Waveguide-based signal filter design method

Abstract

The invention provides a waveguide-based signal filter design method, which mainly utilizes waveguide rods with different materials, structural forms and lengths to amplify or attenuate, pass and cut off damaged signals, and combines the needs of signal acquisition to complete the function of filtering the signals, thereby realizing the acquisition of effective signals. According to the signal filter based on waveguide rod hardware, waveguide and filtering integrated design is adopted, the characteristics of the waveguide rod can be fully utilized, signals are directly filtered, effective information is obtained, signal collection and filtering in complex environments such as high temperature, strong noise and high radiation are achieved, and the collection efficiency of damage acoustic emission signals in the complex environments is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of acoustic non-destructive testing and sensing, and particularly relates to a design method of a signal filter based on a waveguide. Background Art

[0002] With the wide application of acoustic emission technology in engineering, there is a need for damage detection and monitoring technologies in complex environments such as high temperature, strong noise, and high radiation. For areas that operators cannot reach or access, new acoustic emission sensors need to be developed to meet the damage detection and monitoring in extreme environments. The general operating temperature of traditional acoustic emission sensors is not more than 170 degrees, and they cannot be used in high-temperature environments. At the same time, since a coupling agent is required between the structure and the acoustic emission sensor to improve the signal transmission efficiency, the complexity of sensor installation is increased. In this case, a waveguide rod is generally needed to indirectly obtain the damage acoustic emission signal. The selection of inappropriate waveguide rod materials, diameters, and lengths greatly affects the transmission of acoustic emission signals, which will bring great uncertainties to damage location and damage evaluation, and even lead to incorrect results.

[0003] Designing and optimizing the parameters of the waveguide rod so that the waveguide rod not only serves as a wave conduction element but also filters the signal, passing and amplifying the useful frequency signals of interest and attenuating and blocking the unwanted frequency signals will greatly improve the effective evaluation of damage under extreme environmental conditions. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems existing in the prior art, solve the technical problem of effectively collecting damage acoustic emission signals in extremely complex environments, and provide a design method of a signal filter based on a waveguide. This method mainly utilizes the characteristics of waveguide rods of different materials, structural forms, and lengths to amplify or attenuate, pass and cut off damage signals, and combines the needs of collecting signals to complete the function of filtering signals, thereby realizing the collection of effective signals.

[0005] The present invention provides a design method of a signal filter based on a waveguide. This method mainly utilizes the characteristics of the waveguide rod to amplify or attenuate, pass and cut off signals to realize the filtering of signal frequencies. According to the use environment, appropriate waveguide rod materials are selected; according to the requirements of signal acquisition frequencies, through design analysis, parameters such as the structural form, length, and diameter of the waveguide rod are selected to achieve accurate signal acquisition and effectively improve the application efficiency of acoustic emission technology in complex environments.

[0006] The design method mainly includes the selection of waveguide rod materials, the design of structural forms, and the determination of lengths. Parameters such as waveguide rod materials, structural forms, diameters, and lengths are the main factors affecting the characteristics of signal amplification or attenuation, passing and cutting off.

[0007] First, select high-temperature or radiation-resistant materials as the waveguide rod materials according to the working environmental state of the structure to be monitored. Secondly, according to the requirements for the frequency range and signal amplitude of the damage signal, adopt an analysis method combining experiments and theories, and select structural forms such as straight rods, linear shapes, flat shapes, and tubular shapes for analysis. Finally, based on the requirements for signal sensitivity, amplitude characteristics, and effective frequency indicators in damage detection, comprehensively analyze and determine the length parameter of the waveguide rod. According to the requirements of damage detection, the waveguide rod obtained after analysis and design can obtain signals with certain sensitivity and frequency characteristics, thereby realizing signal filtering from the hardware.

[0008] The beneficial effects of the present invention are as follows:

[0009] The signal filter based on the waveguide rod hardware of the present invention adopts an integrated waveguide filtering design, which can make full use of the characteristics of the waveguide rod, directly filter the signal, obtain effective information, and realize signal acquisition and filtering in complex environments such as high temperature, strong noise, and high radiation; improve the acquisition efficiency of damage acoustic emission signals in complex environments. Description of the Drawings

[0010] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation to the present invention:

[0011] Figure 1 is a principle flowchart of a waveguide-based signal filter design method according to an embodiment of the present invention;

[0012] Figure 2 is the dispersion curve of the waveguide rod calculated according to an embodiment of the present invention;

[0013] Figure 3 is the time-frequency analysis feature of the swept-frequency signal according to an embodiment of the present invention. Detailed Embodiments

[0014] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0015] This embodiment provides a waveguide-based signal filter design method. The specific steps are as follows:

[0016] The first step is the selection of the waveguide rod material. According to the usage environmental conditions, select a suitable waveguide rod material. For special environments such as high temperature and radiation resistance, special materials such as high-temperature resistant materials need to be selected.

[0017] The second step is the selection of the waveguide rod structure form. According to the results of theoretical research, preliminarily determine the structure form of the waveguide rod, including but not limited to straight rods, tubular, linear structures, and threaded structures, etc.

[0018] The third step is to determine the acquisition frequency range and amplitude sensitivity. According to the monitored stress state, material type, and damage state, preliminarily estimate the frequency range of damage generation in the material and the requirements for the amplitude size for positioning.

[0019] The fourth step is to determine the diameter of the waveguide rod. According to the structural material and structure form determined in the above two steps 1 and 2, calculate the dispersion curve of the waveguide rod to determine the diameter of the waveguide rod, as Figure 2 shown.

[0020] The fifth step is to manufacture waveguide rod specimens of different lengths according to the material, structure form, and diameter determined in the above steps.

[0021] The sixth step is to obtain the frequency characteristics of the waveguide rod. Input a broadband swept-frequency signal at one end of the waveguide rod, and use a broadband acoustic emission sensor at the other end of the waveguide rod to collect the transmitted signal. Perform time-frequency analysis on the signal to obtain the frequency characteristics of the waveguide rod at different lengths, as Figure 3 shown. According to the requirements of the test for the signal acquisition frequency, determine the waveguide rod length that meets the conditions.

[0022] The seventh step is to design the waveguide rod for actual engineering applications using the waveguide rod parameters obtained from the foregoing analysis, calculation, and tests, which can meet the requirements of the frequency range of the acoustic emission signal generated by damage, realize the signal filter function based on the waveguide rod hardware, and thus avoid the technical problem of frequency distortion generated by the waveguide rod.

[0023] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments are obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A waveguide-based signal filter design method, characterized in that: Here are the steps: Step 1: Selection of waveguide rod material; Select appropriate waveguide rod material according to the use environment conditions; Step 2: Selection of waveguide rod structure; Step 3: Determine the acquisition frequency range and amplitude sensitivity; Step 4: Determine the diameter of the waveguide rod; Step 5: According to the material, structure and diameter determined in the above steps, waveguide rod specimens of different lengths are manufactured; Step 6: Obtain the frequency characteristics of the waveguide rod; input a broadband sweep signal at one end of the waveguide rod, use a broadband acoustic emission sensor at the other end of the waveguide rod to collect the transmitted signal, perform time-frequency analysis, and determine the waveguide rod length that meets the conditions; Step 7: Using the waveguide rod parameters obtained from the above analysis, calculation and test, design the waveguide rod for actual engineering application to meet the requirements of the frequency range of the acoustic emission signal caused by damage.

2. A waveguide-based signal filter design method according to claim 1, characterized in that: The waveguide rod structure includes: straight rod, tubular, linear structure and threaded structure.

3. The waveguide-based signal filter design method according to claim 1, characterized in that: The determination of the acquisition frequency range and amplitude sensitivity is specifically as follows: based on the monitored stress state, material type and damage state, a preliminary estimation is made of the damage frequency range in the material and the amplitude requirement for positioning.

4. The waveguide-based signal filter design method according to claim 1, characterized in that: The determining of the diameter of the waveguide rod specifically includes: calculating the waveguide rod dispersion curve according to the structural material and structural form determined in the first to third steps, and determining the diameter of the waveguide rod.

5. A waveguide-based signal filter design method according to any one of claims 1 to 4, characterized in that: The integrated waveguide filter design can fully utilize the characteristics of the waveguide rod, directly filter the signal, obtain effective information, and realize signal collection and filtering in high temperature, strong noise, and high radiation environments; it can also improve the collection efficiency of damage acoustic emission signals in complex environments.

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