阅读说明：本技术 一种面向机身结构的t型构件r区缺陷超声检测方法 (Ultrasonic detection method for R-region defects of T-shaped component for fuselage structure ) 是由 阚艳 范鑫 宣善勇 张平 李松如 于 2021-09-06 设计创作，主要内容包括：本发明提出一种面向机身结构的T型构件R区缺陷超声检测方法,超声相控阵探头与待检构件之间的有效声耦合可以保证声束尽可能的进入待测件,减小声束能量损失,是实现R区检测和保证检测性能的前提和基础。将超声相控阵探头放置于T型待检测构件背部平面,对内部的R区进行缺陷成像。超声相控阵探头利用声束聚焦延时法则实现合成孔径动态聚焦,获得合成孔径动态聚焦数据库。合成孔径动态聚焦数据库用以后期缺陷的动态聚焦成像,同时对缺陷进行定性定量表征。本发明面向机身结构的T型构件R区,基于超声相控阵合成孔径动态聚焦方法对缺陷进行超声检测,并进行定性定量表征。(The invention provides an ultrasonic detection method for R-area defects of a T-shaped component facing a machine body structure, wherein effective acoustic coupling between an ultrasonic phased array probe and a component to be detected can ensure that an acoustic beam enters a component to be detected as far as possible, and the energy loss of the acoustic beam is reduced, so that the method is a premise and a basis for realizing R-area detection and ensuring detection performance. And placing the ultrasonic phased array probe on the back plane of the T-shaped component to be detected, and carrying out defect imaging on the internal R area. The ultrasonic phased array probe realizes the dynamic focusing of the synthetic aperture by utilizing an acoustic beam focusing delay rule to obtain a synthetic aperture dynamic focusing database. The synthetic aperture dynamic focusing database is used for dynamic focusing imaging of later-stage defects and qualitative and quantitative characterization of the defects. The invention aims at the R area of the T-shaped component of the machine body structure, and carries out ultrasonic detection on defects based on an ultrasonic phased array synthetic aperture dynamic focusing method and qualitative and quantitative characterization.)

1. An ultrasonic detection method for R-region defects of T-shaped components facing a fuselage structure is characterized in that:

before starting detection, firstly fixing a T-shaped component to be detected, placing an ultrasonic phased array probe on the back plane of the T-shaped component to be detected, and coating a coupling agent on a contact interface of the ultrasonic phased array probe and the T-shaped component to be detected to ensure effective acoustic coupling;

the method specifically comprises the following steps:

the method comprises the following steps: synthesizing the n array elements into a synthetic aperture to obtain a synthetic aperture dynamic focusing database;

step two: calculating the propagation time of the ultrasonic wave;

step three: and determining an index value of the synthetic aperture in the echo data, and performing ultrasonic defect detection.

2. The method of claim 1, further comprising: in the first step, the first step is carried out,

determining the number of array elements of a synthetic aperture, wherein the synthetic aperture is synthesized by combining n array elements into a group, and an ultrasonic phased array probe (1) is excited according to an acoustic beam focusing delay rule, so that a synthetic focused acoustic beam of the synthetic aperture passes through the center of an R area arc surface of a T-shaped component to be detected (2) and enters the T-shaped component to be detected (2) in a manner of being vertical to an arc interface of the component to be detected; obtaining echo data of each array element of the synthetic aperture, and storing the acquired data into a register;

moving the synthetic aperture to the right by an array element distance, re-exciting the array elements and acquiring data, and storing the acquired data into a register; completing the excitation of all array elements and the acquisition of data until the synthetic aperture moves all array element distances; and (4) calculating the time difference obtained by the data in the register according to a delay rule, and performing delay adjustment, signal superposition and average processing to complete the dynamic focusing database of the synthetic aperture.

3. The method of claim 1, further comprising: in the second step, the first step is carried out,

when the sound wave has a secondary coordinate of (x)_i，z_i) Reaches the focus point (x) of the T-shaped piece to be detected_r，z_r) The refracted acoustic wave has the coordinate of (x)_j，z_j) The jth array element wafer receives, the ultrasonic propagation acoustic path is obtained by the following formula

In the formula: x is the number of_i＝(i-N/2-0.5)·d(i＝1,2,...,N)；

x_i＝(i-N/2-0.5)·d(i＝1,2,...,N)；

z_i＝z_j＝0。

4. The method of claim 1, further comprising: in the third step, the first step is carried out,

selecting an R area of a T-shaped component (2) to be detected as an imaging area, dividing grids by stepping values in the x direction and the z direction to obtain the coordinates of each imaging focus point in the imaging area, and determining the index value of the focus point in echo data;

determining the position of the array element wafer (1a) corresponding to the sound wave passing through the R area interface of the T-shaped member to be detected (2) from the imaging focus point vertically, namely the intersection position of the imaging focus point and the extension line of the central point of the circular arc and the array element wafer (1 a);

then taking the position of the wafer as the center, selecting an adjacent array element wafer as the synthetic aperture of the imaging focus point, and determining the index value of the synthetic aperture in the echo data;

selecting a circular arc center point O for the left half image area of the T-shaped component (2) to be detected₁For the right half imaging area of the T-shaped component (2) to be detected, selecting a circular arc center point O₂(ii) a The start and stop array elements of the synthetic aperture corresponding to the left and right focal points (x, z) can be derived separately,

performing addressing calculation on signal data in a database according to each index value by each sound path obtained by an ultrasonic propagation sound path calculation formula to obtain the amplitude value as the gray value of the imaging focus point, thereby completing defect detection and qualitative and quantitative characterization of a T-shaped R region;

in the formula: n is the number of array elements of the phased array transducer; d is the array element spacing; h is₂Is the vertical distance d between the center of the R-area curved surface and the upper surface of the T-shaped component (2) to be detected₁Is the center O of a curved surface in the R region₁The horizontal distance between the T-shaped member to be detected (2) and the central line; d₂Is the center O of a curved surface in the R region₂The horizontal distance between the T-shaped member to be detected (2) and the central line;

and according to the obtained sound paths, carrying out addressing calculation on the signal data in the database according to the index values to obtain the amplitude value as the gray value of the imaging focus point, thereby completing the defect detection and qualitative and quantitative characterization of the T-shaped R region.

Technical Field

The invention belongs to the technical field of ultrasonic detection, and particularly relates to an ultrasonic detection method for R region defects of a T-shaped component for a machine body structure.

Background

Compared with the world advanced countries, the current aviation maintenance detection technology in China has certain defects, even though the technology is developed rapidly in recent years, the nondestructive detection technology of airplanes in China is continuously strengthened in the aspects of tip, precision, high grade and the like, and particularly, the related technology in the aspect of self-detection inside airplanes is ensured to be really applied to airplane maintenance. Meanwhile, the accuracy of data processing and collection is required to be continuously improved, the automation in the data collection and analysis process is really realized, and a good foundation is laid for the high-speed development of the detection technology. The aircraft structure is easy to have damages such as cracks, rivet looseness, skin heaving and the like under the action of fatigue load and external environment. These damages reduce the strength and stiffness of the aircraft structure and affect the flight performance and flight safety of the aircraft. Similarly, defects in the fuselage structure are critical to the safety of the aircraft during use. If the fuselage has defects such as breakage, fracture and the like in the flight process, great risk is generated to the flight condition, and unpredictable serious consequences are caused to financial resources, personnel safety and the like. Therefore, the regular detection and repair of the aircraft fuselage structure to ensure that the aircraft is in a good state are important guarantees for ensuring the battle force of the troops.

In order to be suitable for different application occasions, most of the members in aerospace have complex shape structure areas, such as L-shaped members, T-shaped members, omega-shaped members and the like which are collectively called as R areas. The transition region of the T-shaped component R of the fuselage structure is a stress concentration region, and defects such as cracks and gaps are easy to generate during production, manufacturing and use, and phenomena such as fracture occur. In order to guarantee the service life of the airplane and the safety and reliability requirements of users, the R area of the T-shaped component of the airplane body structure is subjected to defect detection and safety performance evaluation by adopting an accurate and reliable nondestructive detection technology, and the method has very important significance.

In recent years, the ultrasonic nondestructive testing technology is rapidly developed in the field of industrial testing, the ultrasonic nondestructive testing technology is more and more emphasized and becomes a hot point of research, and more researchers carry out deep research on the ultrasonic nondestructive testing technology. Zhejiang university provides a subsurface defect detection device and method based on ultrasonic modulation, and a subsurface defect detection device and method based on ultrasonic modulation. Publication No.: CN 110779927B. The device comprises an ultrasonic excitation device, a laser scattering detection device, a motion platform, a sample stage, a photodiode, a diode amplifier and a digital oscilloscope; the method combines an ultrasonic modulation technology with a laser scattering defect detection technology, introduces dynamic change of defect characteristics in a motion state by performing ultrasonic modulation on the surface of a detection sample, observes and analyzes the static light scattering effect of the defect in the motion state, and realizes the detection of the defect by analyzing the amplitude and phase change of scattering light intensity. The invention adds ultrasonic modulation in the scattering detection, provides two defect detection results, and provides a visual defect distribution image by utilizing a scanning mode. The invention can be applied to the defect detection of the precise optical element, and is particularly suitable for the finished product detection of the ultra-precise optical element with strict requirements on subsurface defects. The method has problems that: the detection depth is limited, only the defect detection can be carried out on the sub-surface of the component, and the method cannot be suitable for the defect detection of the R region with a certain depth of the T-shaped component in the airframe structure.

University of the major connecting and technical industries provides a thick-wall structure defect detection method based on oblique incidence ultrasonic synthetic aperture focusing, and a thick-wall structure defect detection method based on oblique incidence ultrasonic synthetic aperture focusing. Publication No.: CN 106093205B. The ultrasonic detection system comprises a phased array ultrasonic flaw detector, a phased array ultrasonic probe and an inclined organic glass wedge block, and a phased array electronic scanning function is utilized to detect a test block with a thick-wall structure, so that an A scanning signal set of each phased array element is obtained. And solving the positions of the emergence points of the phased array elements and the image reconstruction points at the wedge block/test block interface by using the Fermat theorem, and performing time delay and amplitude superposition processing on the A scanning signals. And performing Hilbert transform on the processed A scanning signal, and obtaining a reconstructed ultrasonic detection B scanning image by using a difference function. The method has high defect detection resolution and large detection range, can improve the detection efficiency, and provides an effective solution for the nondestructive detection problem of the defects of the thick-wall structure. The method has problems that: the imaging device and method are not suitable for detecting the defects of the R area of the T-shaped component in the airframe structure.

Shanghai Bao Steel industry technical service company and Shanghai Xii assist detection science and technology company provide an ultrasonic phased array automatic detection system for detecting the defects of continuous casting rolls, wherein the ultrasonic phased array automatic detection system is used for detecting the defects of the continuous casting rolls. Publication No.: CN 104597122B. The device comprises a roller storage unit, a scanning transmission unit, a scanning execution unit, an ultrasonic phased array generator, a coupling liquid supply unit and an industrial control computer, wherein the scanning transmission unit drives the scanning execution unit to be connected with the end of a continuous casting roller to be detected on the roller storage unit, the ultrasonic phased array generator controls the scanning execution unit to detect the defect of the continuous casting roller to be detected, the coupling liquid supply unit supplies coupling liquid for the scanning execution unit to detect the defect of the continuous casting roller to be detected, and the industrial control computer is connected with the ultrasonic phased array generator and the scanning transmission unit and is used for controlling the scanning execution unit to execute the detection of the defect of the continuous casting roller to be detected, recording and storing detection data and controlling the scanning transmission unit to drive the scanning execution unit. The detection system realizes automatic detection of the defects of the continuous casting rolls, effectively improves the detection efficiency and the defect detection rate, can accurately and visually display the transverse information of the defects, is convenient to store complete detection information, and ensures the online operation of the continuous casting rolls. The method has problems that: the imaging device and method are not suitable for detecting the defects of the R area of the T-shaped component in the airframe structure.

At present, ultrasonic defect detection on a to-be-detected piece in the market is usually oriented to common structures such as flat plates, bolts, welding lines and the like. However, in the actual detection requirement of aerospace, the T-shaped component with the R region also needs to be subjected to defect nondestructive detection by a corresponding detection method. In summary, the existing market lacks an ultrasonic detection device and method for the R-region defects of T-shaped components of fuselage structures, and qualitative and quantitative characterization is carried out on the defects.

Disclosure of Invention

Aiming at the defects of the prior art of the ultrasonic detection of the R area defects of the T-shaped component, the invention provides the ultrasonic detection method of the R area defects of the T-shaped component facing to the machine body structure, the effective acoustic coupling between the ultrasonic phased array probe and the component to be detected can ensure that an acoustic beam enters the component to be detected as far as possible, the energy loss of the acoustic beam is reduced, and the method is a premise and a basis for realizing the R area detection and ensuring the detection performance; placing an ultrasonic phased array probe on the back plane of the T-shaped component to be detected, and carrying out defect imaging on an internal R area; the ultrasonic phased array probe realizes synthetic aperture dynamic focusing by utilizing an acoustic beam focusing delay rule to obtain a synthetic aperture dynamic focusing database; the synthetic aperture dynamic focusing database is used for dynamic focusing imaging of later-stage defects and qualitative and quantitative characterization of the defects.

The invention is realized by the following scheme:

an ultrasonic detection method for R-region defects of T-shaped components facing a fuselage structure comprises the following steps:

before starting detection, firstly fixing a T-shaped component to be detected, placing an ultrasonic phased array probe on the back plane of the T-shaped component to be detected, and coating a coupling agent on a contact interface of the ultrasonic phased array probe and the T-shaped component to be detected to ensure effective acoustic coupling;

the method specifically comprises the following steps:

the method comprises the following steps: synthesizing the n array elements into a synthetic aperture to obtain a synthetic aperture dynamic focusing database;

step two: calculating the propagation time of the ultrasonic wave;

step three: and determining an index value of the synthetic aperture in the echo data, and carrying out defect ultrasonic detection.

Further, in the first step,

determining the number of array elements of a synthetic aperture, wherein the synthetic aperture is synthesized by combining n array elements into a group, and the ultrasonic phased array probe 1 is excited according to an acoustic beam focusing delay rule, so that a synthetic focused acoustic beam of the synthetic aperture enters the T-shaped member to be detected 2 through the center of an R-region arc surface of the T-shaped member to be detected 2 and is perpendicular to an arc interface of the member to be detected; obtaining echo data of each array element of the synthetic aperture, and storing the acquired data into a register;

moving the synthetic aperture to the right by an array element distance, re-exciting the array elements and acquiring data, and storing the acquired data into a register; completing the excitation of all array elements and the acquisition of data until the synthetic aperture moves all array element distances; and (4) calculating the time difference obtained by the data in the register according to a delay rule, and performing delay adjustment, signal superposition and average processing to complete the dynamic focusing database of the synthetic aperture.

Further, in the second step, the first step,

when the sound wave has a secondary coordinate of (x)_i，z_i) Reaches the focus point (x) of the T-shaped piece to be detected_r，z_r) The refracted acoustic wave has the coordinate of (x)_j，z_j) The jth array element wafer receives, the ultrasonic propagation acoustic path is obtained by the following formula

In the formula: x is the number of_i＝(i-N/2-0.5)·d(i＝1,2,...,N)；

x_i＝(i-N/2-0.5)·d(i＝1,2,...,N)；

z_i＝z_j＝0。

Further, in the third step,

selecting an R area of the T-shaped component to be detected 2 as an imaging area, dividing grids by stepping values in the x direction and the z direction to obtain coordinates of each imaging focus point in the imaging area, and determining an index value of the focus point in echo data;

determining the position of the array element wafer 1a corresponding to the sound wave passing through the R zone interface of the T-shaped member to be detected 2 from the imaging focus point vertically, namely determining the intersection position of the extension line of the imaging focus point and the arc center point and the array element wafer 1 a;

then taking the position of the wafer as the center, selecting an adjacent array element wafer as the synthetic aperture of the imaging focus point, and determining the index value of the synthetic aperture in the echo data;

selecting a circular arc center point O for the left half image area of the T-shaped member to be detected 2₁For the right half imaging area of the T-shaped component 2 to be detected, the arc center point O is selected₂(ii) a The start and stop array elements of the synthetic aperture corresponding to the left and right focal points (x, z) can be derived separately,

performing addressing calculation on signal data in a database according to each index value by each sound path obtained by an ultrasonic propagation sound path calculation formula to obtain the amplitude value as the gray value of the imaging focus point, thereby completing defect detection and qualitative and quantitative characterization of a T-shaped R region;

in the formula: n is the number of array elements of the phased array transducer; d is the array element spacing; h is₂Is the perpendicular distance d between the center of the R-region curved surface and the upper surface of the T-shaped component 2 to be detected₁Is the center O of a curved surface in the R region₁The horizontal distance from the central line of the T-shaped member to be detected 2; d₂Is the center O of a curved surface in the R region₂The horizontal distance from the central line of the T-shaped member to be detected 2;

and according to the obtained sound paths, carrying out addressing calculation on the signal data in the database according to the index values to obtain the amplitude value as the gray value of the imaging focus point, thereby completing the defect detection and qualitative and quantitative characterization of the T-shaped R region.

The invention has the beneficial effects

(1) The invention is oriented to the R area of the T-shaped component of the machine body structure, ultrasonic detection is carried out on the defects based on an ultrasonic phased array synthetic aperture dynamic focusing method, and qualitative and quantitative characterization is carried out;

(2) the effective acoustic coupling between the ultrasonic phased array probe and the member to be detected can ensure that the acoustic beam enters the member to be detected as far as possible, and the energy loss of the acoustic beam is reduced; placing an ultrasonic phased array probe on the back plane of the T-shaped component to be detected, and carrying out defect imaging on an internal R area;

(3) the ultrasonic phased array probe realizes synthetic aperture dynamic focusing by utilizing an acoustic beam focusing delay rule to obtain a synthetic aperture dynamic focusing database; the synthetic aperture dynamic focusing database is used for dynamic focusing imaging of later-stage defects and qualitative and quantitative characterization of the defects.

Drawings

FIG. 1 is a schematic structural diagram of an ultrasonic testing device of the present invention; wherein 1 is a linear array ultrasonic phased array probe, and 2 is a T-shaped component to be detected;

FIG. 2 is a schematic diagram of a linear array ultrasonic phased array probe structure; wherein 1a is an array element wafer, and 1b is a linear array ultrasonic phased array probe shell;

FIG. 3 is a schematic illustration of the acoustic wave travel time;

FIG. 4 is a schematic diagram of synthetic aperture dynamic focus defect detection;

FIG. 5 is a block flow diagram of a defect ultrasonic inspection scheme.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In conjunction with the figures 1 to 5,

an ultrasonic detection method for R-region defects of T-shaped components facing a fuselage structure comprises the following steps:

before starting detection, firstly fixing a T-shaped component to be detected, enabling an ultrasonic phased array probe to be placed on the back plane of the T-shaped component to be detected by taking 32 array elements as an example, and coating a coupling agent on a contact interface of the ultrasonic phased array probe and the T-shaped component to be detected to ensure effective acoustic coupling;

the method specifically comprises the following steps:

the method comprises the following steps: synthesizing the n array elements into a synthetic aperture to obtain a synthetic aperture dynamic focusing database;

step two: calculating the propagation time of the ultrasonic wave;

step three: and determining an index value of the synthetic aperture in the echo data, and carrying out defect ultrasonic detection.

In the first step, the first step is carried out,

determining the number of array elements of a synthetic aperture, wherein the synthetic aperture is synthesized by taking n array elements as a group, 8 array elements are taken as an example to be expressed, and the number of a linear array ultrasonic phased array probe 1 of 32 array elements is 1-32. Starting from the array element No. 1, 8 array elements form a group of synthetic apertures; the ultrasonic phased array probe 1 is excited according to the acoustic beam focusing delay rule, so that the synthetic focused acoustic beam with the synthetic aperture passes through the center of an R area arc surface of the T-shaped component to be detected 2 and enters the T-shaped component to be detected 2 in a manner of being perpendicular to an arc interface of the component to be detected; obtaining echo data of each array element of the synthetic aperture, and storing the acquired data into a register;

moving the synthetic aperture to the right by an array element distance, re-exciting the array elements and acquiring data, and storing the acquired data into a register; until the synthetic aperture moves 25 array element distances, completing the excitation of 25 array elements and the data acquisition; and (3) calculating the time difference obtained by the data in the register according to a delay rule, and performing a series of operations such as delay adjustment, signal superposition, average processing and the like to realize 25 combination into an aperture dynamic focusing database.

In the second step, the first step is carried out,

when the sound wave has a secondary coordinate of (x)_i，z_i) Reaches the focus point (x) of the T-shaped piece to be detected_r，z_r) The refracted acoustic wave has the coordinate of (x)_j，z_j) The jth array element wafer receives, the ultrasonic propagation acoustic path is obtained by the following formula

In the formula: x is the number of_i＝(i-N/2-0.5)·d(i＝1,2,...,N)；

x_i＝(i-N/2-0.5)·d(i＝1,2,...,N)；

z_i＝z_j＝0。

In the third step, the first step is carried out,

selecting an R area of the T-shaped component to be detected 2 as an imaging area, dividing grids by stepping values in the x direction and the z direction to obtain coordinates of each imaging focus point in the imaging area, and determining an index value of the focus point in echo data;

determining the position of the array element wafer 1a corresponding to the sound wave passing through the R zone interface of the T-shaped member to be detected 2 from the imaging focus point vertically, namely determining the intersection position of the extension line of the imaging focus point and the arc center point and the array element wafer 1 a;

then, taking the position of the wafer as the center, selecting 8 adjacent array element wafers as the synthetic aperture of the imaging focus point, and determining the index value of the synthetic aperture in the echo data;

selecting a circular arc center point O for the left half image area of the T-shaped member to be detected 2₁For the right half imaging area of the T-shaped component 2 to be detected, the arc center point O is selected₂(ii) a The start and stop array elements of the synthetic aperture corresponding to the left and right focal points (x, z) can be derived separately,

performing addressing calculation on signal data in a database according to each index value by each sound path obtained by an ultrasonic propagation sound path calculation formula to obtain the amplitude value as the gray value of the imaging focus point, thereby completing defect detection and qualitative and quantitative characterization of a T-shaped R region;

in the formula: n is the number of array elements of the phased array transducer; d is the array element spacing; h is₂Is the perpendicular distance d between the center of the R-region curved surface and the upper surface of the T-shaped component 2 to be detected₁Is the center O of a curved surface in the R region₁The horizontal distance from the central line of the T-shaped member to be detected 2; d₂Is the center O of a curved surface in the R region₂The horizontal distance from the central line of the T-shaped member to be detected 2;

if a (x, z) < 1, let a (x, z) ═ 1 and b (x, z) ═ 8; if b (x, z) > 32, let a (x, z) 25 and b (x, z) 32.

And according to the obtained sound paths, carrying out addressing calculation on the signal data in the database according to the index values to obtain the amplitude value as the gray value of the imaging focus point, thereby completing the defect detection and qualitative and quantitative characterization of the T-shaped R region.

The ultrasonic detection method for the R-region defects of the T-shaped component facing the fuselage structure, which is provided by the invention, is described in detail above, the principle and the implementation mode of the invention are explained, and the description of the above embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.