Indoor simulation system and evaluation method for subway upper cover property vehicle-induced vibration

Abstract

The invention discloses a subway upper cover property vehicle induced vibration indoor simulation system and method. The system comprises an upper structure model and a lower excitation device. The fiberboard (1) is lapped and laid on the structural framework (2); the holes (5) are formed in the periphery and the center of the fixed plate (4), the screws (6) are vertically fixed in the holes (5) through first nuts (12), and the upper portions of the screws (6) penetrate through hole channels (13) in the periphery of the movable plate (10); an upper spring (7) and a lower spring (8) are arranged on the screw rod (6); the vibration exciter (11) is placed on the bottom fixing plate (4) and located under the center hole channel (14) of the movable plate (10), and the ejector rod (16) penetrates through the center hole channel (14); the ejector rod (16) and the movable plate (10) are fixed through a clamp (17). The device can simulate the vibration state of a metro upper cover property under metro operation indoors, is reliable in connection, is easy to install, does not affect the dynamic characteristics of the structure through excitation and detection equipment, and is more stable in test result.

Description

Technical Field

[0001] This invention relates to the field of structural dynamic modeling technology, and in particular to an indoor simulation system and evaluation method for vehicle-induced vibration in subway-adjacent properties. Background Technology

[0002] With the large-scale development of subways in cities, subway-adjacent properties have gradually emerged and developed as a method of intensive land resource utilization. When a subway runs on the track, it, along with the track structure, generates an environmental vibration system. This system is influenced by factors such as wheels, track irregularities, and discontinuous track joints internally, and by external factors such as earthquakes and wind loads externally. Due to the characteristics of long operating hours and short intervals in subway operation, the resulting vibration waves are characterized by long duration, numerous cycles, and predominantly low-frequency vibrations. These vibration waves, excited by the subway trains, propagate through the track to the tunnel body, and then from the tunnel body to the soil. Within the soil, they attenuate as vibration waves and propagate outwards, causing vibrations on the ground and the structures of the properties above. Although the vibration levels generated by subway operation are relatively low and will not directly damage buildings, they can cause localized vibrations in the structure and its internal facilities, generating secondary structural noise. This significantly impacts the comfort of the living and working environment within the structure, causing discomfort, insomnia, irritability, and other problems. Furthermore, cyclic loading can lead to fatigue effects and deformation damage in the superstructure, causing soil liquefaction, uneven settlement of the foundation, wall cracks, furniture displacement, and cracked doors and windows. In more serious cases, it can even lead to structural safety issues, resulting in significant safety hazards, property damage, and potentially structural collapse or even casualties. Therefore, it is urgent to study the vibration system of superstructure properties excited by subway trains.

[0003] However, research on the vibration system of properties above subway stations under the excitation of subway trains is highly complex and involves multiple disciplines. The main research directions include the study of subway vibration sources and loads, the propagation and attenuation laws of subway vibration waves, and structural vibration. The study of subway vibration sources and loads primarily involves establishing different mechanical models to simulate the excitation of the track by the train. The propagation and attenuation of subway vibration waves are related to vibration energy, vibration source characteristics, different media, and propagation direction. The main theoretical basis is the classical elastic wave propagation theory. The study of structural vibration is conducted through various methods, including theoretical analysis, numerical simulation, and field measurements. However, due to the complexity of actual engineering projects, relying solely on numerical simulation and theoretical analysis is insufficient for effectively studying the vibration system of properties above subway stations under the excitation of subway trains. Field measurement procedures are relatively complex, and the scenarios of properties above subway stations are relatively fixed. Summary of the Invention

[0004] This invention provides an indoor simulation system and evaluation method for vehicle-induced vibration of properties above subway stations. It can simulate the vibration state of properties above subway stations under subway operation indoors. The system is reliable, easy to install, and the excitation and testing equipment does not affect the dynamic characteristics of the structure itself, resulting in more stable test results.

[0005] In a first aspect, embodiments of the present invention provide an indoor simulation system for vehicle-induced vibration in subway-adjacent properties, characterized in that it includes: an upper structure model and a lower excitation device;

[0006] The superstructure model includes fiberboard and a predetermined number of layered structural frames; the structural frames are partially welded from aluminum square tubes; the fiberboard is overlapped and laid on the structural frames;

[0007] The lower excitation device includes a bottom fixed plate, holes, screws, upper springs, lower springs, base plates, movable plates, and a vibrator;

[0008] The bottom fixing plate is placed on the ground, and the holes are arranged around the perimeter and center of the fixing plate. The screw is vertically fixed in the holes through the first nut, and the upper part passes through the perimeter holes of the movable plate. The screw is equipped with an upper spring and a lower spring for moving the movable plate and the upper structure model up and down.

[0009] The vibrator is placed on the bottom fixed plate, directly below the central channel of the movable plate. The top rod of the vibrator passes through the central channel and is used to excite the lower device, thereby driving the upper structure model to vibrate. The top rod is fixed to the movable plate by a clamp to ensure that the excitation force of the vibrator can be effectively transmitted to the test structure.

[0010] Optionally, the first layer of the structural frame has a height of 0.5m, the second, third and fourth layers have a height of 0.4m, and the fiberboard has a size of 0.82×0.82m.

[0011] Optionally, the aluminum square tube includes a first aluminum steel tube, and / or a second aluminum steel tube, and / or a third aluminum steel tube;

[0012] The first aluminum-steel pipe has a cross-sectional dimension of 20×20mm, a thickness of 1mm, and a cross-sectional area of ​​39. The second aluminum-steel pipe has a cross-sectional dimension of 20×20mm, a thickness of 2mm, and a cross-sectional area of ​​76. The third aluminum-steel pipe has a cross-sectional dimension of 20×20mm, a thickness of 3mm, and a cross-sectional area of ​​111. .

[0013] Optionally, the fiberboard may comprise a first fiberboard, and / or a second fiberboard, and / or a third fiberboard;

[0014] The thickness of the first fiberboard is 5mm, the thickness of the second fiberboard is 9mm, and the thickness of the third fiberboard is 12mm.

[0015] Optionally, the upper spring and the lower spring are sleeved on the screw, the screw is used to constrain the upper spring and the lower spring to move in the same vertical plane, the second nut is used to constrain the ends of the springs, and the two ends of the lower spring are respectively fixed to the movable plate and the bottom fixed plate.

[0016] Optionally, the surrounding holes and the central hole are respectively arranged around the perimeter and at the center of the movable plate;

[0017] The distance between the four surrounding holes and the edge of the movable plate is 0.1m, and the central hole is located at the exact center of the movable plate;

[0018] The surrounding holes are connected to the upper structure model via the base, and the upper structure model is bolted to the base.

[0019] Optionally, the thickness of the movable plate is 20mm and the size is 1.0m × 1.0m.

[0020] Optionally, the exciter includes a spring, a magnet, an iron core, a magnetic pole plate, a moving coil, and a housing.

[0021] Secondly, embodiments of the present invention also provide an indoor simulation method for vibration caused by vehicles in buildings with rooftop structures, comprising:

[0022] Based on the actual structural characteristics of the overpass, build the superstructure model required for the indoor simulation system, and select the board material for the test model according to the natural vibration period of different model boards.

[0023] Select a test system and excitation frequency, record the technical specifications of the test system and excitation system, control the peak acceleration input of the foot pad, calculate the model size and impedance, and determine the measurement position of the sensor in the mid-span of each slab and beam.

[0024] Design various preset working conditions and conduct tests on them respectively, and use wired piezoelectric accelerometer and Bluetooth sensor for comparative measurement;

[0025] Frequency domain analysis was performed on the test results. The environmental vibration problem of the subway overpass property was analyzed using one-third octave bands. Acceleration time history curves, Z-axis vibration level and normalized spectrum images were plotted.

[0026] Using the vertical Z-axis vibration level VLmax as the evaluation index, comfort was assessed by comparing it with the daytime and nighttime standard values ​​of the vertical Z-axis vibration level in various urban areas.

[0027] Based on the parameters of the superstructure of the indoor simulation system, a finite element model of the superstructure of the subway overpass property test device is established. Boundary conditions and loading regime are set, excitation load is input, and numerical simulation is performed on the natural vibration modes and vibration response under loading conditions of the test model.

[0028] Acceleration time history curves, Z-axis vibration levels, and normalized spectrum images of beam-slab joints were plotted and compared with experimental and comfort assessment results.

[0029] Optionally, based on the natural vibration period of different model plates, the material used for the test model can be selected as follows: by measuring the data of model plates of different sizes, recording the length and width of the model plate as a and b respectively, the thickness as h, the elastic modulus E and density ρ of the material, calculating the natural vibration period of different model plates, comparing the first-order frequency of different model plates, and selecting the fiberboard material.

[0030] This invention provides an indoor simulation system and method for vehicle-induced vibration of properties above subway stations. It utilizes a lower excitation device to simulate subway loads and excite the property model to generate a structural response. The upper structural model is easily disassembled and can be converted from a single-span structure to a multi-span structure. The lower excitation device can generate different excitation frequencies, enabling the study of the structural response and vibration reduction effects of properties above subway stations under different operating conditions. It can simulate the vibration state of properties above subway stations under subway operation indoors, eliminating the need for on-site measurements. The connection is reliable and easy to install. The excitation and detection equipment used should not affect the structural dynamic characteristics, resulting in more stable test results.

[0031] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of an indoor simulation system for vehicle-induced vibration in a subway-adjacent property, provided in an embodiment of the present invention.

[0034] Figure 2 yes Figure 1A schematic diagram of the upper structure model in the middle;

[0035] Figure 3 yes Figure 1 A schematic diagram of the lower excitation device in the middle;

[0036] Figure 4 This is a flowchart of an indoor simulation method for vehicle-induced vibration in a property under a roof, provided by an embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of a 10Hz excitation frequency provided in an embodiment of the present invention;

[0038] Figure 6 This is a time history diagram of the acceleration at a plate measuring point provided in an embodiment of the present invention;

[0039] Figure 7 This is a time history diagram of beam acceleration at a measuring point provided in an embodiment of the present invention;

[0040] Figure 8 This is a peak acceleration diagram of a plate measuring point provided in an embodiment of the present invention;

[0041] Figure 9 This is a peak acceleration diagram of a plate measuring point provided in an embodiment of the present invention;

[0042] Figure 10 This is a vibration level diagram of a plate measuring point provided in an embodiment of the present invention;

[0043] Figure 11 This is a vibration level diagram of a beam measuring point provided in an embodiment of the present invention;

[0044] Figure 12 This is a normalized spectrum diagram of a plate measurement point provided in an embodiment of the present invention;

[0045] Figure 13 This is a normalized spectrum diagram of a beam measuring point provided in an embodiment of the present invention;

[0046] Figure 14 This is a first-order vibration mode diagram of a plate provided in an embodiment of the present invention;

[0047] Figure 15 This is a first-order vertical vibration mode of a superstructure model provided in an embodiment of the present invention;

[0048] Figure 16 This is a peak acceleration diagram of a plate measuring point provided in an embodiment of the present invention;

[0049] Figure 17 This is a peak acceleration diagram of a beam measuring point provided in an embodiment of the present invention. Detailed Implementation

[0050] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0051] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0052] This invention proposes a novel approach combining experimentation and numerical simulation: it provides an indoor simulation system and method for vehicle-induced vibration in subway-adjacent properties, aiming to offer an efficient and flexible solution for evaluating subway vibration systems under different superstructure building conditions, as detailed below:

[0053] Figure 1 This is a schematic diagram of the structure of an indoor simulation system for vehicle-induced vibration in subway-adjacent properties, provided in an embodiment of the present invention. Figure 2 yes Figure 1 A schematic diagram of the upper structure model. Figure 3 yes Figure 1 A schematic diagram of the lower excitation device. (Reference) Figures 1-3 The system includes: an upper structure model and a lower excitation device; the upper structure model includes fiberboard 1 and a pre-set number of layered structural skeletons 2; the structural skeleton 2 is partially welded from aluminum square tubes 3; the fiberboard 1 is laid on the structural skeleton 2.

[0054] The gaps between fiberboard 1 and the structural frame 2 are firmly bonded with strong adhesive. The superstructure model can vary the number of stories, spans, and the dimensions of the panels and columns to simulate different structural configurations. This allows for the study of the impact of different design parameters on vibration response.

[0055] The lower excitation device includes a bottom fixed plate 4, holes 5, a screw 6, an upper spring 7, a lower spring 8, a base 9, a movable plate 10, and a vibrator 11. The bottom fixed plate 4 is placed on the ground, and holes 5 are arranged around the perimeter and center of the fixed plate 4. The screw 6 is vertically fixed in the holes 5 through the first nut 12, and its upper part passes through the surrounding holes 13 of the movable plate 10. The upper spring 7 and the lower spring 8 are arranged on the screw 6 to move the movable plate 10 and the upper structural model up and down. The vibrator 11 is placed on the bottom fixed plate 4, located directly below the central hole 14 of the movable plate 10. The top rod 16 of the vibrator 11 passes through the central hole 14 and is used to excite the lower device, thereby driving the upper structural model to vibrate. The top rod 16 is fixed to the movable plate 10 by a clamp 17 to ensure that the excitation force of the vibrator 11 can be effectively transmitted to the test structure.

[0056] Understandably, the restoring force of the spring can be used to move the movable plate 10 and the upper structure model up and down.

[0057] The indoor simulation system for vehicle-induced vibration of subway-adjacent properties provided in this invention can simulate subway loads using a lower excitation device to excite the structural response of the subway-adjacent property model. The upper structural model is easily disassembled and can be converted from a single-span structure to a multi-span structure. The lower excitation device can generate different excitation frequencies, providing the conditions for studying the structural response and vibration reduction effect of the subway-adjacent property under different working conditions. It can simulate the vibration state of subway-adjacent properties under subway operation indoors without the need for on-site measurements. The connection is reliable and easy to install. The excitation and detection equipment used should not affect the dynamic characteristics of the structure itself, resulting in more stable test results.

[0058] Optionally, the first layer of the structural frame 2 has a height of 0.5m, the second, third and fourth layers have a height of 0.4m, and the fiberboard 1 has a size of 0.82×0.82m.

[0059] Optionally, the aluminum square tube 3 includes a first aluminum steel tube, and / or a second aluminum steel tube, and / or a third aluminum steel tube;

[0060] The first aluminum-steel pipe has a cross-sectional dimension of 20×20mm, a thickness of 1mm, and a cross-sectional area of ​​39. The second aluminum-steel pipe has a cross-sectional dimension of 20×20mm, a thickness of 2mm, and a cross-sectional area of ​​76. The third aluminum-steel pipe has a cross-sectional dimension of 20×20mm, a thickness of 3mm, and a cross-sectional area of ​​111. .

[0061] Optionally, fiberboard 1 includes a first fiberboard, and / or a second fiberboard, and / or a third fiberboard;

[0062] The thickness of the first fiberboard is 5mm, the thickness of the second fiberboard is 9mm, and the thickness of the third fiberboard is 12mm.

[0063] Optionally, the upper spring 7 and the lower spring 8 are fitted onto the screw 6. The screw 6 is used to constrain the upper spring 7 and the lower spring 8 to move in the same vertical plane. The second nut 15 is used to constrain the ends of the springs. The two ends of the lower spring 8 are respectively fixed to the movable plate 10 and the bottom fixed plate 4.

[0064] For example, considering the maximum amplitude and maximum allowable excitation force of the vibrator top rod 16 and the overall height of each part, the lower spring 8 can be four springs with a length of 600mm, an outer diameter of 35mm, and an inner diameter of 17.5+mm. The upper spring 7 can be four springs with a length of 150mm, an outer diameter of 35mm, and an inner diameter of 17.5+mm.

[0065] Optionally, the four-sided holes 13 and the central hole 14 are respectively arranged around the perimeter and the center of the movable plate 10;

[0066] The distance between the four-sided holes 13 and the edge of the movable plate 10 is 0.1m, and the central hole 14 is located at the exact center of the movable plate 10;

[0067] The four-sided holes 13 are connected to the upper structure model through the base 9, and the upper structure model is bolted to the base 9.

[0068] Optionally, the thickness of the movable plate 10 is 20mm, and its dimensions are 1.0m × 1.0m.

[0069] Optionally, the vibrator 11 includes a spring, a magnet, an iron core, a magnetic pole plate, a moving coil, and a housing.

[0070] In summary, the indoor simulation system for vehicle-induced vibration of subway-adjacent properties provided in this invention has the following technical advantages: 1. Modular and detachable superstructure: The core innovation lies in the fact that the superstructure (building model) is not fixed, but can be flexibly assembled like "building blocks." By replacing three different thicknesses (5mm, 9mm, 12mm) of fiberboard and three different wall thicknesses (1mm, 2mm, 3mm) of aluminum square tubes, floor slabs and columns with different stiffness and mass can be simulated. The structure can be easily changed from single span to multi-span, and from four-story to multi-story, greatly expanding the test range and enabling the simulation of various structural forms in actual engineering projects. 2. Carefully designed double-layer spring excitation system: The lower excitation device adopts a combination of upper spring (short) and lower spring (long), which are fitted onto the screw to form a stable elastic support system. This design utilizes the restoring force of the spring to enable the movable plate and the upper model to move vertically, while the screw and nut constrain its movement trajectory, ensuring the efficiency and stability of the exciter's energy transfer, and adapting to the amplitude and excitation force of the exciter's top rod. 3. Stable and efficient excitation transmission mechanism: The vibrator top rod is directly fixed to the movable plate through a clamp, ensuring that the excitation force can be effectively and losslessly transmitted to the entire upper structure. The movable plate has channels in the center and around its perimeter, which are used to transmit the excitation force and guide the movement of the spring, respectively. The design is reasonable and avoids unnecessary torsion or deflection.

[0071] Figure 4 This is a flowchart of an indoor simulation method for vehicle-induced vibration in a property development, provided by an embodiment of the present invention. (Refer to...) Figure 4 The method includes the following steps:

[0072] S410. Based on the actual structural characteristics of the overlying property, construct the superstructure model required for the indoor simulation system, and select the board material used in the test model according to the natural vibration period of different model boards.

[0073] Specifically, since the vibration excitation is a real load, but the natural frequency of the scaled-down model is generally much higher than that of the original structure, the vibration frequency experienced by the model is lower than expected. Therefore, it is necessary to calculate the natural frequency of a simply supported rectangular plate. Thus, data for model plates of different sizes were measured, with the length and width recorded as a and b, thickness as h, elastic modulus as E, density as ρ, and Poisson's ratio as v. The natural period of different model plates was calculated using the following formula for four materials: the original structural plate, concrete structural plate, aluminum structural plate, and fiber structural plate.

[0074] ;

[0075] Table 1 shows the calculation results, revealing that the original concrete slab, aluminum plate, and fiberboard could all meet the frequency requirements. However, using a concrete model slab resulted in a higher natural frequency that was difficult to measure. While the original concrete slab met the frequency requirements, its large planar dimensions made it difficult to place in the laboratory. Considering the relatively thin aluminum plate and the difficulty in ensuring stiffness, fiberboard was ultimately chosen. This method met the frequency requirements and facilitated manual installation and connection. Scaled-down models typically have higher natural frequencies, but their actual vibration frequencies are lower. This embodiment of the invention, by calculating the natural frequency and selecting suitable materials, ensures that the model accurately simulates real vibrations.

[0076] Table 1

[0077]

[0078] S420. Select the test system and excitation frequency, record the technical specifications of the test system and excitation system, control the peak acceleration input of the foot pad, calculate the model size and impedance, and determine the measurement position of the sensor in the mid-span of each slab and beam.

[0079] Specifically, the voltage, current, volume, measurement dimensions, range, accuracy, data transmission content, data transmission frequency, and Bluetooth transmission distance of the accelerometer can be recorded. Using the law of electromagnetic induction, the maximum excitation force of the JZQ-100 exciter can be calculated, determining its maximum allowable excitation force, force constant, maximum amplitude, total weight, and overall dimensions. Similarly, the maximum peak output current, maximum peak output voltage, maximum peak output power, operating frequency range, and output signal-to-noise ratio of the GF-1000 power amplifier can be determined. The resulting excitation frequency is as follows: Figure 5 As shown.

[0080] The impedance ratio of a plate to a column is calculated using the definition of vibration propagation impedance. Where E represents the elastic modulus, ρ represents the bulk density, v represents Poisson's ratio, A represents the cross-sectional area, and h represents the plate thickness.

[0081] Understandably, by analyzing the propagation of vibration in a structure through impedance ratio analysis, the impact of differences in dynamic stiffness can be understood.

[0082] The S430 was designed with various preset operating conditions and tested separately, using a wired piezoelectric accelerometer and a Bluetooth sensor for comparative measurements.

[0083] The Bluetooth sensor used can be the BWT901CL Bluetooth vibration sensor, which has a small housing and weighs only a dozen grams, reducing the impact of the sensor's own weight on the test. The sensor's sampling frequency is between 0.1-200Hz to ensure compliance with the sampling law requirements; the sampling frequency should be greater than or equal to twice the operating frequency. This embodiment of the invention uses a small Bluetooth sensor to avoid the influence of the sensor's own weight on the test results.

[0084] Specifically, because the upper structure of this indoor simulation system is easily disassembled, it can be changed from a single-span structure to a multi-span structure. The lower excitation equipment can generate different excitation frequencies, allowing for the design of nine different operating conditions and the testing of each condition. The nine different structural size combinations and six external excitation frequencies define each operating condition, resulting in a total of 54 operating conditions, as shown in Table 2.

[0085] Table 2

[0086]

[0087] S440. Perform frequency domain analysis on the test results, and use one-third octave bands to analyze the environmental vibration problem of the subway-above-ground property, and plot the acceleration time history curve, Z-axis vibration level and normalized spectrum image.

[0088] Specifically, the test results are processed, acceleration time history curves are extracted, and Z-axis weighted summation and Fourier transform are performed on the acceleration curves using a MATLAB program to obtain the Z-axis vibration level and normalized spectrum image. The acceleration time history curves of beams and plates measured by wired piezoelectric accelerometers and Bluetooth sensors are extracted as follows: Figure 6 and Figure 7 As shown, the peak acceleration diagrams of the measuring points for each layer of structure 1 are compiled and plotted as follows. Figure 8 and Figure 9 As shown, the Z-axis vibration levels of structures 1, 4, and 7 are as follows: Figure 10 and Figure 11 As shown, the normalized spectral images of structures 1-9 are as follows: Figure 12 and Figure 13 As shown.

[0089] The vibration level acceleration formula used in this embodiment of the invention is as follows: ; This refers to the vibration acceleration level, measured in dB. For the measured vibration acceleration value, As the reference acceleration, the national standard ISO 2631-1:1997 specifies its value as 10⁻⁶ m / s⁻². This formula is the vibration acceleration level obtained after correction using the weighting factors for different frequencies of whole-body vibration specified in the international standard ISO 2631-1:1997, also known as the weighted acceleration level.

[0090] Frequency domain analysis was performed on the measured vibration time history data. The vibration time history curve measured by the accelerometer was decomposed into a series of simple harmonic waves using a Fourier series to obtain a discretized acceleration time history expression. A Fourier transform was then applied to obtain the frequency domain amplitude Yn. Using each frequency domain amplitude Yn and its corresponding frequency, the frequency domain amplitude spectrum of the vibration time sequence can be obtained. The vertical Z-vibration level limits for different areas are specified in the "Urban Area Environmental Vibration Standard" (GB10070-88), and the evaluation criteria are shown in Table 3.

[0091] Table 3

[0092]

[0093] S450. Using the vertical Z-axis vibration level VLmax as the evaluation index, the comfort level is assessed by comparing it with the daytime and nighttime standard values ​​of the vertical Z-axis vibration level in various urban areas.

[0094] Understandably, measuring vibration levels (such as Z-axis vibration level) and comparing them to standard values ​​helps assess whether a building meets comfort requirements. This contributes to designing more comfortable properties above subway stations.

[0095] S460. Based on the parameters of the superstructure of the indoor simulation system, establish a finite element model of the superstructure of the subway overpass property test device, set boundary conditions and loading regime, input excitation load, and perform numerical simulation of the natural vibration modes and vibration response under loading conditions of the test model.

[0096] Understandably, nine structural dimensions need to be input for first-order modal analysis. Since the primary consideration is the vertical natural modes of the structure, the horizontal modes are filtered out in SAP2000, and the first-order vertical modes are extracted, along with stress contour plots for each dimension. Analysis shows that the first-order modes of the local fiberboard are between 30 and 80 Hz, while the first-order modes of the overall structure fall between 28.5 and 35.0 Hz. The first-order modes of both the local boards and the overall structure are between 10 and 80 Hz, which is beneficial for measurement and analysis using a Bluetooth accelerometer in the laboratory. Furthermore, the simulated first-order modes of each structure show good agreement with the frequency distribution patterns of the model experiments. Comparison of experimental data with the SAP2000 finite element model verifies the accuracy of the numerical simulation, thereby aiding in design optimization.

[0097] Specifically, based on the parameters of nine different superstructures in the indoor simulation system, a finite element model of the superstructure of the subway-adjacent property test device was established in SAP2000 software. Elastic three-dimensional Frame elements were used to simulate the frame columns and beams, and elastic three-dimensional Shell elements were used to simulate the floor slabs. Test parameters for the test device's materials and cross-sectional dimensions were input into the model. Boundary conditions and loading regimes were set, and excitation loads were input. Numerical simulations were performed on the natural modes of the test model and its vibration response under loading conditions. The input loads were vertical vibration waves. Since the amplitude of the frame vibration under vertical excitation was relatively small, the material was defined as linearly deformed within the linear elastic range during calculation. Numerical simulations were performed on the natural modes of the model and its vibration response under loading conditions for the nine designed working conditions. The first-order array of the simulation slab was plotted as follows: Figure 14 As shown, the first-order array of the superstructure model is as follows: Figure 15 As shown.

[0098] S470. Plot the acceleration time history curves, Z-axis vibration level, and normalized spectrum images of the beam-slab joints, and compare them with the experimental and comfort assessment results.

[0099] Specifically, based on the location of the acceleration measurement points in the experiment, the acceleration results are extracted from the model. The test results are processed, and the acceleration time history curves, Z-axis vibration level, and normalized spectrum images of the beam-slab joints are plotted. These are then compared with the experimental results, and the acceleration time history curves of the beam-slab joints are plotted as follows: Figure 16 and Figure 17 As shown, the reasons for the errors in the experiment and simulation are analyzed, and the comfort evaluation standard is compared for evaluation.

[0100] For example, the differences between the experimental and simulated products are shown in Table 4. The reasons are as follows: (1) The test plate itself has a certain degree of warping. The thinner the plate, the more severe the warping, which affects the dynamic characteristics of the structure and causes a large error; (2) The gap generated when the test plate and frame are overlapped makes the vibration propagation discontinuous; (3) Slight misalignment during installation will cause the structure to be incompletely symmetrical, which will cause errors in the test results.

[0101] Table 4

[0102]

[0103] Optionally, based on the natural vibration period of different model plates, the material used for the test model can be selected as follows: by measuring the data of model plates of different sizes, recording the length and width of the model plate as a and b respectively, the thickness as h, the elastic modulus E and density ρ of the material, calculating the natural vibration period of different model plates, comparing the first-order frequency of different model plates, and selecting the fiberboard material.

[0104] In summary, the indoor simulation method for vehicle-induced vibration in subway-adjacent properties provided in this invention has the following advantages: 1. A hybrid measurement scheme using wired and Bluetooth sensors: To overcome the influence of the weight of traditional wired sensors on the scaled model, the patent innovatively employs a Bluetooth vibration sensor. Weighing only a few grams, its impact on structural dynamic characteristics is negligible, thus obtaining more accurate experimental data. Simultaneously, comparative measurements with a wired piezoelectric accelerometer ensure data reliability. 2. Introducing "vibration propagation impedance" for mechanism analysis: The patent goes beyond simply measuring vibration magnitude; it delves into the physical mechanism of vibration propagation. By calculating the impedance ratio between the slab and column, it quantitatively assesses the propagation law of vibration energy between structural components, providing a scientific basis for understanding the impact of structural dynamic stiffness differences on vibration propagation. 3. A clear comfort assessment process and indicators: The patent provides a complete process from data acquisition to final evaluation. Ultimately, the vertical Z-level vibration (VLmax) is used as the core evaluation indicator and directly compared with urban area vibration standard values, achieving a quantitative and standardized assessment of vibration comfort in subway-adjacent properties. 4. Closed-loop verification of "experiment-simulation": The patent requires the establishment of corresponding numerical models in finite element software such as SAP2000 based on the actual parameters of the experimental model. By comparing experimental results and numerical simulation results (such as acceleration time history curves, spectrum, etc.), the accuracy of the numerical model can be verified, and the verified model can be used for more extensive parameterization research, forming a complete technical path from physical experiment to digital simulation, which greatly improves research efficiency and reliability. 5. Systematic test design under multiple operating conditions: Utilizing the reconfigurable characteristics of the system, various different operating conditions (different structural forms, different excitation frequencies) are actively designed for comparative experiments, thereby comprehensively studying the influence of various parameters on vehicle-induced vibration response. This indoor simulation evaluation method combines indoor simulation and finite element analysis to analyze the vibration state and structural response generated by subway vibration. The evaluation system is clear and accurate. This indoor simulation evaluation method uses frequency domain analysis, with the Z-axis vibration level of a plumb bob as the evaluation index, which is standardized. The boundary conditions and loading methods of this indoor simulation evaluation method are more clearly defined, which can meet the excitation and measurement requirements of the experiment.

[0105] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0106] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A subway over property vehicle-induced vibration indoor simulation system, characterized in that, The application relates to a structure model and a lower excitation device. The upper structure model comprises fibre plates (1) and a preset number of layer structure skeletons (2); the structure skeletons (2) are partially welded by aluminium square tubes (3); and the fibre plates (1) are overlapped and laid on the structure skeletons (2). The lower excitation device comprises a bottom fixed plate (4), holes (5), screw rods (6), upper springs (7), lower springs (8), foot bases (9), movable plates (10) and exciters (11). The bottom fixed plate (4) is placed on the ground, the holes (5) are arranged around and in the center of the fixed plate (4), the screw rods (6) are vertically fixed in the holes (5) through first nuts (12) and pass through the four around holes (13) of the movable plates (10); the upper springs (7) and the lower springs (8) are arranged on the screw rods (6) and used for moving the movable plates (10) and the upper structure model up and down. The exciter (11) is placed on the bottom fixed plate (4) and located directly below the center hole (14) of the movable plate (10), the top rod (16) of the exciter (11) passes through the center hole (14), the top rod (16) is used for exciting the lower device to drive the upper structure model to vibrate, and the top rod (16) and the movable plate (10) are fixed through a clamp (17), so that the exciting force of the exciter (11) can be effectively transmitted to the test structure. The layer height of the first layer of the structure skeleton (2) is 0.5 m, the layer height of the second layer, the third layer and the fourth layer is 0.4 m, and the size of the fibre plate (1) is 0.82*0.82 m.

2. The system according to claim 1, wherein, The aluminium square tube (3) comprises a first aluminium steel tube, a second aluminium steel tube and / or a third aluminium steel tube.

3. The subway-over property vehicle-induced vibration chamber simulation system of claim 1, wherein, The fibre plate (1) comprises a first fibre plate, a second fibre plate and / or a third fibre plate. The first aluminum steel pipe has a cross-sectional dimension of 20x20 mm, a thickness of 1 mm, and a cross-sectional area of 39 ; the second aluminum steel pipe has a cross-sectional dimension of 20x20 mm, a thickness of 2 mm, and a cross-sectional area of 76 ; and the third aluminum steel pipe has a cross-sectional dimension of 20x20 mm, a thickness of 3 mm, and a cross-sectional area of 111 .

4. The subway-over property vibration system of claim 1, wherein, The thickness of the first fibre plate is 5 mm, the thickness of the second fibre plate is 9 mm, and the thickness of the third fibre plate is 12 mm. The upper spring (7) and the lower spring (8) are sleeved on the screw rod (6), the screw rod (6) is used for restricting the upper spring (7) and the lower spring (8) to move in the same vertical plane, a second nut (15) is used for restricting the spring end, and the two ends of the lower spring (8) are fixed on the movable plate (10) and the bottom fixed plate (4) respectively.

5. The subway-over property vibration system of claim 1, wherein, The four around holes (13) and the center hole (14) are arranged around and in the center of the movable plate (10) respectively.

6. The subway-over property vibration system of claim 1, wherein, The distance between the four around holes (13) and the edges of the movable plate (10) is 0.1 m, and the center hole (14) is located at the center of the movable plate (10). The four around holes (13) are connected with the upper structure model through the foot bases (9), and the upper structure model is bolted with the foot bases (9). The thickness of the movable plate (10) is 20 mm, and the size is 1.0 m*1.0 m.

7. The subway-over property vehicle-induced vibration chamber simulation system of claim 1, wherein, The exciter (11) comprises a spring, a magnetic steel, an iron core, a magnetic pole plate, a moving coil and a shell.

8. The subway-over property vehicle-induced vibration chamber simulation system of claim 1, wherein, ​ 9. A method for simulating vibration of a vehicle in a room, characterized by, Comprise: According to the actual cover property structure characteristics, build indoor simulation system required superstructure model, according to the natural period of different model plate, select the test model using plate; Select test system and excitation frequency, record the technical index of the test system and excitation system, control the acceleration peak value of the input of the foot base, calculate the model size and impedance, determine the measurement position of the sensor in each layer plate span and beam span; Design a variety of preset working conditions and carry out test respectively, use wired piezoelectric acceleration sensor and Bluetooth sensor for contrast measurement; The test results are analyzed in frequency domain, and the environmental vibration problem of the subway cover property is analyzed by using one-third octave band analysis, and the acceleration time history curve, Z direction vibration level and normalized frequency spectrum image are drawn; Taking the lead hammer Z direction vibration level VLmax as the evaluation index, the comfort degree is evaluated by comparing the day and night standard value of the lead hammer Z direction vibration level in various regions of the city; According to the parameters of the superstructure of the indoor simulation system, the finite element model of the superstructure of the test device of the subway cover property is established, the boundary conditions and loading system are set, the excitation load is input, and the numerical simulation of the natural mode of the test model and the vibration response under the loading condition is carried out; Draw the acceleration time history curve, Z direction vibration level and normalized frequency spectrum image of the beam plate node, and compare with the test and comfort evaluation results.

10. The method of claim 9, wherein the method further comprises: According to the natural period of different model plates, the plate used in the test model is selected, including: by measuring the data of model plates of different sizes, recording the length and width of the model plate a and b, the thickness h, the elastic modulus E and the density p of the material, calculating the natural period of different model plates, comparing the first order frequency of different model plates, and selecting fiber plate.

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