping in the conventional ultrasonic detection.)

1. An ultrasonic detection method for damage of an aluminum-based stealth coating is characterized by comprising the following steps:

s1: preparing phased array ultrasonic imaging detection equipment comprising a phased array ultrasonic imaging detection system, filling a water tank on an acoustic wheel with water and removing water bubbles, and then connecting the water tank of the acoustic wheel filled with water with the phased array ultrasonic imaging detection system;

s2: preparing a test block to be detected, and wiping the surface of the test block by using a soaked rag to ensure that the test block is in a surface wet state;

s3: starting the phased array ultrasonic imaging detection equipment, and carrying out system parameter setting on the phased array ultrasonic imaging detection system, wherein the probe parameters are as follows: setting the scanning direction of the probe to be positive, setting the frequency of the probe to be 5MHz, setting the number of array elements to be sixty-four, and setting the center distance of the array elements to be 0.8 mm; wedge parameters: starting the wedge block, setting the angle of the wedge block to be 0 degree, setting the sound velocity of the wedge block to be 1480 m/s, and setting the thickness of the wedge block to be 14.5 mm; workpiece parameters: setting a longitudinal wave sound velocity of 6300m/s in the workpiece, detecting by using full detection, and setting a focal length to be 8 mm; setting system parameters, transceiving parameters and calibration parameters according to default parameters of the phased array ultrasonic imaging detection equipment;

s4: detecting parameter setting is carried out on the phased array ultrasonic imaging detection system, an A + L + C detection mode is selected to enter, and specific parameters are set as follows: the range is 15mm, the gain is 60db, the imaging gate is moved to the bottom wave position, the wave height is set to be 25%, an encoder is selected, and the scanning precision is set to be 0.280;

s5: after the parameters are set, smearing water on the probe, then slowly moving the probe to scan, detecting the test block in a bottom wave detection mode, and observing a C-scan image;

s6: and comparing the C-scan image with the actual defect condition of the test block to obtain a detection conclusion.

2. The ultrasonic testing method for damage of aluminum-based stealth coating according to claim 1, characterized by: when the phased array ultrasonic imaging detection equipment is used for detection, the working temperature of the phased array ultrasonic imaging detection equipment is as follows: -20 ℃ to 50 ℃, the coupling between the probe and the test block: and (3) water.

3. The ultrasonic testing method for damage of aluminum-based stealth coating according to claim 1, characterized by: the probe is a phased array wheel type probe.

4. The ultrasonic testing method for damage of aluminum-based stealth coating according to claim 1, characterized by: the test block adopts aluminum alloy as a base body, a primer layer, a radar layer and an infrared layer are sequentially sprayed on the surface of the base body, and the spraying and manufacturing modes of the primer layer, the radar layer and the infrared layer are consistent with the manufacturing mode of a stealth shell on an airplane.

5. The method for ultrasonic detection of damage to an aluminum-based stealth coating according to claim 4, wherein: in the process of manufacturing the test block, circular defects are embedded in the aluminum alloy substrate and the primer layer, the primer layer and the radar layer on the test block, and are 0.1mm away from the upper surface of the radar layer and in the middle of the radar layer, and the embedded circular defects are uniformly distributed on the test block.

6. The ultrasonic testing method for damage of aluminum-based stealth coating according to claim 5, characterized by: and manufacturing the embedded circular defect by adopting a mode of spraying varnish after digging a pit.

7. The ultrasonic testing method for damage of aluminum-based stealth coating according to claim 1, characterized by: the phased array ultrasonic imaging detection equipment is A/TPAU-01 in model.

Technical Field

The invention belongs to the field of aviation nondestructive testing, and particularly relates to an ultrasonic testing method for damage of an aluminum-based stealth coating.

Background

In order to improve the stealth performance of the airplane, the stealth coating is coated on the whole or part of the airplane in a common way at present, however, the stealth coating is easy to damage due to the unique structure of the airplane and bears the air flow scouring action for a long time, the stealth coating fails in the using process, the electromagnetic wave reflection is enhanced, so that the stealth performance of the airplane is seriously reduced, the very small damage or defect of the stealth coating can cause the great reduction of the stealth performance based on the basic requirement of the integrity of the coating, the formation of fighting capacity is comprehensively restricted, meanwhile, once the fallen coating fragments are sucked into an engine, the blades of the engine can be damaged, the catastrophic consequences of the death of the airplane and the death of people can be caused, the flight safety is seriously threatened, and the inestimable loss can be caused, therefore, the defect detection of the stealth coating is carried out, the possible layering failure of the stealth coating in the using process can be prevented in advance, the method is an important means for ensuring the stealth performance and flight safety of the airplane and has great military significance.

At present, the stealth coating mainly comprises a primer layer, a radar layer and a surface layer, the total thickness of the three layers is about 0.5mm, and due to the particularity of a coating material system and the poor accessibility of some coating parts, the detection by ultrasonic waves becomes a hot spot of the detection of the stealth coating in recent years.

The internal defect of the wave-absorbing coating is detected by an ultrasonic method according to the ultrasonic pulse reflection principle, when the ultrasonic pulse transmitted by the probe reaches the interface surface of the material through a detected object, the pulse is reflected back to the probe, and the internal defect of the wave-absorbing coating can be accurately detected by detecting echo and the like because the ultrasonic wave is transmitted in the defect coating and is transmitted in the normal coating differently.

However, the stealth coating is of a multilayer structure and is thin, reflected echoes of all interfaces can be subjected to aliasing when the stealth coating is detected by adopting conventional ultrasound, and defect signals are difficult to distinguish due to the fact that the defect signals are submerged by initial waves.

Disclosure of Invention

The technical scheme to be solved by the invention is as follows: the defect of the prior art is overcome, and the ultrasonic detection method for the damage of the aluminum-based stealth coating, which can detect the damage of the stealth coating coated in the regions with narrow space, large curvature change and the like such as an air inlet channel, is provided.

The technical scheme adopted by the invention for solving the technical problem is as follows:

an ultrasonic detection method for damage of an aluminum-based stealth coating comprises the following steps:

s1: preparing phased array ultrasonic imaging detection equipment comprising a phased array ultrasonic imaging detection system, filling a water tank on an acoustic wheel with water and removing water bubbles, and then connecting the water tank of the acoustic wheel filled with water with the phased array ultrasonic imaging detection system;

s2: preparing a test block to be detected, and wiping the surface of the test block by using a soaked rag to ensure that the test block is in a surface wet state;

s3: starting the phased array ultrasonic imaging detection equipment, and carrying out system parameter setting on the phased array ultrasonic imaging detection system, wherein the probe parameters are as follows: setting the scanning direction of the probe to be positive, setting the frequency of the probe to be 5MHz, setting the number of array elements to be sixty-four, and setting the center distance of the array elements to be 0.8 mm; wedge parameters: starting the wedge block, setting the angle of the wedge block to be 0 degree, setting the sound velocity of the wedge block to be 1480 m/s, and setting the thickness of the wedge block to be 14.5 mm; workpiece parameters: setting a longitudinal wave sound velocity of 6300m/s in the workpiece, detecting by using full detection, and setting a focal length to be 8 mm; setting system parameters, transceiving parameters and calibration parameters according to default parameters of the phased array ultrasonic imaging detection equipment;

s4: detecting parameter setting is carried out on the phased array ultrasonic imaging detection system, an A + L + C detection mode is selected to enter, and specific parameters are set as follows: the range is 15mm, the gain is 60db, the imaging gate is moved to the bottom wave position, the wave height is set to be 25%, an encoder is selected, and the scanning precision is set to be 0.280;

s5: after the parameters are set, smearing water on the probe, then slowly moving the probe to scan, detecting the test block in a bottom wave detection mode, and observing a C-scan image;

s6: and comparing the C-scan image with the actual defect condition of the test block to obtain a detection conclusion.

When the phased array ultrasonic imaging detection equipment is used for detection, the working temperature of the phased array ultrasonic imaging detection equipment is as follows: -20 ℃ to 50 ℃, the coupling between the probe and the test block: and (3) water.

The probe is a phased array wheel type probe.

The test block adopts aluminum alloy as a base body, a primer layer, a radar layer and an infrared layer are sequentially sprayed on the surface of the base body, and the spraying and manufacturing modes of the primer layer, the radar layer and the infrared layer are consistent with the manufacturing mode of a stealth shell on an airplane.

In the process of manufacturing the test block, circular defects are embedded in the aluminum alloy substrate and the primer layer, the primer layer and the radar layer on the test block, and are 0.1mm away from the upper surface of the radar layer and in the middle of the radar layer, and the embedded circular defects are uniformly distributed on the test block.

And manufacturing the embedded circular defect by adopting a mode of spraying varnish after digging a pit.

The phased array ultrasonic imaging detection equipment is A/TPAU-01 in model.

The invention has the following positive beneficial effects:

the invention utilizes the phased array ultrasonic detection technology to detect the layered damage of the stealth coating, can solve the problem that the reflected signals of each interface cannot be distinguished due to mutual overlapping in the conventional ultrasonic detection, and realizes the damage detection of the stealth coating coated in the area with narrow space and large curvature change, such as an air inlet channel.

Drawings

FIG. 1 is a diagram of the condition that ultrasonic reflection echoes interfere with each other at each interface of a stealth coating;

FIG. 2 is a scan A taken with a phased array ultrasonic inspection system according to the present invention;

FIG. 3 is a B-scan of the detection result of the embedded defect of 0.1mm deep phi 4 from the upper surface of the radar layer in the embodiment;

FIG. 4 is a C-scan of the detection result of the embedded defect of 0.1mm deep phi 4 from the upper surface of the radar layer in the embodiment;

FIG. 5 is a flow chart of the detection steps of the present invention;

fig. 6 is a data diagram showing the detection result of each embedded defect in the present invention.

Detailed Description

The invention will be further explained and explained with reference to the accompanying drawings, fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6 and the embodiments, in which: e-reflecting signals on the upper surface of the test block, F-phi 4 pre-buried defect reflecting signals and G-phi 4 pre-buried defects.

Example (b): in this embodiment, when the phased array ultrasonic imaging detection equipment is used for detection, the working temperature of the phased array ultrasonic imaging detection equipment is as follows: -20 ℃ to 50 ℃, coupling mode between the probe and the test block: and (3) water.

The basic idea of the ultrasonic phased array technology is that the radar electromagnetic wave phased array technology is adopted, the phased array radar is composed of a plurality of radiating units which are arranged into an array, the radiation direction of electromagnetic waves is adjusted by controlling the amplitude and the phase of each unit in an array antenna, and radar beams which are flexibly and quickly focused and scanned are synthesized in a certain space range. The ultrasonic phased array transducer is an array formed by a plurality of independent piezoelectric wafers, and each wafer unit is controlled and excited by an electronic system according to a certain rule and a certain time sequence to adjust and control the position of a focus and the focusing direction.

The probe is a phased array wheel type probe, and the type of the probe is 5L 64-0.8X 10-G1.

Be provided with pre-buried defect on the test block, the size of test block is 300 x 600, at the in-process of preparation test block, on aluminum alloy base member and priming paint layer on the test block, priming paint layer and radar layer apart from radar layer upper surface 0.1mm and radar layer middle part adopt the pre-buried circular defect of mode of digging the hole after the varnish that spouts, pre-buried circular defect equipartition is on the test block, infrared layer pre-buried defect not, pre-buried defect size is respectively: phi 2, phi 4, phi 6, phi 10, phi 15; setting one defect with the diameter of phi 2, phi 4 and phi 6 between the substrate and the primer layer; setting one defect with the diameter phi 2 and the diameter phi 4 between the primer layer and the radar layer; setting defects with the diameter phi 2 and the diameter phi 4 in the middle of the radar layer respectively; setting one defect with the diameter of phi 4, phi 10 and phi 15 at the position 0.1mm away from the upper surface of the radar layer; namely, 10 defects are embedded in total, and the defects are numbered from the base body to the base body according to the sequence from large to small, namely 1-1, 1-2, 1-3, 2-1, 2-2, 3-1, 3-2, 4-4 and 4-5.

The pre-buried defect is made by spraying the varnish, because the acoustic impedance of the varnish is larger than that of air, the defect with smaller acoustic impedance difference is difficult to be found according to the detection principle, so compared with a coating material, the difference between the acoustic impedance of the varnish and the coating material is smaller than that of the air, and the actual damage can be detected by detecting the simulated defect.

A rivet with the diameter of 9mm is embedded in the middle of the test block and used for calibrating an instrument, and the instrument calibration method comprises the following steps: through measuring for phi 9 mm's rivet head on the test block size, contrast instrument C sweeps formation of image and measures size and actual dimensions size, obtains the magnification of measuring size and actual dimensions, accomplishes X axle and Y axle direction size calibration to subsequent layering damage size measurement's calibration of being convenient for.

The total number of the measurements is 6, and the data and the analysis are as follows based on the average value of 6 times: the X-direction magnification a =2.40 and the Y-direction magnification b =1.07 can be obtained.

The probe comprises an acoustic wheel and a handle, magnetic sealing covers are arranged on the left side and the right side of each of two ends of the acoustic wheel, a closed waterproof space is formed by the two sealing covers and the interior of the acoustic wheel, the two sides of the acoustic wheel are respectively connected with the handle through a crank, a cable connected with phased array ultrasonic imaging detection equipment is connected with one end of the acoustic wheel, a water filling port is formed in the other end of the acoustic wheel and used for water injection of the acoustic wheel, an inner waterproof screw and an outer waterproof screw are arranged on the water filling port, when water is injected, an inner hexagonal wrench is used for rotating the outer waterproof screw at the water filling port end and then rotating the inner waterproof screw at the water filling port end and then detaching the outer waterproof screw, a spray can filled with water is connected with the water filling port through the spray can port on the spray can, water can be injected into a water cabin on the acoustic wheel, and then the inner waterproof screws and the outer waterproof screws are installed; the back of the acoustic wheel and the same side end of the handle are also provided with a back roller, the side surface of the back roller is also provided with a one-dimensional linear scanning encoder, and the encoder is in close contact with the acoustic wheel.

During operation, preparing a phased array ultrasonic imaging detection device with a phased array ultrasonic imaging detection system, filling a water tank on the acoustic wheel with water and removing water bubbles, and then connecting the water tank of the acoustic wheel filled with water with the phased array ultrasonic imaging detection system;

preparing a test block to be detected, and wiping the surface of the test block by using a soaked rag to ensure that the test block is in a surface wet state; the test block adopts aluminum alloy as a base body, a primer layer, a radar layer and an infrared layer are sequentially sprayed on the surface of the base body, and the spraying and manufacturing modes of the primer layer, the radar layer and the infrared layer are consistent with the manufacturing mode of a stealth shell on an airplane.

Starting the phased array ultrasonic imaging detection equipment, and carrying out system parameter setting on the phased array ultrasonic imaging detection system, wherein the probe parameters are as follows: setting the scanning direction of the probe to be positive, setting the frequency of the probe to be 5MHz, setting the number of array elements to be sixty-four, and setting the center distance of the array elements to be 0.8 mm; wedge parameters: starting the wedge block, setting the angle of the wedge block to be 0 degree, setting the sound velocity of the wedge block to be 1480 m/s, and setting the thickness of the wedge block to be 14.5 mm; workpiece parameters: setting a longitudinal wave sound velocity of 6300m/s in the workpiece, detecting by using full detection, and setting a focal length to be 8 mm; setting system parameters, transceiving parameters and calibration parameters according to default parameters of the phased array ultrasonic imaging detection equipment;

detecting parameter setting is carried out on the phased array ultrasonic imaging detection system, an A + L + C detection mode is selected to enter, and specific parameters are set as follows: the range is 15mm, the gain is 60db, the imaging gate is moved to the bottom wave position, the wave height is set to be 25%, an encoder is selected, and the scanning precision is set to be 0.280.

A + L + C detection mode: linear C-scan, the beam translates along the probe direction, while the probe moves along the scan direction.

After the parameters are set, water is smeared on the probe, then the probe is moved slowly to scan, the test block is detected in a bottom wave detection mode, and a C-scan image is observed.

And comparing the C-scan image with the actual defect condition of the test block to obtain a detection conclusion.

The invention is not limited to the above embodiments, and those skilled in the art can make equivalent modifications or substitutions without departing from the spirit of the invention, and such equivalent modifications or substitutions are included in the scope defined by the claims of the present application.