8 results about "Nonlinear phenomena" patented technology

The invention relates to the technical field of water monitoring and detection, in particular to a simulation system and an early warning method for multi-point dam break flood. The simulation system comprises a data collection module, a data processing module, a model construction module and a simulation calculation module, and the simulation calculation module is used for completing calculation of multi-point dam break flood in the flood dynamic coupling model and outputting a simulation result. Different reference data are unified to the same projection coordinate system through a coordinate conversion algorithm, and terrain splicing dislocation is avoided; the model construction module firstly generates an unstructured grid based on accurate topographic data, and grid nodes are overlapped with actual topographic feature points through a grid boundary optimization algorithm; extracting a grid where a potential overflow point is located, and writing the grid into a parameter file as a dynamic boundary condition; finally integrating geometry, boundaries, parameters and source files to construct a coupling model; the problem that an existing simulation system cannot truly reflect nonlinear phenomena such as turbulence and vortex in the flood routing process is solved.

The invention provides a method, equipment, medium and product for monitoring the state of a power device by using the nonlinear characteristic of a stress wave in a local frequency domain. The method comprises the following steps: acquiring a stress wave signal released by the tested power device at the current turn-off moment; preprocessing the stress wave signal, and extracting a stress wave signal component of a characteristic frequency band; performing frequency domain analysis on the stress wave signal component, and calculating characteristic parameters of a characteristic frequency band; and comparing the calculated characteristic parameters with the characteristic parameters of the tested power device in the initial state, and evaluating the health state of the tested power device at the current moment. According to the power device health state monitoring method, the health state of the power device is identified through the characteristic parameters of the local frequency band on the basis of the nonlinear phenomenon of the stress wave signal generated at the turn-off moment of the power device in the power circulation process in the frequency domain; the non-linear phenomenon on the frequency domain can better reflect the health state of the power device in the early stage and the whole life cycle, and the monitoring accuracy and sensitivity are higher.

The invention provides a design method for an equivalent scaling model of a high-voltage shunt reactor. The design method comprises the following steps: step 1, determining an initial scaling coefficient range according to research requirements; step 2, predicting and optimizing model parameters by utilizing machine learning based on a dynamic similarity criterion; 3, verifying the effectiveness of the model through multi-physics field coupling simulation; and Step 4, in combination with machine learning, model parameters are adjusted in real time to adapt to dynamic operation conditions. By integrating multi-physics field coupling and machine learning, the method is used for dynamic optimization of the scaling model of the high-voltage electrical equipment, can adapt to calculation of different scaling coefficient models under complex working conditions, considers coupling of various physics fields, and can process nonlinear phenomena and dynamic working conditions of the electrical equipment by dynamically optimizing parameters.

The invention relates to the field of computer simulation and polymer physics, particularly discloses a simulation method for joint coupling motion of a flexible boundary and an internal active chain based on an annular polymer model, and aims to solve the problem that complex dynamic coupling and nonlinear deformation behaviors between the active chain and the flexible boundary are difficult to really simulate in the prior art. The method comprises the following steps: constructing an annular polymer model formed by connecting inactive particles through chemical bonds so as to characterize a flexible boundary; initializing an active chain model based on boundary geometric constraint, and dynamically aligning driving force and chain segment orientation; adjusting the chain parameters according to the conformation features to generate conformation evolution data; kinetic parameters are extracted to establish a diffusion gradient and volume fraction feedback mechanism, and a bidirectional coupling model is formed by combining the acting force of a local density and velocity field calculation chain on the boundary. According to the technical scheme, non-linear phenomena such as asymmetric collapse, oscillation and bud growth of the boundary can be reproduced in a high-fidelity mode, and the physical authenticity and predictive ability of simulation are remarkably improved.

The invention discloses an electric power system nonlinear participation factor calculation method based on Carleman linearization and modal energy, and belongs to the field of nonlinear system dynamics. According to the technical scheme, the nonlinearity of Taylor high-order expansion is reflected in the increase of a coupling product of a plurality of state variables, and n-order Taylor expansion needs to consider the influence of common disturbance of n state variables on a mode; taking a second order as an example, deriving nonlinear modal energy based on a Carleman linearization method; when xk is equal to 1 and xl is equal to 1, the nonlinear participation factor is equal to two times of modal energy. According to the nonlinear participation factor calculation method, the nonlinear phenomenon of multivariable coupling can be mined. According to the method, under the condition that a nonlinear term brought by Taylor high-order expansion of a differential equation is fully considered, a key influence link is positioned by using a state variable and a mode association degree, and the problem that a traditional linearization method is insufficient in precision and difficult to capture multivariable coupling nonlinear dynamic is solved.

The invention provides a flexible joint mechanical arm tracking control method based on UDE, which is applied to the field of robot intelligence, and comprises the following steps: defining a similar gap lag nonlinear phenomenon based on a gap lag phenomenon of a robot dynamic model; based on the time derivative of the tracking error and the expected error dynamic characteristics of the filtering error, in combination with a robot dynamic model and a class gap lag nonlinear phenomenon, a dynamic equation carrying uncertain items is obtained; carrying out approximation on the uncertain item to obtain an estimated value of the uncertain item; and obtaining a control model of the controller based on uncertainty and disturbance estimation by combining the estimated value of the uncertain item with the kinetic equation carrying the uncertain item. According to the method, modeling errors, parameter uncertainty and hysteresis nonlinear characteristics are collectively called'total disturbance ', so that the common complexity of modeling interference sources one by one in a traditional method is avoided, disturbance can be compensated in real time by simply adjusting bandwidth parameters of the UDE filter, and the control precision is remarkably improved.

The application discloses a trimaran motion and wave load calculation method considering strong nonlinear load, and relates to the field of ship hydrodynamic performance calculation. The method solves the problems that the traditional potential flow method is inaccurate in predicting strong nonlinear phenomena such as slamming and large amplitude motion, and the full viscous flow method is too high in calculation cost by coupling potential flow theory and viscous flow theory. The core comprises the following steps: a motion equation framework considering instantaneous wet surface change is constructed based on three-dimensional time domain potential flow theory; a viscous flow CFD method is used to accurately quantify the slamming load and identify the nonlinear damping caused by the entry and exit of a piece into water; and one-way / weak coupling is performed between a parameterized database and a potential flow model, so that the nonlinear load parameters are fed back to the motion equation for correction and rapid solution. The application considers both accuracy and efficiency, and is suitable for engineering design and analysis of various trimarans.

This invention discloses a multi-dimensional dynamic prediction method for bypass ratio of a variable cycle engine. Its core lies in establishing a multi-dimensional prediction model and predicting data based on this model: establishing a baseline dynamic sub-model of bypass ratio with respect to area ratio and its rate of change; constructing a physical correction sub-model; and coupling the inlet pressure ratio to the baseline bypass ratio output by the baseline dynamic sub-model to correct the predicted bypass ratio corresponding to the actual inlet pressure ratio ε. This ultimately forms a multi-dimensional prediction model that simultaneously considers area ratio, area ratio rate of change, and inlet pressure ratio. This invention innovatively introduces three dimensions: area ratio AR, area ratio rate of change dAR / dt, and inlet pressure ratio ε, and constructs a prediction model. The obtained model can accurately characterize the inherent hysteresis loop and nonlinear phenomena in the dynamic adjustment of RVABI, overcoming the limitations of steady-state models.