Method and system for testing vibration performance of steel reinforced concrete frame structure

Abstract

The invention relates to the technical field of steel reinforced concrete vibration testing, and discloses a method and system for testing the vibration performance of a steel reinforced concrete frame structure, and the state of the steel reinforced concrete frame structure is judged through vibration amplitude and frequency changes under the conditions of different excitation modes, measurement point positions, sampling frequencies, collection durations and the like. By accurately measuring and analyzing the change of the damping ratio, potential damage or performance change of the structure can be found in time, and a powerful basis is provided for safety assessment and maintenance of the structure; the signal is decomposed and analyzed based on Hilbert-Huang transform, the internal composition and the change rule of the structure vibration signal can be analyzed more finely, and the method has advantages for identifying weak vibration characteristics and early damage signs of the structure in a complex stress state, so that the test structure can be evaluated in time in the early damage stage, and the test accuracy is improved. And therefore, coping treatment can be conveniently carried out.

Description

Technical Field

[0001] The invention relates to the technical field of steel-concrete vibration testing, and in particular to a steel-concrete frame structure vibration performance testing method and system. Background Art

[0002] As a new type of building structural material, steel-concrete frame structure combines the high strength of traditional steel structure and the good ductility of concrete, making this structure widely used in modern buildings. Due to its unique material properties and structural form, steel-concrete frame structure exhibits excellent seismic performance and stability when subjected to dynamic loads such as earthquakes and wind loads. Vibration performance testing of steel-concrete frame structures is an important means to ensure structural safety, optimize design, verify theoretical analysis, monitor health status, adapt to complex environmental requirements, and promote the development of new materials. These tests are crucial for evaluating the safety of structures under dynamic loads, can guide structural design optimization, provide data support for code revisions, and help maintain and reinforce existing buildings. Ensure the reliability and stability of building structures when facing dynamic effects such as earthquakes and wind loads.

[0003] In the prior art, when testing the vibration performance of steel-concrete frame structures, it is difficult to obtain effective structural analysis from the test results under different conditions, which affects the judgment of the structural state and cannot provide a favorable basis. Therefore, it is urgent to invent a vibration performance testing method and system for steel-concrete frame structures to solve the above problems. Summary of the invention

[0004] Technical problem to be solved: In view of the deficiencies in the prior art, the present invention provides a method and system for testing the vibration performance of a steel-concrete frame structure.

[0005] Technical solution: To achieve the above-mentioned solution, the present invention provides the following technical solution: A method for testing the vibration performance of a steel-concrete frame structure, comprising the following steps: Step 1: Sensor arrangement: Install acceleration sensors at key locations of the steel concrete frame structure; Step 2: Vibration excitation: Use a variety of excitation methods to obtain the impulse response of the structure, collect data for a long time, and accumulate enough information to analyze the vibration characteristics of the structure; Step 3: Data acquisition: Use data acquisition equipment, set the appropriate sampling frequency, and set the acquisition time length to ensure that sufficient vibration signal data can be obtained for analysis; Step 4: Perform signal processing based on short-time Fourier transform (STFT): Perform STFT calculation on the preprocessed signal to obtain a time-frequency diagram in which the horizontal axis represents time and the vertical axis represents frequency. The color or grayscale represents the energy or amplitude of the signal at the time and frequency point. By observing the time-frequency diagram, the structure is analyzed and evaluated. Step 5: Signal processing based on Hilbert-Huang transform (HHT): Identify the weak vibration characteristics of the structure. In the early stage of structural damage, the local stiffness changes caused by the damage will cause weak vibration frequency and amplitude changes. HHT can capture these changes more sensitively than traditional methods, thus providing a basis for early damage detection. Step 6: Vibration performance analysis: Based on the results of STFT and HHT, analyze the vibration parameters of the structure such as natural frequency and damping ratio.

[0006] Preferably, in signal processing - short-time Fourier transform STFT, the amplitude reflects the intensity of the vibration. Under normal circumstances, the vibration amplitude of the test structure under a certain load is within a reasonable range. When the amplitude suddenly increases or fluctuates abnormally, the test structure will be locally damaged, resulting in a decrease in stiffness, thereby increasing the vibration response.

[0007] Preferably, HHT includes two main steps: empirical mode decomposition (EMD) and Hilbert spectrum analysis. The EMD method decomposes the original signal into a finite number of intrinsic mode functions (IMFs), processes nonlinear and non-stationary signals, and has good adaptability to vibration signals generated by steel-concrete frame structures under complex forces and dynamic loads. Each IMF component represents the vibration mode of the signal at different local characteristic scales, and can reveal the intrinsic composition and variation law of the signal more finely. At the same time, the differences between different IMF components and Hilbert spectra under normal structural states and different damage states are compared, and evaluation indicators and damage identification models for structural health states are established, so as to achieve more accurate and earlier performance evaluation and damage diagnosis of steel-concrete frame structures.

[0008] A steel concrete frame structure vibration performance test system includes the following modules: Module 1, sensor module: It is composed of multiple high-precision acceleration sensors. The sensors have the characteristics of wide-band response, high sensitivity and low noise. The sensors are firmly installed on the steel concrete frame structure through suitable mounting fixtures to ensure accurate measurement of the vibration acceleration of the structure. Module 2, data acquisition module: including data acquisition card and supporting computer software. The data acquisition card has enough channels to connect multiple sensors and has high sampling rate and high resolution analog-to-digital conversion function. The computer software is used to set acquisition parameters, such as sampling frequency, acquisition time, etc., control the data acquisition process and store the collected data; Module 3, signal processing and analysis module: including software modules for running STFT and HHT algorithms. This module can receive the collected data and process it in real time or offline. In software design, the implementation of the algorithm should be optimized and the computing efficiency should be improved to meet the needs of large-scale data processing; Module 4, excitation module: using vibration table excitation or impact hammer excitation.

[0009] Preferably, the signal processing and analysis module has a data visualization function, which can display the analysis results of STFT and HHT in a graphical manner, so that users can intuitively observe and analyze the vibration characteristics of the structure.

[0010] Preferably, when the excitation module is excited by a vibration table, it includes a vibration table and its controller. The vibration table should be able to generate vibration signals of different types, amplitudes and frequencies. The controller is used to accurately set the vibration parameters of the vibration table and synchronize with the data acquisition system to ensure that the collected vibration response data corresponds to the excitation signal.

[0011] Preferably, when the excitation module adopts an impact hammer for excitation, it includes an impact hammer with hammer heads of different masses and a force sensor. The force sensor is used to measure the impact force applied by the impact hammer, and combined with the data collected by the acceleration sensor, the impulse response characteristics of the structure can be analyzed more accurately.

[0012] Beneficial effects: Compared with the prior art, the present invention provides a steel concrete frame structure vibration performance testing method and system, which has the following beneficial effects: 1. The vibration performance test method and system of the steel concrete frame structure judges the state of the steel concrete frame structure by the changes in vibration amplitude and frequency under different excitation modes, measurement point locations, sampling frequencies and acquisition durations. By accurately measuring and analyzing the changes in the damping ratio, potential damage or performance changes of the structure can be discovered in a timely manner, providing a strong basis for the safety assessment and maintenance of the structure.

[0013] 2. The vibration performance test method and system of this type of steel concrete frame structure processes the vibration signal based on the short-time Fourier transform time-frequency analysis method, and decomposes and analyzes the signal in combination with the Hilbert-Huang transform, which is helpful to judge the dynamic characteristics and damage development process of the structure during an earthquake, and can more finely analyze the inherent composition and change law of the structural vibration signal. It has advantages in identifying the weak vibration characteristics and early signs of damage of the structure under complex stress states, thereby facilitating the evaluation of the dynamic characteristics and damage development process of the test structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the testing method flow of the present invention; Figure 2It is a schematic diagram of the test system module of the present invention. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0016] See also Figure 1-2 , this application proposes a steel concrete frame structure vibration performance testing method and system: 1. Vibration performance test method of steel concrete frame structure Step 1: Sensor layout Acceleration sensors are installed at key locations of steel-concrete frame structures. In order to collect vibration signals of steel-concrete frame structures, acceleration sensors need to be arranged at key locations of the structure, usually including column tops, beam midspans, beam-column joints, etc. In multi-story steel-concrete frame buildings, sensors need to be arranged at column tops and beam midspans on each floor to facilitate the acquisition of signals that can reflect the overall vibration characteristics of the structure. When installing sensors, the number and location of sensors should be determined based on factors such as the symmetry and complexity of the structure to fully obtain the response information of the structure during vibration.

[0017] Step 2: Vibration Excitation A variety of excitation methods are used, such as vibration table excitation, impact hammer excitation or environmental excitation (such as natural wind, small vibrations caused by nearby traffic, etc.). For vibration table excitation, sine waves, random waves and other excitation signals of different frequencies and amplitudes can be set according to the design parameters of the structure to simulate the actual vibration conditions that may be encountered. Impact hammer excitation can perform single or multiple impacts at the selected measuring point to obtain the impulse response of the structure.

[0018] Under environmental excitation, data acquisition over a long period of time is required to accumulate sufficient information to analyze the vibration characteristics of the structure.

[0019] Step 3: Data Collection Use data acquisition equipment, such as a data logger, to set an appropriate sampling frequency. The sampling frequency should be selected based on the expected vibration frequency range of the structure. To avoid aliasing, the sampling frequency should be greater than twice the highest frequency of the structure's vibration. At the same time, the acquisition time length needs to be set to ensure that sufficient vibration signal data can be obtained for analysis.

[0020] Step 4: Signal processing based on short-time Fourier transform (STFT) Signal preprocessing: First, the collected vibration signal is denoised and filtered to remove high-frequency noise and low-frequency interference in the signal to improve the accuracy of STFT analysis.

[0021] Window function selection and parameter determination: Select a suitable window function according to the characteristics of the signal, and determine parameters such as window length and overlap rate. The window length determines the time resolution of the STFT. A shorter window length can provide better time resolution, but will reduce the frequency resolution; conversely, a longer window length will improve the frequency resolution but reduce the time resolution. The overlap rate is generally selected between 50% and 75%. Selecting a suitable overlap rate can reduce spectrum leakage caused by window function truncation.

[0022] According to the selected window function and signal data, the STFT of the signal is calculated by the discrete short-time Fourier transform formula. Assume that the collected vibration signal is , the window function is , short-time Fourier transform The calculation formula is: In the above formula Represents the time index, Indicates the frequency index. In actual calculations, the STFT calculation is usually efficiently implemented through the fast Fourier transform algorithm.

[0023] STFT calculation and result analysis: Perform STFT calculation on the preprocessed signal to obtain a time-frequency diagram. In the time-frequency diagram, the horizontal axis represents time, the vertical axis represents frequency, and the color or grayscale represents the energy or amplitude of the signal at that time and frequency point.

[0024] By observing the time-frequency diagram, we can analyze the change pattern of the structural vibration frequency over time, determine the main vibration frequency of the structure at different stages of an earthquake, as well as the frequency drift and mutation, and thus evaluate the dynamic characteristics of the test structure and possible damage development.

[0025] The specific analysis includes: 1) Frequency-time distribution analysis: The spectrum (frequency-time diagram) obtained by STFT can intuitively observe the changes of the frequency components of the vibration signal over time. Under the action of external force, the vibration frequency of the steel concrete frame structure will change at different times. The main vibration frequency of the structure and the time interval of its occurrence can be identified from the spectrum. If a new frequency component appears in a certain time interval or the main frequency component has a large shift, it means that the test structure has been damaged or affected by abnormal loads.

[0026] 2) Amplitude change analysis: The change in the amplitude of the vibration signal can also be observed in the STFT spectrum. The amplitude reflects the intensity of the vibration. Under normal circumstances, the vibration amplitude of the test structure under a certain load is within a reasonable range. When the amplitude suddenly increases or fluctuates abnormally, it will cause local damage to the test structure, resulting in reduced stiffness, thereby increasing the vibration response. Therefore, when cracks appear at the beam-column node, the amplitude of the vibration signal collected near the node may increase significantly.

[0027] The short-time Fourier transform (STFT) time-frequency analysis method is used to process the vibration signal. Unlike the traditional Fourier transform which only provides frequency information, the time-frequency analysis method can simultaneously display the distribution of the signal in time and frequency, and more accurately capture the time-varying characteristics of the structural vibration signal. When analyzing the vibration response of the structure under the action of an earthquake, the time-frequency analysis can clearly show the changes in the structural vibration frequency at different times, which helps to judge the dynamic characteristics and damage development process of the test structure during an earthquake, thereby facilitating the processing of the test structure.

[0028] Step 5: Signal processing based on Hilbert-Huang transform (HHT) HHT includes two main steps: empirical mode decomposition (EMD) and Hilbert spectrum analysis. The EMD method decomposes the original signal into a finite number of intrinsic mode functions (IMFs). IMFs must meet two conditions: first, in the entire data sequence, the number of extreme points and zero crossings must be equal or differ by at most one; second, at any time, the average value of the upper and lower envelopes defined by the local maximum and local minimum points is 0.

[0029] For a given signal The decomposition process of EMD is as follows: first find all local extreme points of the signal, then use the cubic spline function to fit the upper and lower envelopes, and calculate the average value of the upper and lower envelopes , subtract the average value from the original signal to get a new signal , repeat this process until Satisfy the IMF conditions and get the first IMF component , then As the new original signal, continue to repeat the above decomposition process to obtain a series of IMF components , … , until the remaining signal Satisfy certain termination conditions (such as becoming a monotonic function or its amplitude being less than a certain threshold).

[0030] HHT can effectively process nonlinear and non-stationary signals, and has good adaptability to the vibration signals generated by steel-concrete frame structures under complex forces and dynamic loads. Each IMF component represents the vibration mode of the signal at different local characteristic scales, which can reveal the intrinsic composition and variation law of the signal in a more detailed manner.

[0031] By performing Hilbert transform on the IMF components, the instantaneous frequency and instantaneous amplitude of the signal can be obtained, thereby constructing the Hilbert spectrum. The Hilbert spectrum can intuitively show the change of the signal frequency over time, as well as the energy distribution of different frequency components at different times. When analyzing structural vibration signals, HHT can be used to identify the weak vibration characteristics of the structure. In the early stage of structural damage, the local stiffness changes caused by the damage will cause weak vibration frequency and amplitude changes. HHT can capture these changes more sensitively than traditional methods, thus providing a basis for early damage detection. At the same time, by comparing the differences between different IMF components and Hilbert spectra in the normal state and different damage states of the structure, it is possible to establish evaluation indicators and damage identification models for the health status of the structure, and achieve more accurate and earlier performance evaluation and damage diagnosis of steel-concrete frame structures, thereby facilitating the treatment of test structures at the early stage of damage.

[0032] Step 6: Vibration performance analysis According to the results of STFT and HHT, analyze the vibration parameters of the structure, such as natural frequency and damping ratio. Evaluate the stiffness and stability of the structure by observing the changes in the vibration frequency and amplitude of the structure under different excitations. A sudden increase in the vibration amplitude at a certain frequency may indicate that the structure has resonance at this frequency, and further analysis of the safety of the structure under this condition is required.

[0033] Compare the results of different measuring points, analyze the propagation characteristics of structural vibration, and judge the integrity and coordination of the test structure during vibration. When the vibration signal difference between certain measuring points is large, it indicates that the test structure has problems such as local damage or poor connection.

[0034] 2. Steel concrete frame structure vibration performance test system includes the following modules: Module 1: Sensor module It is composed of multiple high-precision acceleration sensors with characteristics such as wide-band response, high sensitivity and low noise. The sensors are firmly mounted on the steel concrete frame structure through suitable mounting fixtures to ensure accurate measurement of the vibration acceleration of the structure.

[0035] Module 2: Data acquisition module It includes a data acquisition card and supporting computer software. The data acquisition card should have enough channels to connect multiple sensors and have high sampling rate and high resolution analog-to-digital conversion functions. The computer software is used to set acquisition parameters (such as sampling frequency, acquisition time, etc.), control the data acquisition process and store the acquired data.

[0036] Module 3: Signal processing and analysis module Includes software modules for running STFT and HHT algorithms. This module can receive the collected data and process it in real time or offline. In software design, the implementation of the algorithm should be optimized and the computing efficiency should be improved to meet the needs of large-scale data processing.

[0037] It has data visualization function and can display the analysis results of STFT and HHT in the form of graphics (such as time-frequency diagram, spectrum diagram, IMF diagram, etc.), which is convenient for users to intuitively observe and analyze the vibration characteristics of the structure.

[0038] Module 4: Motivation module Vibration table excitation or impact hammer excitation can be used.

[0039] If a vibration table excitation is used, including the vibration table and its controller, the vibration table should be able to generate vibration signals of different types (sinusoidal, random, etc.) and different amplitudes and frequencies. The controller is used to accurately set the vibration parameters of the vibration table and synchronize with the data acquisition system to ensure that the collected vibration response data corresponds to the excitation signal.

[0040] If impact hammer excitation is used, including an impact hammer with hammer heads of different masses and a force sensor, the force sensor is used to measure the impact force applied by the impact hammer. Combined with the data collected by the acceleration sensor, the impulse response characteristics of the structure can be analyzed more accurately.

[0041] Six groups of experimental tests were conducted on the vibration performance of steel concrete frame structures using the method and system of the present application, as shown in the following table:

[0042] According to the above conditions, the data was measured and analyzed to obtain the following results, as shown in the following table:

[0043] According to the above two tables, we can analyze: In the first set of data: Vibration amplitude change: The vibration amplitude is stable within a reasonable range, indicating that the structure's vibration response is normal under this excitation, and there is no sudden change in amplitude caused by abnormal stiffness changes.

[0044] Main vibration frequency: The main vibration frequency is 10 Hz, which is consistent with the excitation frequency, indicating that the structure vibrates normally at this frequency and the vibration frequency is not affected by damage.

[0045] Structural status judgment: Based on various indicators, it is judged that the structure is in a normal state. The damping ratio is 0.05, which is within the common damping ratio range of normal structures. This shows that the structure has normal energy dissipation capacity during vibration and can effectively suppress vibration, keeping the vibration amplitude within a stable range, further proving that the structure is in a normal state.

[0046] In the second set of data: Change in vibration amplitude: The amplitude increases at the moment of impact, which is a normal impact response, and then returns to the normal range, indicating that the structure can regain stability after the impact and no permanent damage occurs, resulting in a continuous decrease in stiffness.

[0047] Main vibration frequency: The main vibration frequency caused by the impact is 15Hz, which is the response frequency of the structure to the impact and is in line with expectations.

[0048] Structural status judgment: The overall performance is normal, the impact did not cause damage to the structure, the damping ratio is 0.06, slightly higher than the first set of data. Under the excitation of the impact hammer, the higher damping ratio helps the structure to dissipate the impact energy faster, so that the impact amplitude can quickly return to the normal range after the instantaneous increase, indicating that the structure can effectively absorb energy through damping during the impact process, maintain the stability of the structure, and the structure is not affected by damage.

[0049] In the third set of data: Changes in vibration amplitude: The amplitude fluctuates within the normal range. Occasionally, a small increase may be caused by random wave characteristics or environmental perturbations. It does not exceed the reasonable range, indicating that the structural stiffness has not changed significantly.

[0050] Main vibration frequency: The main vibration frequency varies with time between 8 and 12 Hz. This is the normal response of the structure under random wave excitation and is within the expected frequency range.

[0051] Structural status judgment: The structure is normal, without obvious damage or abnormal loads. The damping ratio is 0.055, which is consistent with the normal range. Under random wave excitation, this damping ratio ensures that the structure can dissipate energy appropriately when vibrating at different frequencies, so that the amplitude fluctuates within the normal range. Although there are occasional small surges, the overall vibration characteristics are still in a normal state, indicating that the structural stiffness and damping characteristics have not changed significantly.

[0052] In the fourth set of data: Changes in vibration amplitude: The overall amplitude is small, and occasional small fluctuations are consistent with the vibration characteristics of the structure under natural wind excitation. There is no abnormal increase or fluctuation, indicating that the structural stiffness is stable.

[0053] Main vibration frequency: The main vibration frequency varies with wind force at 3 to 5 Hz, which is the normal vibration frequency range of the structure under natural wind excitation.

[0054] Structural status judgment: the structure vibrates normally under environmental excitation and is not damaged. The damping ratio is 0.04, which is relatively low but still within a reasonable range. Under low-energy excitation such as natural wind, the lower damping ratio enables the structure to vibrate to a certain extent under the action of breeze. Occasional small fluctuations are also in line with the vibration characteristics of the structure under natural wind excitation. There is no abnormal increase or fluctuation, indicating that the structural stiffness is stable, the damping characteristics are normal, and it is not damaged.

[0055] In the fifth set of data: Change in vibration amplitude: During the vibration process, the amplitude suddenly increases to twice the original value, which is beyond the normal range. This may be due to damage to the beam-column joint, which leads to a decrease in stiffness and an increase in the vibration response.

[0056] Main vibration frequency: In addition to the excitation frequency of 8Hz, a new frequency component of 18Hz appears, which indicates that the structure may be damaged and the vibration characteristics have changed.

[0057] Structural status judgment: According to the changes in amplitude and frequency, it is judged that the beam-column node may be damaged and further inspection is required. The damping ratio drops to 0.03, which is significantly lower than the normal range. When the structure experiences a sudden increase in amplitude and a new frequency component under sinusoidal wave excitation, the decrease in the damping ratio indicates that the energy dissipation capacity of the structure is weakened. This may be due to the damage to the beam-column node, which causes changes in the internal damping mechanism of the structure and makes it impossible to effectively suppress vibration, thereby increasing the vibration amplitude. This further confirms the judgment that the structure may be damaged and a detailed inspection of the beam-column node is required.

[0058] In the sixth set of data: Changes in vibration amplitude: The amplitude remains large and fluctuates abnormally after the impact, indicating that the structure has not been able to return to its normal vibration state after the impact. The beam may be damaged in the middle of the span, resulting in changes in stiffness.

[0059] Main vibration frequency: The impact response frequency of 12Hz is normal, but the frequency then shifts to the range of 10-14Hz, which also indicates that the structure may be damaged, affecting the vibration characteristics.

[0060] Structural status judgment: There may be damage in the mid-span of the beam. It is recommended to conduct detailed inspection and evaluation of this area. The damping ratio becomes 0.045, which is different from the normal situation. The amplitude continues to be large and the frequency shifts after the impact. At the same time, the change in the damping ratio indicates that the structure has been affected during the impact. It may be that the damage in the mid-span of the beam has changed the mechanical properties of the structure, including the damping properties, resulting in the structure being unable to dissipate energy normally and maintain stable vibration. Further evaluation and inspection of the beam span is needed.

[0061] The state of the steel concrete frame structure is judged by the changes in vibration amplitude and frequency under different excitation modes, measurement point locations, sampling frequencies and acquisition durations, which illustrates the effectiveness and value of this test method and system in practical applications. In engineering, by accurately measuring and analyzing the changes in the damping ratio, potential damage or performance changes in the structure can be discovered in time, providing a strong basis for safety assessment and maintenance of the structure.

[0062] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for testing vibration performance of a steel-concrete frame structure, characterized in that: The following steps are included: Step 1: Sensor arrangement: Install acceleration sensors at key locations of the steel concrete frame structure; Step 2: Vibration excitation: Use a variety of excitation methods to obtain the impulse response of the structure and obtain information to analyze the vibration characteristics of the structure; Step 3: Data acquisition: Use data acquisition equipment, set the appropriate sampling frequency, and set the acquisition time length to ensure that sufficient vibration signal data can be obtained for analysis; Step 4: Perform signal processing based on short-time Fourier transform (STFT): Perform STFT calculation on the preprocessed signal to obtain a time-frequency diagram in which the horizontal axis represents time and the vertical axis represents frequency. The color or grayscale represents the energy or amplitude of the signal at the time and frequency point. By observing the time-frequency diagram, the structure is analyzed and evaluated. Step 5: Perform signal processing based on Hilbert-Huang transform (HHT): Identify the weak vibration characteristics of the structure. In the early stage of structural damage, the local stiffness change caused by the damage will cause weak vibration frequency and amplitude changes; Step 6: Vibration performance analysis: Analyze the vibration parameters such as the natural frequency and damping ratio of the structure based on the results of STFT and HHT.

2. A steel concrete frame structure vibration performance testing method according to claim 1, characterized in that: In the signal processing-short-time Fourier transform, the amplitude reflects the intensity of the vibration. Under normal circumstances, the vibration amplitude of the test structure under a certain load is within a reasonable range. When the amplitude suddenly increases or fluctuates abnormally, the test structure will be locally damaged, resulting in a decrease in stiffness, thereby increasing the vibration response.

3. A steel concrete frame structure vibration performance testing method according to claim 1, characterized in that: The HHT includes two main steps: empirical mode decomposition (EMD) and Hilbert spectrum analysis. The EMD method decomposes the original signal into finite intrinsic mode functions (IMFs). Each IMF component represents the vibration mode of the signal at different local characteristic scales. At the same time, the differences between different IMF components and Hilbert spectra under normal structural states and different damage states are compared to establish evaluation indicators for structural health status and damage identification models.

4. A steel-concrete frame structure vibration performance testing system, used to perform the method according to claims 1 to 3, characterized in that: Includes the following modules: Module 1, sensor module: It is composed of a high-precision acceleration sensor with characteristics such as wide-band response, high sensitivity and low noise. The sensor is firmly mounted on the steel concrete frame structure through a mounting fixture; Module 2, data acquisition module: including data acquisition card and supporting computer software. The data acquisition card has enough channels to connect multiple sensors and has high sampling rate and high resolution analog-to-digital conversion function. The computer software is used to set acquisition parameters, control the data acquisition process and store the collected data. Module 3, signal processing and analysis module: including software modules running STFT and HHT algorithms, which is responsible for receiving the collected data and performing real-time or offline processing; Module 4, excitation module: using vibration table excitation or impact hammer excitation.

5. A steel concrete frame structure vibration performance testing system according to claim 4, characterized in that: The signal processing and analysis module has a data visualization function and displays the analysis results of STFT and HHT in a graphical manner.

6. A steel concrete frame structure vibration performance testing system according to claim 4, characterized in that: When the excitation module is excited by a vibration table, it includes a vibration table and its controller. The vibration table generates vibration signals of different types, amplitudes and frequencies. The controller accurately sets the vibration parameters of the vibration table and is synchronized with the data acquisition system.

7. A steel concrete frame structure vibration performance testing system according to claim 4, characterized in that: When the excitation module is excited by an impact hammer, it includes an impact hammer with hammer heads of different masses and a force sensor. The force sensor is used to measure the impact force applied by the impact hammer and combine it with the data collected by the acceleration sensor.

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