Welding seam change detection device and detection method for steel structure in building

Abstract

The invention discloses a welding seam change detection device and method for a steel structure in a building, and relates to the technical field of building steel structure welding seam detection.The welding seam change detection device comprises a protective shell, a sensing module, a data processing module and an alarm module are arranged in the protective shell, and a mounting unit is further arranged at the bottom of the protective shell; the method further comprises the steps of S1 pretreatment of a weld joint detection area, S2 device positioning and installation, S3 system initialization and parameter configuration, S4 weld joint deformation signal collection, S5 signal processing and transmission, S6 anomaly analysis and alarm triggering and S7 continuous monitoring. According to the invention, the array-type magnetoelastic sensing unit is combined with the AD conversion chip unit and the signal amplification unit, so that high-resolution acquisition of microvolt-level signals is realized, and tiny deformation in transverse, longitudinal and shearing directions can be captured; meanwhile, through signal amplification in the step S3, the step S4 and the step S5, the early recognition capability of the tiny defects of the welding seam is remarkably improved, the sensitivity reaches 5 mu epsilon, and 0.1 mm-level microcracks can be accurately recognized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building steel structure weld detection, in particular to a weld change detection device and method for building steel structure. BACKGROUND

[0002] Building steel structure has become the core load-bearing structure in the fields of large venues, high-rise buildings, bridge engineering, etc. due to its advantages of high strength, lightweight, convenient construction, etc. Weld, as the key part of steel structure connection, is subjected to long-term load stress, temperature change, vibration impact and other complex actions, and is prone to produce micro-cracks or deformation due to fatigue damage and stress concentration. If not found in time, it may cause structural safety hazards. Therefore, accurate detection and monitoring of the weld state is the core link to ensure the long-term safe operation of the steel structure. The current mainstream weld detection technology mainly includes traditional manual inspection combined with ultrasonic flaw detection, fixed monitoring based on resistance strain gauges and three-dimensional laser scanning technology.

[0003] In actual application, the existing technology has the following problems: manual inspection relies on personnel experience and is highly subjective, single detection takes as long as several hours, and is limited by the erection of scaffolding, etc., making it difficult to cover blind spots such as high altitude and narrow space, and there is a risk of missed detection; fixed strain gauges are easily disturbed by temperature, humidity and electromagnetic environment, have poor signal stability, and are complicated to wire, and are prone to aging and falling off during long-term use, resulting in shortened service life; three-dimensional laser scanning can obtain high-precision shape data, but the equipment cost is high, and frequent calibration is required, making it impossible to achieve 24-hour continuous monitoring and difficult to capture real-time dynamic changes of the weld; a weld change detection device and method for building steel structure need to be designed to solve the above problems. SUMMARY

[0004] To achieve the above purpose, the present application realizes the following technical scheme: a weld change detection device for building steel structure, comprising a protective shell, a sensing module, a data processing module and an alarm module are arranged inside the protective shell, and an installation unit is further arranged at the bottom of the protective shell. The sensing module comprises an array type magnetoelastic sensing unit and a temperature compensation unit, the data processing module comprises a signal amplification unit, an AD conversion chip unit and a wireless transmission unit, and the alarm module comprises an audible and visual alarm unit and a push interface. The output end of the array type magnetoelastic sensing unit is connected in communication with the input end of the signal amplification unit, for converting the physical signals such as stress change and slight deformation of the steel structure weld perceived by the array type magnetoelastic sensing unit into weak electric signals, and transmitting the weak electric signals to the signal amplification unit for enhancement processing. The output end of the signal amplification unit and the temperature compensation unit is connected with the input end of the AD conversion chip unit, for fusing the amplified electrical signal and the temperature compensation signal, and transmitting them to the AD conversion chip unit together, to realize high-precision conversion of analog signals to digital signals. The output end of the AD conversion chip unit is connected with the input end of the wireless transmission unit, for transmitting the converted digital signal to the wireless transmission unit, to realize remote and stable transmission of data through the wireless transmission unit. The output end of the wireless transmission unit is connected with the input end of the sound-light alarm unit through a push interface, for triggering the sound-light alarm unit through the push interface when the wireless transmission unit receives abnormal data, to realize synchronous pushing of on-site sound-light warning and abnormal information.

[0005] Further, the array type magneto-elastic sensing unit adopts Fe-Ga alloy sheet with a thickness of 0.2mm and a magnetostriction coefficient ≥80ppm. The AD conversion chip unit selects a 24-bit high-precision model ADS1248. The wireless transmission unit supports LoRa protocol and the transmission distance is ≥500m.

[0006] Further, the mounting unit includes a fixed seat and a mounting seat, the bottom end of the protective shell is fixedly connected to the upper end of the fixed seat, the left and right sides of the mounting seat are both slidingly connected with push rods, the inner ends of the push rods are both fixedly provided with clamping blocks, the outer ends of the push rods are both fixedly provided with pull rings, and the outer sides of the push rods are both provided with springs. The upper end of the mounting seat is provided with a positioning column in the middle, and the bottom of the fixed seat is provided with a positioning hole.

[0007] Further, the bottom of the fixed seat is also provided with a mounting groove, the mounting groove is shape-fitted with the middle part of the bottom end of the mounting seat, the left and right sides of the fixed seat are both provided with fitting grooves, the fitting grooves are respectively abutted with the corresponding clamping blocks, and the bottom of the fixed seat is made of magnetic material. The left and right sides of the bottom end of the mounting seat are both fixedly connected with magnetic suction pieces, and the front and rear sides of the mounting seat are both provided with grooves.

[0008] A welding seam change detection method for steel structures in buildings is applied to the welding seam change detection device for steel structures in buildings, and includes the following detection steps: S1, pre-process the welding seam detection area: clean the welding seam surface to expose the metal matrix, remove rust, oil stains and oxide layers, and ensure that the signal conduction between the sensing module and the welding seam area is not blocked. S2, device positioning installation: the mounting seat is symmetrically adsorbed on the symmetric position of the steel structure surface on both sides of the weld through the bottom end magnetic adsorption piece, the pull ring on the left and right sides of the mounting seat is pulled, the push rod and the clamping block are moved outward and the spring is compressed, the positioning hole at the bottom of the fixing seat is inserted into the positioning column of the mounting seat, the pull ring is loosened, the spring resets and pushes the clamping block to move inward, so that the inner side of the clamping block is tightly abutted with the embedded groove of the fixing seat, and the mounting groove at the bottom of the fixing seat is embedded with the middle part of the bottom end of the mounting seat, so that the magnetic material at the bottom end of the fixing seat is adsorbed on the surface of the steel structure; S3, system initialization and parameter configuration: turn on the power of the device, start the internal module of the protection shell, collect the initial environment temperature through the temperature compensation unit and record the reference value, and calibrate the zero point of the array type magnetoelastic sensing unit; Through the wireless transmission unit, the device ID and the installation position information are uploaded to the cloud server, and the weld strain alarm threshold is set to 200με; S4, weld deformation signal acquisition: the array type magnetoelastic sensing unit senses the small deformation of the weld caused by stress change through the magnetostrictive effect of Fe-Ga alloy sheet, converts the deformation into micro-voltage signal, and the resolution is≤1μV; The temperature compensation unit collects the change of the environment temperature in real time, generates the temperature compensation coefficient, and eliminates the interference of the temperature drift on the sensing signal; S5, signal processing and transmission: the micro-voltage signal is linearly amplified by 1000 times to millivolt level by the signal amplification unit, the analog signal is converted into digital signal by the 24-bit AD conversion chip unit, the sampling frequency is 1kHz, and the digital signal carrying the temperature compensation information is sent to the cloud server through the wireless transmission unit; S6, abnormality analysis and alarm triggering: the cloud server performs trend analysis on the received digital signal, calculates the strain change rate of the weld, and when the change rate exceeds the preset threshold 200με or the single strain value suddenly increases≥50με, the server generates an alarm instruction, which is returned to the push interface through the wireless transmission unit, triggers the audible and light alarm unit to issue audible and light warning, the sound pressure level is≥85dB, the red light flashing frequency is 2Hz, and the alarm information is pushed to the specified terminal at the same time; S7, continuous monitoring: the device remains in real-time monitoring state, the temperature reference value is updated by the temperature compensation unit every 30 minutes, and the zero point of the array type magnetoelastic sensing unit is automatically calibrated every 24 hours; The cloud server regularly stores historical data, and when the deviation between the continuous 3 alarm signals and the actual detection results is≤5%, the alarm threshold is automatically optimized to improve the adaptability of long-term monitoring.

[0009] Further, in the S3 step, the zero point calibration of the array type magnetoelastic sensing unit adopts a multi-channel synchronous calibration method, a 10 mV reference voltage is input to the standard resistance network built in the protective shell, the output signals of each sensing channel are synchronously collected, the channel deviation is calculated and the calibration coefficient is stored, so that the signal consistency error of the six sensing units is less than or equal to 2%; In the S4 step, the Fe-Ga alloy sheets of the array type magnetoelastic sensing unit are arranged equidistantly along the length direction of the weld seam, forming a three-dimensional strain monitoring array, which can simultaneously capture the deformation components in the transverse, longitudinal and shear directions of the weld seam.

[0010] Further, in the S5 step, the signal amplification unit adopts a programmable gain amplifier, which automatically switches the amplification multiple according to the input signal strength, and automatically enables 2000 times gain when the signal amplitude is less than 5 mu V, so that the weak deformation signal is not lost. In the S6 step, the alarm mode of the acousto-optic alarm unit is set according to the strain level difference, when the strain change rate exceeds the threshold but does not reach the emergency state, the intermittent acousto-optic alarm is triggered, and when the single strain value suddenly increases by more than 50 mu epsilon, the continuous acousto-optic alarm is triggered, so that the risk level and the disposal priority are accurately matched.

[0011] Further, in the S7 step, the correction coefficient of the temperature compensation unit adopts a dynamic weight algorithm, when the environmental temperature fluctuation amplitude is less than or equal to 5 DEG C / h, the compensation weight is 0.3, when the fluctuation amplitude is greater than 5 DEG C / h, the compensation weight is automatically increased to 0.7, so that the influence of temperature on the detection result is controlled within ± 3 mu epsilon by adjusting the temperature drift correction strength in real time.

[0012] In summary, the application provides a weld change detection device and method for steel structure in building, which has the following beneficial effects: 1. The three-dimensional strain monitoring array is formed by the Fe-Ga alloy sheets of the array type magnetoelastic sensing unit, combined with the 24-bit high-precision AD conversion chip unit and the signal amplification unit, which realizes high-resolution acquisition of micro-volt level signals, can capture small deformations in transverse, longitudinal and shear directions, and through the synergistic effect of the multi-channel synchronous calibration in the S3 step to ensure that the signal consistency error is less than or equal to 2%, the three-dimensional array in the S4 step to capture multi-dimensional deformation, and the signal amplification of 1000-2000 times and high-precision conversion in the S5 step, the early identification ability of the weld small defects is significantly improved, the sensitivity is 5 mu epsilon, and the 0.1 mm level micro-cracks can be accurately identified.

[0013] 2. Through the fixed seat, the mounting seat adopts the mode of magnetic attraction, positioning and spring, clamping block locking, without complex tools, the traditional bolt fixing or wiring cumbersome steps can be completed, at the same time, through the installation process of S2, quick disassembly and assembly are realized, compared with the scaffold erection and strain sheet wiring operation of artificial inspection, the efficiency is improved, the installation process is greatly simplified, the deployment time is shortened to <3 minutes of a single module, and the comprehensive cost is reduced by 60%.

[0014] 3. Through the wireless transmission unit supporting LoRa protocol, the data cooperative transmission of multiple sensor nodes can be realized, the centralized analysis function of the cloud server is matched, and the distributed deployment is supported through the S5 step of multi-node data synchronous transmission to the cloud and the S6 step of trend analysis of the cloud to the multi-node data, the problem of limited single-point coverage of traditional laser scanning is solved, the maximum coverage length of a single weld is 20m, and the demand for full domain monitoring of large steel structures is met.

[0015] 4. Through the temperature compensation unit adopting a dynamic weight algorithm, in combination with the periodic zero point calibration mechanism of the array type magnetoelastic sensing unit, environmental temperature interference is eliminated in real time, and through the S4 step, a temperature compensation coefficient is generated in real time, and through the S7 step, a temperature reference value is updated every 30 minutes, 24 hours of automatic calibration zero point continuous correction error, overcoming the defect that the traditional strain sheet is greatly affected by temperature and humidity, dynamically compensating the measurement error within ±3%, and ensuring the long-term monitoring stability in complex environments. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a front view of the welding seam change detection device and detection method for the steel structure in the building of the application; Figure 2 It is a three-dimensional structure schematic diagram of the welding seam change detection device and detection method for the steel structure in the building of the application; Figure 3 It is a fixed seat and mounting seat split structure schematic diagram of the welding seam change detection device and detection method for the steel structure in the building of the application; Figure 4 It is a flow architecture schematic diagram of the welding seam change detection device and detection method for the steel structure in the building of the application.

[0017] MARKING OF THE DRAWINGS: 1, protective shell; 2, array type magnetoelastic sensing unit; 3, temperature compensation unit; 4, signal amplification unit; 5, AD conversion chip unit; 6, wireless transmission unit; 7, sound and light alarm unit; 8, push interface; 9, fixed seat; 10, mounting seat; 11, push rod; 12, clamping block; 13, pull ring; 14, spring; 15, magnetic attraction piece; 16, positioning column; 17, mounting groove; 18, positioning hole; 19, slot; 20, fitting groove. DETAILED DESCRIPTION

[0018] The application will be further described below in conjunction with the accompanying drawings. Figure 1 - the drawings Figure 4 The application will be further described below in conjunction with the accompanying drawings.

[0019] Embodiments: Please refer to Figures 1-4 As shown in the drawings, the application provides a technical solution: a welding seam change detection device for steel structure in buildings, comprising a protective shell 1, a sensing module, a data processing module and an alarm module are arranged in the protective shell 1, and a mounting unit is further arranged at the bottom of the protective shell 1; The sensing module comprises an array type magnetoelastic sensing unit 2 and a temperature compensation unit 3, the data processing module comprises a signal amplification unit 4, an AD conversion chip unit 5 and a wireless transmission unit 6, and the alarm module comprises an audible and visual alarm unit 7 and a push interface 8; The output end of the array type magnetoelastic sensing unit 2 is connected with the input end of the signal amplification unit 4, for converting physical signals such as sensed stress changes and slight deformations of the steel structure welding seam into weak electric signals and transmitting the weak electric signals to the signal amplification unit for enhancement processing; The output ends of the signal amplification unit 4 and the temperature compensation unit 3 are connected with the input end of the AD conversion chip unit 5, for fusing the amplified electric signals and the temperature compensation signals and transmitting them to the AD conversion chip unit together, so as to realize high-precision conversion of analog signals to digital signals; The output end of the AD conversion chip unit 5 is connected with the input end of the wireless transmission unit 6, for transmitting the converted digital signals to the wireless transmission unit, so as to realize remote and stable transmission of data through the wireless transmission unit 6; The output end of the wireless transmission unit 6 is connected with the input end of the audible and visual alarm unit 7 through the push interface 8, for triggering the audible and visual alarm unit through the push interface when the wireless transmission unit receives abnormal data, so as to realize synchronous pushing of on-site audible and visual warning and abnormal information.

[0020] The array type magnetoelastic sensing unit 2 adopts Fe-Ga alloy sheet with a thickness of 0.2 mm and a magnetostriction coefficient ≥80ppm, through the Fe-Ga alloy sheet with high magnetostriction coefficient, compared with traditional metal sensing materials, the welding seam slight deformation can be more sensitively captured, and the efficiency of converting mechanical signals to electric signals is improved; The AD conversion chip unit 5 selects a 24-bit high-precision type ADS1248, compared with low-bit chips, the 24-bit high-precision AD conversion chip can more accurately convert analog signals to digital signals, and reduces distortion in the signal conversion process; The wireless transmission unit 6 supports LoRa protocol, and the transmission distance is ≥500m, while ensuring long-distance transmission, the wireless transmission unit reduces the risk of interference and loss in the data transmission process.

[0021] The mounting unit comprises a fixing base 9 and a mounting base 10, the bottom end of the protective shell 1 is fixedly connected to the upper end of the fixing base 9, the left and right sides of the mounting base 10 are slidingly connected with push rods 11, the inner ends of the push rods 11 are fixedly provided with clamping blocks 12, the outer ends of the push rods 11 are fixedly provided with pull rings 13, and the outer sides of the push rods 11 are provided with springs 14, so that the elastic locking of the mounting base 9 and the fixing base 10 is realized, the installation is more convenient, the connection stability is higher, and the problem that the traditional fixing mode is prone to loosening is avoided; The upper end of the mounting base 10 is provided with a positioning column 16 in the middle, the bottom of the fixing base 9 is provided with a positioning hole 18, the positioning hole 18 is inserted outside the positioning hole 18, and the positioning column 16 is inserted and matched with the positioning hole 18, so that the accurate alignment of the fixing base 9 and the mounting base 10 is ensured, and the installation deviation affecting the monitoring accuracy of the sensing module on the weld is avoided.

[0022] The bottom of the fixing base 9 is also provided with a mounting groove 17, the mounting groove 17 is embedded with the bottom end of the mounting base 10, the left and right sides of the fixing base 9 are provided with embedded grooves 20, the embedded grooves 20 are respectively abutted with the corresponding clamping blocks 12, the bottom of the fixing base 9 is made of a magnetic material, the embedding of the mounting groove 17 and the mounting base 10 and the adsorption of the magnetic material are matched with the abutment of the embedded grooves 20 and the clamping blocks, a multiple fixing structure is formed, the connection strength of the device and the steel structure is enhanced, and the stable monitoring demand in the building vibration environment is met; The bottom end of the mounting base 10 is fixedly connected with magnetic suction pieces 15 on the left and right sides, and the front and back sides of the mounting base 10 are provided with grooves 19, the magnetic suction pieces 15 realize the pre-fixing of the mounting base, the grooves 19 facilitate installation operation, the installation efficiency is improved, compared with no pre-fixing structure, the position adjustment time in the installation process is reduced, and the stability of subsequent installation is ensured.

[0023] A weld change detection method for a steel structure in a building is applied to the weld change detection device for a steel structure in a building, and comprises the following detection steps: S1, pretreatment of the weld detection area: clean the weld surface to expose the metal matrix, remove rust, dirt and oxide layer, ensure that the signal transmission of the sensing module and the weld area is not blocked, eliminate the interference of surface impurities on signal transmission through cleaning treatment, so that the sensing module can directly sense the real state of the weld, and avoid signal attenuation or distortion caused by impurity blockage; S2, device positioning and installation: the mounting seat 10 is symmetrically adsorbed on the symmetric position of the steel structure surface on both sides of the weld through the bottom end magnetic adsorption piece 15, the pull ring 13 on the left and right sides of the mounting seat 10 is pulled, the push rod 11 and the clamping block 12 are moved outward and the spring 14 is compressed, the positioning hole 18 at the bottom of the fixed seat 9 is inserted into the positioning column 16 of the mounting seat 10, the pull ring 13 is loosened, the spring 14 resets and pushes the clamping block 12 to move inward, so that the inner side of the clamping block 12 is tightly abutted with the embedded groove 20 of the fixed seat 9, meanwhile, the installation groove 17 at the bottom of the fixed seat 9 is embedded with the middle part of the bottom end of the mounting seat 10, so that the magnetic material at the bottom end of the fixed seat 9 is adsorbed on the steel structure surface, through the installation process of magnetic pre-fixing, accurate positioning, elastic locking and multiple embedding, the device is quickly and stably installed; S3, system initialization and parameter configuration: turn on the device power, start the internal module of the protection shell 1, collect the initial environment temperature through the temperature compensation unit 3 and record the reference value, calibrate the zero point of the array type magnetoelastic sensing unit 2, collect the initial temperature reference value and calibrate the zero point of the sensing unit, establish the reference for subsequent detection, avoid the influence of initial state deviation on the detection result; Through the wireless transmission unit 6, the device ID and installation position information are uploaded to the cloud server, the weld strain alarm threshold is set to 200με, the device information uploading is convenient for the cloud to manage uniformly, the alarm threshold setting provides a standard for subsequent abnormal judgment, realizes the standardization and intelligentization of detection; S4, weld deformation signal collection: the array type magnetoelastic sensing unit 2 perceives the slight deformation of the weld caused by stress change through the magnetostrictive effect of Fe-Ga alloy sheet, converts the deformation into micro-voltage signal, the resolution is ≤1μV, uses the magnetostrictive effect to convert the slight deformation into electric signal, combines with the high resolution characteristic, can capture the subtle deformation which is difficult to identify by traditional method, improves the detection ability of early change of weld; The temperature compensation unit 3 collects the change of environment temperature in real time, generates temperature compensation coefficient, eliminates the interference of temperature drift on sensing signal, real-time temperature compensation avoids the influence of environment temperature change on sensing signal, ensures the consistency of detection data under different temperature environment; S5, signal processing and transmission: the micro-voltage level voltage signal is linearly amplified 1000 times to millivolt level by the signal amplification unit 4, the analog signal is converted into digital signal by the 24-bit AD conversion chip unit 5, the sampling frequency is 1kHz, the digital signal carrying temperature compensation information is sent to the cloud server through the wireless transmission unit 6, the signal amplification, high-precision conversion and transmission with compensation information ensure the integrity and accuracy of data from collection to transmission; S6, Abnormal analysis and alarm triggering: The cloud server performs trend analysis on the received digital signals, calculates the weld strain change rate, and when the change rate exceeds the preset threshold 200 με or the single strain value suddenly increases by ≥50 με, the server generates an alarm instruction, which is returned to the push interface 8 through the wireless transmission unit 6, triggering the audible and light alarm unit 7 to issue audible and light warnings, with a sound pressure level ≥85 dB and a red light flashing frequency of 2 Hz. At the same time, the alarm information is pushed to the designated terminal. The cloud trend analysis combined with double abnormality judgment criteria improves the accuracy of abnormality identification. The combination of audible and light warnings and information pushing ensures that abnormal situations can be known and handled in a timely manner. S7, Continuous monitoring: The device remains in real-time monitoring state. The temperature reference value is updated every 30 minutes by the temperature compensation unit 3, and the zero point of the array-type magnetoelastic sensing unit 2 is automatically calibrated every 24 hours. Regularly updating the temperature reference and calibrating the zero point ensures the stability and accuracy of long-term monitoring. The cloud server regularly stores historical data. When the deviation between the continuous 3 alarm signals and the actual detection results is ≤5%, the alarm threshold is automatically optimized to improve the adaptability of long-term monitoring. The storage of historical data and the automatic optimization of alarm threshold enable the system to adapt to the long-term changes in weld performance.

[0024] In step S3, the zero point calibration of the array-type magnetoelastic sensing unit 2 uses a multi-channel synchronous calibration method. A 10 mV reference voltage is input to the standard resistance network built-in the protective shell 1, and the output signals of each sensing channel are simultaneously collected. The channel deviation is calculated and the calibration coefficient is stored to ensure that the signal consistency error of the 6 sensing units is ≤2%. Multi-channel synchronous calibration ensures the consistency of the signals of each sensing unit, reducing the influence of the differences between channels on the detection results. In step S4, the Fe-Ga alloy sheets of the array-type magnetoelastic sensing unit 2 are arranged equidistantly along the length direction of the weld, forming a three-dimensional strain monitoring array that can simultaneously capture the deformation components in the transverse, longitudinal and shear directions of the weld. The three-dimensional monitoring array can comprehensively capture the deformation in different directions of the weld.

[0025] In step S5, the signal amplification unit 4 uses a programmable gain amplifier that automatically switches the amplification factor according to the input signal strength. When the signal amplitude is lower than 5 μV, a 2000 gain is automatically enabled to ensure that weak deformation signals are not lost. The programmable gain amplifier adjusts the amplification factor according to the signal strength to ensure that weak signals can be effectively identified. In step S6, the alarm mode of the audible and light alarm unit 7 is differentiated according to the strain level. When the strain change rate exceeds the threshold but does not reach the emergency state, intermittent audible and light alarms are triggered. When the single strain value suddenly increases by ≥50 με, continuous audible and light alarms are triggered, realizing precise matching of risk level and disposal priority. The differentiated alarm mode enables workers to quickly judge the risk level.

[0026] In the step S7, the correction coefficient of the temperature compensation unit 3 adopts a dynamic weight algorithm, when the fluctuation amplitude of the ambient temperature is less than or equal to 5 ℃ / h, the compensation weight is 0.3; when the fluctuation amplitude is greater than 5 ℃ / h, the compensation weight is automatically increased to 0.7, the influence error of the temperature on the detection result is controlled within ±3 με by adjusting the correction strength in real time, and the dynamic weight temperature compensation adjusts the correction strength according to the temperature fluctuation amplitude, and can effectively reduce the influence of the temperature on the detection under different temperature changes.

[0027] The embodiments of the present specific embodiment are the preferred embodiments of the present application, and are not intended to limit the protection scope of the present application, wherein the same parts are denoted by the same reference numerals. Therefore, any equivalent changes made according to the structure, shape and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A device for detecting weld changes in steel structures within buildings, comprising a protective shell (1), characterized in that: The protective shell (1) is equipped with a sensing module, a data processing module and an alarm module inside, and an installation unit is also provided at the bottom of the protective shell (1); The sensing module includes an array-type magnetoelastic sensing unit (2) and a temperature compensation unit (3); the data processing module includes a signal amplification unit (4), an AD conversion chip unit (5), and a wireless transmission unit (6); and the alarm module includes an audible and visual alarm unit (7) and a push interface (8). The output end of the array-type magnetoelastic sensing unit (2) is connected to the input end of the signal amplification unit (4) to convert the sensed physical signals such as stress changes and small deformations of steel structure welds into weak electrical signals and transmit them to the signal amplification unit for enhancement processing. The output terminals of the signal amplification unit (4) and the temperature compensation unit (3) are connected to the input terminal of the AD conversion chip unit (5) to fuse the amplified electrical signal with the temperature compensation signal and transmit them together to the AD conversion chip unit to achieve high-precision conversion of analog signals to digital signals. The output of the AD conversion chip unit (5) is connected to the input of the wireless transmission unit (6) to transmit the converted digital signal to the wireless transmission unit, thereby enabling remote and stable data transmission through the wireless transmission unit (6). The output end of the wireless transmission unit (6) is connected to the input end of the audible and visual alarm unit (7) through the push interface (8). When the wireless transmission unit receives abnormal data, it triggers the audible and visual alarm unit through the push interface to realize the synchronous push of on-site audible and visual warnings and abnormal information.

2. The device for detecting weld changes in steel structures within buildings according to claim 1, characterized in that: The array-type magnetoelastic sensing unit (2) uses an Fe-Ga alloy sheet with a thickness of 0.2 mm and a magnetostriction coefficient ≥80 ppm; The AD conversion chip unit (5) is a 24-bit high-precision model ADS1248; The wireless transmission unit (6) supports the LoRa protocol and has a transmission distance of ≥500m.

3. The device for detecting weld changes in steel structures within buildings according to claim 1, characterized in that: The installation unit includes a fixed base (9) and an installation base (10). The bottom end of the protective shell (1) is fixedly connected to the upper end of the fixed base (9). Push rods (11) are slidably connected to the left and right sides of the installation base (10). A locking block (12) is fixedly provided at the inner end of the push rod (11). A pull ring (13) is fixedly provided at the outer end of the push rod (11). A spring (14) is provided on the outer side of the push rod (11). The upper end of the mounting base (10) is provided with a positioning post (16) in the middle, and the bottom of the fixing base (9) is provided with a positioning hole (18), which is inserted into the outside of the positioning hole (18).

4. The weld change detection device for steel structures in buildings according to claim 3, characterized in that: The bottom of the fixing base (9) is also provided with an installation groove (17), the installation groove (17) fits into the shape of the bottom center of the mounting base (10), the left and right sides of the fixing base (9) are provided with fitting grooves (20), the fitting grooves (20) respectively abut against the corresponding card blocks (12), and the bottom of the fixing base (9) is made of magnetic material. The bottom left and right sides of the mounting base (10) are fixedly connected with magnetic suction pieces (15), and the front and rear sides of the mounting base (10) are provided with slots (19).

5. A method for detecting weld changes in steel structures within buildings, applied to the weld change detection device for steel structures within buildings as described in any one of claims 1-4, characterized in that: The following testing steps are included: S1. Pre-treatment of weld inspection area: Clean the weld surface to expose the metal substrate, remove rust, oil and oxide layer to ensure unobstructed signal transmission between the sensing module and the weld area; S2. Device positioning and installation: The mounting base (10) is symmetrically attached to the steel structure surface on both sides of the weld seam by the bottom magnetic suction plate (15). Pull the pull ring (13) on the left and right sides of the mounting base (10) to drive the push rod (11) and the locking block (12) to move outward and compress the spring (14). Align the positioning hole (18) at the bottom of the fixed base (9) with the positioning post (16) of the mounting base (10) and insert it. Release the pull ring (13), and the spring (14) will reset and push the locking block (12) to move inward, so that the inner side of the locking block (12) is in close contact with the fitting groove (20) of the fixed base (9). At the same time, the mounting groove (17) at the bottom of the fixed base (9) fits into the shape of the middle part of the bottom end of the mounting base (10), so that the magnetic material at the bottom end of the fixed base (9) is attached to the steel structure surface. S3. System initialization and parameter configuration: Connect the device power supply, start the internal module of the protective shell (1), collect the initial ambient temperature through the temperature compensation unit (3) and record the reference value, and calibrate the zero point of the array magnetoelastic sensing unit (2). The device ID and installation location information are uploaded to the cloud server through the wireless transmission unit (6), and the weld strain alarm threshold is set to 200με. S4. Weld deformation signal acquisition: The array-type magnetoelastic sensing unit (2) senses the small deformation of the weld caused by stress change through the magnetostrictive effect of Fe-Ga alloy sheet, and converts the deformation into a microvolt voltage signal with a resolution of ≤1μV. The temperature compensation unit (3) collects the changes in ambient temperature in real time, generates a temperature compensation coefficient, and eliminates the interference of temperature drift on the sensing signal. S5. Signal processing and transmission: The signal amplification unit (4) linearly amplifies the microvolt-level voltage signal by 1000 times to the millivolt level. The analog signal is converted into a digital signal by the 24-bit AD conversion chip unit (5). The sampling frequency is 1kHz. The digital signal carries temperature compensation information and is sent to the cloud server through the wireless transmission unit (6). S6. Anomaly Analysis and Alarm Trigger: The cloud server performs trend analysis on the received digital signal and calculates the strain change rate of a single layer. When the change rate exceeds the preset threshold of 200με or the single strain value increases by ≥50με, the server generates an alarm command and transmits it back to the push interface (8) through the wireless transmission unit (6), triggering the sound and light alarm unit (7) to issue a sound and light warning with a sound pressure level ≥85dB and a red light flashing frequency of 2Hz. At the same time, the alarm information is pushed to the designated terminal. S7. Continuous monitoring: The device maintains a real-time monitoring state, updates the temperature reference value every 30 minutes through the temperature compensation unit (3), and automatically calibrates the zero point of the array magnetoelastic sensing unit (2) every 24 hours. The cloud server regularly stores historical data. When the deviation between three consecutive alarm signals and the actual detection results is ≤5%, the alarm threshold is automatically optimized to improve the adaptability of long-term monitoring.

6. The device and method for detecting weld changes in steel structures within buildings according to claim 5, characterized in that: In step S3, the zero-point calibration of the array magnetoelastic sensing unit (2) adopts a multi-channel synchronous calibration method. By inputting a 10mV reference voltage into the standard resistor network built into the protective shell (1), the output signals of each sensing channel are collected synchronously, the channel deviation is calculated and the calibration coefficient is stored to ensure that the signal consistency error of more than 6 sensing units is ≤2%. In step S4, the Fe-Ga alloy sheets of the array magnetoelastic sensing unit (2) are arranged at equal intervals along the length of the weld to form a three-dimensional strain monitoring array, which can simultaneously capture the deformation components of the weld in the transverse, longitudinal and shear directions.

7. The device and method for detecting weld changes in steel structures within buildings according to claim 5, characterized in that: In step S5, the signal amplification unit (4) uses a programmable gain amplifier, which automatically switches the amplification factor according to the input signal strength. When the signal amplitude is lower than 5μV, it automatically enables a 2000-fold gain to ensure that weak deformation signals are not lost. In step S6, the alarm mode of the audible and visual alarm unit (7) is set differently according to the strain level. When the strain change rate exceeds the threshold but does not reach the emergency state, an intermittent audible and visual alarm is triggered; when the single strain value increases by ≥50με, a continuous audible and visual alarm is triggered, so as to achieve accurate matching between risk level and disposal priority.

8. The device and method for detecting weld changes in steel structures within buildings according to claim 5, characterized in that: In step S7, the correction coefficient of the temperature compensation unit (3) adopts a dynamic weighting algorithm. When the ambient temperature fluctuation range is ≤5℃ / h, the compensation weight is 0.3; when the fluctuation range is >5℃ / h, the compensation weight is automatically increased to 0.

7. By adjusting the temperature drift correction intensity in real time, the error of the temperature on the detection result is controlled within ±3με.

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