33results about How to "Few measuring points" patented technology

The invention relates to a large span rail traffic bridge damage recognition method, including the steps:(1) a sensor is arranged on the bridge which will be examined, the dynamic response signal of a large span rail traffic bridge is measured and is driven by that when a rail vehicle crosses the large span bridge, the signal on the sensor is red by a computer; (2) the benchmark bridge numerical model and the rail vehicle numerical model of the bridge are established; (3) a coupled mechanical analysis system comprising the benchmark bridge numerical model and the rail vehicle numerical model is initialized, an explicit integral method is used to solve the system, the simulated dynamic response signal of the benchmark bridge numerical model on a relative position is red according to the installment position of the sensor; (4) the energy spectrums of the dynamic response signal obtained by monitoring and the simulated dynamic response signal obtained by numerical simulation calculation of the bridge are solved by a multi-scale wavelet packet analysis method, and a damage recognition is carried on by recognizing index. The invention increases the precision of the bridge damage recognition, and the normal use of the bridge structure can not be affected.

The invention discloses a measuring method for a crane cart wheel pressure. The measuring method for the crane cart wheel pressure includes steps that (1) distributing foils, to be specific, pasting strain foils at the lateral surface of a cart track; (2) building a wheel pressure monitoring system, to be specific, connecting the strain foils and wireless strain nodes with a monitoring host; (3) calibrating, to be specific, enabling a crane to locate in a no-load state, enabling a crane dolly to locate at a proper position, enabling the cart to pass the cart track in a constant speed, and using the wheel pressure monitoring system to record a strain-time curve so as to obtain a wheel pressure and strain calibrating coefficient (shown in the description); (4) measuring the cart wheel pressure on site, to be specific, when the dolly is located at a set position according to a set lifting capacity, gathering the corresponding strain value, and converting the strain value into the corresponding wheel pressure (shown in the description). The measuring method for the crane cart wheel pressure is easy and practical, is capable of precisely measuring the actual value of each wheel pressure, is more direct and reliable than a calculation method, is capable of directly reflecting the wheel pressure non-uniformity of the crane under different working conditions and provides essential data for optimizing, using and maintaining the crane wheels and saving civil engineering cost.

The invention discloses a method for detecting exhaust enthalpy of a turbine. The method includes the following steps of measuring and calculating a change rule of a specific parameter when a working condition changes according to designed data or test measured data, calculating to obtain a numerical value of the specific parameter under one certain working condition, acquiring partial heating power data of a low pressure cylinder under the certain working condition by the aid of a measuring instrument, reasonably assuming on the basis of a stage loss theory to obtain a numerical model for calculating the exhaust enthalpy of the turbine, substituting the numerical value of the specific parameter and the partial heating power data into the numerical model for calculating the exhaust enthalpy of the turbine to calculate the value of exhaust enthalpy of the turbine under the certain working condition. On the basis of stage loss theory, stage losses of the turbine are sorted into exhaust steam loss relating to volume flow, moisture loss relating to moisture and other losses relating to ideal enthalpy drop, and the calculation is simple, clear and highly precise. Detailed structural parameter of the low pressure cylinder is not needed, so measure points are reduced, and influence on calculated result caused by measuring error is small.

The invention discloses a current meter high-speed linear formula integration detection method and a detection device. The method comprises the following steps: cleaning a ball bearing; detecting average frictional resistance moment M of the ball bearing; detecting a propeller current meter rotating speed V0 and an instrument rotation bearing internal frictional resistance moment M, and confirming that a standard is reached; fixedly installing three detected current meters at the lower end of a measuring rod and placing them into water of a detection water tank; adjusting an axial directions of the current meters; tranquilizing a water body in the tank; starting a motor, a detection vehicle running from a lowest speed and gradually increasing its speed, and detecting instrument output signals and data; and according to a GB/T21699 detection method of rotor type current meter in linear open channel, by use of a least square method, calculating values of a and b of a detection formula and a middle and high-speed whole-line average mean square deviation sigma. According to the invention, the program and steps of a conventional detection method in the prior art are substantially simplified, the precision of detection results of the current meters can be ensured, at the same time, the production efficiency is improved, the working conditions are improved, the management rules are simplified, manpower and material resources are reduced, and the production operation cost is decreased.

The invention discloses a measuring method of deepwater reservoir vertical direction water temperature distribution. Control spacing of measuring points is obtained according to measuring accuracy of an instrument, from the water depth of 10 meters to 15 meters to the bottom of a reservoir, the points are measured in every 10 meters to 15 meters, temperature gradients of the points are calculated by a method of back inserting, if the temperature gradient of a certain point is larger than 0.05 DEG C/m, the ratio of the absolute value of the difference of the temperature gradient of the certain point and that of an adjacent point to the temperature gradient of the certain point is calculated, if the ratio is larger than 15%, measuring water temperature is increased to a middle point of the certain point and the adjacent point so as to enable the water temperature of all points to satisfy the condition that the absolute value of the temperature gradient of water temperature is not more than 0.05 DEG C/m or the ratio of the absolute value of the difference of the temperature gradient of the certain point and that of the adjacent point to the temperature gradient of the certain point is not more than 15% or the spacing of the measuring points is not more than two times of the control spacing. The temperatures of all points are sequenced according to the water depth, and then the deepwater reservoir vertical direction water temperature distribution can be obtained through spline interpolation.

The invention relates to a wind turbine generating set fault diagnosis method based on bispectral entropy. The method includes the steps: collecting vibration signals of a wind turbine generating set in a normal running state, a minor faulty state, a medium faulty state and a severe faulty state; calculating fault characteristic bands of all the vibration signals; establishing a fault deviation degree detection model; collecting vibration signals of a to-be-detected wind turbine generating set, carrying out fault characteristic band calculation on the to-be-detected vibration signals, obtained fault characteristics are input to the fault deviation degree detection model, calculating the fault deviation degree between the faulty state and the above four faulty states, and finally obtaining the minimal deviation degree which is the faulty state of the wind turbine generating set. The fault characteristics of non-stationary signals can be effectively extracted, fault diagnosis for the wind turbine generating set can be carried out, and the fault diagnosis precision can be improved. The method can be widely applied to fault diagnosis for wind turbine generating set equipment.

The invention relates to a turbocharger abnormal sound diagnosis method. The method comprises steps of 1) noise vibration analysis; 2) filtering playback, the engine crankshaft rotating speed and theturbocharger rotor rotating speed corresponding to the frequency when abnormal sound occurs in the noise in a vehicle and the turbocharger near-field noise are filtered and separated; 3) excitation source control, the opening and closing time proportion of a turbocharger waste gas bypass valve is controlled by adjusting the duty ratio; 4) subjective evaluation, subjective evaluation is performed on in-vehicle abnormal sounds and turbocharger near-field noise in three states of an original vehicle state, adjustment of the duty ratio of a waste gas bypass valve controller to be zero and fixationof a waste gas bypass valve; 5) confirmation of the source of abnormal noise; and 6) conclusion verification, a pressure stabilizer is arranged at an air outlet of an air compressor of the turbocharger, and the conclusion is verified through objective improvement of abnormal sound quantification. The method is advantaged in that the abnormal sound source is quickly found by controlling possible excitation source state change, and the test period is short.

The invention provides a near-field acoustic holography test method based on a spherical function basic solution and a near-field acoustic holography test device thereof. The test method comprises the steps that the order N of the used spherical function basic solution and the number and the position of microphones on a spherical holographic measuring surface are determined, sound pressure measurement is performed on the determined measurement points and the acoustic physical quantity of the surface of a vibration structure is reversely reconstructed by using the acquired measurement result. The device comprises a base (1), a rotating shaft (2), a semicircular support (3) and a test mechanism (4). The semicircular support (3) can circumferentially rotate along with the rotating shaft (2). The test mechanism (4) is fixedly installed on the semicircular support (3) and can measure acoustic pressure information of the spherical holographic measuring surface surrounding the vibration structure (5).

The invention provides a wind power plant current collection line single-phase earth fault positioning method. The method comprises the following steps: training a regression model combining a self-encoding neural network and a random forest model; collecting three-phase voltage phasors of a booster station medium-voltage bus connected to a wind power plant current collection line and the tail end of the current collection line in real time, and three-phase current phasors of the head end and the tail end of the current collection line; calculating zero-sequence voltage phasors of a medium-voltage bus and the tail end of a current collection wire in the booster station and zero-sequence current phasors of the head end and the tail end of the current collection wire; judging whether a single-phase earth fault occurs or not; and if YES, inputting the effective values and phases of the three-phase voltage and the zero-sequence voltage of the booster station medium-voltage bus and the tail end of the current collection line and the effective values and phases of the three-phase current and the zero-sequence current of the head end and the tail end of the current collection line into the trained regression model, and calculating the distance from the fault point to the booster station medium-voltage bus. According to the invention, the problems of inaccurate single-phase earth fault positioning and multiple measuring points of the current collection line in the prior art can be solved.

The invention discloses a rail vehicle body vibration fatigue monitoring system and a method. The rail vehicle body vibration fatigue monitoring system comprises on-vehicle equipment, off-vehicle equipment and a user terminal. The on-vehicle device is in communication connection with the off-vehicle device and the user terminal. The system provided by the invention needs few sensor measuring points, and is simple in equipment hardware composition, small in size and convenient to carry. And the system can also feed back the real-time situation to the user, so that the user is guided to focus ondesign and maintenance. According to the method, the power spectral density is adopted as calculation input, the calculation speed is high, and the collection period of the under-vehicle equipment can be greatly shortened. Meanwhile, the fatigue weak part of the vehicle body provided by the method can provide an important basis for vehicle body structure design, so that workers are guided to payattention to a vehicle body maintenance area during maintenance; the sensitive frequency provided by the method can guide the design of a vehicle suspension system; and the real-time change of the fatigue damage value of the vehicle body is also one of guidance bases for workers to perform line maintenance and vehicle body maintenance period adjustment.

The invention discloses a frequency domain distribution random dynamic load identification method considering spatial correlation. The method comprises the steps: S1, establishing a finite element model of the thin-wall structure according to the geometrical shape of the thin-wall structure; S2, measuring points are arranged on the actual thin-wall structure, and a self-power spectral density function of the response is calculated according to the dynamic response of the measurement; S3, determining a corresponding measuring point position on the finite element model according to the geometric position of an actual measuring point, calculating a measuring point response in the finite element model under the excitation action of a random dynamic load distributed in an orthogonal polynomial form in a distance space, and assembling into a recognition matrix; S4, calculating a cross-power spectral density function of the distributed random dynamic load according to the identification matrix and the responded auto-power spectral density function, and reconstructing the distributed random dynamic load. The distributed random dynamic load outside the structure is identified through the structural strain response, the spatial distribution function of the distributed random dynamic load can be accurately obtained, and an indirect distributed random dynamic load obtaining method is provided.

The invention discloses a power grid single large disturbance online detection method based on a WAMS. The method comprises steps of 1), information acquisition; 2), disturbance detection; 3), information fusion; and 4), diagnosis and decision. According to the method, the algorithm is simple, the detection speed is relatively fast, accuracy is relatively high, the precise phase angle information is provided through utilizing a PMU, so whether disturbance occurs is detected, and a determination problem that whether single large disturbance occurs is solved, moreover, as the uploaded information is with a certain error probability, whether disturbance occurs is verified by utilizing the data fusion theory in combination with the data uploaded by the WAMS and a SCADA, and a problem of an error large disturbance occurrence determination result caused by the error uploaded information is solved.

The invention relates to a heating area ash degree judgment method considering global heat transfer influence of a coal-fired boiler. The heating area ash degree judgment method comprises the following steps of 1) acquiring a load P of a current moment and inlet and outlet steam temperature difference Delta Tk of each convection heating surface; 2) acquiring an inlet and outlet steam temperature difference change value vector Delta T<a-k> of a heating surface k which is not ash-blown; 3) correcting inlet and outlet steam temperature difference of other heating surfaces to obtain a corrected inlet and outlet steam temperature difference correction value Delta T'<k>; 4) calculating an ash degree coefficient Beta k of each heating surface according to the inlet and outlet steam temperature difference correction value Delta T'<k> of the heating surface; and 5) starting ash blowing until ash accumulation coefficient is reduced to a value below a starting threshold when the ash accumulationcoefficient of a certain heating surface is larger than the starting threshold, and completing ash blowing of the heating surface of the coal-fired boiler. Compared with the prior art, the heating area ash degree judgment method is scientific, practical, accurate and simple.

The invention discloses a heat consumption characteristic analysis method for a main pipe thermal power plant turboset, and belongs to the technical field of turboset heat consumption characteristics.The method aims at solving the technical problems that in the prior art, the operation condition of a main pipe thermal power plant is complex, instrument measuring points are incomplete, and real-time monitoring and thermal economy evaluation of a unit are difficult. The method includes: dividing operation mode of a turboset of the main pipe thermal power plant into operation without a deaeratorand operation with the deaerator; respectively establishing a heat consumption model of the running unit without the deaerator and a heat consumption model of the running unit with the deaerator; collecting measuring point data of a main pipe thermal power plant turboset; and analyzing the heat consumption characteristics of the main pipe thermal power plant in different operation modes based onthe collected measuring point data and the established heat consumption model. According to the method, the heat consumption models are respectively established by dividing the unit into a deaerator-free operation mode and a deaerator-containing operation mode, so that the thermal economy of the unit can be analyzed only through a small amount of measuring point data, and the operation condition of the unit can be conveniently monitored on line.