46 results about "Secant method" patented technology

The invention discloses a fatigue life prediction method for a friction stir welded component based on small crack propagation, and belongs to the technical field of fatigue diagnosis and analysis ofmechanical structures. The method comprises the steps that a bone-shaped flat plate sample is prepared, fatigue small crack propagation replica tests under different stress loads and different stressratios are conducted on different areas of a joint, and a secant method is adopted for calculating the propagation rate of small cracks; a New-Raju model is adopted for calculating the stress intensity factor range of the small cracks of the joint; c values in the depth direction and a/2 values in the vertical direction of semi-arc shapes of fatigue crack propagation zones in fracture shapes of different areas of the joint, and the depth-to-length ratio 2c/a of the cracks is calculated; a curve of the propagation rate of the cracks along with the change of the stress intensity factor range isdrawn; an effective stress intensity factor is calculated; a formula of the propagation rate of the small cracks is determined; an initial crack size a0 and a critical crack size ac are determined; the formula of the propagation rate of the small cracks is integrated to obtain the fatigue life of the welded component. By means of the scheme, the fatigue life of the friction stir welded component can be more easily and accurately predicted.

The invention discloses an independent micro-grid energy storage margin detection method. Wind power, photovoltaic output and load random models are built on the basis of a latin hypercube sampling scene generation technology and a probability distance scene reduction technology; a scene generation and reduction technologies-based micro-grid energy storage margin detection model combining with a storage battery charge-discharge optimization technology and a secant method is built by constructing an expected value of island power shortage and the expected value of island power surplus as reliability evaluation indexes; on the basis of considering a micro-source and load stochastic characteristics, due to introduction of energy storage equipment and the ratio of newly increased load carrying capacity to an original load of a system, the micro-grid energy storage margin is detected or calculated to obtain the required minimum capacity of the energy storage equipment when a micro-grid reaches one energy storage margin under the condition of maintaining the reliability of the system unchanged.

The invention discloses a fast factorized back-projection SAR self-focusing method. A phase error optimization model is established by combining a fast factorized back-projection imaging algorithm (FFBP), and the optimization model is solved by using a coordinate descent method and a secant method so that the problem of phase error compensation can be effectively solved. Compared with the methods in the prior art, the phase error can be more accurately estimated and a great focusing SAR image can be obtained so that the problems of high computational burden, low accuracy and low adaptability of the existing FFBP self-focusing method can be solved, and accurate motion error estimation and great focusing combining FFBP imaging can be realized.

The invention relates to a spline curve interpolation method based on a secant method. The spline curve interpolation method is applied to spline curve interpolation of a numerical control system. The spline curve interpolation method comprises the steps of establishing a structure equation according to the cutter feeding speed during processing, a spline curve equation and an interpolation cycle, and enabling the equation root to be an interpolation parameter; utilizing the structure equation and applying a secant iteration method to solve the interpolation parameter, and predicting an initial value of the interpolation parameter by adopting a Taylor prediction equation and a Bill Adams prediction equation; substituting the solved interpolation parameter into the spline curve equation, and obtaining the actual cutter feeding amount of every movement axis. The method is small in calculation amount, and execution efficiency of a numerical control machine tool is high; limitation of chord height errors is considered, and processing contour precision is guaranteed; the secant method has superlinear convergence, so that when the method is utilized to calculate the interpolation parameter, the convergence rate is high, the calculation amount is small, and the stability is good.

The invention provides a method for precisely solving the length of an unstressed cable of a cable-stayed bridge. The length of the unstressed cable is solved by substituting the average value of the nodal force at the end of the stayed cable with a precise calculation method for the force at the end of the stayed cable, and by building a precise expression s0 of the length of the unstressed stayed cable and a characteristic parameter beta constraint equation of the stayed cable when a tensile force at the end of a tower is known without selecting the primary value of the length of the unstressed cable. The method comprises the following steps of: building the precise expression of the length of the unstressed stayed cable and the characteristic parameter beta constraint equation of the stayed cable when the tensile force Tj at the end of the tower is known, and solving the length of the unstressed stayed cable. The method has the advantages of solving the problem on the selection of the primary value of the length of the unstressed cable, with high convergence rate and small calculation error. Compared with the linear search, the dichotomy and the improved chord secant method for iteratively solving the length of the unstressed cable, the method of the invention greatly improves the solution precision and solution efficiency of the length of the unstressed stayed cable, so the method is of relatively high application value in practical projects.

The invention provides a novel arrangement method of a bionic solar thermal mirror field. The method comprises the following steps: 1, selecting mirror field bionic spiral initial value; 2, calculating influence factors of optimal heliostat arrangement and the mirror field efficiency; 3, optimizing heliostat position adjusting coefficients according to optimizing algorithm process until the optimal value is obtained; 4, determining heliostat coordinates; and 5, setting the mirror field arrangement; selecting and determining the bionic spiral initial value through a hill-climbing method; iteratively optimizing through an improved ion cluster algorithm based on the initial value; setting the heliostat position adjusting coefficients into a variable which varies according to the actual condition; and then solving and interpolating through an improved secant method and a golden section method, so as to obtain an efficient tower type solar thermal mirror field arrangement method. According to the method, a unique polygonal linked-list method is carried out to calculate shadow and blocking loss, so that the annual optical efficiency of the mirror field is maximum, and the land use area is minimum.

The invention discloses a method and device for obtaining a synthetic ground electric field of a high-voltage DC transmission split form line. The method comprises the steps of building an optimized simulation charge calculation model of solving a nominal electric field and a surface electric field according to physical characteristics of the split form line and solving the nominal electric field, nominal potential and the surface electric field; and calculating the ratio of a surface roughness coefficient of the split form line to the surface roughness coefficient of a steel-cored aluminum strand according to self-sustained conditions of wire corona discharge, and substituting the ratio into a Peek's formula to solve the corona inception field intensity. A space charge density value and a final value of a scalar function are iteratively solved through a secant method in numerical analysis, and the final value of the scalar function is multiplied by the solved nominal electric field to obtain the synthetic ground electric field. The method and the device have the characteristics of being easy to model, convenient to operate, high in accuracy and wide in application range, and can be used for the technical fields of ultra-high voltage power transmission, an engineering electromagnetic field and the like.

The invention discloses a pavement performance evaluation method based on the pavement use performance and material performance. The method comprises the following steps: detecting the pavement damage, a rut, a flatness value and a skid resistance performance; calculating a use performance index; carrying out coring on an evaluated pavement; collecting a uniaxial repeated direct tensile test and determining a fatigue parameter correction parameter; determining the number of rheological times by adopting a two-step secant method; determining apavement performance index, the rheological frequency and Marshall stabilityall evaluated road sections; constructing evaluation indexes of all evaluated road sections to form a matrix; constructing a standardized matrix and constructing an index maximum gray matter element; calculating an association degree matrix; calculating a determination matrix; calculating a maximum feature value according to the determination matrix and measuring the matrixconsistency by adopting a consistency index; determining an evaluation index weight matrix; determining the association degreesbetween all road sections and an optimal matter grey element; and evaluating the pavement performance of each road section according to the association degree between each road section and the optimal matter grey element. Therefore, the maintenance priority sequence of the road section can be determined and maintenance funds can be utilized reasonably.

The invention relates to a generalized prediction control algorithm of a continuous stirring tank reactor system. A nonlinear model is established for the continuous stirring tank reactor system and is converted into an output prediction model based on a U model. A reference trajectory is set, the generalized prediction control of the output prediction model is carried out, and a pseudo input of the system is obtained. Then a secant method is used to carry out iterative calculation to obtain an actual input of the system. According to the generalized prediction control algorithm, the combination of the secant method and the U model is used, thus when a nonlinear equation about the actual input is solved, a derivation problem in using a Newton iterative algorithm is avoided, the computation time is reduced, at the same time the convergence rate is fast, and a nonlinear system control design problem is simplified.

The invention provides an anti-abrasion and attrition-reducible circulating fluidized bed boiler. The circulating fluidized bed boiler comprises a plurality of water wall tubes for forming a furnace water wall, wherein a plurality of horizontal flow blocking beams perpendicular to the water wall tubes in the length direction are arranged on the water wall; the positions of the horizontal flow blocking beams on the water wall meets an exponential formula that a<n+1>-(L+1)*a+L is equal to U; the value of the a can be obtained by using a mathematical Newton secant method; the root of a being equal to 1 is omitted to obtain a first horizontal flow blocking beam; the distance between the first horizontal flow blocking beam and an anti-abrasion plastic upper edge of a dense-phase zone is a; the distance between a second horizontal flow blocking beam and the first horizontal flow blocking beam is a<2>; and so on, the distance between a nth horizontal flow blocking beam and a (n-1)th horizontal flow blocking beam is a<n>. According to the invention, the horizontal flow blocking beams are arranged in the boiler, do not obviously affect rated operating parameter of the boiler, can effectively reduce abrasion of grains on the water wall tubes, and can reduce abrasion effect of swirl, turbulence, swirl flow, angle gather and the like, and can realize an excellent protective effect on the whole inner wall of the boiler.

The present invention discloses an aircraft radar target detection method based on the GCV, comprising the following steps: (1) converting a detection problem of the aircraft radar to the target to a constraint optimization problem of solution of a diagonal loading parameter; (2) converting the constraint optimization problem of solution of the diagonal loading parameter to a penalty function coefficient estimation problem of a Tikhonov project, and constructing a constraint optimization problem of solution of the penalty function coefficient on the basis of the generalized cross validation criterion; (3) performing singular value decomposition of a coefficient matrix in the constraint optimization problem of solution of the penalty function coefficient, obtaining a simplified objective function according to the expansion mode of the singular value of the coefficient matrix, and obtaining a final diagonal loading parameter by utilizing the secant method; and (4) calculating a filtering output value of a detection unit according to the final diagonal loading parameter, comparing the filtering output value of the detection unit with a default threshold value, and determining whether the detection unit has a target signal or not.

The invention relates to a correction method used for a creep crack growth numerical simulation result. The correction method comprises the following steps of: (1) through finite element software ABAQUS, calculating a creep crack growth process, and obtaining a relationship among crack growth length, load linear displacement and time (t); (2) comparing a creep crack growth situation obtained by numerical simulation with an experiment result, and if the creep crack growth situation and the experiment result are matched but the load linear displacement obtained by calculation is smaller than the experiment result, correcting the load linear displacement; (3) utilizing a secant method to calculate the linear displacement rate and the crack growth rate of the corrected load linear displacement; and (4) adopting the corrected load linear displacement rate to calculate a load level (C*). The correction method is suitable for the correction of a creep crack growth simulation result of an element failure technology, and has the advantages of being simple in operation and accurate in results.

The invention relates to an underwater acoustic positioning method, especially to a large-incidence-angle sound ray tracking and positioning method based on layered constant-gradient sound ray tracking. A Snell constant p is represented by the curvature radius R of the first layer according to a formula of the curvature radius of the first layer in a layered constant-gradient hypothesis; the Snell constant p, in a horizontal displacement formula in the water layer, of the sound wave is represented by the curvature radius R; the P in a newly established formula is iterated in a secant method; an iteration result is converted into an incidence angle; and the obtained incidence angle is used to track the sound ray. According to the large-incidence-angle sound ray tracking and positioning method provided by the invention, traditional layered constant-gradient sound ray tracking is improved, the reason of positioning failure under the large-incidence-angle sound ray condition is analyzed, positioning failure is overcome, the maximal range of initial incidence angle iteration is expanded, and the positioning efficiency is improved.

The invention relates to a secant-method based internal model position control method for a permanent magnet linear synchronous motor and belongs to a novel internal model control system. The novel internal model control system comprises a kernel ridge regression internal model and a secant method controller; the kernel ridge regression internal model is high-precision linear motor nonlinear model built by the kernel ridge regression process. The inverse of the kernel ridge regression internal model is acquired through iteration solving by the secant method to serve as the controller; the output of the kernel ridge regression internal model and the real position of the motor are subjected to difference operation, the difference value is fed back to the input of the secant method controller through a filter, so that the internal model control method based on the secant method is formed to realize position control for the permanent magnet linear synchronous motor. The secant-method based internal model position control method is characterized in that, the internal model of the permanent magnet linear synchronous motor is built by the kernel ridge regression process, and the inverse of the kernel ridge regression internal model is acquired through iteration solving by the secant method to serve as the controller. By the secant-method based internal model position control method, high tracking precision of the internal model position control system of the permanent magnet linear synchronous motor, high robustness and interference resistance capacity are achieved.

A nano-silica hybrid vinyl phenyl silicon intermediate, a preparation method therefor and a use thereof in an environmentally-friendly insulating varnish are provided. The nano-silica particles are dispersed uniformly and stably; the nana-silica hybrid vinyl phenyl silicon intermediate has the advantages of resisting high temperatures and coronas and being high in activity; the temperature index measured according to a secant method is 200° C.-240° C., the measured corona-resistant time is 18-36h, and the vinyl active sites carried thereon can have a good compatibility with polyesterimide, heat-resistant polyesters, hydrogen-containing siloxane and modified epoxy; the intermediate is particularly suitable for preparing a high-temperature-resistant and corona-resistant solvent-free insulating varnish; and there are on volatile gases during use, thereby causing on pollution to the atmospheric environment.

The invention provides a capacity confidence level evaluation method for multiple wind power plants on the basis of a Copula function. The method comprises the following steps of: firstly, constructing a multidimensional Copula function to estimate the parameters of the marginal distribution functions of the wind power plants and parameters in the Copula function t hrough a distribution parameter estimation method; then, utilizing a shortest distance method to select an optimal Copula function; and utilizing a conditional sampling method to generate a multidimensional wind speed sample with correlation. On the basis, the output-related capacity confidence level evaluation method for the multiple wind power plants is put forward, and a secant method is adopted to carry out calculation to obtain the capacity confidence level of the wind power plant.

The invention relates to a space corner smoothing method based on a three-dimensional generalized Euler spiral. The method comprises the following steps: firstly, through coordinate rotation, enablinga tangent plane of adjacent straight line sections or arc sections at a space corner to be parallel to an XY plane; then, letting the three-dimensional generalized Euler spiral be same with third-order derivatives of the straight line sections or the arc sections at end points, and calculating each parameter of the three-dimensional generalized Euler spiral; calculating the distance between the three-dimensional generalized Euler spiral and each straight line section or arc section by adopting a Newton method, and limiting the distance within a tolerance allowable range by adopting a secant method; and finally, through coordinate inverse rotation, making the adjacent straight line sections or arc sections and the three-dimensional generalized Euler spiral switched to the original positions to obtain a smoothed space corner. The method realizes smoothing of a tool trajectory, of which the adjacent straight line sections or arc sections are not in the same plane, that is, the tool trajectory containing the space corner, and can be applied to trajectory pretreatment of a numerical control machine tool, so that the machining efficiency is improved.

The invention provides a firing data obtaining method of an artillery fire control system. On the basis of a traditional secant method, the firing data obtaining method increases the convergence rateof iterative solution by optimizing selection of iterative initial values, so as to achieve higher calculation efficiency and precision. The firing data obtaining method stores recent historical bounce-off time data in a fixed sliding window, estimates the bounce-off time at the current moment according to the stored bounce-off time data, and takes the estimated bounce-off time as an iterative initial point of a hit equation solution to solve the current actual bounce-off time, and then other hit data elements are obtained.

The invention discloses a method for choosing tasks by foresight. The method comprises the following steps of: (1) dividing a task area into strips according to the width of a camera; (2) calculating visible time intervals of a satellite on all strips according to the maximum pitching angle and maximum rolling angle of the satellite, sequencing according to starting moments of visible time windows to obtain a task sequence; (3) calculating the observation duration of each task strip in the task sequence by using a secant method; (4) according to satellite attitude maneuver time between the current task and the last scheduled task, judging whether the current task conflicts with the last scheduled task, wherein if the current task conflicts with the last scheduled task, the current task cannot be scheduled, and if the current task does not conflict with the last scheduled task, the next step is executed; (5) acquiring a foresight task group of the current task, and judging whether the current task conflicts with tasks in the foresight task group, wherein if the current task does not conflict with the tasks in the foresight task group, the current task can be scheduled, and if the current task conflicts with the tasks in the foresight task group, the current task is chosen; and (6) outputting a foresight result of the current task.