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98 results about "Inverse analysis" patented technology

Inverse Analysis Overview. Inverse analysis characterizes the unknown stochastic parameters of a system using a model of the system and corresponding noisy data. Unknown parameters are common in simulations and physical data analysis and this technique plays an important role in quantifying a parameter’s value, uncertainty, and distribution.

Experiment-numerical analysis combined determination method for relative permeability coefficient of unsaturated soil

The invention relates to an experiment-numerical analysis combined determination method for the relative permeability coefficient of unsaturated soil. The method comprises simple experiment tests and numerical analyses, the relative permeability coefficient equation of soil under unsaturated state is obtained via simple laboratory experiments and numerical optimization fitting analyses, therefore, the relative permeability coefficient of the unsaturated soil is obtained by calculation. The method is mainly suitable for cohesive soil with a small permeability coefficient. At the same time, the invention provides a numerical analysis procedure which comprises a basic analysis module and an optimization back analysis module, wherein the basic analysis module simulates the dehydration process of test specimens under the condition of a given boundary; the optimization back analysis module takes a determined dehydration mass-time curve as basic input to confirm two parameters Pr and m describing the changes of the relative permeability coefficient of the unsaturated soil along with saturation via an orthogonal optimization method in the numerical analyses. The method is simple in experiments, convenient to operate, wide in usable ranges and good in accuracy; the determined relative permeability coefficient equation can be directly applied to soil engineering structure analyses.
Owner:SHANDONG AGRICULTURAL UNIVERSITY

Nonlinear inverse control method used for dynamic hysteresis compensation of piezoelectric actuator

ActiveCN106707760AAccurately describe dynamic hysteresis characteristicsHigh positioning accuracyAdaptive controlHysteresisLoop control
The invention discloses a nonlinear inverse control method used for dynamic hysteresis compensation of a piezoelectric actuator. Nonlinear inverse control of the piezoelectric actuator is performed based on a Prandtl-Ishlinskii model by aiming at the problem that most models cannot perform accurate inverse analysis for the modeling difficulty of a dynamic hysteresis system; a dynamic critical value related to the input frequency is established to obtain a rate-dependent play operator, and the rate-dependent play operator is combined with a density function so as to obtain a rate-dependent Prandtl-Ishlinskii model; a hysteresis main ring is measured under different input frequencies so as to determine model parameters; the inverse parameters of the model are inversely solved by solving an initial load curve so as to obtain a rate-dependent Prandtl-Ishlinskii inverse model; and the Prandtl-Ishlinskii model and the inverse model thereof are used for an open-loop control system so as to compensate the hysteresis nonlinear property of the piezoelectric actuator. The experiment proves that the rate-dependent Prandtl-Ishlinskii model can accurately describe the hysteresis nonlinearity of the piezoelectric actuator and the rate-dependent Prandtl-Ishlinskii inverse model enhances the positioning and control precision of a hysteresis nonlinear system.
Owner:NANJING UNIV OF SCI & TECH

Estimating method for stratum deformation induced by shield subway construction and influence of stratum deformation on ancient buildings

ActiveCN107489424AImplement System EvaluationGeometric CADTunnelsFeedback analysisEarth surface
The invention discloses an estimating method for stratum deformation induced by shield subway construction and the influence of stratum deformation on ancient buildings. The estimating method comprises an induction back analysis and value inversion analysis method based on actually-measured data, the calculation method, based on the stratum loss principle, of ground surface settlement induced by shield construction and an ancient building foundation deformation characteristic evaluation method based on the stiffness correction method. Through the induction back analysis and value inversion analysis method based on the actually-measured data in engineering practice, the characteristic parameters and the characteristic parameter rules of stratum displacement induced by shield subway construction are obtained; based on the stratum loss principle and the Peck formula, the ground surface settlement predicting formula of shield construction parameters is provided; and finally, the stiffness correction method principle is introduced into the formula to estimate the deformation characteristics of the ancient building foundations, so that the systematic evaluation of stratum displacement and the influence of the stratum displacement on the ancient buildings is achieved, and a feedback analysis method is provided for prediction of stratum displacement induced by shield subway construction and the control measures of the construction technique.
Owner:XIAN UNIV OF TECH

Hydration degree measurement method for cement-based materials based on nuclear magnetic resonance

The invention discloses a hydration degree measurement method for cement-based materials based on nuclear magnetic resonance, which belongs to the technical field of cement material measurement. The hydration degree measurement method disclosed by the invention adopts a nuclear magnetic resonance technique to test nuclear magnetic signals of the cement-based materials at different ages; a relation between transverse relaxation time and the nuclear magnetic signals is obtained by inverse analysis; furthermore, a ratio of nuclear magnetic semaphores of left and right peaks is taken as a nuclear magnetic signal ratio of gel pore water and capillary pore water, and then the hydration degree of the cement-based materials to be detected at the age is solved according to a Powers model. Compared with traditional methods including a muffle furnace method and the like, the hydration degree measurement method disclosed by the invention is a nondestructive testing method, can reduce operation steps of a test greatly and shorten a testing period greatly, and can be used for monitoring samples continuously so as to ensure that the errors of test results are small; meanwhile, the method disclosed by the invention does not need to calibrate nuclear magnetic resonance semaphores and sample water content and directly adopts the ratio of the nuclear magnetic semaphores of the left and right peaks, namely a microstructure factor, as a parameter to represent the hydration degree, and therefore, measurement procedures and errors are reduced.
Owner:HOHAI UNIV

Multi-means, dynamic and whole-process landslide prewarning method

The invention provides a multi-means, dynamic and whole-process landslide prewarning method. The method includes: performing macroscopic observation, engineering exploration data monitoring and displacement monitoring on landslide; performing macro damage phenomenon analysis and influence factor analysis according to a result of macro observation; building a numerical value model and performing parameter indicator determination according to a result of engineering exploration data monitoring; performing displacement back analysis and displacement tendency analysis according to a result of displacement monitoring; building a correcting numerical value model according to influence factor analysis and the built numerical value model; determining calculating parameters through parameter indicator determination and displacement back analysis; performing numerical value analog calculation analysis according to the correcting numerical value calculating model and the calculating parameters; calculating a displacement-time curve under a series of different stability safe coefficients according to numerical value analog calculation analysis; drawing a monitoring displacement-time curve according to displacement tendency analysis; comparing the above two curves to determine stability state of the landslide. By the method, landslide disaster recognition, prewarning and control level can be improved effectively.
Owner:唐晓松 +1

Early warning method for sudden gushing water danger of undersea tunnel

InactiveCN104035142AImprove rational designTimely economic comprehensive prevention and control countermeasuresGeological measurementsInstabilityHigh pressure water
The invention relates to an early warning method for a sudden gushing water danger of an undersea tunnel. The early warning method for the sudden gushing water danger of the undersea tunnel includes that step S1, using a geophysical exploration method and an advanced geological drilling method to extract rock and soil test samples, and performing indoor physical and mechanical tests and a penetration test; step S2, monitoring and measuring measured data, surrounding rock and vault sedimentation and side wall displacement in the field, and building a grey cusp catastrophe time forecasting model for the instability of a surrounding rock or surrounding rock-primary support system; step S3, obtaining surrounding rock support design parameters through a parabolic vertex numerical inverse analysis method; step S4, building a visco-elastic plastic model of the surrounding rock or surrounding rock-primary support system of the undersea tunnel under high pressure water based on an ABAQUS platform simulation software according to the step S1, step S2 and step S3 to early warn the danger. The early warning method for the sudden gushing water danger of the undersea tunnel is capable of improving the reasonable design, safe construction, comprehensive water bursting control and the like of the undersea tunnel of the soft cracked surrounding rock under high pressure water.
Owner:TONGJI UNIV

Method for solving solution of elastic foundation beams and for back analysis of value m

The invention provides a method for solving solution of elastic foundation beams and for back analysis of value m, belonging to the technical field of geotechnical engineering. The method comprises the following steps of: 1, firstly, converting a fourth order partial differential equation of the elastic foundation beam into a low order partial differential equation set, and setting iteration times and admissible errors; 1, taking a minimum error function of a displacement value sol.y obtained in the step one and an actually-measured displacement value as an objective function, wherein the minimum error function is the sum of squares of difference values; 3, optimizing the objective function in the second step by the application of MATLAB nonlinear optimization algorithm fmincon functions, when reaching the iteration times or the admissible errors set in the first step, stopping iteration, and in this case, the objective function reaching the minimum value; and 4, the parameters corresponding to the minimum value of the objective function being the optimum solution of horizontal resistance factor value m of the to-be-determined soil layer foundation soil. The method provided by the invention is simple in analysis process and easy for programming.
Owner:SOUTHEAST UNIV

Method for indoor measurement surface heat emission coefficient of concrete

The invention discloses a method for indoor measurement of the surface heat emission coefficient of concrete. According to the method, the temperature of the environment where an experiment block is located, the moisture content of a heat preservation material and other parameters can be precisely controlled, the surface heat emission coefficient of the experiment block is subjected to high-precision inverse analysis and calculation, and then the surface heat emission coefficient of the concrete covering the heat preservation material (including a water containing frozen heat preservation material) can be precisely tested. The method comprises the steps that 1, the experiment block is manufactured, and a certain number of temperature testing points are buried in the experiment block; 2, the experiment block with the heat preservation material laid is placed in a freezing and thawing test box for automatically controlling and recording the temperatures of the testing points, the temperature of an antifreezing solution and the temperature in the box, wherein the heat preservation material comprises a water containing frozen material, and reasonable temperature value is set for an experiment; 3, according to experiment data, inverse analysis is carried out to obtain the experiment block surface heat emission coefficient beta1 of the experiment block with the heat preservation material laid under the experiment condition; 4, through formula derivation and calculation, the surface heat emission coefficient betaS of the concrete under the field condition is obtained.
Owner:CHINA INST OF WATER RESOURCES & HYDROPOWER RES

Method of detecting dynamic developmental situation of overburden mining-induce fissure in radon gas earth surface

The invention provides a method of detecting the dynamic developmental situation of an overburden mining-induce fissure in a radon gas earth surface. The position of a boundary, corresponding to a working surface, of the earth surface is determined according to the geographic coordinates of the position of an underground working surface in combination with a surface-underground contrast plan of the working surface; measuring lines are arranged from the position of an open-off cut of the working surface in the direction perpendicular to the trend of the working surface within a measuring area range defined at the position of the boundary, and then measuring points are arranged on all the measuring lines; a probe cup of an emanometer is buried in soil on the earth surface at the measuring points in an inverted mode, the probe cup is taken out and placed into the emanometer for measurement four hours later, and a measurement result is stored in the emanometer after the measurement is completed; after the measurement at all the measuring points is completed, measurement data in the emanometer are uploaded to a notebook computer through a data line, and a radon gas concentration variation diagram of the measuring area is drawn. According to the abnormal characteristics of radon gas concentration variation of the measuring area, the dynamic developmental situation of the overburden mining-induce fissure is obtained through inverse analysis. The method is high in operability, low in cost, high in efficiency, and broad in practicability and popularization.
Owner:CHINA UNIV OF MINING & TECH

Back analysis identification method for parameters of dynamic re-crystallizing model

The invention discloses a back analysis identification method for parameters of a dynamic re-crystallizing model. Based on a genetic neural network cellular automatic machine, the method is characterized in that the method comprises the following steps of: 1) confirming a value range of parameters and designing and establishing a test scheme; 2) performing analog computation and establishing a learning sample library; 3) establishing a BP (Back Propagation) neural network; 4) training the BP neural network and establishing a nonlinear mapping relation; 5) randomly selecting at least one set of parameters and forecasting a flow stress; 6) comparing a precast value with a really measured value till an error meets a design demand; and 7) storing an optimum parameter value with the error meeting the design demand. Haphazardry of a dynamic re-crystallizing parameter value is overcome; the dynamic re-crystallizing parameter value is calculated by utilizing an orthogonal test, a genetic algorithm, a neural network and numerical simulation optimization; the problems of instability, strong nonlinearity, large calculating quantity and uneven learning sample during a back analysis optimizingcalculation are solved; and the accuracy and the rapidity of re-crystallizing parameter value are obviously promoted.
Owner:SHENZHEN UNIV +1

Method for inversely analyzing transparency of water body by virtue of inherent optical parameter

The invention belongs to the technical field of water color remote sensing, and relates to a method for inversely analyzing the transparency of a water body by virtue of an inherent optical parameter. The method for inversely analyzing the transparency of the water body by virtue of the inherent optical parameter comprises the following steps: (1) reading data of measured transparency and data of remote sensing reflectance; (2) calculating an absorption and scattering coefficient through the remote sensing reflectance; (3) constructing an algorithm for inversely analyzing the transparency of the water body by virtue of the inherent optical parameter; (4) calculating an error between an inverse analysis value and a measured value to estimate the accuracy of the algorithm by taking the measured transparency as a true value. Compared with the prior art, the method for inversely analyzing the transparency of the water body by virtue of the inherent optical parameter has the advantages that the inherent optical parameter of the water body can be estimated according to the remote sensing reflectance to further inversely analyze the transparency of the water body, so that the problem of time-space limits of a case-two water body color constituent inverse analysis algorithm is solved, and universal applicability is achieved.
Owner:OCEANOGRAPHIC INSTR RES INST SHANDONG ACAD OF SCI

Three-dimensional landslide motion risk probability evaluation method

The invention discloses a three-dimensional landslide motion risk probability evaluation method, and relates to the technical field of landslide motion risk prediction. According to the method, a dynamic numerical model is used for landslide motion analysis, the final accumulation depth serves as observation information, the uncertainty of input parameters of the dynamic numerical model is calibrated through a multi-observation Bayesian inverse analysis method based on MCMC simulation, and posterior distribution is obtained. Then, the posterior distribution is used as the input of the potential landslide to estimate the override probability of the maximum motion height and the maximum motion speed of the potential landslide on the three-dimensional terrain, and a probabilistic motion risk map for quantitative risk evaluation of the individual landslide is generated. According to the method, the multi-response global Kriging agent model is adopted to approximate the relationship between the input and output of the model, so that the multi-response global Kriging agent model completely replaces a dynamic numerical model to carry out Bayesian back analysis and probability motion risk assessment, and the calculation efficiency is greatly improved on the premise that the precision is not lost.
Owner:CHENGDU UNIVERSITY OF TECHNOLOGY

Identification method for prestressing loss of PC simply supported girder-bridge based on inverse analysis

The invention discloses an identification method for prestressing loss of PC simply supported girder-bridge based on inverse analysis, and belongs to technical field of in-service bridge virtual condition analysis. The identification method for prestressing loss of PC simply supported girder-bridge based on inverse analysis is precise and reliable, and can track andprecisely predict the prestressing loss of bridges in service. The identification method comprises the steps of establishing a finite element model, and adopting the prestressing loss of the PC simply supported girder-bridge as unknown parameter to be initiallyvectorized to carry out finite element analyzing and calculating; according to the result of finite element analyzing and calculating, performing back analysis calculation with a measured deflection value of a bridge body, calculating the objective function, and judging whether the objective function is convergence or not; if the objective function is convergent, outputting the result of prestressing loss of PC simply supported girder-bridge identification;if the objective function is not convergent, returning to the finite element model to carry out iterative calculation. The identification method provides calculable analysis parameters for prestressing loss identification of in0service prestressing bridge structure and damage evaluation, and has significant practical value in engineering.
Owner:LANZHOU UNIVERSITY OF TECHNOLOGY
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