73 results about "Characteristic equation" patented technology

The invention relates to the technical field of physical acoustics, in particular to a saturated porous medium metasurface Portrait wave frequency dispersion relation calculation method and system, and the method comprises the following steps: obtaining expressions of solid skeleton displacement, fluid relative displacement, total stress, solid shear stress and pore pressure under the action of Portrait waves; obtaining an expression of a fluid displacement component and a fluid normal stress; obtaining an expression about the relative motion of the resonator; according to all the expressions, stress and displacement continuity boundary conditions are applied to the interface of the saturated porous medium and the fluid layer, a characteristic equation of frequency dispersion characteristics is obtained and solved, and a frequency dispersion curve is obtained. According to the method, the explicit frequency dispersion relation of the saturated porous medium metasurface portrait waves is provided, the calculation efficiency and prediction precision of complex interface wave propagation are improved, the optimal design of the metasurface resonator array can be guided, and a key theoretical tool and technical support are provided for design of high-performance acoustic functional devices and structures.

The invention discloses a design method of a pressure control throttle valve with the pressure drop linearly changing along with the stroke, and belongs to the technical field of automation of oil and gas exploitation equipment.The design method comprises the following steps that the linear relation between the pressure drop and the stroke of the throttle valve serves as a target; a mathematical model of a valve element contour is established by establishing a minimum throttling area equation of a cylindrical valve and a wedge-shaped valve, correcting a flow pressure drop characteristic equation and deducing a differential pressure linear adjustment equation, a valve element contour curve meeting the linear requirement is deduced through variable-diameter contour optimization design, and therefore the valve element structure of the throttling valve is obtained. By means of the design method, the valve element contour curve with the wider linearity range of pressure control adjustment and the better precision can be obtained, and the design method is more efficient and universal.

The invention relates to the technical field of composite material structure dynamics analysis, and provides a method and system for predicting the inherent frequency of a three-phase functionally graded composite material conical plate, and the method comprises the steps: employing an improved Halpin-Tsai model to calculate the equivalent parameters of a GPL-containing two-phase composite matrix, solving the equivalent parameters of a three-phase composite layer, and calculating the inherent frequency of the three-phase composite material conical plate. The method comprises the following steps: constructing a nonlinear geometrical relationship between a displacement field and a strain field, calculating a stiffness coefficient of each layer, constructing kinetic energy of the three-phase composite material conical plate, calculating an energy coefficient according to the stiffness coefficient of each layer, constructing potential energy of the conical plate according to the energy coefficient, and constructing a modal displacement function by adopting a Chebyshev polynomial and a boundary function. And establishing a characteristic equation based on a minimum potential energy principle and solving to obtain the inherent frequency of the three-phase composite material conical plate. According to the method, efficient calculation of the inherent frequency of the three-phase composite material conical plate is achieved, and the reliability and engineering application value of structural dynamics analysis are remarkably improved.

The invention discloses a critical parameter prediction method for a vertical cantilever fluid conveying pipe comprising a water injection pump and a Y-shaped nozzle, and relates to the field of fluid conveying pipe critical parameter calculation. The prediction method is based on an Euler-Bernoulli beam model and a momentum theorem, bending force, centrifugal force, Coriolis force, inertia force, gravity and additional force generated by an elbow are comprehensively considered, and an oscillatory differential equation of the fluid conveying pipe is established. The method comprises the following steps: performing dimensionless processing on an oscillatory differential equation by introducing dimensionless parameters, deducing a characteristic equation, a characteristic function and a characteristic value under a cantilever boundary condition, converting a partial differential equation into an ordinary differential equation set, and performing matrix solution; and finally, accurate prediction values of the critical flow velocity and the critical frequency can be obtained. The method can effectively reflect the influence rule of the nozzle and the concentrated mass on the vibration characteristics of the fluid conveying pipe, and realizes the accurate prediction of the critical parameters of the vertical cantilever containing the concentrated mass belt Y-shaped nozzle fluid conveying pipe.

The invention belongs to the technical field of power system stability analysis and control, and relates to a wind power plant characteristic root rapid solving method and system based on the circular ring theorem, and the method comprises the following steps: S1, carrying out the online identification of impedance; s2, constructing a wind power plant grid-connected system characteristic equation; s3, establishing a circular ring theorem model; s4, analyzing the stability of the wind power plant grid-connected system; according to the technical scheme, the calculation method of the circular ring theorem is adopted, the order number of the wind power plant grid-connected system does not need to be reduced, the feature root of the high-order wind power plant grid-connected system can be rapidly calculated, the solving efficiency is high, meanwhile, the directional capturing capacity of the main feature root is high, and the main feature root of the wind power plant grid-connected system can be rapidly searched.

The application relates to the field of circuit state space equation solving technology in the real-time simulation field, and discloses a state space equation discretization method for capacitor and inductor element characteristics, which comprises the following steps: A) establishing a state space differential equation of a circuit; B) establishing a characteristic equation of a capacitor and an inductor element, determining a numerical integration method used by each capacitor and inductor element in the circuit, and obtaining a discrete time domain characteristic equation by using the numerical integration method; C) combining the discrete time domain characteristic equation of step B) and the state space differential equation of step A) to obtain a state space discrete equation of the circuit; and D) cyclic simulation. The state space equation discretization method for capacitor and inductor element characteristics improves the speed and precision of real-time simulation of a circuit system by independently discretizing the characteristic equations of each capacitor and inductor element and optimizing the discretization process of the state space equation.

The invention discloses an electric vehicle experiment table mechanical inertia compensation method for high-precision dynamic simulation. According to the method, an expansion state observer is introduced into an inertia compensator to replace a traditional differential link, system total disturbance including acceleration dynamics and unmodeled dynamics is expanded into new state variables for unified observation and compensation, and the problem that the rotation speed simulation precision is reduced due to high-frequency noise amplification of an experiment table under high-multiple compensation is solved; constructing a system closed-loop discrete mathematical model containing ESO, and determining a stability boundary of the system under high-multiple compensation by using a characteristic equation of the system closed-loop discrete mathematical model and a Jure criterion; a sparrow search algorithm with a working condition adaptive boundary early warning mechanism is adopted in a stable domain to optimize observer gain, and the conflict between the low-speed and high-precision requirement and the high-speed and high-robustness requirement is solved. According to the invention, the interference of high-frequency noise on a compensation loop is effectively solved, and high-precision and high-stability simulation of the mechanical dynamic state of the large-inertia electric vehicle under all working conditions is realized.

The invention discloses a parameter estimation and adaptive control method, device, medium and product of a high-performance aircraft pitch angular velocity control system with stability margin self-configuration, and relates to the field of aircraft control, the method comprises the following steps: collecting the pitch angular velocity of an aircraft and the deflection angle of an elevator in real time, and calculating a tracking error; constructing a relation equation of system parameters and stability margin based on a PI controller, and performing approximate simplification by adopting a numerical approximation method; estimating system parameters and time delay on line by adopting an approximate nonlinear least square algorithm; and substituting the target stability margin, the system parameter estimation value and the time delay estimation value into a system frequency domain characteristic equation for solving to obtain a proportional gain and an integral time constant of a PI controller, and adjusting an elevator deflection angle of the aircraft in combination with a tracking error so as to control the pitch angular velocity of the aircraft. According to the invention, the autonomous configuration of the stability margin is realized, and the stability, robustness and dynamic adaptation capability of the control system are improved.

The invention provides a vibration modal analysis method for a large-span cable-stayed bridge, and belongs to the technical field of bridge engineering, the cable-stayed bridge is simplified into a multi-cable cable-stayed beam structure considering the influence of cable force, and a cable-stayed bridge dynamic model is constructed through a parameterized order reduction technology; deducing a frequency characteristic equation of the cable-stayed bridge by combining a transfer matrix method and boundary conditions of the cable-stayed bridge; by solving the characteristic equation, the inherent frequency and modal characteristics can be determined more accurately and quickly; according to the method, the technical bottleneck of insufficient calculation efficiency of a traditional finite element method is innovatively solved, and fine evaluation of the fundamental frequency and the dynamic characteristics of the large-span cable-stayed bridge is completed; the method has both theoretical preciseness and engineering practicability, the calculation efficiency is remarkably improved, a new technical means is provided for dynamic performance evaluation of the kilometer-scale cable-stayed bridge, and the method has important engineering application value.

The application provides a control method and a control system of a steer-by-wire system. The method comprises the following steps: constructing a steering system dynamics equation based on a target front wheel running parameter, a configuration parameter and a target damping coefficient of a magneto-rheological damper in a shimmy instability mode, wherein the product of the target damping coefficient and a front wheel rotation speed is equal to the product of an initial damping coefficient of the magneto-rheological damper and a magneto-rheological damper current; obtaining a characteristic equation and all characteristic value expressions based on the steering system dynamics equation; obtaining real-time values of the target front wheel running parameter, a value of the configuration parameter, a magneto-rheological damper current real-time value and a value of the initial damping coefficient; obtaining real part values of all characteristic values of the characteristic value expressions based on the obtained values; and adjusting the magneto-rheological damper current real-time value until the real part values of all characteristic values are not greater than zero to obtain a value of the target damping coefficient, if there is at least one characteristic value whose real part value is greater than zero. The method according to the application can solve the front wheel shimmy problem.

This invention provides a method and instrument for measuring the thickness of multilayer films based on Taylor polynomial fitting coefficient analysis. The method involves acquiring the interference signal of the multilayer film under test output by a shared-arm interference structure, wherein the reference optical path of the shared-arm interference structure and the sample optical path share the same physical transmission optical path. The interference signal is down-processed to obtain a baseband interference signal with a center frequency near zero. Taylor polynomial expansion is performed on the baseband interference signal at the point where the optical path difference is zero, and a Taylor expansion coefficient sequence is obtained. A linear equation system is constructed based on the Taylor expansion coefficient sequence, and the coefficients of the characteristic equation are solved. The optical path difference corresponding to each layer of the multilayer film under test is obtained by solving the characteristic equation. The physical thickness of each layer is calculated based on the optical path difference corresponding to each layer and the refractive index of the film material.

A kind of X-ray telescope support truss hierarchical thermal control method and system based on frequency domain analysis, the method includes establishing physical domain heat transfer model and carrying out model reduction, extracting first-order linear characteristic equation;Through the frequency domain analysis of characteristic equation, the transfer law of equivalent heat transfer coefficient G and equivalent absorption coefficient λ to different frequency band thermal disturbance is quantitatively revealed, and the design target of passive insulation and active control is determined accordingly;Based on the conclusion of frequency domain analysis, a two-stage passive suppression system composed of individual isolation and system isolation is constructed to attenuate low-frequency platform disturbance, while the upper and lower datum plates are optimized for differential passive thermal characteristics, and an active control loop operating at a specific high frequency band is configured, ultimately forming a frequency domain collaborative temperature control mechanism of passive low-frequency suppression and active high-frequency control.The present application realizes ultra-high temperature stability at low energy consumption cost in extremely complex thermal environment, effectively solving the problem that the precision and energy consumption of traditional thermal control method are difficult to be considered in through structure.

The invention discloses a steady-state fault electrical quantity calculation method containing a virtual synchronous machine control converter system, and belongs to the technical field of new energy power generation system control protection. The method comprises the following steps: determining a fault condition set and system parameters of a system; forming a node voltage equation, a power supply characteristic equation and a fault boundary condition of the fault network according to the fault condition and the system parameter; a trust-region-dogleg algorithm is adopted for simultaneous solution, and an adaptive virtual impedance value is obtained; judging whether the self-adaptive virtual impedance value is smaller than a set minimum virtual impedance value or not so as to determine the operation state of the converter; solving a current vector according to the operation state and the node voltage vector; and traversing the fault condition set to complete all calculations. According to the method, the technical problem that the adaptive virtual impedance of the virtual synchronous machine control converter in the fault ride-through state is unpredictable is solved, and accurate calculation of the steady-state fault electrical quantity of the virtual synchronous machine-containing converter system is realized.

The embodiment of the invention provides a multi-motor control method and device for a seat, electronic equipment and a storage medium. The method comprises the following steps: constructing a dynamic characteristic equation of a multi-motor system of a seat based on current running data of a vehicle and body shape information of a passenger on the seat; the multi-motor system comprises a plurality of motors; for each motor, determining a plurality of candidate set point sequences of the motor based on the dynamic characteristic equation of the motor; determining the comprehensive fitness of the plurality of candidate set point sequences of the motor, and determining a target set point sequence in the plurality of candidate set point sequences according to the comprehensive fitness; the target set point sequence comprises a target rotating speed and a target position of the motor; and controlling the multi-motor system according to the target rotating speeds and the target positions of the plurality of motors. The method is used for cooperatively controlling a multi-motor system of the seat in a self-adaptive manner according to an actual application scene, so that the adjustment of the seat conforms to the actual application scene.

The application relates to the technical field and discloses a method and system for measuring and calculating apparent resistivity of horizontally layered earth, wherein a characteristic equation of horizontally layered earth is constructed according to an integral variable set obtained through an exponential discrete sampling method and horizontally layered earth parameters; an uplink electromagnetic wave amplitude kernel function of the characteristic equation at each integral variable is calculated to obtain an integral upper limit of horizontally layered earth, and the integral upper limit of horizontally layered earth is set as the maximum value of the integral variable satisfying a preset criterion; based on the integral upper limit of horizontally layered earth, the integral range of the constructed apparent resistivity relationship formula of an unbounded domain is limited to obtain an apparent resistivity relationship formula of a bounded domain; and based on a 151-point Gauss-Legendre integral algorithm and Euler transformation, the apparent resistivity relationship formula of the bounded domain is iteratively solved to obtain a measurement and calculation result of the apparent resistivity. The method meets the dual requirements of precision and efficiency for the measurement and calculation of the apparent resistivity of horizontally layered earth.

The present disclosure relates to the technical field of compressor analysis, and particularly provides a method and device for evaluating the flow stability of a compressor under circumferential distortion, the method comprising: constructing Euler control equations of a compressor to be evaluated; obtaining small perturbation equations of the compressor based on small perturbation assumption and the Euler control equations, and solving the small perturbation equations based on flow field data at multiple circumferential points to obtain small perturbation solutions of the compressor; determining boundary conditions of blades in the compressor based on a cascade model and parallel compressor theory, and determining a system stability characteristic equation of the compressor under circumferential flow field unevenness according to the boundary conditions and the small perturbation solutions; and determining a flow stability evaluation result of the compressor according to a solving result of the system stability characteristic equation; the present disclosure can improve the accuracy of the flow stability evaluation result of a high-load compressor with circumferential flow field unevenness.

This invention discloses an ADRC method for attenuating periodic disturbances in time-delay systems, belonging to the field of automatic control technology. The method includes: 1. Obtaining the controlled process model and disturbance frequency, and establishing an extended state model containing the periodic disturbance; 2. Constructing a reduced-order extended state observer and tuning the gain using the bandwidth parameter method; 3. Introducing a pure time-delay module into the observer's output channel to construct an ADRC structure; 4. Revealing the mechanism by which periodic disturbances in time-delay systems cannot be attenuated through two-degree-of-freedom equivalent transformation analysis; 5. Based on the frequency domain characteristic equation, analytically determining the delay of the time-delay module to achieve effective attenuation of periodic disturbances at specific frequencies. This invention solves the problem of attenuating periodic disturbances in time-delay systems without significantly increasing structural complexity. Compared to traditional schemes that require high-gain or complex prediction structures, this invention only requires adjusting the pure time delay of the observer's output channel, and the parameter tuning process is clear and intuitive, significantly lowering the threshold for engineering applications.

The invention discloses a multi-suspended-span elastic bearing fluid conveying pipe stability parameter prediction method, and relates to the technical field of fluid conveying pipe vibration characteristic analysis. A multi-suspended-span pipeline is divided into a plurality of independent pipe sections at the supporting position, vibration control equations for describing all the suspended-span pipelines are established respectively, and the vibration control equations only consider the coupling effect of bending force, centrifugal force, gravity, Coriolis force and inertia force of the pipeline and do not contain any middle supporting constraint term; the intermediate support constraint is completely written into the cross-coupling boundary condition, so that the defects that the traditional Dirac function method is fuzzy in significance and the numerical calculation is difficult to converge are avoided; carrying out dimensionless processing on an oscillatory differential equation by introducing a dimensionless parameter, deducing to obtain a characteristic equation, a characteristic function and a characteristic value under the complex boundary condition by combining the end elastic boundary and the cross coupling constraint, converting a partial differential equation into an ordinary differential equation set, and carrying out matrix solution, so as to obtain an oscillatory differential equation set; and finally, an accurate prediction value of the inherent frequency can be obtained.

The application provides a heading dynamic stability evaluation method, device, equipment and storage medium, wherein the method comprises the following steps: establishing a lateral heading third-order matrix representing aircraft motion, and converting the lateral heading third-order matrix into a general characteristic equation; converting the general characteristic equation into a decomposition formula in the subsonic, transonic and supersonic stages, solving the motion frequency and damping value under the Dutch roll mode through the decomposition formula, setting the damping value as a preset size in the hypersonic stage, and solving the motion frequency under the Dutch roll mode through an angle of attack formula; combining the motion frequency and the damping value to obtain the Dutch roll mode characteristic root; judging the current flight state under the Dutch roll mode according to the Dutch roll mode characteristic root, and evaluating the current dynamic stability of the aircraft according to the current flight state by using the corresponding evaluation rule. The application establishes a lateral heading third-order matrix considering only the roll and Dutch roll, and improves the accuracy of the evaluation of the dynamic stability related index calculation.

The invention provides an automatic soil moisture distribution measuring method based on multi-source data decoupling. The automatic soil moisture distribution measuring method comprises the following steps: collecting multi-source heterogeneous data and carrying out time alignment operation; performing feature enhancement and decoupling on the multi-source heterogeneous data to obtain anti-interference features; performing tensor fusion on the anti-interference features, and constructing a credibility weight matrix; performing feature matching on the multi-source heterogeneous data and a soil database to determine a soil type; taking the soil type as a constraint condition, and combining with the credibility weight matrix to construct a characteristic equation; solving the characteristic equation through a two-channel network model to obtain a theoretical moisture value; performing interpolation operation on the theoretical moisture values in the space-time coordinate system based on the plurality of theoretical moisture values to obtain a three-dimensional moisture field; and performing gradient calculation on the three-dimensional moisture field through a finite element analysis method to obtain a real moisture value. According to the method, through dynamic alignment of multi-source heterogeneous data, anti-interference feature decoupling and soil type constraint modeling, the precision and universality of soil moisture measurement are improved.

The invention provides a heat supply pipe network analytical solution method and system based on spectral decomposition, and belongs to the technical field of heat supply simulation, and the method comprises the steps: building and solving a primary network water supply matrix operation model based on a heat supply pipe network topological structure, and obtaining a primary network water supply temperature; constructing an analysis response model based on a secondary network multi-node structure; performing spectral decomposition on the primary network water supply temperature to obtain a harmonic component serving as a sine boundary condition; obtaining the analytic solution temperature of the first node of the secondary network by using the characteristic equation of the analytic response model and the sine boundary condition; and on the basis of the primary network water supply temperature and the analytical solution temperature of the first node of the secondary network, a primary network return water and CHP inlet temperature calculation model is constructed and solved, and the primary network return water temperature and the CHP inlet temperature are obtained. According to the method, the whole process of primary network water supply, secondary network heat exchange and primary network water return is integrally solved from the perspective of heat flow, so that full-process efficient simulation of the heat supply network is realized.

This invention discloses a method and device for measuring the flow rate of a condensate feedwater system oriented towards edge computing. The method includes the following steps: Step S1, extracting pump operating parameters under multiple typical operating conditions from a historical database of an industrial internet platform; Step S2, performing simulation modeling of the condensate feedwater system, and constructing a nonlinear mapping relationship between the pipe resistance coefficient and flow rate by combining the pipe geometry, fluid properties, and pump mechanical characteristics, thus obtaining the pipe resistance equation; Step S3, simultaneously solving the pipe resistance equation and the centrifugal pump head-flow characteristic equation using the Newton-Raphson iterative method to obtain the theoretically calculated flow rate value; Step S4, comparing the theoretically calculated flow rate value with the real-time measured flow rate value, and dynamically adjusting the model parameters to ensure that the model error is less than a set threshold. This invention achieves high accuracy in measuring the flow rate of the condensate feedwater system.

The invention provides a method for selecting a segmented maintenance strategy of an asphalt pavement, which comprises the following steps of: detecting the pavement damage condition of the asphalt pavement to be maintained, and recording pavement damage index data of each road section; combining the data into an original data matrix X, and then obtaining a standardized matrix; processing the standardized matrix by adopting a principal component analysis method to obtain a correlation matrix; calculating the contribution rate of each component after solving feature values corresponding to all components capable of representing the original data according to the feature equation, and extracting the component with the cumulative contribution rate greater than X% as a principal component; solving a feature vector corresponding to the principal component feature value according to the feature equation, constructing a sample set F, and carrying out nondimensionalization on the sample set F; and performing K-mean clustering analysis on the dimensionless result of the score of the principal component to obtain the final classification result of the damage conditions of the different road sections, and selecting a corresponding maintenance strategy according to the final classification result.

The application discloses a kind of functional gradient material crack plate structure dynamics analysis methods, comprising the following steps: obtaining the structure parameters and physical property parameters of crack plate, constructs the physical property parameter distribution function of functional gradient material;Based on first-order shear deformation theory and penalty function, crack plate energy functional is established;Based on the displacement of normal plate is extended to the improved fourier series, constructs the displacement function of normal plate;Establish polar coordinates on crack plate, based on polar coordinates, crack complementary function is constructed;The displacement function of normal plate and crack complementary function are added to obtain the overall displacement function of crack plate;Based on the expansion coefficient vector of overall displacement function, the characteristic equation of functional gradient crack plate structure is constructed;Based on crack plate energy functional, functional gradient crack plate structure characteristic equation is solved, and the dynamic response of functional gradient crack plate is solved by iteration.The application has less limitation to plate thickness, and most of crack plate modeling requirements can be realized according to actual demand.

This invention discloses a time-delay compensation control method for wave energy converters, belonging to the field of wave energy converter control technology. Based on the physical model of the wave energy converter, this method establishes the dynamic equations of the wave energy converter system. After defining the maximum power control problem of the wave energy converter, the dynamic equations of the wave energy converter system are transformed into a second-order linear system form, obtaining the system state variables, system parameters, and input time delay. After constructing an auxiliary system, an error variable is defined. Based on the error variable, a virtual control law is designed, and then an actual control law is constructed. By constructing the characteristic equation, the critical time delay threshold of the wave energy converter system is calculated. Lyapunov stability analysis proves that the system tracking error converges to a preset small neighborhood, thus completing the time-delay compensation control method for the wave energy converter. This invention can ensure that the critical time delay threshold of the system is always greater than the actual input time delay by adjusting the control parameters, guaranteeing system controllability.

A method for multi-objective vector fitting includes the following steps: 1) processing a given dataset to construct a single-objective fitting dataset; 2) determining initial poles and using the initial poles and frequency sampling points to establish a fundamental matrix; 3) separating the real and imaginary parts of the fundamental matrix to construct a real fundamental matrix; 4) performing a simplified QR decomposition on the real fundamental matrix to obtain the first M columns of the complete Q matrix, denoted as Q. s Matrix, and for Q s The matrix is ​​stored; 5) Construct and solve the pole coefficient equation to obtain the pole coefficients; 6) Construct the pole characteristic equation using the pole coefficients and the initial poles to calculate the new poles; 7) Calculate the residues of each matrix element corresponding to the new poles to complete the vector fitting. This invention provides a method for multi-objective vector fitting that significantly reduces the computational complexity and improves computational efficiency.

The invention relates to the technical field of oilfield development, in particular to a method and system for rapidly predicting the spontaneous imbibition recovery ratio of a tight reservoir, and the method comprises the steps: constructing a control equation for representing the saturation degree of fluid in a matrix according to a current nonlinear seepage equation and a pressure-sensitive characteristic equation in combination with a relation of current capillary force and relative permeability changing along with the saturation degree; according to a current matrix internal fluid saturation control equation, initial conditions and boundary conditions are given, and fluid saturation distribution in the matrix blocks at different moments is determined; determining the average saturation of fluid in the matrix at different moments according to the saturation distribution of the fluid in the matrix block at different moments; and determining a change equation of the imbibition recovery ratio along with time according to the average saturation degree of the fluid in the matrix block at different moments in combination with an imbibition recovery ratio formula. According to the method, the stress sensitivity of the tight reservoir and the nonlinear seepage characteristics of the matrix are considered, the spontaneous imbibition rule of the tight reservoir can be accurately described, and dynamic productivity prediction and optimization evaluation of tight oil and shale oil are facilitated.

The application discloses a kind of multi-span elastic supporting flow pipe stability parameter prediction method, it is related to flow pipeline vibration characteristic analysis technical field.By splitting the support position of multi-span pipeline into multiple independent pipe sections, vibration control equations describing each span pipeline are established respectively, the vibration control equations only consider the coupling effect of bending force, centrifugal force, gravity, coriolis force and inertia force of the pipeline, and do not contain any intermediate support constraint term;The intermediate support constraint is completely written into the inter-span coupling boundary condition, which avoids the defects of ambiguous meaning and difficult to converge in numerical calculation of traditional Dirac function method;By introducing dimensionless parameters to dimensionless the vibration differential equation, combined with the above elastic boundary and inter-span coupling constraint, the characteristic equation, characteristic function and eigenvalue under the complex boundary condition are derived, and the partial differential equation is converted into a system of ordinary differential equations after matrixization solution, and finally the accurate prediction value of natural frequency can be obtained.

The application provides a combined cycle single-extraction heat supply unit characteristic equation and power operation limit derivation method, obtains a gas turbine temperature correction coefficient, a gas turbine intake amount and a steam turbine extraction amount; obtains combined cycle power according to a first coefficient, a second coefficient and a third coefficient in a steam turbine power expression, a fourth coefficient, a fifth coefficient, a sixth coefficient, a seventh coefficient and an eighth coefficient in a gas turbine power expression and the gas turbine temperature correction coefficient; the application saves the number of field performance test working conditions of a gas-steam combined cycle single-extraction heat and power cogeneration unit, and is beneficial to relieving the phenomenon of excessive power generation of a heat and power unit, heat and power unit peak regulation difficulty and wind and light abandonment in grid peak regulation.

The invention relates to a double-suspender system containing a stiffness-adjustable damper and an analysis and optimization method. According to the analysis method of the double-suspender system comprising the adjustable stiffness damper, a transverse free vibration equation of each rod section is obtained according to the composition and related parameters of the double-suspender system, a shape function of each rod section can be obtained through the transverse free vibration equation of each rod section, and the shape function of each rod section relates to a shape function constant sum. 4H equations capable of determining all sums are obtained through boundary conditions, displacement coordination conditions and force balance conditions, then a matrix equation is obtained, a non-zero solution of the matrix equation is obtained, a characteristic equation for controlling free vibration of the double-suspender system is derived, and then the non-dimensional frequency of the double-suspender system is obtained. According to the method, the expression of the damping ratio zeta n of the double-suspender system can be determined, the damping ratio zeta n of the double-suspender system is solved, the dynamic characteristics of the double-suspender system can be effectively analyzed, and the method has universal applicability and can be used for analyzing any number of rigidity-adjustable inter-cable dampers.