KR20230037312A - Piezocomposite damage detecting sensor and non-destructive inspection apparatus - Google Patents

Abstract

The present invention provides a highly reliable and stable piezocomposite damage detecting sensor and a non-destructive inspection apparatus through a support film including a first insulating layer, a circuit pattern layer, and a second insulating layer. The piezocomposite damage detecting sensor according to an embodiment of the present invention includes a plurality of piezoelectric elements; a base accommodating each of the plurality of piezoelectric elements to be spaced apart from each other; and a support film supporting the base and the plurality of piezoelectric elements, wherein the support film includes a first insulating layer provided on the base and the plurality of piezoelectric elements, a circuit pattern layer formed on the first insulating layer, and a second insulating layer provided on the circuit pattern layer to protect the circuit pattern layer.

Description

Piezocomposite damage detecting sensor and non-destructive inspection apparatus

The present invention relates to a piezoelectric composite damage detection sensor and a non-destructive testing device, and more particularly, to a highly reliable and stable piezoelectric composite damage detection sensor and a non-destructive testing device.

Conventional non-destructive testing techniques were able to inspect only localized damage on the surface of a structure, but recent non-destructive testing techniques evaluate the integrity of a structure using, for example, ultrasonic thickness detection, and the residual of the structure. It can help predict lifespan, and condition-based maintenance rather than conventional schedule-driven inspections can be possible.

These non-destructive inspection technologies are closely related to related sensor technologies. Sensors are used as basic tools for monitoring structures and assessing their safety and health. Various sensor development and sensing technology are core technologies used in all modern industries and research fields, and are actively used in the field of soundness and damage detection of structures. In order to develop non-destructive testing technology, the development of new and efficient sensors must be carried out in parallel. .

Accordingly, non-destructive inspection technology using a guided wave such as a lamb wave is attracting great attention by reflecting the recent requirements. A lamb wave is an elastic wave that can propagate a long distance within a thin-walled structure. When using a lamb wave, the number of sensors required for damage detection can be significantly reduced compared to conventional ones. In particular, sensors using piezoelectric ceramics have advantages such as small size, light weight, low price, and various shapes, as well as structural integrity monitoring, damage detection, and non-destructive inspection. It is emerging as a useful technique.

In ultrasonic non-destructive testing including Lamb wave, transducers and sensors using disc-shaped piezoelectric ceramics are mainly used. Such non-destructive testing using piezoelectric ceramics typically includes a method of utilizing wave propagation, frequency response characteristics, and impedance change.

However, due to high brittleness, which is a typical characteristic of ceramics, piezoelectric ceramics may cause a problem in that they are easily broken by a large external impact. Therefore, a technique for solving the problem of high brittleness of piezoelectric ceramics used in piezoelectric sensors is required.

In addition, the structure for which damage is to be detected may be damaged due to fatigue damage, environmental damage, accidents caused by lightning, hail, algae, and external objects occurring during its operating life. This damage has a problem that has a fatal effect on the soundness of the structure. Therefore, a technology capable of maintaining stable performance in extreme environments including lightning strikes is also required.

Korean Registered Patent Publication No. 10-1346557

The present invention provides a highly reliable and stable piezoelectric composite damage detection sensor and a non-destructive testing device.

A piezoelectric composite damage detection sensor according to an embodiment of the present invention includes a plurality of piezoelectric elements; a base portion accommodating each of the plurality of piezoelectric elements so as to be spaced apart from each other; and a support film supporting the base and the plurality of piezoelectric elements, wherein the support film includes: a first insulating layer provided on the base and the plurality of piezoelectric elements; a circuit pattern layer formed on the first insulating layer; and a second insulating layer provided on the circuit pattern layer to protect the circuit pattern layer.

Each of the plurality of piezoelectric elements is provided in a pellet shape and is a piezoelectric ceramic made of a ceramic material, and the base portion may be plate-shaped.

The base portion may exhibit a higher elastic modulus than the support film and a lower elastic modulus than the piezoelectric element.

A thickness of the second insulating layer may be greater than a thickness of the first insulating layer.

The second insulating layer may be provided in a plurality of layers.

The support film may include a first support film disposed between an object to be damaged and the piezoelectric element; and a second support film disposed to face the first support film based on the piezoelectric element, wherein the first insulating layers of the first support film and the second support film are respectively provided at positions corresponding to each other. and a via hole electrically connecting the first support film and the second support film.

The second support film may further include an external connection terminal provided on the second insulating layer and electrically connecting the circuit pattern layer and an external device.

The base portion may include a plurality of accommodating holes spaced apart from each other, and the plurality of piezoelectric elements may be accommodated in each of the plurality of accommodating holes.

The piezoelectric element includes a protruding portion provided in a form in which a portion of a side surface protrudes, and an end portion of the protruding portion may contact a portion of an inner wall of the receiving hole.

The plurality of piezoelectric elements may be spaced apart from each other at regular intervals.

The first insulating layer may include a plurality of through holes spaced apart at the interval.

Each of the base part and the support film may include an alignment mark, and the base part and the support film may be aligned based on the alignment mark and attached to each other.

The base may have a strip shape extending in one direction, and the plurality of piezoelectric elements may be arranged in a line along the one direction.

A non-destructive testing device according to another embodiment of the present invention includes a piezoelectric composite damage detection sensor according to an embodiment of the present invention; a power supply unit for applying a voltage so that at least one selected piezoelectric element among the plurality of piezoelectric elements generates an elastic wave; a signal measurer for measuring an electrical signal output when the generated elastic wave reaches a piezoelectric element adjacent to the selected piezoelectric element; and a switch unit selectively connecting the plurality of piezoelectric elements to the power supply unit or the signal measurement unit, respectively.

It may further include a damage determination unit that receives data measured by the signal measurement unit, compares the measured data with reference data, and determines that damage exists when it is out of a preset range.

The piezoelectric composite damage detection sensor according to an embodiment of the present invention includes a support film having a first insulating layer, a circuit pattern layer, and a second insulating layer, and is resistant to electrical shock to maintain stable sensing performance in extreme environments. . In particular, since the thickness of the second insulating layer is thicker than that of the first insulating layer, reliability of the sensor can be secured by suppressing damage that has a fatal effect on the integrity of an object to be detected. In addition, the piezoelectric composite damage detection sensor may provide a damage detection sensor in which the brittleness of piezoelectric ceramics is supplemented by providing a base portion accommodating a plurality of piezoelectric elements spaced apart to form a piezoelectric composite, and the distance between each piezoelectric element is Since they are kept spaced apart by branches, a separate distance measurement procedure for damage detection may not be necessary, and convenient damage detection may be provided.

At this time, by making the modulus of elasticity of the base part lower than that of the piezoelectric element, it is possible to prevent the elastic wave from propagating directly to other piezoelectric elements around it through the support part in contact with the piezoelectric element when damage to the object is detected using the elastic wave, and the reliability of the sensor can improve

In addition, the support film may include a first support film and a second support film disposed to face each other based on the piezoelectric element to insulate and protect the piezoelectric element from the outside. In this case, the first support film and the second support film may be electrically connected to each other by including via holes. The second support film may include an external connection terminal to electrically connect the circuit pattern layer and an external device.

In particular, the first insulating layer includes a plurality of through-holes in which a plurality of piezoelectric elements are spaced apart, and is attached to the surface of a curved object by being bent, and the piezoelectric element can reach the inside of the through-holes at a fixed position. That is, the piezoelectric composite damage detection sensor of the present invention can be attached to the surface of a complex structure to detect damage.

In addition, the non-destructive testing device using the piezoelectric composite damage detection sensor according to the present invention can selectively change its function among actuating in which each piezoelectric element generates an elastic wave or sensing in which an electrical signal is output by an elastic wave, and one Since the piezoelectric element can function as an actuator and a sensor, a complicated design can be reduced and the weight of the device can be reduced.

1 is a cross-sectional view showing a support film of a piezoelectric composite damage detection sensor according to an embodiment of the present invention.
2 is a view showing a piezoelectric composite damage detection sensor according to an embodiment of the present invention.
3 is a cross-sectional view showing a first support film and a second support film according to an embodiment of the present invention.
4 is a schematic view showing a support film according to an embodiment of the present invention.
5 is a cross-sectional view showing a piezoelectric composite damage detection sensor according to an embodiment of the present invention.
6 is a cross-sectional view showing a piezoelectric element of the piezoelectric composite damage detection sensor according to an embodiment of the present invention.
7 is an exploded perspective view showing a piezoelectric composite damage detection sensor according to an embodiment of the present invention;
8 is a configuration diagram showing a non-destructive testing device according to another embodiment of the present invention.
9 is a graph showing electrical signals measured over time in a non-destructive testing device according to another embodiment of the present invention.
10 is a conceptual diagram illustrating a method for generating damage data of a non-destructive testing device according to another embodiment of the present invention.
11 is a conceptual diagram illustrating a non-destructive inspection method of a piezoelectric composite damage detection sensor according to an embodiment of the present invention.
12 is a conceptual diagram illustrating a non-destructive inspection method of a plurality of piezoelectric composite damage detection sensors according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only these embodiments will complete the disclosure of the present invention, and will fully cover the scope of the invention to those skilled in the art. It is provided to inform you. During the description, the same reference numerals are assigned to the same components, and the drawings may be partially exaggerated in size in order to accurately describe the embodiments of the present invention, and the same numerals refer to the same elements in the drawings.

1 is a cross-sectional view showing a support film 130 of a piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention.

2 is a diagram showing a piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention.

1 and 2, the piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention includes a plurality of piezoelectric elements 110; a base portion 120 accommodating each of the plurality of piezoelectric elements 110 so as to be spaced apart from each other; and a support film 130 supporting the base portion 120 and the plurality of piezoelectric elements 110, wherein the support film 130 includes the base portion 120 and the plurality of piezoelectric elements ( 110) provided on the first insulating layer 131; a circuit pattern layer 132 formed on the first insulating layer 131; and a second insulating layer 133 provided on the circuit pattern layer 132 to protect the circuit pattern layer 132 .

The piezoelectric element 110 is a material that exhibits characteristics of converting electrical energy into mechanical energy or vice versa, and the piezoelectric effect occurs when a voltage is applied to the piezoelectric element 110 from the outside. refers to the phenomenon of mechanical displacement. These piezoelectric effects include the direct piezoelectric effect in which an electrical signal is generated at the output terminal when an external stress or vibration displacement is applied to the piezoelectric element 110, and the mechanical displacement of the element when a voltage is applied to the piezoelectric element 110 from the outside. There is a reverse piezoelectric effect.

Due to the piezoelectric effect, the piezoelectric element 110 can cause mechanical displacement and generate elastic waves when a voltage is applied, for example, a solid such as a thin plate representing two parallel and adjacent free interfaces such as a Lamb Wave. A non-destructive test may be performed by using an elastic wave capable of propagating to a long distance within the object, propagating the elastic wave to an object, and measuring a change in the elastic wave.

The types of piezoelectric materials include quartz, Rochelle salt, barium titanate (PbTiO ₃ ), PZT, and Non-Pb piezoelectric ceramics. Since it is a very high and precisely controllable material, it can be suitable for use in sensor technology that requires precision.

Accordingly, a plurality of piezoelectric elements 110 may be attached to the surface of an object to be damaged to be spaced apart from each other, and a voltage may be applied to the piezoelectric element 110 to generate elastic waves, and the elastic waves may be generated on the surface of the object. An electrical signal may be generated in another spaced piezoelectric element 110 by propagating along, and damage to the object may be detected by analyzing the electrical signal.

However, such a damage detection sensor may require a cumbersome procedure of directly measuring the distance between each piezoelectric element 110 and analyzing data, and since piezoelectric ceramics are a brittle material, the piezoelectric element 110 is exposed to the external environment as it is, and a problem that can be easily destroyed may occur.

In order to solve the above problem, by using a thin film or the like that can be attached on at least one surface of the plurality of piezoelectric elements 110, by arranging the plurality of piezoelectric elements 110 at regular intervals, each There may be an attempt to reduce the cumbersome work procedure of measuring the distance between the piezoelectric elements 110 of each time.

However, it may be difficult to solve the problem of brittleness of piezoelectric ceramics by only disposing the piezoelectric element 110 using the film or the like, and the lifespan and reliability of the sensor may also decrease. In addition, since the film may be stretched according to the shape of an object, it may be difficult to maintain a constant distance between the piezoelectric elements 110 .

Therefore, a technique capable of compensating for the brittleness of the piezoelectric ceramics and a technique capable of maintaining a constant distance between the piezoelectric elements 110 may be additionally required.

On the other hand, in the piezoelectric composite damage detection sensor 100 of the present invention, a material having excellent mechanical properties is provided as a matrix to compensate for the brittleness of the piezoelectric element 110, and the piezoelectric element 110 is placed inside the matrix. By arranging, the piezoelectric element 110 and the base phase may form a piezoelectric composite, and a sensor technology in which brittleness of the piezoelectric element 110 is compensated may be provided. In addition, since the distance between the plurality of piezoelectric elements 110 can be maintained constant by the base phase, it may not be necessary to measure the distance between the plurality of piezoelectric elements 110, and a convenient sensor technology can be provided. .

A plurality of piezoelectric elements 110 are provided and can be spaced apart and accommodated by the base 120, and the upper and lower surfaces of the piezoelectric elements 110 and the base 120 are each a support film. Supported by 130, the piezoelectric element 110 can be insulated from the outside. The support film 130 may be attached to the surface of an object to be damaged, and electrodes 111 are connected to both ends of the piezoelectric element 110, and the electrodes 111 are connected to the support film 130. It is connected to the circuit pattern (132a) formed in. The circuit pattern 132a is connected to an external connection terminal 135 through a wire 138, and the piezoelectric element 110 may be electrically connected to an external device through the external connection terminal 135. In addition, the piezoelectric element 110 may generate an elastic wave by receiving a voltage from an external device connected to the external connection terminal 135 through the wire 138 .

Accordingly, the elastic wave may propagate along the contact surface of the support film 130 and the object to be damaged, and other piezoelectric elements 110 adjacent to the elastic wave generation point may transmit electrical signals by the elastic wave. can be printed out. The electrical signal may be transferred to an external device through the wire 138 and the external connection terminal 135, and damage to the object may be detected by analyzing the electrical signal.

The base portion 120 and the plurality of piezoelectric elements 110 may be disposed on a surface sharing the same plane, and the arrangement is such that the piezoelectric elements 110 are inside the base portion 120. It may be dispersed and inserted, and the base portion 120 and the plurality of piezoelectric elements 110 may form a piezoelectric composite on the one surface which is the same plane.

At this time, the base part 120 may be a material with flexibility, and the stress applied to the piezoelectric element 110 is distributed by the structural support of the base part 120, so that the piezoelectric element 110 ) can be compensated for, the piezoelectric element 110 can be prevented from being broken by an external impact, and the reliability of the piezoelectric composite damage detection sensor 100 can be improved.

Such a base portion 120 may use a polymer having excellent flexibility or a composite including a polymer, for example, a material strong against external impact and flexible such as FRP (Fiber Reinforced Plastics) may be used. In particular, If a glass epoxy such as flame retardant 4 (FR4) is used, it may be more suitable for the present invention because it exhibits electrical insulation as well as high mechanical strength.

In addition, since the distance between the plurality of piezoelectric elements 110 can be maintained constant by the base part 120, a cumbersome work procedure in which the distance between each of the piezoelectric elements 110 must be measured every time is eliminated. can be reduced

In addition, the piezoelectric element 110 and the base part 120 are structurally supported on the back side facing the one surface, which is the same plane shared by the base part 120 and the plurality of piezoelectric elements 110, and A support film 130 capable of protecting may be attached to each of them, and the support film 130 may prevent the one side and the back side of the piezoelectric element 110 and the base part 120 from being directly exposed to the outside. In addition, even if the piezoelectric composite in which the piezoelectric element 110 and the base 120 are combined is bent, the piezoelectric element 110 can be structurally protected from being separated from the base 120, and damage to the piezoelectric composite can be detected. The outer shape of the sensor 100 can be stably maintained.

In addition, the support film 130 may be made of an insulating material, can maintain the electrical connection of the piezoelectric element 110, and protect the piezoelectric element 110 and the base 120 from the outside. can As the support film 130, for example, a polyimide (PI) film may be used, but is not particularly limited thereto.

The base portion 120 may be provided, for example, by arranging the plurality of piezoelectric elements 110 in a mold and injecting and molding the base portion 120 into the mold, and the piezoelectric element ( 110) does not interfere with the actuating and sensing functions, it can be provided so that an error space does not occur between the plurality of piezoelectric elements 110 provided, and it does not interfere with attaching to the surface of an object to detect damage. It is sufficient if it can be provided in a form that does not.

For example, when using a sensor composed of only the piezoelectric element 110 and the support film 130, an empty space between each of the plurality of piezoelectric elements 110 is attached to the upper surface of the piezoelectric element 110. The support film 130 attached to the lower surface of the piezoelectric element 110 and the support film 130 attached to the lower surface of the piezoelectric element 110 may be provided in a form in contact with each other, and around the piezoelectric element 110, the piezoelectric element 110 Due to the thickness, the support films 130 do not come into contact with each other and a space containing air may occur.

The shape of the contact surface attached to the object may be distorted (eg, the support film 130 does not come into contact with the surface of the object and is lifted) due to the air-containing space, and thus, the object and the support A surface exposed to air may be formed on a part of the contact surface between the films 130, and the shape of the elastic wave generated from the piezoelectric element 110 may be deformed or the propagation speed may be reduced to detect damage to the object, , the reliability of the sensor may deteriorate.

On the other hand, when a space containing the air exists when a sensor is used in a harsh external environment such as a lightning test, the air in the space is rapidly expanded by lightning electricity and a shock wave may be generated, and the performance of the sensor is improved by the shock wave may be lowered

Therefore, by providing the base portion 120 to accommodate the plurality of piezoelectric elements 110, the space containing air may not be generated around the piezoelectric elements 110, and a part of the contact surface with the object A surface exposed to air may not be formed on the sensor, performance of the sensor may be prevented from deteriorating when used in a harsh external environment, and reliability of the sensor may be increased.

The support film 130 may be disposed above and below the base portion 120 and the plurality of piezoelectric elements 110 to support the base portion 120 and the plurality of piezoelectric elements 110 . For example, as described later, the support film 130 includes a first support film 130a and a second support film 130b, and the first support film 130a and the second support film 130b are It is provided on the upper and lower surfaces of the piezoelectric element 110, respectively, and may be formed in a shape symmetrical to each other. The support film 130 may include a first insulating layer 131 , a circuit pattern layer 132 , and a second insulating layer 133 .

The first insulating layer 131 is provided on the base portion 120 and the plurality of piezoelectric elements 110 to electrically protect the electrodes 111 connected to both ends of the piezoelectric elements 110. can

The circuit pattern layer 132 may be formed on the first insulating layer 131 and printed with a metallic material. In this case, the circuit pattern layer 132 may include a plurality of circuit patterns 132a and wires 138 connected to external devices. Due to this, the piezoelectric element 110 may exchange electrical signals with an external device through the circuit pattern 132a and the wire 138 . At this time, the circuit pattern layer 132 and the wiring 138 may be provided on the upper and lower surfaces of the piezoelectric element 110, respectively, and are formed in a form symmetrical to each other, so that the piezoelectric composite damage detection sensor 100 ) Even if a plurality of piezoelectric elements 110 are disposed inside, an electrical connection to an external connection terminal 135 for connecting the piezoelectric elements 110 to an external device can be conveniently provided.

The second insulating layer 133 may be provided on the circuit pattern layer 132 to protect the circuit pattern layer 132 . That is, the piezoelectric composite damage detection sensor 100 of the present invention includes the first insulating layer 131 and the second insulating layer 133 provided on the upper and lower portions of the circuit pattern layer 132, so that through this dual structure Since the circuit pattern layer 132 is protected, the stability of the sensor can be secured. For example, when the piezoelectric composite damage detection sensor 100 of the present invention is attached to an aircraft structure and used as an object to detect damage, the reliability of the sensor can be secured. Aircraft structures manufactured in complex structures may be damaged due to accidents caused by fatigue damage, environmental damage, lightning strikes, hailstones, algae, and external substances that occur during the operational life span. Such damage can have a catastrophic effect on the integrity of the aircraft structure. In particular, a sensor attached to an aircraft must maintain stable performance in an extreme environment including lightning strikes, and for this purpose, a structure for ensuring reliability of the sensor may be essential. At this time, the piezoelectric composite damage detection sensor 100 of the present invention can secure the stability of the sensor by including the second insulating layer 133 protecting the circuit pattern layer 132 .

That is, the piezoelectric composite damage detection sensor 100 of the present invention includes the support film 130 having the first insulating layer 131, the circuit pattern layer 132 and the second insulating layer 133, It is resistant to impact and can maintain stable sensing performance in extreme environments. In particular, the circuit pattern layer 132 may serve as a shield due to the wiring 138 included in the circuit pattern layer 132 .

In addition, the support film 130 includes an adhesive layer between the first insulating layer 131 and the circuit pattern layer 132 or between the circuit pattern layer 132 and the second insulating layer 133, Structural stability can be increased by suppressing interlayer separation.

The plurality of piezoelectric elements 110 are each provided in a pellet shape and are piezoelectric ceramics made of a ceramic material, and the base portion 120 may be plate-shaped.

Each of the plurality of piezoelectric elements 110 is provided in a pellet shape, and the base portion 120 may have a plate shape. In addition, the piezoelectric element 110 may be provided in a form showing the same thickness in one piezoelectric element 110 itself. That is, the upper surface and the lower surface may be in a flat shape, for example, a pellet shape, but are not particularly limited thereto.

The amount of displacement of the piezoelectric element 110 due to the piezoelectric effect may be proportional to the thickness of the piezoelectric element 110, and if the thickness of the piezoelectric element 110 is not constant, the amount of displacement may not be constant, and elastic waves generated at this time The shape of may also be non-homogeneous. Therefore, by providing a constant amount of displacement in the thickness direction of the piezoelectric element 110 by the piezoelectric effect in one piezoelectric element 110, the displacement amount in the thickness direction within one piezoelectric element 110 can be provided constant. In addition, the strength of the elastic wave generated when the voltage is applied to the piezoelectric element 110 may also be constant, and the reliability of the piezoelectric composite damage detection sensor 100 may be improved.

Therefore, the base portion 120 may also be provided in a plate shape so that it can exist on the same plane as the piezoelectric element 110, so that the support film 130 can be easily supported, and it is possible to detect It may be provided so as to be easily attached to the surface of the object.

At this time, the thickness of the base portion 120 may be 90% to 110% of the average thickness of the plurality of piezoelectric elements 110 . Each of the plurality of piezoelectric elements 110 may be provided with the same thickness, and the meaning of the same may mean that they are functionally the same in an error range of -5% to +5%, not only physically identical. .

When a difference in thickness occurs between the plurality of piezoelectric elements 110 and the base 120, the support film 130 is attached to the upper and lower surfaces of the piezoelectric elements 110 and the base 120, respectively. When this occurs, the support film 130 may be bent due to a difference in thickness between the piezoelectric element 110 and the base 120, and a space containing air may occur, resulting in an error in transmitting elastic waves. .

Accordingly, the thickness of the base portion 120 may be provided at 90% to 110% of the average thickness of the piezoelectric element 110 so as to be functionally the same as the average thickness of the plurality of piezoelectric elements 110, It is possible to prevent the support film 130 from being bent due to a difference in height between the piezoelectric element 110 and the base part 120, it is possible to prevent a space containing air from being generated, and an error in elastic wave transmission can be prevented. It is possible to improve the reliability of the piezoelectric composite damage detection sensor 100 by preventing damage.

Also, the piezoelectric element 110 may include piezoelectric ceramics made of a ceramic material. Types of piezoelectric materials include quartz, Rochelle salt, barium titanate (PbTiO ₃ ), PZT, and Non-Pb piezoelectric ceramics. It has excellent piezoelectricity and may be suitable for use in the present invention.

However, due to high brittleness, which is a typical characteristic of ceramics, the piezoelectric ceramics may be easily broken by external impact, and when used as a sensor, a problem of reducing durability of the sensor device may occur.

Thus, the base portion 120 may be flexible. The base portion 120 of the present invention may be provided to have flexibility, and may form a piezoelectric composite with the piezoelectric element 110 to disperse stress acting on the piezoelectric element 110, and may be piezoelectric. The brittleness of the ceramic may be compensated for, and the piezoelectric element 110 may be prevented from being broken from an external impact.

Such a base portion 120 may use a polymer having excellent flexibility or a composite including a polymer, for example, a material strong against external impact and flexible such as FRP (Fiber Reinforced Plastics) may be used. In particular, If a glass epoxy such as flame retardant 4 (FR4) is used, it may be more suitable for the present invention because it exhibits electrical insulation as well as high mechanical strength.

At this time, the base portion 120 may exhibit a higher elastic modulus than the support film 130 . The support film 130 may be provided with a material that can be bent or stretched so that it can be adhered to the surface of objects of various shapes in close contact. Even if the object has a curved surface, the support film 130 is bent and the It can be attached to an object.

The base portion 120 may exhibit a higher elastic modulus than the support film 130 and a lower elastic modulus than the piezoelectric element 110 .

Accordingly, the base portion 120 may exhibit a higher modulus of elasticity than the support film 130, may prevent the support film 130 from being stretched, and may prevent the entire structure of the piezoelectric composite damage detection sensor 100. can be kept stable. In addition, the distance between the plurality of piezoelectric elements 110 can be kept constant, the occurrence of errors in the piezoelectric composite damage detection sensor 100 can be reduced, and the piezoelectric composite damage detection sensor 100 Reliability can be improved.

Meanwhile, the support film 130 may directly contact the object to be damaged, and at this time, the elastic wave generated from the piezoelectric element 110 must pass through the support film 130 to be transmitted to the object. can

Since the elastic wave generated from the piezoelectric element 110 is propagated by the restoring force to return to its original state when deformation is applied to the medium, when the elastic modulus of the medium is small, the recovery rate for deformation decreases and the transmission of the elastic wave becomes difficult. can

Since the support film 130 should be provided with a material that is easily deformable so that it can be attached to the surface of objects having various shapes, that is, a material exhibiting a low elastic modulus can be used, and therefore, the Due to the modulus of elasticity, it may be difficult for the elastic wave to pass through, problems may arise in which the propagation of the elastic wave to the object may be hindered, and reliability of the piezoelectric composite damage detection sensor 100 may decrease.

Accordingly, it is possible to provide a thin thickness of the support film 130, minimize the effect of the modulus of elasticity of the support film 130, and prevent the elastic wave from becoming difficult to pass through the support film 130. And, the elastic wave can be smoothly propagated to the object, and the performance of the piezoelectric composite damage detection sensor 100 can be improved.

Meanwhile, the base portion 120 may exhibit a lower modulus of elasticity than the piezoelectric element 110 . When an elastic wave is generated by applying a voltage to the piezoelectric element 110, the elastic wave propagates through the base part 120 in contact with the piezoelectric element 110, not the contact surface with the object to be detected. Since damage information may not be measured on the object, and radio wave interference may occur, electrical signals output from other piezoelectric elements 110 in the vicinity may be distorted, and the piezoelectric composite damage detection sensor 100 ) may decrease the reliability.

Accordingly, the base portion 120 may be provided to exhibit a lower elastic modulus than the piezoelectric element 110, and as described above, the elastic wave may be more difficult to propagate as the elastic modulus is lower, so in the piezoelectric element 110 The generated elastic wave is difficult to propagate in the base portion 120 having a low modulus of elasticity, it is possible to minimize distortion of electrical signals output from other piezoelectric elements 110, and to improve the reliability of the piezoelectric composite damage detection sensor 100. can improve

Therefore, the modulus of elasticity of the base portion 120 may be determined by the modulus of elasticity of the support film 130 and the piezoelectric element 110, and exhibits a higher modulus of elasticity than the support film 130, and a higher modulus than that of the piezoelectric element 110. It can be determined in a range showing a low elastic modulus.

At this time, the preferred elastic modulus of the material that can be used as the support film 130 of the present invention may represent an elastic modulus of several GPa, for example, a PI film or the like may be used, and suitably 1 to 5 GPa elasticity can be expressed.

In addition, the elastic modulus of the piezoelectric element 110 of the present invention may preferably be a high elastic modulus of several hundred GPa, and by such a high elastic modulus, the elastic wave may be easily generated, and the elastic wave may be easily generated as a target for detecting damage. Elastic waves may be easily transmitted, and thus reliability of the piezoelectric composite damage detection sensor 100 may be improved.

Therefore, the base part 120 may preferably exhibit an elastic modulus of 10 GPa to 50 GPA in consideration of the elastic modulus of the support film 130 and the piezoelectric element 110, and the piezoelectric composite damage detection sensor 100 By supporting the internal structure, it is possible to prevent the piezoelectric composite damage detection sensor 100 from being deformed to the extent that it cannot function, and to prevent the elastic wave generated from the piezoelectric element 110 from being transmitted through the base part 120. And the reliability of the piezoelectric composite damage detection sensor 100 can be improved.

A thickness of the second insulating layer 133 may be greater than a thickness of the first insulating layer 131 .

When the thickness of the second insulating layer 133 is greater than that of the first insulating layer 131 , the circuit pattern layer 132 may be protected. In addition, when the thickness of the second insulating layer 133 is thicker than that of the first insulating layer 131, insulation characteristics may be improved. For example, when the object to be damaged is an aircraft structure, the circuit pattern layer 132 prevents fatigue damage, environmental damage, lightning, hail, birds, and accidents caused by external substances through the second insulating layer 133. ) can be protected. Due to this, since the piezoelectric composite damage detection sensor 100 of the present invention maintains stable performance in an extreme environment including lightning, it is possible to secure the stability of the sensor and ensure reliability.

The second insulating layer 133 may be provided in a plurality of layers.

Since the second insulating layer 133 is provided as a plurality of layers, the circuit pattern layer 132 may be protected. In addition, since the second insulating layer 133 is provided as a plurality of layers, insulating properties may be improved. For example, when the object to be damaged is an aircraft structure, the circuit pattern layer 132 prevents fatigue damage, environmental damage, lightning, hail, birds, and accidents caused by external substances through the second insulating layer 133. ) can be protected. Due to this, since the piezoelectric composite damage detection sensor 100 of the present invention maintains stable performance in an extreme environment including lightning, it is possible to secure the stability of the sensor and ensure reliability.

Additionally, by including an adhesive layer between a plurality of layers of the second insulating layer 133, separation between the layers may be suppressed to increase structural stability.

The support film 130 includes a first support film 130a disposed between an object to be damaged and the piezoelectric element 110; and a second support film 130b disposed to face the first support film 130a based on the piezoelectric element 110, wherein the first support film 130a and the second support film 130b Each of the first insulating layers 131 of ) may include a via hole 134 provided at a position corresponding to each other and electrically connecting the first support film 130a and the second support film 130b. can

The first support film 130a (ie, the lower support film) may be disposed between an object to be damaged and the piezoelectric element 110 . That is, the first support film 130a may be attached to the surface of an object to be damaged. In this case, the circuit pattern layer 132 of the first support film 130a may include a common electrode (ie, a common wiring).

The second support film 130b (ie, the upper support film) may be disposed to face the first support film 130a based on the piezoelectric element 110 . Due to this, the piezoelectric element 110 may be insulated from the outside. In this case, the circuit pattern layer 132 of the second support film 130b may include a plurality of circuit patterns 132a connected to external connection terminals 135 as will be described later. The plurality of circuit patterns 132a connected to the external connection terminal 135a may be connected to the common electrode (ie, a common wire) through a via hole 134 as will be described later. Also, the common electrode may be connected to an external connection terminal 135b connected to the common electrode through the via hole 134 .

The via hole 134 of the first support film 130a and the via hole 134 of the second support film 130b are provided at positions corresponding to each other in the first insulating layer 131 so that they match each other. can be reached In this case, the via hole 134 may be filled with a conductive material. Accordingly, the first support film 130a and the second support film 130b may be electrically connected through the via hole 134 . In particular, the plurality of circuit patterns 132a connected to the external connection terminal 135 may be connected to the common electrode (ie, a common wire) through the via hole 134 .

Here, the via hole 134 of the first support film 130a and the via hole 134 of the second support film 130b are provided at positions corresponding to each other in the first insulating layer 131. , The support film 130 may include an alignment mark 137 as will be described later.

The second support film 130b may further include an external connection terminal 135 provided on the second insulating layer 133 and electrically connecting the circuit pattern layer 132 and an external device. .

The external connection terminal 135 is provided on the second insulating layer 133 and can electrically connect the circuit pattern layer 132 and an external device through a wire 138 . In this case, the external connection terminal 135 may include an external connection terminal 135a connected to the circuit pattern 132a and an external connection terminal 135b connected to the common electrode. In addition, the piezoelectric element 110 may generate an elastic wave by receiving a voltage from an external device connected to the external connection terminal 135 through the wire 138 . In this case, the number of external connection terminals 135a connected to the circuit pattern 132a may be the same as the number of piezoelectric elements 110 . That is, each of the plurality of piezoelectric elements 110 may be connected to each of the external connection terminals 135a connected to the plurality of circuit patterns 132a.

Here, since all areas of the piezoelectric composite damage detection sensor 100 of the present invention must be in close contact with the structure to detect damage, the plurality of external connection terminals 135 are attached to a part of the piezoelectric composite damage detection sensor 100. can be placed. That is, the connection from the piezoelectric composite damage detection sensor 100 to the external connection terminal 135 may be made on one side of the piezoelectric composite damage detection sensor 100 . To this end, the piezoelectric composite damage detection sensor 100 of the present invention may electrically connect the first support film 130a and the second support film 130b through the via hole 134 .

3 is a cross-sectional view showing the first support film 130a and the second support film 130b according to an embodiment of the present invention.

Referring to FIG. 3 , it can be seen that each of the first support film 130a and the second support film 130b includes a first insulating layer 131, a circuit pattern layer 132, and a second insulating layer 133. there is. In addition, it can be confirmed that each of the first insulating layers 131 of the first support film 130a and the second support film 130b has a via hole 134 . And it can be seen that the external connection terminal 135 is further included on the second insulating layer 133 of the second support film 130b. In addition, it can be confirmed that the second insulating layer 133 of the second support film 130b is provided in a plurality of layers and is thicker than the thickness of the first insulating layer 131 .

4 is a schematic diagram showing a support film 130 according to an embodiment of the present invention.

Referring to FIG. 4 , the support film 130 includes a circuit pattern 132a, a wiring 138, an external connection terminal 135a connected to the circuit pattern 132a, and an external connection terminal 135b connected to the common electrode. can know that At this time, it can be seen that each of the plurality of circuit patterns 132a of the support film 130 is connected to the upper external connection terminal 135a through the wiring 138 .

5 is a cross-sectional view showing a piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention. FIG. 5 (a) shows the sheet-shaped piezoelectric composite damage detection sensor 100, and FIG. 5 (b) Indicates a strip-shaped piezoelectric composite damage detection sensor 100.

Referring to FIG. 5 , the piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention may provide various forms of disposing the piezoelectric element 110 according to the shape of an object to be detected. For example, the sheet-shaped piezoelectric composite damage detection sensor 100 as shown in FIG. 100) can be used for an object with a narrow width and a shape extending in the longitudinal direction.

The base portion 120 includes a plurality of accommodation holes 121 spaced apart from each other, and the plurality of piezoelectric elements 110 may be accommodated in each of the plurality of accommodation holes 121 .

The base portion 120 may include a plurality of accommodating holes 121 for accommodating the piezoelectric element 110, and the upper surface of the piezoelectric element 110 is opposed by the accommodating hole 121. A lower surface may be provided to be exposed from the base portion 120 . Accordingly, propagation of elastic waves by the base portion 120 can be prevented, signal interference caused by elastic waves passing through the base portion 120 can be prevented, and the piezoelectric composite damage detection sensor ( 100) can improve reliability.

The piezoelectric element 110 includes a protruding portion 112 provided in a form in which a portion of a side surface protrudes, and an end portion of the protruding portion 112 may come into contact with a portion of an inner wall of the receiving hole 121 .

The piezoelectric element 110 may generate an elastic wave by receiving a voltage, and the elastic wave directly propagates to other piezoelectric elements 110 around it through the base part 120 in contact with the piezoelectric element 110. To prevent this, a protrusion 112 may be provided on the piezoelectric element 110, and the base part 120 and the piezoelectric element 110 may come into contact only by the end of the protrusion 112, and the base part Transmission of the elastic wave through 120 may be minimized.

The plurality of piezoelectric elements 110 may be spaced apart from each other at regular intervals.

Since each of the plurality of piezoelectric elements 110 must function as an actuator and a sensor, the plurality of piezoelectric elements 110 are spaced apart at regular intervals, so that the same distance is maintained between the actuator and the sensor even if the functions as the actuator and the sensor are switched. can keep Thus, the same distance value can be used as reference data for determining the change of the elastic wave, and data processing for detecting damage to the object can be conveniently provided.

6 is a cross-sectional view showing the piezoelectric element 110 of the piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention.

Referring to FIG. 6 , it can be seen that the piezoelectric element 110 includes a protrusion 112 provided in a form in which a portion of a side surface protrudes, and an end portion of the protrusion 112 is in contact with a portion of the inner wall of the receiving hole 121. . In addition, it can be confirmed that the plurality of piezoelectric elements 110 are spaced apart from each other at regular intervals.

The first insulating layer 131 may include a plurality of through holes 136 spaced at the above interval.

The plurality of through holes 136 are spaced at the interval at which the plurality of piezoelectric elements 110 are spaced apart, so that the plurality of through holes 136 and the plurality of piezoelectric elements 110 are at positions corresponding to each other. can be provided. Here, at least a portion of the inside of the through hole 136 may come into contact with the piezoelectric element 110 due to external pressure. Also, the first insulating layer 131 may be bent due to the plurality of through holes 136 . Due to this, the piezoelectric composite damage detection sensor 100 of the present invention can be flexibly attached in response to the shape of an object to be damaged. That is, it can be attached to the surface of a curved object and can detect damage in objects of various shapes. At this time, the through hole 136 may be filled or empty.

Each of the base part 120 and the support film 130 includes an alignment mark 137, and the base part 120 and the support film 130 are aligned based on the alignment mark 137 and attached to each other. can

Each of the base part 120 and the support film 130 includes an alignment mark 137, so that the base part 120 and the support film 130 are aligned and attached to each other based on the alignment mark 137. can Here, each of the first insulating layer 131 , the circuit pattern layer 132 , and the second insulating layer 133 of the support film 130 may also include an alignment mark 137 . As a result, the via hole 134 of the first support film 130a and the via hole 134 of the second support film 130b are provided at positions corresponding to each other in the first insulating layer 131, , they may come into contact with each other at the right position and be electrically connected. In addition, each of the plurality of piezoelectric elements 110 and the plurality of through holes 136 of the first support film 130a are provided at positions corresponding to each other, so that the piezoelectric elements 110 are inserted into the through holes at the correct positions. (136) can touch the inside.

The base portion 120 may have a strip shape extending in one direction, and the plurality of piezoelectric elements 110 may be arranged in a line along the one direction.

The shape of the base portion 120 may be provided in a form suitable for the object to be damaged, but as shown in FIG. can be used for objects of The piezoelectric composite damage detection sensor 100 made of such a strip-shaped base 120 can be easily attached to various curved surfaces, and is provided so that a plurality of them can be used in a horizontal direction, so that an object to be damaged does not meet the standard. Even without it, the piezoelectric composite damage detection sensor 100 can be tightly attached, and the area where damage cannot be detected can be minimized.

7 is an exploded perspective view showing a piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention.

Referring to FIG. 7 , the base portion 120 includes a plurality of spaced accommodating holes 121 , and a plurality of piezoelectric elements 110 may be accommodated in each of the plurality of accommodating holes 121 . In addition, it can be confirmed that the electrodes 111 are connected to both ends of the piezoelectric element 110 . Also, it can be seen that the first support film 130a and the second support film 130b are disposed to face each other based on the piezoelectric element 110 . In addition, it can be confirmed that each of the base portion 120 and the support film 130 includes an alignment mark 137 .

8 is a configuration diagram showing a non-destructive testing device according to another embodiment of the present invention.

Referring to FIG. 8, a non-destructive testing device according to another embodiment of the present invention will be looked at in more detail. Matters overlapping with those described above in relation to the piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention are omit it.

A non-destructive testing device according to another embodiment of the present invention includes a piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention; a power supply unit 300 that applies a voltage so that at least one selected piezoelectric element 110 among the plurality of piezoelectric elements 110 generates an elastic wave; a signal measurer 400 for measuring an electrical signal output when the generated elastic wave reaches the piezoelectric element 110 adjacent to the selected piezoelectric element 110; and a switch unit 500 selectively connecting the plurality of piezoelectric elements 110 to the power supply unit 300 or the signal measuring unit 400, respectively.

It may further include a damage determining unit 210 that receives data measured by the signal measurement unit 400 and compares the measured data with reference data to determine that damage exists when it is out of a preset range. there is.

A plurality of piezoelectric elements 110 are provided and can be spaced apart and accommodated by the base 120, and the upper and lower surfaces of the piezoelectric elements 110 and the base 120 are each a support film. Supported by 130, the piezoelectric element 110 can be insulated from the outside. That is, the support film 130 includes a first support film 130a and a second support film 130b, and the first support film 130a and the second support film 130b comprise the piezoelectric element 110 ) are provided on the upper and lower surfaces of each, and may be formed in a form symmetrical to each other. The support film 130 may include a first insulating layer 131 , a circuit pattern layer 132 , and a second insulating layer 133 . In this case, since the second insulating layer 133 has a thicker thickness than the second insulating layer 131, insulation characteristics may be improved. Due to this, the piezoelectric composite damage detection sensor 100 of the present invention is resistant to electrical shock and can maintain stable sensing performance in extreme environments.

The support film 130 may be attached to the surface of an object to be damaged, and electrodes 111 are connected to both ends of the piezoelectric element 110, and the electrodes 111 are connected to the support film 130. The circuit pattern 132a is connected to an external connection terminal 135 through a wire 138, and the piezoelectric element 110 is connected to the external connection terminal 135 through the external connection terminal 135. It can be electrically connected to an external device. In addition, the piezoelectric element 110 may generate an elastic wave by receiving a voltage from an external device connected to the external connection terminal 135 through the wire 138 .

Accordingly, the elastic wave may propagate along the contact surface between the object and the support film 130, and other piezoelectric elements 110 adjacent to the generation point of the elastic wave may output an electric signal by the elastic wave. . The electrical signal may be transmitted to the signal measurement unit 400 through the circuit pattern 132a, and the data obtained by measuring the strength of the electrical signal in the signal measurement unit 400 is transmitted to the damage determination unit 210 and the damage determination unit 210. It can be transmitted to the control unit 200 including the information unit 220. The damage determination unit 210 may compare the measured data with a reference value to detect whether or not the object is damaged, and the damage information unit 220 may analyze the data to determine the location of the damage and the size of the damage. In addition, the piezoelectric element 110 may be selectively connected to the power supply unit 300 or the signal measuring unit 400 by the switch unit 500 .

9 is a graph showing electrical signals measured over time in a non-destructive testing device according to another embodiment of the present invention.

Referring to FIG. 9 , damage detection by elastic waves may include a method of accumulating reference data when there is no damage and comparing the reference data when damage occurs to analyze a difference.

Such reference data may be, for example, the time taken for the elastic wave to arrive. Therefore, it is determined that the damage has occurred by measuring the time for which the elastic wave reaches through the damage and confirming that the time for the elastic wave to arrive has increased compared to the reference data when there is damage to the object to be measured. can detect

At this time, since the distance from the actuated piezoelectric element A to the sensing piezoelectric element S is already known, the signal generated from the actuated piezoelectric element A is transmitted to the sensing piezoelectric element S. When the arrival time is measured, the elastic wave velocity (V _g, group velocity) can be obtained as in the above formula, and the distance to damage (d _d ) can be calculated using the thus obtained velocity of the elastic wave.

10 is a conceptual diagram illustrating a method of generating damage data of a non-destructive testing device according to another embodiment of the present invention.

Referring to FIG. 10 , an elliptic equation having an actuated piezoelectric element A and a sensing piezoelectric element S as two focal points may be configured.

By measuring at least three experimental data consisting of the actuated piezoelectric element (A) and the sensing piezoelectric element (S), three elliptic equations can be obtained, and the damage location can be estimated with the overlapping center point of the ellipse. .

11 is a conceptual diagram illustrating a non-destructive inspection method of the piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention.

Referring to FIG. 11 , the non-destructive testing method includes selecting at least one piezoelectric element 110 from among the plurality of piezoelectric elements 110; generating an elastic wave by applying a voltage to the selected piezoelectric element 110; and measuring an electrical signal output by the elastic wave from the piezoelectric element 110 adjacent to the selected piezoelectric element 110 .

A process of re-selecting at least one piezoelectric element 110 among the piezoelectric elements 110 at a position different from the selected piezoelectric element 110; and generating the elastic wave, and measuring the electrical signal. The process can be repeated.

The plurality of piezoelectric elements 110 included in the piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention each have two functions of actuating to generate elastic waves and sensing to output electrical signals by the elastic waves. It may be provided to perform, and by providing the plurality of piezoelectric elements 110 to sequentially actuate and sense, it is possible to detect a specific location of damage to a large area of an object.

Accordingly, an elastic wave can be generated by applying a voltage to the frontmost piezoelectric element 110, and the elastic wave reaches another piezoelectric element 110 adjacent to the periphery through an object to be detected, and the other piezoelectric element 110 may output an electrical signal, and may detect damage to the object by measuring the electrical signal.

In addition, by releasing the voltage and applying a voltage from the piezoelectric element 110 from which the voltage is released to another adjacent piezoelectric element 110, the position of the piezoelectric element A sequentially actuated can be changed, and the object can detect the specific location of the damage that has occurred.

12 is a conceptual diagram illustrating a non-destructive inspection method for a plurality of piezoelectric composite damage detection sensors 100 according to an embodiment of the present invention.

Referring to FIG. 12 , the non-destructive testing method includes arranging a plurality of the piezoelectric composite damage detection sensors 100 in parallel with each other; A process of selecting at least one of the plurality of piezoelectric elements 110; generating an elastic wave by applying a voltage to the selected piezoelectric element 110; And among the plurality of piezoelectric elements 110 provided in the piezoelectric composite damage detection sensor 100 including the selected piezoelectric element 110 and the piezoelectric composite damage detection sensor 100 adjacent thereto, the selected piezoelectric element 110 A step of measuring an electrical signal output by the elastic wave from the piezoelectric element 110 adjacent to the piezoelectric element 110 may be included.

The piezoelectric composite damage detection sensor 100 according to an embodiment of the present invention may have a strip shape, and may be provided so that a plurality of strip-shaped piezoelectric composite damage detection sensors 100 can be used in a horizontal direction.

The piezoelectric composite damage detection sensor 100 in the form of a strip transmits elastic waves generated from the piezoelectric element 110 included in one piezoelectric composite damage detection sensor 100 to another piezoelectric composite damage detection sensor 100 adjacent to the piezoelectric composite. It can be detected by the device 110, and, for example, by measuring the distance between the plurality of strip-shaped piezoelectric composite damage detection sensors 100 and inputting reference data, damage to the plurality of strip-shaped piezoelectric composites is detected. Damage to the object may be detected using the sensor 100 .

Accordingly, even if the object to be damaged does not meet the standard, the piezoelectric composite damage detection sensor 100 can be tightly attached and the area where damage cannot be detected can be minimized.

As such, in the present invention, the piezoelectric composite damage detection sensor includes a support film having a first insulating layer, a circuit pattern layer, and a second insulating layer, and can maintain stable sensing performance in an extreme environment. In particular, since the thickness of the second insulating layer is thicker than that of the first insulating layer, reliability of the sensor can be secured by suppressing damage that has a fatal effect on the integrity of an object to be detected. In addition, the piezoelectric composite damage detection sensor may provide a damage detection sensor in which the brittleness of piezoelectric ceramics is supplemented by providing a base portion accommodating a plurality of piezoelectric elements spaced apart to form a piezoelectric composite, and the distance between each piezoelectric element is Since they are kept spaced apart by branches, a separate distance measurement procedure for damage detection may not be necessary, and convenient damage detection may be provided.

At this time, by making the modulus of elasticity of the base part lower than that of the piezoelectric element, it is possible to prevent the elastic wave from propagating directly to other piezoelectric elements around it through the support part in contact with the piezoelectric element when damage to the object is detected using the elastic wave, and the reliability of the sensor can improve

In addition, the support film may include a first support film and a second support film disposed to face each other based on the piezoelectric element to insulate and protect the piezoelectric element from the outside. In this case, the first support film and the second support film may be electrically connected to each other by including via holes. Here, the second support film may include an external connection terminal to electrically connect the circuit pattern layer and the external device.

In particular, the first insulating layer includes a plurality of through-holes in which a plurality of piezoelectric elements are spaced apart, and is attached to the surface of a curved object by being bent, and the piezoelectric element can come into contact with the inside of the through-holes at a fixed position. That is, the piezoelectric composite damage detection sensor of the present invention can be attached to the surface of a complex structure to detect damage.

In addition, the non-destructive testing device using the piezoelectric composite damage detection sensor according to the present invention can selectively change its function among actuating in which each piezoelectric element generates an elastic wave or sensing in which an electrical signal is output by an elastic wave, and one Since the piezoelectric element can function as an actuator and a sensor, a complicated design can be reduced and the weight of the device can be reduced.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above embodiments, and common knowledge in the field to which the present invention pertains without departing from the gist of the present invention claimed in the claims. Those who have will understand that various modifications and other equivalent embodiments are possible from this. Therefore, the technical protection scope of the present invention should be determined by the claims below.

100: piezoelectric composite damage detection sensor 110: piezoelectric element
111: electrode 112: protrusion
120: base 121: accommodation hall
130: support film 130a: first support film
130b: second support film 131: first insulating layer
132: circuit pattern layer 132a: circuit pattern
133: second insulating layer 134: via hole
135: external connection terminal 136: through hole
137: alignment mark 138: wiring
200: control unit 210: damage determination unit
220: damage information unit 300: power unit
400: signal measurement unit 500: switch unit
A: Actuated piezoelectric element S: Sensing piezoelectric element

Claims (15)

a plurality of piezoelectric elements;
a base portion accommodating each of the plurality of piezoelectric elements so as to be spaced apart from each other; and
Including; a support film supporting the base and the plurality of piezoelectric elements,
The support film,
a first insulating layer provided on the base and the plurality of piezoelectric elements;
a circuit pattern layer formed on the first insulating layer; and
A piezoelectric composite damage detection sensor including a second insulating layer provided on the circuit pattern layer to protect the circuit pattern layer. The method of claim 1,
The plurality of piezoelectric elements are each provided in a pellet shape and are piezoelectric ceramics made of a ceramic material,
The base portion is a plate-shaped piezoelectric composite damage detection sensor. The method of claim 1,
The base part,
A piezoelectric composite damage detection sensor exhibiting a higher elastic modulus than the support film and a lower elastic modulus than the piezoelectric element. The method of claim 1,
The thickness of the second insulating layer is thicker than the thickness of the first insulating layer piezoelectric composite damage detection sensor. The method of claim 1,
The second insulating layer is a piezoelectric composite damage detection sensor provided in a plurality of layers. The method of claim 1,
The support film,
a first support film disposed between an object to be damaged and the piezoelectric element; and
A second support film disposed to face the first support film based on the piezoelectric element;
Each of the first insulating layers of the first support film and the second support film,
A piezoelectric composite damage detection sensor comprising via holes provided at corresponding positions to electrically connect the first support film and the second support film. The method of claim 6,
The second support film,
The piezoelectric composite damage detection sensor further comprising an external connection terminal provided on the second insulating layer and electrically connecting the circuit pattern layer and an external device. The method of claim 1,
The base portion includes a plurality of receiving holes spaced apart and penetrating,
The plurality of piezoelectric elements are respectively accommodated in the plurality of receiving holes, respectively, the piezoelectric composite damage detection sensor. The method of claim 8,
The piezoelectric element includes a protrusion provided in a form in which a portion of a side surface protrudes,
The end of the protrusion is in contact with a portion of the inner wall of the receiving hole piezoelectric composite damage detection sensor. The method of claim 1,
The plurality of piezoelectric elements are piezoelectric composite damage detection sensors provided at regular intervals. The method of claim 10,
The first insulating layer is a piezoelectric composite damage detection sensor comprising a plurality of through-holes spaced apart at the interval. The method of claim 1,
Each of the base portion and the support film includes an alignment mark,
The piezoelectric composite damage detection sensor in which the base and the support film are aligned based on the alignment mark and attached to each other. The method of claim 1,
The base portion has a strip shape extending in one direction,
A piezoelectric composite damage detection sensor in which the plurality of piezoelectric elements are arranged in a line along the one direction. Claims 1 to 13 of any one of the piezoelectric composite damage detection sensor;
a power supply unit for applying a voltage so that at least one selected piezoelectric element among the plurality of piezoelectric elements generates an elastic wave;
a signal measurer for measuring an electrical signal output when the generated elastic wave reaches a piezoelectric element adjacent to the selected piezoelectric element; and
A non-destructive testing device including a switch unit for selectively connecting the plurality of piezoelectric elements to the power supply unit or the signal measurement unit, respectively. The method of claim 14,
A damage determination unit that receives the data measured by the signal measurement unit, compares the measured data with reference data, and determines that damage exists when it is out of a preset range.

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