A millimeter-wave-based in-situ detection device and method for composite material damage

Abstract

The present invention discloses a millimeter-wave-based in-situ detection device and method for composite material damage. The device includes a base, a support mechanism, a horn antenna mechanism, a screw drive mechanism, a clamping mechanism, and a vector network analyzer mechanism. The screw drive mechanism drives the nut seat to move up and down by rotating a handwheel, and simultaneously drives the L-shaped connecting block to move. The L-shaped connecting block, the upper movable crossbeam, and the clamping mechanism are interconnected, and the lower movable crossbeam is fixed by a locking block, thereby driving the two clamp assemblies to move away from or toward each other, enabling real-time stretching or compression of the composite material. The vector network analyzer mechanism connects the vector network analyzer to the horn antenna via a coaxial line, radiating millimeter waves toward the composite material to achieve detection of the composite material. This in-situ detection device can perform in-situ real-time detection of internal defects in composite materials based on millimeter waves, and has a simple structure, stable operation, and easy use.

Description

Technical Field

[0001] The present invention relates to the technical field of in-situ material damage detection, and in particular to a millimeter wave-based in-situ detection device and a measurement method for composite material damage. Background Art

[0002] The macroscopic properties of any material depend on its constituent substances and their microstructure. Generally speaking, tensile or compression tests on a material can yield a load-displacement curve, which in turn can reveal macroscopic mechanical properties such as yield strength and tensile strength. However, this method cannot observe the initiation and development of damage such as cracks within the material in real time, and can only phenomenologically study the material's failure process. In the field of composite material research, different material components and composite forms have a significant impact on the material's macroscopic properties. Therefore, in-situ material detection and evaluation technology has become a highly technical hotspot and research direction in the industry, which requires the development of appropriate test equipment and measurement technologies. In recent years, significant progress has been made in nondestructive material testing using methods such as ultrasound, X-rays, infrared, terahertz, eddy current, and electrical resistance. Meanwhile, increasing research has begun on the application of millimeter waves in this field. Yang et al. used millimeter wave (65-67 GHz) imaging technology to detect impact damage in carbon fiber reinforced composites. However, the system could only detect surface damage, not internal defects, and lacked real-time performance. The Jilin University Nondestructive Testing Laboratory built a three-dimensional imaging radar system for nondestructive material testing based on millimeter waves and terahertz. The system achieved a center frequency of approximately 200 GHz, a bandwidth of up to 47 GHz, and planar and range resolutions of 2.1 mm and 3.2 mm, respectively. However, the system was complex, expensive, and lacked real-time performance. Summary of the Invention

[0003] The purpose of the present invention is to address the defects of the existing technology and provide a millimeter wave based in-situ detection device and measurement method for composite material damage, which realizes the function of real-time detection of internal defects of materials and has the advantages of easy clamping and compact structure.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A millimeter-wave-based in-situ detection device for composite material damage, characterized in that it includes a base, a support mechanism, a horn antenna mechanism, a test piece clamping mechanism, a screw transmission mechanism and a vector network analyzer, wherein the support mechanism includes a longitudinal beam, a fixed crossbeam, an upper movable crossbeam, a lower movable crossbeam, a guide rail and a slider, the longitudinal beam is fixedly connected to the base, the fixed crossbeam is fixedly connected between two longitudinal beams, the guide rail is fixedly arranged below the fixed crossbeam along the inner side of the longitudinal beam, the upper movable crossbeam and the lower movable crossbeam are movably connected to the guide rail through a slider, the test piece clamping mechanism is provided with two groups, which are respectively fixedly connected to the upper movable crossbeam and the lower movable crossbeam, and are used to clamp and fix the test piece, one end of the screw transmission mechanism is fixedly connected to the fixed crossbeam, and the other end is fixedly connected to the upper movable crossbeam, and can drive the upper movable crossbeam to move up and down along the guide rail, the horn antenna mechanisms are respectively arranged on both sides of the support mechanism and fixed to the base, and the vector network analyzer is connected to the horn antenna mechanism via a coaxial line.

[0006] Furthermore, the screw transmission mechanism includes a handwheel, a fixed support, a screw, a nut seat, a support support and an L-shaped connecting block. The fixed beam includes an upper fixed beam and a lower fixed beam. The fixed support and the support support are fixedly connected to the upper fixed beam and the lower fixed beam respectively. The upper end of the screw is threadedly connected to the handwheel, and the lower end is fixedly connected to the nut seat. One end of the L-shaped connecting block is connected to the nut seat, and the other end is connected to the upper movable beam.

[0007] Furthermore, the clamping mechanism of the workpiece to be tested includes a clamp, a clamping plate, a buffer plate and a connecting bolt. The clamp includes a cylindrical rod and a chuck connected to each other. The chuck is provided with two-level grooves, including a first groove and a second groove. The second groove is arranged in the first groove. The two ends of the workpiece to be tested can cooperate with the second groove. The clamping plate is bolted in the first groove. The buffer plate is arranged between the workpiece to be tested and the clamping plate. One end of the cylindrical rod is provided with a threaded hole, and the other end is welded to the chuck. One end of the connecting bolt is threadedly connected to the cylindrical rod, and the other end is fixedly connected to the upper movable beam or the lower movable beam.

[0008] Furthermore, the connecting bolt includes a disc and a threaded rod connected to each other, the disc is provided with a threaded hole, and is bolted to the upper movable beam or the lower movable beam, and the threaded rod is threadedly connected to the cylindrical rod.

[0009] Furthermore, the horn antenna mechanism includes a horn antenna and a supporting bracket connected to each other, and the supporting bracket is fixedly connected to the base.

[0010] Furthermore, a locking block is provided between the lower movable crossbeam and the guide rail, and the locking block can fix the relative position between the lower movable crossbeam and the guide rail.

[0011] A composite material damage detection method based on millimeter waves, using any of the above-mentioned composite material damage in-situ detection devices based on millimeter waves, is characterized by comprising the following steps:

[0012] S1: The test piece is clamped and fixed by the test piece clamping mechanism;

[0013] S2: Adjust the screw drive mechanism so that the test piece faces the horn antenna mechanism;

[0014] S3: Through the power source and control system, the vector network analyzer acts as a radiation source and transmits millimeter waves to the device under test through the horn antenna mechanism on one side. The horn antenna mechanism on the other side receives the transmitted wave signal and transmits it back to the vector network analyzer;

[0015] S4: Fix the lower movable crossbeam and change the position of the upper movable crossbeam by adjusting the screw transmission mechanism, thereby achieving in-situ stretching or compression of the test piece;

[0016] S5: Repeat S3 and S4 until the measurement is completed.

[0017] Furthermore, the waveform of the millimeter wave emitted by the horn antenna is a stepped frequency modulated continuous wave, and the received echo signal is a transmitted wave.

[0018] Compared with the prior art, the beneficial effects of the present invention are: 1. The screw transmission mechanism installed in the present invention, in actual use, drives the nut seat to move up and down by rotating the handwheel, and at the same time drives the L-shaped connecting block to move. Since the L-shaped connecting block, the upper movable crossbeam, and the clamping mechanism are interconnected, and the lower movable crossbeam is fixed by the locking block, the two clamp assemblies are driven to move away from or close to each other, which can realize the in-situ stretching or compression of the material. 2. The present invention adopts a vector network analyzer as a radiation source, and the radiation wave waveform is a step-frequency modulated continuous wave, which can ensure that high-frequency millimeter wave signals are obtained quickly and the millimeter wave signals are radiated outward stably. Millimeter waves are radiated through a horn antenna, and the other horn antenna receives the transmitted signal, which reduces the interference of noise signals, making the overall structure compact, stable in operation, and easy to use. 3. The vector network analyzer structure of the present invention performs real-time in-situ stretching or compression of the material while it is running, realizing the function of real-time in-situ detection of internal defects of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the overall structure of a millimeter wave-based in-situ detection device for composite material damage according to the present invention;

[0020] Figure 2 This is a schematic diagram of the partial structure of a millimeter wave-based in-situ detection device for composite material damage according to the present invention;

[0021] Figure 3 This is a schematic diagram of a support mechanism for a millimeter-wave-based in-situ detection device for composite material damage according to the present invention;

[0022] Figure 4 This is a schematic diagram of a screw transmission mechanism of a millimeter wave-based composite material damage in-situ detection device of the present invention;

[0023] Figure 5 This is a schematic diagram of a guide rail slider of a millimeter wave-based composite material damage in-situ detection device of the present invention;

[0024] Figure 6 This is a schematic diagram of the horn antenna mechanism of a millimeter-wave-based composite material damage in-situ detection device of the present invention;

[0025] Figure 7 This is a schematic diagram of a clamping mechanism for a test piece of an in-situ detection device for composite material damage based on millimeter waves according to the present invention;

[0026] Figure 8 This is a schematic diagram of the connecting bolts of a millimeter wave-based composite material damage in-situ detection device of the present invention;

[0027] Figure 9 This is a schematic diagram of a chuck of a millimeter wave-based composite material damage in-situ detection device of the present invention;

[0028] Among them: 1-base; 2-support mechanism; 3-horn antenna mechanism; 4-screw transmission mechanism; 5-test piece; 6-test piece clamping mechanism; 7-vector network analyzer; 8-coaxial line; 21-longitudinal beam; 22-upper fixed beam; 23-lower fixed beam; 24-upper movable beam; 25-lower movable beam; 26-guide rail; 27-slider; 28-locking block; 31-horn antenna; 32-support bracket; 33-connecting piece; 41-handwheel; 42-fixed support; 43-screw; 44-nut seat; 45-support support; 46-L-shaped connecting block; 61-connecting bolt; 611-circular disc; 612-threaded rod; 62-clamp; 621-cylindrical rod; 622-chuck; 623-first groove; 624-second groove; 63-pressing plate; 64-buffer plate. DETAILED DESCRIPTION

[0029] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0030] Figure 1-9 A specific embodiment of a millimeter wave-based composite material damage in-situ detection device is shown, as shown in FIG. Figure 1 、 2As shown, it includes a base 1, a support mechanism 2, a horn antenna mechanism 3, a test piece clamping mechanism 6, a screw transmission mechanism 4 and a vector network analyzer 7. Figure 3 As shown, the support mechanism 2 includes a longitudinal beam 21, an upper fixed beam 22, a lower fixed beam 23, an upper movable beam 24, a lower movable beam 25, a guide rail 26 and a slider 27. The longitudinal beam 21 is fixedly connected to the base 1 and has a threaded hole on one side. The upper fixed beam 22 and the lower fixed beam 23 are fixedly connected between the two longitudinal beams 21. The guide rail 26 is fixed by bolts along the inner threaded holes of the longitudinal beam 21 below the lower fixed beam 23. The upper movable beam 24 and the lower movable beam 25 are movably connected to the guide rail 26 through the slider 27. Two groups of test piece clamping mechanisms 6 are provided, which are respectively fixedly connected to the upper movable beam 24 and the lower movable beam 25, and are used to clamp and fix the test piece 5. One end of the screw transmission mechanism 4 is fixedly connected to the fixed beam, and the other end is fixedly connected to the upper movable beam 24, which can drive the upper movable beam 24 to move up and down along the guide rail 26. The horn antenna mechanisms 3 are respectively arranged on both sides of the support mechanism 2 and fixed on the base 1. The vector network analyzer 7 is connected to the horn antenna mechanism 3 through the coaxial cable 8.

[0031] like Figure 1 、 4 As shown, the screw drive mechanism 4 includes a handwheel 41, a fixed support 42, a screw 43, a nut seat 44, a support 45, and an L-shaped connecting block 46. The fixed support 42 and the support 45 are fixedly connected to the upper fixed beam 22 and the lower fixed beam 23, respectively. The upper end of the screw 43 is threadedly connected to the handwheel 41, and the lower end is fixedly connected to the nut seat 44. One end of the L-shaped connecting block 46 is connected to the nut seat 44, and the other end is connected to the upper movable beam 24. By rotating the handwheel 41, the nut seat 44 is moved up and down, and the L-shaped connecting block 46 is also moved. Because the L-shaped connecting block 46, the upper movable beam 24, and the test piece clamping mechanism 6 are interconnected, and the lower movable beam 25 is fixed by the locking block 28, the two clamp assemblies are driven to move away from or towards each other, thereby achieving tension or compression of the material.

[0032] like Figure 1 、 7As shown in , 8 and 9, the clamping mechanism of the workpiece to be tested includes a clamp 62, a clamping plate 63, a buffer plate 64 and a connecting bolt 61. The clamp 62 includes a cylindrical rod 621 and a chuck 622 connected to each other. The chuck 622 is provided with two-stage grooves, including a first groove 623 and a second groove 624. The second groove 624 is arranged in the first groove 623. Both ends of the workpiece to be tested 5 can cooperate with the second groove 624. The clamping plate 63 is bolted in the first groove 623. The buffer plate 64 is arranged between the workpiece to be tested 5 and the clamping plate 63. One end of the cylindrical rod 621 is provided with a threaded hole, and the other end is welded to the chuck 622. The connecting bolt 61 includes a circular piece 611 and a threaded rod 612 connected to each other. The circular piece 611 is provided with a threaded hole, which is bolted to the upper movable beam 24 or the lower movable beam 25. The threaded rod 612 and the cylindrical rod 621 are threadedly connected.

[0033] like Figure 6 As shown, the horn antenna mechanism 3 includes a horn antenna 31 and a support bracket 32 connected to each other. The support bracket 32 is fixedly connected to the base 1. By connecting the horn antenna 31 and the support bracket 32 using different threaded holes, the horn antenna 31 can be adjusted vertically. By connecting the connector 33 to the base 1 using different threaded holes, the horn antenna mechanism 3 can be adjusted longitudinally.

[0034] like Figure 5 As shown, a locking block 28 is provided between the lower movable cross beam 25 and the guide rail 26 , and the locking block 28 can fix the relative position between the lower movable cross beam 25 and the guide rail 26 .

[0035] Preferably, the base 1 is assembled from three approximately rectangular structures, ultimately forming a cross shape. The upper fixed beam 22, the lower fixed beam 23, the upper movable beam 24 and the lower movable beam 25 are all provided with weight-reducing holes.

[0036] A composite material damage detection method based on millimeter waves using the above embodiment includes the following steps:

[0037] S1: Place the upper and lower ends of the test piece 5 into the second groove 624 of the test piece clamping mechanism 6, and stack the buffer plate 64 and the pressing plate 63 on top of them to fix them;

[0038] S2: Turn the handwheel 41 of the screw transmission mechanism 4 so that the test piece 5 faces the horn antenna mechanism 3, and then fix the locking block 28 to fix the lower movable crossbeam 25 and the guide rail 26;

[0039] S3: Through the power source and control system, the vector network analyzer 7 acts as a radiation source and transmits millimeter waves to the device under test 5 through the horn antenna mechanism 3 on one side. The horn antenna mechanism 3 on the other side receives the transmitted wave signal and transmits it back to the vector network analyzer 7;

[0040] S4: The position of the upper movable crossbeam 24 is changed by rotating the hand wheel 41, thereby achieving in-situ stretching or compression of the test piece 5;

[0041] S5: Repeat S3 and S4 until the measurement is completed.

[0042] Preferably, the waveform of the millimeter wave emitted by the horn antenna 31 is a stepped frequency modulated continuous wave, and the received echo signal is a transmitted wave.

[0043] The above specific implementation methods are only for illustrating the technical concept and structural features of the present invention, and the purpose is to enable relevant persons familiar with this technology to implement them accordingly. However, the above content does not limit the scope of protection of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A millimeter wave-based in-situ detection device for composite material damage, characterized by: The invention comprises a base (1), a support mechanism (2), a horn antenna mechanism (3), a test piece clamping mechanism (6), a screw transmission mechanism (4) and a vector network analyzer (7), wherein the support mechanism (2) comprises a longitudinal beam (21), a fixed crossbeam, an upper movable crossbeam (24), a lower movable crossbeam (25), a guide rail (26) and a slider (27), wherein the longitudinal beam (21) is fixedly connected to the base (1), the fixed crossbeam is fixedly connected between the two longitudinal beams (21), the guide rail (26) is fixedly arranged below the fixed crossbeam along the inner side of the longitudinal beam (21), and the upper movable crossbeam (24) and the lower movable crossbeam (25) are connected by the slider (27) to form a plurality of movable crossbeams. ) is movably connected to the guide rail (26), the test piece clamping mechanism (6) is provided with two groups, which are respectively fixedly connected to the upper movable crossbeam (24) and the lower movable crossbeam (25), and are used to clamp and fix the test piece (5), one end of the screw transmission mechanism (4) is fixedly connected to the fixed crossbeam, and the other end is fixedly connected to the upper movable crossbeam (24), and can drive the upper movable crossbeam (24) to move up and down along the guide rail (26), the horn antenna mechanism (3) is respectively arranged on both sides of the support mechanism (2) and fixed on the base (1), and the vector network analyzer (7) is connected to the horn antenna mechanism (3) through a coaxial line (8); The screw transmission mechanism (4) includes a handwheel (41), a fixed support (42), a screw (43), a nut seat (44), a support seat (45) and an L-shaped connecting block (46); the fixed beam includes an upper fixed beam (22) and a lower fixed beam (23); the fixed support (42) and the support seat (45) are fixedly connected to the upper fixed beam (22) and the lower fixed beam (23), respectively; the upper end of the screw (43) is threadedly connected to the handwheel (41), and the lower end is fixedly connected to the nut seat (44); one end of the L-shaped connecting block (46) is connected to the nut seat (44), and the other end is connected to the upper movable beam (22).

2. The millimeter wave-based in-situ detection device for composite material damage according to claim 1, characterized in that: The test piece clamping mechanism (6) comprises a clamp (62), a pressing plate (63), a buffer plate (64) and a connecting bolt (61); the clamp (62) comprises a cylindrical rod (621) and a clamp (622) connected to each other; the clamp (622) is provided with a two-stage groove, comprising a first groove (623) and a second groove (624); the second groove (624) is provided in the first groove (623); the two ends of the test piece (5) can be connected to the clamp (621) and the clamp (622) The second groove (624) cooperates with the clamping plate (63), the clamping plate (63) is bolted in the first groove (623), the buffer plate (64) is arranged between the test piece (5) and the clamping plate (63), one end of the cylindrical rod (621) is provided with a threaded hole, and the other end is welded to the chuck (622), one end of the connecting bolt (61) is threadedly connected to the cylindrical rod (621), and the other end is fixedly connected to the upper movable beam (24) or the lower movable beam (25).

3. The millimeter wave-based in-situ detection device for composite material damage according to claim 2, characterized in that: The connecting bolt (61) comprises a circular piece (611) and a threaded rod (612) connected to each other. The circular piece (611) is provided with a threaded hole and is bolted to the upper movable crossbeam (24) or the lower movable crossbeam (25). The threaded rod (612) is threadedly connected to the cylindrical rod (621).

4. The millimeter wave-based in-situ detection device for composite material damage according to claim 1, characterized in that: The horn antenna mechanism (3) comprises a horn antenna (31) and a support bracket (32) connected to each other, and the support bracket (32) is fixedly connected to the base (1).

5. The millimeter wave-based in-situ composite material damage detection device according to claim 1, characterized in that: A locking block (28) is provided between the lower movable crossbeam (25) and the guide rail (26), and the locking block (28) is capable of fixing the relative position between the lower movable crossbeam (25) and the guide rail (26).

6. A composite material damage measurement method based on millimeter waves, using the composite material damage in-situ detection device based on millimeter waves according to any one of claims 1 to 5, characterized in that: The steps include: S1: clamping and fixing the test piece (5) with the test piece clamping mechanism (6); S2: adjusting the screw drive mechanism (4) so that the test piece (5) faces the horn antenna mechanism (3); S3: Through the power source and control system, the vector network analyzer (7) acts as a radiation source to transmit millimeter waves to the device under test (5) through the horn antenna mechanism (3) on one side, and the horn antenna mechanism (3) on the other side receives the transmitted wave signal and transmits it back to the vector network analyzer (7); S4: Fixing the lower movable crossbeam (25), and changing the position of the upper movable crossbeam (24) by adjusting the screw transmission mechanism (4), thereby achieving in-situ stretching or compression of the test piece (5); S5: Repeat S3 and S4 until the measurement is completed.

7. The composite material damage determination method based on millimeter waves according to claim 6, characterized in that: The waveform of the millimeter wave emitted by the horn antenna mechanism (3) is a step frequency modulation continuous wave, and the received echo signal is a transmitted wave.

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