291 results about "Vibrating wire" patented technology

The invention provides a method for monitoring convergence deformation of tunnels. A plurality of anchoring points are distributed annularly along a lining on a selected tunnel cross section and serve as monitoring reference points; every two of the anchoring points are connected through a rigid measuring installation arm with a standard length and a sliding sleeve successively, a tilter sensor is installed on the measuring installation arm, and a vibrating wire displacement meter is mounted between the measuring installation arm and the sliding sleeve; two free ends of a system component formed by the measuring installation arm, the sliding sleeve, and the tilter sensor and the vibrating wire displacement meter are anchored on two adjacent anchoring points on the lining through anchoring-point hinged support; and a plurality of the system components are formed in this way to be continuously catenated annularly till the unit number required by observation design is achieved. According to the method for monitoring convergence deformation of tunnels, the monitoring method is simple, the cost is low, the device occupies a small tunnel sectional area, and high-accuracy monitoring can be achieved.

An excitation method of a vibrating wire sensor mainly comprises the following operating steps: performing single excitation for exciting coils of the vibrating wire sensor by an intermittent excitation mode to obtain a resonant frequency measured value f1 with low precision; calculating statistical characteristics of vibration signals during various periods, and inspecting the statistical characteristics; exciting the exciting coils of the vibrating wire sensor by adopting a signal with the frequency being f1 and stopping excitation after vibrating wire resonance, or performing frequency-sweep excitation at the position of a narrower bandwidth near the frequency f1; and finally processing signals from vibration pickup coils, and measuring the signal frequency to obtain a measured value f2 as an exact value of vibrating wire resonance frequency. The excitation method of the vibrating wire sensor has the advantages of fast starting of vibration, large amplitude, shortened detection time, improved working efficiency, improved excitation reliability and improved measuring precision. The excitation method of the vibrating wire sensor is applicable to observation on stress strain, deformation, seepage, liquid level, temperature and the like of the projects such as reservoir dams, bridges, foundation pits and the like.

The invention discloses a monitoring system for formation stability and tunnel structure long-term health of a shield tunnel. The system comprises a vibrating wire type or fiber grating type earth pressure gauge, an osmotic pressure gauge, a steel stress gauge, a strain gauge, vibrating wire type surface crack meters, vibrating wire type liquid level sensors, a crack meter and data acquisition units. The vibrating wire type or fiber grating type earth pressure gauge is embedded on the outer surface of a duct piece with the pressure surface facing a soil body. The osmotic pressure gauge is embedded in a tunnel lining and used for monitoring the osmotic pressure of the tunnel lining. The steel stress gauge is arranged in a concrete segment. The strain gauge is embedded in the concrete segment and used for monitoring the strain of concrete. The two ends of the vibrating wire type surface crack meters are separately arranged on adjacent tunnel concrete segments by universal joints, and thevibrating wire type surface crack meters are used for monitoring the opening degree of the adjacent concrete segments. The vibrating wire type liquid level sensors measure the change of elevations ofa measuring point and a reference point. The crack meter is embedded in the concrete segment and used for measuring the crack condition of the tunnel segments. The data acquisition units are used forcollecting sensor signals in various geotechnical engineering safety monitoring projects.

The invention relates to a system and a method for monitoring stress of civil engineering based on a CAN network, belonging to the technical field of civil engineering monitoring. The device comprises a master control computer, a PC-CAN interface module, an acquisition unit and a topology network of a CAN bus, wherein the acquisition unit comprises a microprocessor, a CAN module, a CAN indication setting module, a date and time setting module, a memory extensive module, a wire collecting case, a vibration exciting and pick-up circuit, a shift switch for an analog channel and a power supply management module. The master control computer and the acquisition unit on the CAN network exchange commands and data through the PC-CAN interface module; the acquisition unit receives a command of the master control compute to complete the acquisition of data of a multi-path vibrating wire sensor, and packages the data according to a standard format to be uploaded to the CAN network. The system can acquire the physical quantity of a sub-node distantly, flexibly and reliably. The system and the method can be widely applied to stress monitoring for various civil engineering.

The invention relates to a method and device for measuring the equal precision frequency of a single coil vibrating wire instrument. The method comprises the following steps of: generating induced voltage signals having frequencies accordant with the natural frequency of a string wire and attenuated amplitudes at the two ends of the frequency measuring coil; monitoring the amplitude attenuating conditions of the induced voltage signals through an induced voltage attenuating monitoring circuit; when the monitored amplitude attenuating speeds of the induced voltage signals are up to a preset value, providing a triggering signal for an equal precision frequency measuring circuit; adjusting the measuring time of the equal precision frequency measuring circuit by adjusting a standard referencepulse frequency through the precision frequency measuring circuit; and calculating the frequency of the string wire by using the equal precision frequency measuring circuit according to the induced voltage pulse sample number obtained by counting and the count value of a set standard reference pulse frequency counter. In the method, the lasting time of the measuring process can be adjusted adaptively according to the monitored amplitude attenuating conditions of the induced voltage signals activated by the string wire, so that the equal precision frequency measuring reliability of the single coil vibrating wire instrument is improved.

The invention relates to a vibrating wire-feeding method which is characterized in that right and left swinging of a welding gun is combined with reciprocating vibration of a welding wire; the automatic wire-feeding process is accompanied by the axial vibration of the welding wire; a molten welding material is deposited on the internal wall of a pipe, and the fluidity of a welding pool is greatly improved, so as to further improve the surfacing efficiency; the vibrating welding wire can uniformly stir the molten pool in the melting process of the welding wire, especially for the material with poor fluidity, such as nickel-base alloy, so that gas can escape rapidly when metal in the molten pool is stirred, and hot welding cracks and pores are reduced; as the vibrating wire-feeding stirs the molten pool, solidification and crystallization in the molten pool are uniform; the metallurgical structure of a surfacing layer is uniform and exquisite; the mechanical property of the surfacing layer is greatly superior to those of normal argon tungsten-arc welding and gas metal-arc welding; the quality of a surfacing joint is improved to a great extent; the property is good; the yield of products is greatly increased; and the property of the surfacing joint is greatly improved.

The invention relates to a monitoring method for remotely measuring and controlling damage depths of floor strata. The monitoring method is characterized in that vibrating wire type rock fracture meters and temperature sensors are arranged in drilled holes of a seam floor stratum, and a monitoring system comprises a signal acquisition unit, signal transmission cables and a reading device; and the signal acquisition unit acquires displacement and temperature data of fractures at measuring points of the floor stratum, the displacement and temperature data are transmitted to the reading device via the signal transmission cables, analog quantities are converted into digital quantities on the reading device, and the digital quantities are recorded and displayed. The monitoring method has the advantages that damage conditions of the measuring points of the floor stratum of a stope can be monitored before a roof propelled along with a working face in a mining procedure falls, damage conditions of the measuring points of the floor stratum can also be monitored after the working face is pushed across a monitoring point and the roof falls, and accordingly the integral mining procedure is continuously monitored; and the maximum damage depth and an activity low of the floor stratum of the working face can be obtained by analyzing the monitoring data, and a foundation is laid for predicting water inrush of a seam floor.

The present invention relates to an excitation method and device of a vibrating wire instrument. The method generates a SPWM wave, and then filters the generated SPWM wave through a filter circuit to obtain a sinusoidal waveform signal, and then applies the sinusoidal waveform signal to the vibrating wire instrument. The two ends of the frequency measuring coil in the instrument generate alternating electromagnetic force under the action of the permanent magnet, which drives the steel string to generate resonance. The SPWM waveform excitation signal whose pulse width changes according to the sinusoidal waveform rule generated by the method improves the precise control ability of the excitation signal and solves various limitations caused by the traditional excitation method using a pulse square wave.

Systems and methods for analyzing the resonant frequency of vibratory wires within vibratory wire gauges. The resonant frequency of the vibrating wire is determined by using an interface that digitizes the response of an excited wire in the gauge. A transform then converts the digitized data into a frequency spectrum. The resulting spectrum is used to estimate the resonant frequency of the vibrating wire. The resulting measurement or estimate of the resonant frequency can be used to measure or determine some physical characteristic of the device or structure or system connected to the gauge.

The invention relates to the technical field of bridge engineering construction and discloses a bridge strain monitoring and sensing device and a monitoring method thereof. The bridge strain monitoring and sensing device comprises a bridge body and a bridge strain monitoring and sensing system, wherein a supporting column is fixedly mounted in the middle of the bridge body; the back surface of thesupporting column is movably connected with a supporting plate; locking screws sleeve two sides of the front surface of the supporting column through threads; the other ends of the locking screws penetrate through and extend to the back surface of the supporting column and are sleeved with the outer surface of the supporting plate through threads. According to the bridge strain monitoring and sensing device provided by the invention, the supporting plate is fixed on the back surface of the supporting column through the two locking screws and the supporting plate is convenient to replace; a vibrating wire strain gauge in a sleeve groove is convenient to overhaul; a fixed plate, a supporting rod and a base plate are combined to use and the balance stability of the supporting plate is easy to improve, so that the accuracy of monitored data of the vibrating wire strain gauge is improved and a condition that normal monitoring is influenced, caused by the fact that the vibrating wire straingauge falls off or is damaged by accident, is avoided.

The invention discloses a construction method of an oval suspended dome structure. The method comprises the steps that collision of frame body erection and a prestressed component is inspected by adopting a BIM technology; a tension value and a deformation value of a prestressed rod piece are determined by adopting Midas software; precise blanking is conducted on a special-shaped rod pieces by adopting Tekla software; a ring lock scaffold is adopted as a reticulated shell support frame body, and prestressed rod piece installation is conducted; surrounding trusses are installed and welded by adopting a crank arm lift truck as an operation platform; matchstick-type small assembling is adopted, folding is conducted in the shaped of a Chinese character 'mi', and air assembling is conducted on a single-layer reticulated shell turn by turn from bottom to top in a partition and ring division mode; a total station and a three-dimensional adjustable device are adopted to determine the welding ball point location; prestress tension is conducted in a tension radial rod pulling mode according to the sequence from inside to outside to inside and to outside; a general displacement meter, a vibrating wire gage, a magnetic flux sensor and the total station are adopted to conduct omnibearing monitoring. According to the construction method of the oval suspended dome structure, the constructed project only has an error of 8 mm with a designed camber value after being subjected to tensioning, and advancement of the method is proved.

The present invention discloses a concrete structure combined strain monitoring unit, which comprises a cube main body, wherein 18 vibrating wire strain sensors are arranged on the diagonal lines of each edge and each surface of the cube main body, both ends of each vibrating wire strain sensor are respectively connected to the bolt ball nodes positioned at eight top corner positions of the cube main body through connection rods and helical springs in a threaded manner, a cylindrical separation cylinder with an opening top portion is fixedly arranged in the cube main body, the cylinder wall ofthe separation cylinder sequentially comprises an elastic separation net, a water-permeation and gas-permeation layer and an elastic separation net from outside to inside, and a reference sensor formeasuring the concrete temperature and the shrinkage strain in the absence of a load is centrally arranged in the separation cylinder. The present invention further provides a concrete state evaluation method based on the combined strain monitoring unit. According to the present invention, with the concrete structure combined strain monitoring unit, the force applying on the concrete structure canbe accurately analyzed while the comparing to the index in the concrete failure criterion can be performed according to the requirement, and the possibility of concrete cracking can be evaluated.

The invention discloses a high-accuracy frequency measurement system. The high-accuracy frequency measurement system comprises an excitation circuit, a vibrating wire sensor, a sensor vibration testing circuit and a temperature compensating circuit, wherein the sensor vibration testing circuit consists of an amplifying circuit, a shaping circuit, a frequency dividing circuit and a counter which are connected together; and the temperature compensating circuit consists of a temperature converting circuit, an amplifying circuit and an analog/digital converting circuit which are connected together. The high-accuracy frequency measurement system adopts the temperature compensating circuit, so that the influence of temperature on frequency measurement of the vibrating wire sensor is effectively reduced, and the measurement accuracy is improved.

The invention provides a water level signal lamp alarm device which is equipment for automatic monitoring of urban road water level height in urban water logging so that road water level monitoring is enabled to be intelligent, a water level alarm value can be artificially set, passing vehicles can be alerted to pay attention to driving safety of the road ahead by accurately utilizing light, and thus a problem of road driving safety in urban water logging can be effectively solved. The device comprises a water level acquisition terminal and a sound-light alarm terminal which are connected by adopting a wired or wireless mode. The concrete components include a solar panel, a radio frequency transmitting antenna, a controller, a water level difference value verification device, a standby lithium battery, a water gauge, an eight-bit parallel bus, water level sensors, a vibrating wire type sensor, a pressure transmitter, an RS-485 serial bus transmitting terminal, an eight-bit parallel bus interface, a reed switch contact type water level sensor, a capacitive contact type water level sensor, a hydrogen-oxygen fuel battery, a water level difference vale encoder, an RS-485 serial bus receiving terminal, red, yellow and green three-color LED alarm lamps, a radio frequency receiving antenna and an ESD electrostatic protection module. The arrangement position of the device is confirmed by remote sensing detection and water area simulation and division.

The invention discloses a vibrating wire sensor excitation optimization method and a vibrating wire acquisition device, which belong to the technical field of sensor detection control. According to the vibrating wire sensor excitation optimization method disclosed in the invention, fast onset, short detection time and high precision can be realized when the vibrating wire sensor is detected. The excitation optimization method combines two excitation modes of high voltage pulses and low voltage sweep frequency, the excitation reliability is improved, and the method is applicable to measurementon various kinds of vibrating wire sensors. The vibrating wire acquisition device which uses the vibrating wire sensor excitation optimization method mainly comprises a power management circuit, a vibrating wire excitation sampling circuit, a micro control unit MCU, a burning debugging interface, a wireless communication module and a temperature and humidity sensor module. The method is high-efficiency and convenient, and the corresponding device is high in integration, convenient in remote data transmission, low in cost and convenient in debugging.

The invention discloses a low-power consumption vibrating wire sensor. The low-power consumption vibrating wire sensor comprises a vibrating wire, a coil, a sensor housing, an excitation circuit unit, a vibration picking circuit unit and a main control unit. The main control unit comprises a pre-vibration module, a complex-vibration module, a frequency detection module and a signal processing module. The signal processing module records effective complex-vibration efficiency signals, controls excitation detection processes of the sensor so as to allow the sensor to work in steady-state and non-steady state modes, and calculates an excitation frequency value output by the complex-vibration module in the steady-state working mode according to recorded effective complex-vibration frequency value. According to the invention, by changing excitation modes of the vibrating wire, changing a traditional low-voltage sweep-frequency excitation mode into an excitation mode combining pre-vibration and complex-vibration, and using a frequency value during pre-vibration detection as the excitation pulse frequency of the re-vibration, an energy saving effect is achieved.

The invention discloses an excitation detection device for a low power consumption vibrating wire transducer. The device comprises an exciting circuit unit, a pickup vibrating circuit unit and a main control unit, wherein the main control unit comprises a pre-vibration module, a compound vibration module, a frequency detection module and a signal processing module; the signal processing module is used for recording effective compound vibration frequency signals, controlling the excitation detection flow of the transducer to enable the transducer to work in stable and unstable modes and computing the excitation frequency value output by the compound vibration module in the stable working mode according to the recorded effective compound vibration frequency values. The low power consumption vibrating wire transducer provided by the invention has the beneficial technical effects that the vibrating wire excitation modes are changed, the traditional low voltage swept excitation mode is changed to the pre-vibration and compound vibration combined excitation mode, and the frequency value during pre-vibration detection serves as the excitation pulse frequency of compound vibration, thus achieving the effect of saving energy.

The present invention relates to a frequency spectrum calculation-based measuring device and a measuring method for a multi-string vibrating string sensor and belongs to the field of civil engineering, wherein the device and the method are applied to the structural safety and health monitoring industry. The device comprises a chordal vibrating wire sensor, a signal switching circuit, a boost module, an instrument amplifier, anti-aliasing filter, an analog-to-digital converter, and a digital signal processor (DSP) controller. According to the technical scheme of the invention, the market application limitations of multi-string sensors are solved and the conventional measurement technique is broken through. Meanwhile, the measurement limitation of existing equipment is solved. Therefore, the measurement technical difficulties of the multi-string vibrating string sensor can be solved while no hardware cost (including the number of measurement channels, system complexity, size, power consumption, cable laying and the like) is increased for no matter wired monitoring schemes or wireless monitoring schemes.

The invention relates to an excitation method and an apparatus thereof of a vibrating wire instrument. According to the method, sinusoidal waveform data with adjustable frequency are generated based on a digital synthesis principle; the sinusoidal waveform data is converted into a sinusoidal waveform signal through parallel DA converters; a filter circuit filters and removes higher harmonics and the sinusoidal waveform signal is smoothed into a smoothed sinusoidal waveform signal; and then the smoothed sinusoidal waveform signal is exerted on two ends of a frequency measurement coil of a vibrating wire instrument and an alternative electromagnetic force is generated under the effect of a permanent magnet, so that string wires are driven to generate a resonance. According to the method provided in the invention, a sinusoidal waveform exciting signal with adjustable frequency is generated and an accurate control capability of the exciting signal is improved; and various limitations caused by a pulsed square wave employed in a traditional excitation method.

The invention discloses an embankment safety monitoring method based on a self-adaption feedback-type vibrating wire sensor. The method comprises the steps that initial resonant frequency is taken as initial exciting frequency, and the total number of pulses N<f> needed by string wire minimum vibration is adopted to achieve self-adaption adjustment of exciting time; a double trigger mode of an interrupt counter and a time-out timer of a STM32 processor is adopted to determine the end of vibration picking, vibration picking time is counted, and vibration picking frequency is calculated according to an equal-precision frequency measuring method; a concept of a frequency difference value state S<f> is introduced, a different value between the vibration picking frequency and the exciting frequency is calculated, and the state of the S<f> is determined. When the S<f> is in an ideal state, the vibration picking frequency is the resonant frequency; when the S<f> is in a non-ideal state, the exciting frequency is updated according to a formula which is shown in a specification, and excitation is conducted again. By means of the embankment safety monitoring method based on the self-adaption feedback-type vibrating wire sensor, one-time exciting time is reduced, and the safety monitoring efficiency of an embankment is improved; equal-precision self-adaption adjustment is achieved based on a feedback-type frequency sweep method, the safety monitoring time of the embankment is shortened.

The invention discloses a single-cable acquisition method for acquiring vibrating wire stress data, and also relates to a device and a system. The method includes the following steps: a plurality of controllable switching devices which can be triggered by external signals to close and open are sequentially packaged in a cable body along the length direction of the cable body, the lead of one end of each controllable switching device serves as a connecting wire which is connected with an external vibrating wire sensor, the lead of the other end serves as a controllable switching device control and sensor signal acquisition wire which is connected with an assorted vibrating wire sensor reading instrument, the vibrating wire sensor reading instrument centrally sends the data back to a remote monitoring terminal by way of wired or wireless communication after the data of all the sensors are acquired, and thereby integrated distributed measurement is fulfilled. The invention realizes rapid multi-channel stress data acquisition by only one special cable, moreover, the invention is more notably superior to the conventional artificial reading method, and not only can rapidly and accurately read the data of the sensors at any time, but also can directly send the data back to the remote terminal via the GPRS (General Packet Radio Service) network, and thereby a user can carry out data acquisition and know the state of a structure without going out.

The invention discloses a novel bridge safety detection device and relates to the technical field of safety detection. A monitoring field station is connected with a monitoring data center through a GPRS (general packet radio service) wireless communication and transmission device, and the monitoring field station comprises a collected water flow rate sensor, a support vibrating wire type sensor, a voltage and current type sensor, a pulse type sensor and a single-chip microcomputer; and the collected water flow rate sensor, the support vibrating wire type sensor, the voltage and current type sensor and the pulse type sensor are connected with the single-chip microcomputer through data wires. The novel bridge safety detection device disclosed by the invention has a simple structure, and can collect, store, transmit and manage data in a fast, real-time and automatic manner, observe the safety condition of a bridge at any time, avoid unnecessary negligence, reduce potential safety hazards and reduce risk and economic loss, thereby having far-reaching significance for social stability.

The present invention relates to a system for measuring the frequency of a vibrating wire sensor using a digital counter system, which measures changes in the length of a structure to monitor changes in the structure, comprising: a processor which outputs an excitation signal to an excitation signal interface unit for a vibrating wire sensor, and compares the counted value input from an external source with a consumed time to calculate a resonant frequency; said excitation signal interface unit for a vibrating wire sensor, which receives the excitation signal from the processor, converts the received signal into a form capable of generating an excitation, and outputs the converted signal; said vibrating wire sensor, which outputs an intrinsic vibration signal in response to the excitation signal; a received signal interface unit for the vibrating wire sensor, which receives an intrinsic vibration signal output by the vibrating wire sensor, converts the received signal into a signal recognizable by the processor, and outputs the converted signal to the processor; a signal-converting unit which converts the amplified intrinsic vibration signal into a digital signal; and a counter which counts the digital intrinsic vibration signal output from the signal converting unit and outputs the counted value to the processor.

The invention relates to a test method for simulating the erosion loss of a sandy soil layer surrounding a shield tunnel segment seam. An apparatus used in the invention comprises an air pump, a main test system, a pressure water tank system and a data acquisition system, and the main test system comprises a main test box with the bottom being opened; the upper portion of the main test box is provided with a sealing top cover, and the top cover is connected with a detachable pressurization airbag and is fixedly provided with a precise pressure regulating valve and a digital display pressure gauge; the lower portion of the main test box is provided with a miniature vibrating wire piezometer and a miniature earth pressure gauge; and the bottom of the main test box is in sealing connection with two L-shaped adjustable baseboards through an elastic sealing gasket and an L-shaped baseboard elastic sealing gasket which are arranged at the lower portion of the main test portion, the two L-shaped adjustable baseboards are connected through screws, and the two L-shaped adjustable baseboards are provided with grooves used for fixing the L-shaped baseboard elastic sealing gasket. The screws are adjusted in the test process to make the seam width be consistent with the open amount of a shield tunnel segment. The method can be used to assess the erosion condition of different types of soil surrounding the seam.

The invention provides a frequency measuring method of a vibrating wire type sensor. The frequency measuring method of a vibrating wire type sensor is characterized by for the previous two times of measurement, according to the leave-factory characteristics and mounting position of the sensor, using a large-range frequency sweeping technology and a wide window median frequency sweeping technologyto quickly find out the approximate measurement frequency, using a memory to store the measurement result; in the subsequent measurement, using a dynamic window frequency sweeping measurement method taking the historical data as the median, deciding the frequency sweeping median by means of the last data recorded in the memory, obtaining the frequency sweeping window range by means of weighted calculation of the fluctuation situation of the historical data, wherein the smaller the frequency sweeping window range every time becomes, and the higher the accuracy becomes; and when no resonance results appear in the frequency sweeping range, utilizing an upward backtrack method and an original replacement method to expand the frequency sweeping range. The frequency measuring method of a vibrating wire type sensor overcomes the defects that a traditional high voltage excitation mode is low in accuracy and large in damage and a traditional low voltage frequency sweeping mode consumes long time, and has the advantages of high accuracy, short consumed time, and low damage to the sensor.