Dynamic performance testing device and method for electromagnetic shielding cabinet

Abstract

This invention relates to the field of electromagnetic shielding cabinet testing technology, specifically a dynamic performance testing device and method for electromagnetic shielding cabinets. The device includes an environmental testing chamber for placing the cabinet under test and providing a controlled electromagnetic background environment; a dynamic load simulation system mechanically connected to the cabinet under test, used to apply a preset intensity of physical excitation to the cabinet to simulate structural deformation of the cabinet under operation; and a signal transmission system including a transmitting antenna located outside the cabinet under test for generating electromagnetic signals covering a preset frequency band. This invention simulates actual dynamic operating conditions such as vibration and cabinet door opening and closing through the dynamic load simulation system, combines a temperature and humidity control module to simulate different climatic environments, and utilizes a high-speed synchronous triggering module to achieve high-precision synchronization of dynamic load application, electromagnetic signal transmission, and data acquisition. This enables multi-condition collaborative simulation and precise synchronous testing, significantly improving the authenticity and reference value of the test results.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic shielding cabinet testing technology, specifically to a dynamic performance testing device and method for electromagnetic shielding cabinets. Background Technology

[0002] Electromagnetic shielding cabinets are widely used in industrial, military, and communications fields to protect internal electronic equipment from external electromagnetic interference and prevent internal electromagnetic signal leakage. Their shielding performance directly determines the operational stability and information security of the electronic equipment. Currently, performance testing of existing electromagnetic shielding cabinets is mostly static testing, which can only test the shielding effectiveness under conditions of no structural deformation and a single environment. It cannot simulate the dynamic loads faced by the cabinet during actual service, such as transportation bumps, equipment vibration, repeated opening and closing of cabinet doors, and complex climatic environments with high and low temperatures and high and low humidity.

[0003] Meanwhile, existing testing equipment has many shortcomings: First, the dynamic load and electromagnetic signal acquisition are not synchronized, making it impossible to accurately capture the electromagnetic leakage pattern during structural deformation; second, the test environment is highly interfered with, and background noise and line interference can easily lead to distorted test data; third, the test methods lack standardized procedures and do not consider the superimposed effects of factors such as material thermal expansion and contraction and structural micro-deformation on shielding performance, resulting in test results that are out of sync with actual service conditions, making it impossible to accurately identify the dynamic electromagnetic weak points of the cabinet, and also making it difficult to assess the reliability of electromagnetic seals during long-term service of the cabinet, thus failing to meet the requirements for high-precision and comprehensive testing.

[0004] Therefore, there is an urgent need for a testing device and method that can simulate actual service conditions, achieve precise synchronous testing, and comprehensively evaluate the dynamic shielding performance of the cabinet. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a dynamic performance testing device and method for electromagnetic shielding cabinets.

[0006] The technical solution adopted by this invention to solve its technical problem is: a dynamic performance testing device for an electromagnetic shielding cabinet, comprising:

[0007] An environmental testing chamber is used to house the rack under test and provide a controlled electromagnetic background environment.

[0008] The dynamic load simulation system is mechanically connected to the cabinet under test and is used to apply a physical excitation of a preset intensity to the cabinet under test in order to simulate the structural deformation of the cabinet under test in the working state.

[0009] The signal transmission system includes a transmitting antenna located outside the cabinet under test, used to generate electromagnetic signals covering a preset frequency band;

[0010] A multi-channel signal acquisition system includes multiple receiving antennas arranged in an array inside the cabinet under test, used to acquire electromagnetic field strength data of various spatial points inside the cabinet under test in real time.

[0011] The central control and processing system is connected to the dynamic load simulation system, the signal transmission system, and the multi-channel signal acquisition system to synchronously control the application of excitation and signal acquisition, and to calculate the spatiotemporal distribution characteristics of the shielding effectiveness of the cabinet under test under dynamic load based on the acquired data.

[0012] Preferably, the dynamic load simulation system includes:

[0013] A multi-axis vibration table is installed at the bottom of the cabinet under test to simulate random vibrations during transportation or earthquake conditions.

[0014] The multi-axis vibration table includes at least one electrically controlled push rod for driving vibration. The electrically controlled push rod is connected to the upper surface of the test plate in the environmental test chamber through a first fixed base. The electrically controlled push rod is hinged to the first fixed base so that the power output direction of the electrically controlled push rod can be changed. The telescopic end of the electrically controlled push rod pulls the vibration arm to rotate. The end of the vibration arm is connected to the end of the electrically controlled push rod through a pin. The middle part of the vibration arm is connected to the upper surface of the test plate through a second fixed base. The end of the vibration arm drives the vibration seat to shake and push the cabinet under test to vibrate.

[0015] An automatic opening and closing mechanism is connected to the cabinet door of the cabinet under test to simulate the repeated opening and closing actions of the cabinet door during long-term service.

[0016] The automatic opening and closing mechanism includes at least one first guide rail and an adjusting seat that moves along its axial direction. The first guide rail is fixed at the edge of the upper surface of the inner platform. The position of the opening and closing bracket to the door of the cabinet under test can be adjusted by adjusting the position of the adjusting seat. After the moving seat slides along the second guide rail to a preset position and is fixed, the side of the mechanical arm with the suction cup is then adsorbed onto the door of the cabinet under test. The mechanical arm and the mechanical small arm move in coordination by the drive motor and the second electric control push rod to control the reciprocating opening and closing action of the cabinet door of the cabinet under test.

[0017] The central control and processing system triggers a multi-channel signal acquisition system to perform synchronous sampling based on the action phase of the automatic opening and closing mechanism, in order to obtain the dynamic curve of electromagnetic leakage during the opening and closing process of the cabinet door.

[0018] Preferably, the environmental testing chamber is also equipped with a temperature and humidity control module to simulate the service status of the rack under test in different climatic environments; the central control and processing system is configured to analyze the cumulative effect of thermal expansion and contraction of materials induced by temperature cycling on the shielding performance of rack seams.

[0019] Preferably, the multi-channel signal acquisition system also includes:

[0020] The 3D scanning instrument performs spatial scanning inside the cabinet under the drive of the central control and processing system;

[0021] A receiving antenna is installed inside the environmental testing chamber for receiving radio frequency signals;

[0022] The fiber optic radio frequency transmission link is used to convert the radio frequency signal collected by the receiving antenna into an optical signal for transmission, so as to reduce the disturbance of the electromagnetic field inside the test cabinet by the metal cable.

[0023] Preferably, the device further includes a micro-displacement monitoring module, which includes multiple laser displacement sensors arranged at the joints and key shielding parts of the cabinet under test, for monitoring changes in the structural gaps of the cabinet under test under dynamic loads.

[0024] Preferably, the multi-channel signal acquisition system also includes a high-speed synchronous triggering module. The high-speed synchronous triggering module and the excitation source of the dynamic load simulation system are clock-aligned through the PTP synchronization protocol to ensure that the time deviation between the load excitation point and the electromagnetic sampling point is less than 1ms.

[0025] Preferably, the walls of the environmental testing chamber are covered with a layer of absorbing material, and all power lines and signal lines entering the chamber are connected in series with corresponding low-pass filters to suppress the interference of background noise on the dynamic test results.

[0026] A method for testing the dynamic performance of an electromagnetic shielding cabinet includes the following steps:

[0027] Step S1: Initialize the test environment, install the rack under test on the dynamic load simulation system, and deploy antenna arrays inside and outside the rack;

[0028] Step S2: Set the dynamic load spectrum through the central control and processing system, and drive the dynamic load simulation system to apply physical excitation to the cabinet under test;

[0029] Step S3: During the application of physical excitation, the signal transmission system and the multi-channel signal acquisition system are started simultaneously to obtain the raw electromagnetic intensity data during the dynamic process;

[0030] Step S4: Extract key feature points of dynamic loads, and calculate the shielding effectiveness of the cabinet under test at different dynamic moments by combining synchronously acquired electromagnetic data.

[0031] Step S5: Identify the dynamic electromagnetic weak points of the cabinet under test based on the evolution law of shielding effectiveness at each spatial point.

[0032] Preferably, step S5 includes:

[0033] An interpolation algorithm is used to fit the sampling points of multiple receiving antennas into a continuous shielding performance cloud map;

[0034] Calculate the spatial coordinates corresponding to the maximum value of the shielding effectiveness gradient in the cloud map, and define them as the structural coupling failure source.

[0035] Preferably, the dynamic load spectrum in step S2 includes a fatigue load sequence based on a preset frequency; the method further includes: evaluating the reliability of the electromagnetic seal of the cabinet under test during its service life based on the attenuation slope of the shielding effectiveness after multiple cyclic loading.

[0036] The beneficial effects of this invention are:

[0037] (1) This invention realizes multi-condition collaborative simulation and precise synchronous testing, which greatly improves the authenticity and reference value of the test results. This application simulates actual dynamic conditions such as vibration and cabinet door opening and closing through a dynamic load simulation system, and simulates different climate environments by combining a temperature and humidity adjustment module. At the same time, it uses a high-speed synchronous triggering module to realize high-precision synchronization of dynamic load application, electromagnetic signal transmission and data acquisition, and suppresses environmental interference through absorbing materials and low-pass filters. It effectively solves the problems of disconnect between traditional static testing and actual service conditions and test data distortion, and can truly reflect the dynamic shielding performance of the cabinet under complex actual conditions.

[0038] (2) This invention enables comprehensive quantitative evaluation of shielding performance and precise location of weak points, providing strong support for cabinet optimization and reliability prediction. This application uses multi-channel array acquisition, three-dimensional spatial scanning combined with micro-displacement monitoring to comprehensively capture the electromagnetic field distribution and structural micro-deformation data inside the cabinet. It quantifies shielding effectiveness through standardized formulas, uses interpolation algorithms to fit shielding performance cloud maps and identify structural coupling failure sources, and combines fatigue load testing to evaluate the long-term reliability of the sealing components. This not only accurately locates dynamic electromagnetic weak points but also predicts the service life of the cabinet, solving the pain points of traditional testing that cannot quantify evaluation and locate the root cause of failure, thus helping to optimize the cabinet structure and improve its quality. Attached Figure Description

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0040] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0041] Figure 2 A schematic diagram of the three-dimensional scanning instrument provided by the present invention;

[0042] Figure 3 A three-dimensional structural schematic diagram of the automatic opening and closing mechanism provided by the present invention;

[0043] Figure 4 A three-dimensional structural diagram of the connection between the electrically controlled push rod and the vibration rotating frame provided by the present invention;

[0044] Figure 5 A three-dimensional structural diagram of the mechanical upper arm and mechanical lower arm provided by the present invention;

[0045] Figure 6 The overall flowchart provided for this invention.

[0046] In the diagram: 100, Environmental testing chamber; 300, Temperature and humidity control module; 400, Automatic opening and closing mechanism; 410, Opening and closing bracket; 411, Adjustment seat; 420, Second guide rail; 430, Moving seat; 440, Horizontal frame; 450, Drive motor; 460, Mechanical arm; 470, Second electrically controlled push rod; 480, Mechanical forearm; 490, First guide rail; 600, Multi-axis vibration table; 610, First fixed seat; 620, Electrically controlled push rod; 630, Second fixed seat; 640, Vibration rotating frame; 650, Support; 700, 3D scanning instrument. Detailed Implementation

[0047] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0048] like Figures 1-6 As shown, the present invention provides a dynamic performance testing device for an electromagnetic shielding cabinet, comprising: an environmental testing chamber 100 for placing the cabinet under test and providing a controlled electromagnetic background environment;

[0049] The dynamic load simulation system is mechanically connected to the cabinet under test and is used to apply a physical excitation of a preset intensity to the cabinet under test in order to simulate the structural deformation of the cabinet under test in the working state.

[0050] The signal transmission system includes a transmitting antenna located outside the cabinet under test, used to generate electromagnetic signals covering a preset frequency band;

[0051] A multi-channel signal acquisition system includes multiple receiving antennas arranged in an array inside the cabinet under test, used to acquire electromagnetic field strength data of various spatial points inside the cabinet under test in real time.

[0052] The central control and processing system is connected to the dynamic load simulation system, the signal transmission system, and the multi-channel signal acquisition system to synchronously control the application of excitation and signal acquisition, and to calculate the spatiotemporal distribution characteristics of the shielding effectiveness of the cabinet under test under dynamic load based on the acquired data.

[0053] A controlled testing environment and multi-system collaborative architecture are established. The Environmental Testing Chamber 100 provides a stable and controllable electromagnetic background environment, avoiding the impact of external electromagnetic interference on test accuracy. The dynamic load simulation system applies preset physical excitations to the cabinet under test to simulate its structural deformation during actual operation. The signal transmission system generates electromagnetic signals in a specified frequency band through an external transmitting antenna as an interference source. The multi-channel signal acquisition system uses an array of receiving antennas inside the cabinet to capture electromagnetic field strength data at various spatial points in real time. The central control and processing system serves as the core hub, synchronously controlling the application of dynamic loads, electromagnetic signal transmission, and data acquisition. Then, based on the acquired electromagnetic field data, the spatiotemporal distribution characteristics of the cabinet's shielding effectiveness under dynamic loads are calculated, achieving comprehensive testing of the cabinet's dynamic electromagnetic shielding performance.

[0054] It achieves full-process synchronization of dynamic load, electromagnetic signal, data acquisition, and analysis, solving the problems of traditional static testing being unable to simulate the actual working deformation of the cabinet and the disconnect between test results and actual service conditions. The multi-channel array acquisition design can comprehensively capture the electromagnetic field distribution inside the cabinet, avoiding the limitations of single-point acquisition and improving the comprehensiveness and accuracy of test data. The central control system uniformly schedules and ensures that all links work together, reducing human operation errors and improving test efficiency and repeatability. It can directly obtain the spatiotemporal distribution of shielding effectiveness, providing core data support for subsequent identification of electromagnetic weak points in the cabinet.

[0055] An electromagnetic shielding cabinet, measuring 1800mm × 800mm × 600mm, with a rated shielding effectiveness ≥ 80dB, was used as the test sample. It was placed in an environmental testing chamber 100, where the electromagnetic background noise was controlled to be ≤ 1μV / m. The dynamic load simulation system was set to apply a random vibration excitation of 0.5g to the cabinet, simulating the vibration of equipment operating in an industrial field. The signal transmission system generated electromagnetic signals in the 10kHz~1GHz frequency band through an external transmitting antenna, with a fixed transmission power of 1W. The multi-channel signal acquisition system evenly arranged 16 receiving antenna arrays with a spacing of 100mm inside the cabinet, acquiring the electromagnetic field strength at each antenna in real time. The central control and processing system simultaneously started the vibration excitation and signal acquisition, with an acquisition frequency of 100Hz, continuously acquiring data for 30 minutes. Finally, through data calculation, the shielding effectiveness distribution of the cabinet at different times and spatial points under vibration load was obtained, showing that the shielding effectiveness in the central area of ​​the cabinet was relatively stable, while slight fluctuations were observed at the bottom and the connection point with the cabinet door.

[0056] The temperature and humidity control module 300 can adjust the humidity inside the environmental test chamber 100, monitor the test cabinet under different humidity environments, simulate more environments, and increase the reliability of monitoring data.

[0057] As a preferred technical solution, the dynamic load simulation system includes:

[0058] The multi-axis vibration table 600 is installed at the bottom of the cabinet under test and is used to simulate random vibration or impact excitation under transportation or seismic conditions.

[0059] The multi-axis vibration table 600 includes at least one electrically controlled push rod 620 for driving vibration. The electrically controlled push rod 620 is connected to the upper surface of the test disk 210 in the environmental test chamber 100 via a first fixed base 610. The electrically controlled push rod 620 is hinged to the first fixed base 610 so that the power output direction of the electrically controlled push rod 620 can be changed. The telescopic end of the electrically controlled push rod 620 pulls the vibration arm 640 to rotate. The vibration arm 640 is connected to the end of the electrically controlled push rod 620 via a pin. The middle part of the vibration arm 640 is connected to the upper surface of the test disk 210 via a second fixed base 630. The end of the vibration arm 640 drives the vibration seat 650 to shake up and down, thereby realizing the vibration test of the cabinet under test. The multi-axis vibration table 600 has multiple sets, which can perform vibration tests on the cabinet under test from different positions.

[0060] The automatic opening and closing mechanism 400 is connected to the cabinet door of the cabinet under test and is used to simulate the repeated opening and closing action of the cabinet door during long-term service.

[0061] The automatic opening and closing mechanism 400 includes at least one first guide rail 490 and an adjusting seat 411 that moves along its axial direction. The first guide rail 490 is fixed at the edge of the upper surface of the inner platform 200. The position of the opening and closing bracket 410 to the door of the cabinet under test can be adjusted by adjusting the position of the adjusting seat 411. After the moving seat 430 slides along the second guide rail 420 to a preset position and is fixed, the side of the mechanical arm 480 with the suction cup is then adsorbed to the door of the cabinet under test. Then, the drive motor 450 and the second electric control push rod 470 work in coordination. The cross frame 440 supports the control of the mechanical arm 460, the mechanical arm 480 and the drive motor 450, and controls the movement of the mechanical arm 460 and the mechanical arm 480 to control the reciprocating opening and closing action of the cabinet door of the cabinet under test. During this process, the opening degree of the cabinet door of the cabinet under test can be set according to the specific situation.

[0062] The central control and processing system triggers the multi-channel signal acquisition system to perform synchronous sampling based on the action phase of the automatic opening and closing mechanism 400, so as to obtain the dynamic curve of electromagnetic leakage during the opening and closing process of the cabinet door.

[0063] A multi-axis vibration table 600 is installed at the bottom of the cabinet under test, simulating loads in different scenarios such as bumpy vibrations during transportation and impact vibrations under seismic conditions according to preset parameters. An automatic opening and closing mechanism 400 is connected to the cabinet door, repeatedly opening and closing the door at a set frequency and speed to simulate the opening and closing actions of the door during long-term service. Simultaneously, the central control and processing system captures the action phase of the automatic opening and closing mechanism 400 and triggers a multi-channel signal acquisition system to synchronously sample, accurately capturing the real-time changes in electromagnetic leakage during the door opening and closing process, forming a dynamic curve, and enabling targeted testing of the dynamic performance of this critical shielded component. This synchronous triggering of the door opening and closing action and electromagnetic signal acquisition accurately captures the peak value and variation pattern of electromagnetic leakage during the door opening and closing process, solving the problem that traditional tests cannot capture dynamic leakage processes. The multi-axis vibration table can simulate multi-directional vibration, covering different operating conditions and improving the comprehensiveness of the test. The automatic opening and closing mechanism 400 enables standardized and repeatable door actions, avoiding the randomness of manual door opening and closing and improving the consistency of test data.

[0064] As a preferred technical solution, the environmental testing chamber 100 is also equipped with a temperature and humidity control module 300 to simulate the service status of the cabinet under test in different climatic environments; the central control and processing system is configured to analyze the cumulative effect of thermal expansion and contraction of materials induced by temperature cycling on the shielding performance of the cabinet joints.

[0065] A temperature and humidity control module 300 is added to the environmental testing chamber 100. This module can adjust the temperature inside the chamber, such as from -40℃ to 85℃, and the humidity, such as from 10%RH to 95%RH, according to preset parameters, simulating the service status of the cabinet under different climatic environments, such as high temperature, low temperature, high humidity, and dry cold. The central control and processing system simultaneously records temperature and humidity data while controlling the application of dynamic loads and acquiring signals. By comparing the shielding effectiveness data under different temperature and humidity conditions, the system analyzes the cumulative effect of thermal expansion and contraction of the cabinet materials caused by temperature cycling on the shielding performance at the cabinet joints, thus realizing the cabinet shielding performance test under both dynamic load and climatic environmental factors.

[0066] Simulating the actual service environment of the cabinet in different regions and seasons overcomes the limitations of traditional testing that only considers dynamic loads and ignores the influence of climate. It can quantitatively analyze the impact of material thermal expansion and contraction on the shielding performance of cabinet joints, clarify the synergistic effect of climate environment and dynamic load, and improve the practicality of test results. The temperature and humidity control module 300 can achieve precise temperature and humidity control to meet different test requirements and expand the applicability of the device. It provides data support for the selection of cabinet seals and cabinet materials, helps to optimize the cabinet structural design, and improves the shielding reliability in extreme environments.

[0067] As a preferred technical solution, the multi-channel signal acquisition system also includes:

[0068] The 3D scanning instrument 700 performs spatial scanning inside the cabinet under the drive of the central control and processing system;

[0069] A receiving antenna is installed inside the environmental testing chamber for receiving radio frequency signals;

[0070] The fiber optic radio frequency transmission link is used to convert the radio frequency signal collected by the receiving antenna into an optical signal for transmission, so as to reduce the disturbance of the electromagnetic field inside the test cabinet by the metal cable.

[0071] Driven by the central control and processing system, the 3D scanning instrument 700 achieves a comprehensive scan of the internal space of the cabinet. The fiber optic radio frequency transmission link converts the radio frequency signals collected by the receiving antenna into optical signals for transmission. Since optical fibers are non-conductive and do not generate electromagnetic interference, they can effectively reduce the disturbance to the electromagnetic field inside the cabinet during the transmission of traditional metal cables, ensuring that the collected electromagnetic field strength data is true and accurate.

[0072] The three-dimensional adjustable bracket enables spatial scanning of the receiving antenna, eliminating the blind spots of fixed arrays and comprehensively capturing the spatial distribution details of the electromagnetic field inside the cabinet, thus improving the integrity of test data. The fiber optic RF transmission link solves the problem of interference from traditional metal cables with the electromagnetic field inside the cabinet, significantly reducing test errors and improving the accuracy of data acquisition. The scanning process is automatically controlled by the central control system, achieving standardized scanning and avoiding acquisition deviations caused by human operation. The scanning path and antenna spacing can be flexibly adjusted according to the cabinet size and structure to adapt to the testing needs of different cabinet models, improving the versatility of the device.

[0073] Sampling points were placed every 50mm along the X-axis (length), every 50mm along the Y-axis (width), and every 100mm along the Z-axis (height), at a scanning speed of 10mm / s. The receiving antenna array transmitted the acquired radio frequency signals to the central control and processing system via a fiber optic RF transmission link, with a transmission loss ≤0.5dB. Comparative tests showed that after adopting fiber optic transmission, the fluctuation range of the acquired electromagnetic field strength data decreased from ±3μV / m to ±0.8μV / m, significantly reducing the error. Three-dimensional scanning revealed a blind spot at the top corner of the cabinet; supplementary scanning completely acquired the shielding effectiveness data for all spatial points inside the cabinet, avoiding the omission of critical weak points.

[0074] As a preferred technical solution, the device also includes a micro-displacement monitoring module, which includes multiple laser displacement sensors arranged at the joints and key shielding parts of the cabinet under test, for monitoring changes in the structural gaps of the cabinet under test under dynamic loads.

[0075] The micro-displacement monitoring module consists of multiple laser displacement sensors, which are evenly distributed at the joints of the cabinet under test, such as the joints between the cabinet door and the cabinet body, the joints between the side panels and the top panel, and key shielding areas such as cable interfaces and ventilation openings. During the application of dynamic loads, the laser displacement sensors monitor the minute displacement changes at each monitoring point in real time with an accuracy of up to μm. The data is then transmitted to the central control and processing system for correlation analysis with synchronously acquired electromagnetic field strength data. This analysis clarifies the correspondence between changes in cabinet structural gaps and electromagnetic leakage, and accurately locates the electromagnetic shielding failure points caused by structural deformation.

[0076] This system enables linked monitoring of cabinet structural deformation and electromagnetic shielding performance, accurately identifying the correlation between structural gap changes and electromagnetic leakage, and pinpointing the root cause of shielding failure. High-precision laser displacement sensors can capture minute structural deformations, avoiding misjudgments of shielding performance due to gaps invisible to the naked eye. Simultaneous analysis of monitoring and electromagnetic data acquisition provides precise data support for subsequent cabinet structure optimization and improved sealing performance. Real-time monitoring of cabinet structural stability under dynamic loads allows for early prediction of cabinet structural failure risks, enhancing cabinet service safety.

[0077] Eight laser displacement sensors were installed at the joints between the cabinet door and the cabinet body, the joints between the side panels and the bottom plate, and the cable interfaces. The sensors have an accuracy of 1μm, and the sampling frequency is consistent with the electromagnetic signal acquisition frequency of 100Hz. A dynamic load simulation system applied a random vibration excitation of 0.8g for 20 minutes, while the central control and processing system simultaneously acquired structural micro-displacement data and electromagnetic field strength data. Analysis revealed that when the micro-displacement at the cabinet door joint exceeded 5μm, the shielding effectiveness of the corresponding area decreased by more than 12dB; when the micro-displacement at the cable interface exceeded 3μm, the electromagnetic leakage increased significantly. This clarified that changes in structural gaps are the core reason for the decline in electromagnetic shielding performance, providing a basis for subsequent optimization of the joint sealing structure.

[0078] As a preferred technical solution, the multi-channel signal acquisition system also includes a high-speed synchronous triggering module. The high-speed synchronous triggering module and the excitation source of the dynamic load simulation system are clock-aligned through the PTP synchronization protocol to ensure that the time deviation between the load excitation point and the electromagnetic sampling point is less than 1ms.

[0079] A high-speed synchronous trigger module is added to the multi-channel signal acquisition system. This module is clock-aligned with the excitation source of the dynamic load simulation system via the PTP synchronization protocol, ensuring that the excitation point of the dynamic load application time and the sampling point of the electromagnetic signal acquisition time are highly synchronized, controlling the time deviation between the two to within 1ms. Through precise clock synchronization, real-time correspondence between load excitation, structural deformation, and electromagnetic leakage is achieved, avoiding test data misalignment caused by time deviation and ensuring the accuracy of analysis results.

[0080] The application of the PTP synchronization protocol achieves high-precision clock alignment with a time deviation of <1ms, meeting the real-time response requirements in dynamic testing; the synchronization trigger module can automatically adapt to changes in dynamic loads without manual adjustment, improving the automation level and efficiency of testing; precise synchronization control provides a reliable data foundation for subsequent analysis of the shielding effectiveness variation under different load excitations, ensuring the scientific nature of the analysis results.

[0081] As a preferred technical solution, the walls of the environmental testing chamber 100 are covered with a layer of absorbing material, and all power lines and signal lines entering the chamber are connected in series with corresponding low-pass filters to suppress the interference of background noise on the dynamic test results.

[0082] The environmental chamber walls are covered with a layer of absorbing material, which is polyurethane absorbing foam, to absorb stray electromagnetic signals within the chamber and reduce background electromagnetic noise. All power lines and signal lines entering the environmental chamber are connected in series with corresponding low-pass filters to filter out high-frequency interference signals in the lines, prevent external line interference from entering the environmental chamber, ensure that the electromagnetic background of the test environment meets the test requirements, reduce the interference of background noise on dynamic test results, and improve the authenticity and reliability of test data.

[0083] A method for testing the dynamic performance of an electromagnetic shielding cabinet includes the following steps:

[0084] Step S1: Initialize the test environment, install the rack under test on the dynamic load simulation system, and deploy antenna arrays inside and outside the rack;

[0085] Step S2: Set the dynamic load spectrum through the central control and processing system, and drive the dynamic load simulation system to apply physical excitation to the cabinet under test;

[0086] Step S3: During the application of physical excitation, the signal transmission system and the multi-channel signal acquisition system are started simultaneously to obtain the raw electromagnetic intensity data during the dynamic process;

[0087] Step S4: Extract key feature points of dynamic loads, and calculate the shielding effectiveness of the cabinet under test at different dynamic moments by combining synchronously acquired electromagnetic data.

[0088] Step S5: Identify the dynamic electromagnetic weak points of the cabinet under test based on the evolution law of shielding effectiveness at each spatial point.

[0089] Step S1 is test preparation, where the rack under test is installed on the dynamic load simulation system, and the antenna array, sensors, and other equipment are deployed to ensure normal equipment connection. Step S2 is load setting, where the dynamic load spectrum, such as vibration parameters and rack door opening and closing parameters, is set through the central control and processing system to drive the dynamic load simulation system to apply physical excitation to the rack. Step S3 is synchronous acquisition, where the signal transmission system and multi-channel signal acquisition system are started simultaneously with the excitation to acquire raw electromagnetic intensity data in real time during the dynamic process. Step S4 is data processing, where key feature points of the dynamic load, such as vibration peak values ​​and key phases of rack door opening and closing, are extracted, and the rack shielding effectiveness at different dynamic moments is calculated in combination with the synchronously acquired electromagnetic data. Step S5 is weak point identification, where the dynamic electromagnetic weak points of the rack are located based on the evolution law of shielding effectiveness at each spatial point, completing the test process.

[0090] As a preferred technical solution, step S5 includes:

[0091] An interpolation algorithm is used to fit the sampling points of multiple receiving antennas into a continuous shielding performance cloud map;

[0092] Calculate the spatial coordinates corresponding to the maximum value of the shielding effectiveness gradient in the cloud map, and define them as the structural coupling failure source.

[0093] First, using an interpolation algorithm, the discrete sampling points of multiple receiving antennas acquired by the multi-channel signal acquisition system are fitted into a continuous shielding performance cloud map, which intuitively presents the spatial distribution of shielding effectiveness inside the cabinet. Then, the spatial coordinates corresponding to the maximum value of the shielding effectiveness gradient in the shielding performance cloud map are calculated. The shielding effectiveness changes most drastically at this coordinate, indicating that the structural coupling failure is most severe at this point. This is defined as the source of structural coupling failure, i.e., the dynamic electromagnetic weak point of the cabinet.

[0094] By fitting discrete sampling points into a continuous cloud map using an interpolation algorithm, the spatial distribution of shielding effectiveness is presented intuitively, facilitating rapid location of weak points. The identification of structural coupling failure sources is based on the maximum value of the shielding effectiveness gradient, making the identification method scientific and accurate, avoiding the subjectivity of human judgment. The specific spatial coordinates of weak points can be clearly identified, providing a precise location basis for cabinet structure optimization and sealing improvement. The identification process can be automatically completed by the central control and processing system, improving identification efficiency and accuracy.

[0095] As a preferred technical solution, the dynamic load spectrum in step S2 includes a fatigue load sequence based on a preset frequency; the method also includes: evaluating the reliability of the electromagnetic seal of the cabinet under test during its service life based on the attenuation slope of the shielding effectiveness after multiple cyclic loading.

[0096] The dynamic load spectrum in step S2 includes a fatigue load sequence based on a preset frequency to simulate the fatigue conditions of the cabinet during long-term service. After multiple cyclic loading cycles, the shielding effectiveness data of the cabinet is continuously collected, and the attenuation slope of the shielding effectiveness is calculated, i.e., the decrease in shielding effectiveness after a certain number of cycles. The reliability of the electromagnetic seal of the cabinet under test throughout its service life is evaluated by the attenuation slope, and it is determined whether the seal can meet the shielding requirements for long-term service. By introducing the fatigue load sequence to simulate the long-term service conditions of the cabinet, the long-term stability of the cabinet's shielding performance can be evaluated, which solves the limitation of traditional tests that can only evaluate short-term performance. The reliability of the seal is quantified by the attenuation slope of the shielding effectiveness, providing data support for the prediction of the cabinet's service life. The fatigue failure risk of the seal can be detected in advance, providing a basis for the maintenance and replacement of the cabinet and improving the service safety of the cabinet. The functionality of the test method is enriched, which can not only identify weak parts, but also evaluate long-term reliability and expand the application scope of the test method.

[0097] Using the same cabinet as described above, the dynamic load spectrum in step S2 is set to a fatigue load sequence: vibration frequency 50Hz, acceleration 0.5g, and number of cycles 10. 4 The cabinet door opens and closes once per minute, with a cycle count of 10. 4 During the cyclic loading process, the shielding effectiveness data of the cabinet was collected every 1000 cycles. After the test, the shielding effectiveness attenuation slope was calculated to be 0.002dB / cycle, meaning that the shielding effectiveness decreased by 2dB every 1000 cycles. Considering the design service life of the cabinet, the shielding effectiveness at the end of its service life is predicted to be 80dB (initial shielding effectiveness 90dB), meeting the rated shielding requirements. Therefore, the electromagnetic seals of the cabinet are judged to have good reliability throughout its service life.

[0098] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0099] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of protection claimed by the present invention. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A dynamic performance testing device for an electromagnetic shielded cabinet, characterized by, include: An environmental testing chamber is used to house the rack under test and provide a controlled electromagnetic background environment. The dynamic load simulation system is mechanically connected to the cabinet under test and is used to apply a physical excitation of a preset intensity to the cabinet under test in order to simulate the structural deformation of the cabinet under test in the working state. The dynamic load simulation system includes: A multi-axis vibration table is installed at the bottom of the cabinet under test to simulate random vibrations during transportation or earthquake conditions. The multi-axis vibration table includes at least one electrically controlled push rod for driving vibration. The electrically controlled push rod is connected to the upper surface of the test plate in the environmental test chamber through a first fixed base. The electrically controlled push rod is hinged to the first fixed base so that the power output direction of the electrically controlled push rod can be changed. The telescopic end of the electrically controlled push rod pulls the vibration arm to rotate. The end of the vibration arm is connected to the end of the electrically controlled push rod through a pin. The middle part of the vibration arm is connected to the upper surface of the test plate through a second fixed base. The end of the vibration arm drives the vibration seat to shake and push the cabinet under test to vibrate. The signal transmission system includes a transmitting antenna disposed outside the cabinet under test, for generating electromagnetic signals covering a preset frequency band; A multi-channel signal acquisition system includes multiple receiving antennas arranged in an array inside the cabinet under test, for real-time acquisition of electromagnetic field strength data at various spatial points inside the cabinet under test; The central control and processing system is connected to the dynamic load simulation system, the signal transmission system and the multi-channel signal acquisition system respectively. It is used to synchronously control the application of excitation and signal acquisition, and to calculate the spatiotemporal distribution characteristics of the shielding effectiveness of the cabinet under test under dynamic load based on the acquired data. It also includes an automatic opening and closing mechanism, which is connected to the cabinet door of the cabinet under test, and is used to simulate the repeated opening and closing actions of the cabinet door during long-term service. The automatic opening and closing mechanism includes at least one first guide rail and an adjustment seat that moves along its axial direction. The first guide rail is fixed at the edge of the upper surface of the inner platform. The position of the opening and closing bracket to the door of the cabinet under test can be adjusted by adjusting the position of the adjustment seat. After the moving seat slides along the second guide rail to a preset position and is fixed, the side of the mechanical arm with the suction cup is then adsorbed onto the door of the cabinet under test. The mechanical arm and the mechanical arm move in coordination by the drive motor and the second electric control push rod to realize the action of controlling the reciprocating opening and closing of the cabinet door of the cabinet under test. The central control and processing system triggers the multi-channel signal acquisition system to perform synchronous sampling based on the action phase of the automatic opening and closing mechanism, so as to obtain the dynamic curve of electromagnetic leakage during the opening and closing process of the cabinet door. The device also includes a micro-displacement monitoring module, which includes multiple laser displacement sensors arranged at the joints and key shielding parts of the cabinet under test, for monitoring changes in the structural gaps of the cabinet under test under dynamic loads. The multi-channel signal acquisition system also includes a high-speed synchronous triggering module. The high-speed synchronous triggering module and the excitation source of the dynamic load simulation system are clock-aligned through the PTP synchronization protocol to ensure that the time deviation between the load excitation point and the electromagnetic sampling point is less than 1ms.

2. The dynamic performance testing apparatus of claim 1, wherein, The environmental testing chamber is also equipped with a temperature and humidity control module to simulate the service status of the rack under test in different climatic environments; the central control and processing system is configured to analyze the cumulative effect of thermal expansion and contraction of materials induced by temperature cycling on the shielding performance of rack seams.

3. The dynamic performance testing apparatus of claim 2, wherein, The multi-channel signal acquisition system also includes: The 3D scanning instrument performs spatial scanning inside the cabinet under the drive of the central control and processing system; A receiving antenna is installed inside the environmental testing chamber for receiving radio frequency signals; The fiber optic radio frequency transmission link is used to convert the radio frequency signal collected by the receiving antenna into an optical signal for transmission, so as to reduce the disturbance of the electromagnetic field inside the cabinet under test by the metal cable.

4. The dynamic performance testing device according to claim 3, characterized in that, The walls of the environmental testing chamber are covered with a layer of absorbing material, and all power lines and signal lines entering the chamber are connected in series with corresponding low-pass filters to suppress background noise interference with the dynamic test results.

5. A method for testing the dynamic performance of an electromagnetic shielding cabinet, comprising the dynamic performance testing device as described in any one of claims 1 to 4, characterized in that, The dynamic performance testing method includes the following steps: Step S1: Initialize the test environment, install the rack under test on the dynamic load simulation system, and deploy antenna arrays inside and outside the rack; Step S2: Set the dynamic load spectrum through the central control and processing system, and drive the dynamic load simulation system to apply physical excitation to the cabinet under test; Step S3: During the application of physical excitation, the signal transmission system and the multi-channel signal acquisition system are started simultaneously to obtain the raw electromagnetic intensity data during the dynamic process; Step S4: Extract key feature points of dynamic loads, and calculate the shielding effectiveness of the cabinet under test at different dynamic moments by combining synchronously acquired electromagnetic data. Step S5: Identify the dynamic electromagnetic weak points of the cabinet under test based on the evolution law of shielding effectiveness at each spatial point.

6. The dynamic performance testing method according to claim 5, characterized in that: Step S5 includes: An interpolation algorithm is used to fit the sampling points of multiple receiving antennas into a continuous shielding performance cloud map; Calculate the spatial coordinates corresponding to the maximum value of the shielding effectiveness gradient in the cloud map, and define them as the structural coupling failure source.

7. The dynamic performance testing method according to claim 6, characterized in that: The dynamic load spectrum in step S2 includes a fatigue load sequence based on a preset frequency. The method further includes: evaluating the reliability of the electromagnetic seal of the cabinet under test during its service life based on the attenuation slope of the shielding effectiveness after multiple cyclic loading.

Images