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84 results about "Reliability theory" patented technology

Reliability theory describes the probability of a system completing its expected function during an interval of time. It is the basis of reliability engineering, which is an area of study focused on optimizing the reliability, or probability of successful functioning, of systems, such as airplanes, linear accelerators, and any other product. It developed apart from the mainstream of probability and statistics. It was originally a tool to help nineteenth century maritime insurance and life insurance companies compute profitable rates to charge their customers. Even today, the terms "failure rate" and "hazard rate" are often used interchangeably. The failure of mechanical devices such as ships, trains, and cars, is similar in many ways to the life or death of biological organisms. Statistical models appropriate for any of these topics are generically called "time-to-event" models. Death or failure is called an "event", and the goal is to project or forecast the rate of events for a given population or the probability of an event for an individual.

Composite material laminate non-probability reliability double-level optimization method

The invention discloses a composite material laminate non-probability reliability double-level optimization method. The method comprises: firstly, according to load-carrying characteristics of a composite material laminate, considering nondeterminacy effect of an intensity parameter of the composite material under condition of limited samples, based on a non-probability reliability theory, establishing a composite material laminate non-probability reliability evaluation model; in optimization of a first ply, using a simulated annealing method to optimize the composite material laminate, with thickness as a variable, and intensity reliability and rigid reliability as constraint; in optimization of a second ply, considering process constraint using stacking sequence as a variable, and optimizing with maximum intensity as target, through establishing a stacking scheme library which satisfies process requirements, using a genetic algorithm to optimize the stacking sequence of the laminate. The method ensures the composite material laminate has relatively high reliability and relatively low weight under nondeterminacy conditions, and meanwhile the method satisfies engineering actual technology level, and gives consideration to safety and economical efficiency.
Owner:BEIHANG UNIV

Well wall instability risk quantitative evaluation method based on reliability theory

ActiveCN109858147AOvercoming the inability to account for the effects of parameter uncertaintyAccurate decision basisResourcesSpecial data processing applicationsState modelInstability
The invention discloses a well wall instability risk quantitative evaluation method based on a reliability theory. The well wall instability risk quantitative evaluation method comprises the followingsteps: S1, according to basic data of a drilled stratum andS2, according to the input parameter uncertainty statistical table established in the step S1; S3, establishing a well wall collapse and well wall fracture instability limit state model; S4, according to the well wall instability limit state model in the step S3, respectively solving a well wall collapse pressure value and a well wall rupture pressure value under the limitation of a basic random variable; S5, giving a wellbore pressure mean value and a variable coefficient, and adopting Monte Carlo simulation to generate a wellbore pressure value under the given mean value and the variable coefficient; and S6, counting calculation results to obtain a quantitative evaluation result of the risk of borehole wall collapse and fractureinstability. The method has the beneficial effects that the well wall instability risk under the influence of parameter uncertainty can be quantitatively evaluated, and more accurate and effective decision basis can be provided for drilling technicians and constructors.
Owner:SOUTHWEST PETROLEUM UNIV

Mechanism movement accuracy reliability analysis method based on fuzzy out-crossing model

The invention discloses a mechanism movement accuracy reliability analysis method based on a fuzzy out-crossing model. The mechanism movement accuracy reliability analysis method includes the steps of (1) building a generalized fuzzy random stress-strength interference model (please see the specifications for the model) according to task characteristics, (2) determining a subordinating degree function mu(x) of movement errors, (3) determining the reliability R(tau0) at the moment tau0, and calculating the complete up-crossing rate v+(tau) and the complete down-crossing rate v-(tau), and (4) calculating the fuzzy time-variation reliability R in the mechanism task executing process. By means of the mechanism movement accuracy reliability analysis method, influences of the errors and tolerances of mechanism movement on the mechanism accuracy reliability are considered, a time-variation reliability calculation method-PHI2 and a state fuzzy analysis method are combined, and the mechanism fuzzy time-variation reliability problem can be effectively solved; the aim that in a classical mechanism movement reliability theory, when the time-variation performance and the fuzzy performance are considered at the same time, the failure probability is calculated by properly changing the out-crossing model is achieved.
Owner:BEIHANG UNIV

Spare part demand predicting method based on state monitoring and reliability of equipment part

The invention relates to a spare part demand predicting method based on state monitoring and reliability of an equipment part and belongs to the technical field of mechanical manufacturing. The method includes the following steps that firstly, according to a maintenance record list of equipment, the reliability theory is used for processing burn-out life data of parts in the maintenance record with the reliability theory, and the probability cumulative distribution function of the burn-out life of the parts is obtained; the probability cumulative distribution function of the burn-out life of the parts, the total working time of the equipment, the history record of the real spare part demand quantity, the year-to-year value record and the month-to-month value record of the spare part demand quantity, the experience predicting values of planners and the like are compared with errors, used for comparison predicting, of the real spare part demand quantity so as to obtain the predicting value of the demand quantity of equipment spare parts. According to the method, the prediction result of the method has the practical bases, the inactive stock of an enterprise can be effectively reduced, resource waste is reduced, cost is reduced and the method has good adaptability to different spare parts which are prone to damage.
Owner:TSINGHUA UNIV

Power station high-temperature pipe system maintenance method based on non-probability reliability theory

The invention relates to a power station high-temperature pipe system maintenance method based on the non-probability reliability theory. The power station high-temperature pipe system maintenance method includes the steps of conducting finite element calculation on the strength of a power station high-temperature pipe system, determining key detection parts of the power station high-temperature pipe system, determining creep damage parameters with the non-probability reliability theory, building a creep damage probability model by determining the creep damage parameters, calculating structural failures according to the creep damage probability model, building a maintenance method model based on reliability analysis according to detected data, materials of the power station high-temperature pipe system and structure test results, and determining the optimum maintenance time of the high-temperature pipe system according to the maintenance method model and the actual engineering maintenance cost. The non-probability reliability maintenance method is achieved through the power station high-temperature pipe system, the structural probability reliability is efficiently and accurately determined, maintenance plans can be accurately determined, the maintenance method can solve similar problems of high-temperature pipes in other fields, and therefore the application range is wide.
Owner:ELECTRIC POWER RES INST OF GUANGDONG POWER GRID +1

Method for evaluating and assessing state of relay protection equipment

InactiveCN103823972AState assessment is accurateEvaluation Rules OptimizationSpecial data processing applicationsPower gridMaintenance management
The invention relates to a method for evaluating and assessing the state of relay protection equipment. The method includes building a relay protection equipment state assessment model according to classical reliability theories and historical maintenance data and combining the relay protection equipment state assessment model with related reference systems to give reasonable assumption for state information missing items of the protection equipment; evaluating and assessing running environments of relay protection devices and secondary circuits, fault-free time of operation boxes, insulation conditions of the circuits, anti-interference measures conditions, blocking conditions, device and circuit inspection conditions and the like according to the state assessment model and acquiring evaluating and assessing results; integrally evaluating the states of the relay protection devices and the states of the secondary circuits by the aid of the relay protection equipment state assessment model according to the evaluating and assessing results of the relay protection devices and the secondary circuits. The method has the advantages that the relay protection equipment maintenance management level and the equipment running reliability can be improved, the maintenance operation time and power grid maintenance shutdown time can be shortened, and the maintenance efficiency can be enhanced.
Owner:STATE GRID ANHUI ELECTRIC POWER +1

Optimization method of micro-electronic encapsulation thermal expansion coefficient reliability matching

ActiveCN104408325AImprove reliabilityReduced thermomechanical failure rateSpecial data processing applicationsFailure rateThree level
The invention discloses an optimization method of micro-electronic encapsulation thermal expansion coefficient reliability matching which introduces artificial intelligence theory, reliability theory and robust design theory into thermal design of micro-electronic encapsulation; micro-electronic encapsulation thermal expansion coefficient reliability matching and robust optimization based on the fusion of self-adaptive Gaussian neural network, three-level robust experimental design and non-linear finite element, use the thermal fatigue strain for encapsulating main thermal failure parts as the objective function in order to optimally match the thermal expansion coefficient of micro-electronic encapsulation device material under the effect of thermal cycle load, the optimally matched thermal expansion coefficient set is obtained in the design range, thereby reducing the maximum equivalent thermal fatigue strain inside the main thermal failure parts as much as possible. The method can both reduce the thermal mechanical failure rate of micro-electronic encapsulation under the effect of thermal cycle load, and ensure that the thermal expansion coefficient of material enables the encapsulation to maintain in high reliability under the disturbance of the thermal cycle load.
Owner:广州飞虹微电子有限公司

Method for valuing construction period wind load of ultra-large cooling tower

The invention relates to a method for valuing the construction period wind load of an ultra-large cooling tower. The method is characterized by comprising the following steps of: (1) establishing a structural design reference period, a time interval relation among different time intervals in the structural design reference period, a construction period, and a reliability relation among different time intervals of the construction period respectively by taking a reliability theory as a theoretical foundation with a time interval analysis method of structural reliability to form a time interval relation expression and a reliability relation expression; (2) resolving the relation expressions in the step (1) to obtain the proportion of a construction period wind load standard value to a design reference period wind load standard value; and (3) resolving a construction period wind load factor according to the proportion in the step (2). The valuing standard problem of the construction period design wind load of a tower is researched on the premise of the same reliability in the construction period of a cooling tower and the design reference period by taking the basic theory of a structural reliability design as a foundation, the determination of the design wind load in the construction period of the cooling tower is facilitated, and the method plays a role in deciding the stability and manufacturing cost of the cooling tower in the construction period.
Owner:CHINA ENERGY ENG GRP GUANGDONG ELECTRIC POWER DESIGN INST CO LTD

Intelligent connected vehicle corner danger warning system and method

The invention provides an intelligent connected vehicle corner danger warning method. The method comprises a step of establishing a vehicle aerodynamic model and a three-degree-of-freedom vehicle torque balance equation, further deriving a centrifugal force expression when a vehicle passes a corner, and then jointly calculating a threshold speed of vehicle rollover, a step of extracting state parameters related to the vehicle rollover, establishing a limit state equation of the vehicle rollover, optimizing the solution process of the limit state equation by a first-order quadratic matrix method in the reliability theory and obtaining a performance function, a step of establishing a vehicle rollover state prediction model through a checkpoint method, obtaining a vehicle rollover state indexand thus calculating the probability of vehicle driving safety, and a step of determining whether to carry out vehicle hazard warning or not according to the probability of vehicle driving safety. According to the method, the danger of a forward corner can be predicted in advance, the risk indicators of vehicle cornering risks caused by various vehicles, roads and environments are comprehensivelyanalyzed, quantitative prediction indicators are provided in real time, and the stability and safety of the vehicle in driving in a corner are ensured.
Owner:WUHAN UNIV OF TECH

Grey confidence interval-based reliability analysis method for structure stress-intensity interference model set

The invention discloses a grey confidence interval-based reliability analysis method for a structure stress-intensity interference model set. For the problem that a conventional probability thought cannot provide effective estimation of a structure stress and intensity mean value due to finite sample information of structure stress and intensity parameters and difficult determination of statistic characteristics, the method comprises the steps of first defining grey distance measure of an inter-finite-sample topological relation and a distance relation, and performing grey generation of the grey distance measure to obtain an estimated value of the structure stress and intensity mean value; defining and solving a grey density index to obtain a confidence interval of the stress and intensity mean value under the condition of meeting the requirement of a certain grey confidence degree; and finally, introducing a structure reliability theory in a non-probability set theory framework to derive a two-dimensional reliability measure index for structure stress-intensity interference models, thereby realizing reasonable mapping of structure reliability analysis and confidence degree evaluation from samples, wherein the two-dimensional reliability measure index is of confidence degree significance.
Owner:BEIHANG UNIV

BP neural-network algorithm-based status evaluation method of relay protection equipment

PendingCN107918690APrecise assessment of statusImprove maintenance management levelComputer aided designNeural learning methodsDependabilitySecondary circuit
The invention discloses a BP neural-network algorithm-based status evaluation method of relay protection equipment. The method includes: constructing neural units of a status evaluation model on the basis of classical reliability theory and historical maintenance data, carrying our training and learning on the basis of a large number of samples, and forming a status evaluation model algorithm through a BP algorithm; adopting the status evaluation model to estimate situations of an equipment running environment of the relay protection equipment and the like to obtain estimation results on the relay protection device; adopting the status evaluation model to estimate device circuit inspection situations of a running environment of a secondary circuit and the like to obtain estimation resultson the secondary circuit; and obtaining an overhaul range according to the estimation results of the relay protection device and the secondary circuit. By applying the embodiment provided by the invention, quantitative analysis, monitoring and early warning are carried out on the relay protection equipment through the perfect estimation and evaluation method of the relay protection device and thesecondary circuit and combination of the data model of the relay protection equipment.
Owner:STATE GRID ANHUI ELECTRIC POWER +1

Mobile node vulnerability discrimination method by using reliability vector projection decomposition

InactiveCN102394886AImprove accuracyAvoid the influence of uncertain factorsData switching networksComputation complexityDecomposition
The invention provides a mobile node vulnerability discrimination method by using reliability vector projection decomposition. The method comprises the following steps: (1) determining reliability vector space according to multi-source vulnerability information; (2) calculating a reliability value of each vulnerability scan tool scan result; (3) calculating each reliability vector and a cosine value of each reference axis included angle in the reliability vector space; (4) calculating a projection decomposition value of each reference axis in each reliability vector to the reliability vector space; (5) accumulating obtained projection values on reference axes to obtain a sum, and carrying out normalization; (6) determining reliability of each vulnerability, and according to a reliability size, determining vulnerability existed in the mobile node. Compared with the prior art, the method in the invention has the following substantial advantages: based on a reliability theory, influence of an uncertainty factor in a vulnerability detection process is effectively avoided; by taking a plurality of detection tools as information source, accuracy of vulnerability discrimination is raised; by employing a calculation method of reliability vector projection decomposition, each decomposed vector is converted into a monoatomic set, and calculation complexity is decreased.
Owner:李千目

Marine diesel engine waste gas desulfurization high-reliability spray liquid transporting and measurement and control device

The invention discloses a high-reliability spray liquid transporting and measurement and control device used in marine diesel engine waste gas desulfurization and belongs to the fields of air pollution control and ship waste gas emission control. A desulfurization system is composed of a washing kettle, a neutralizing treatment device, a water sump, an alkaline solution pot, a solid-liquid separator, a saturated liquid pot, a solid material discharge cabin, transporting and measurement and control devices for treatment mixed liquids and the like, and the like other units. Marine diesel engine waste gas enters the washing kettle and is fully mixed and contacted with a sprayed desulfurizing alkaline water solution, and then is subjected to neutralization treatment to dissolve and absorb the sulfur oxides in the waste gas to form sulfates, wherein other particles in the waste gas are also adhered to and mixed with the water solution. The treated waste gas finally is subjected to separation, treatment and recycling. On the basis of reliability theories and methods, series-parallel connection combined design of the parts of the spray liquid transporting and measurement and control device in the marine diesel engine waste gas desulfurization system is carried out. The device is reduced in fault probability, greatly increases the reliability of the waste gas desulfurization system and can satisfy the demand of marine diesel engine waste gas desulfurization.
Owner:CHINA UNIV OF MINING & TECH (BEIJING) +1

Accelerated test and prediction method for service life of laser optical component

The invention discloses an accelerated test and prediction method for the service life of a laser optical component so that a problem that the service life of the large-caliber optical component underrandom flux illumination can not be obtained in the prior art can be solved. The method comprises: fitting is carried out by using a transmitting number or time as an independent variable and a corresponding service life probability as a dependent variable to obtain a service life probability function of a large-caliber optical component under a specific laser parameter; and the irradiation fluxof illuminating laser with a set parameter is changed to obtain a service life probability curve of the large-caliber optical component under different irradiation fluxes and data fitting is carried out on the function to obtain a service life flux function under the specific service life probability. According to the invention, accelerated testing of the service life of the laser optical component is realized; the test time is shortened. With the test result, the service life of the large-caliber optical component under the specific flux can be obtained; and on the basis of the classical reliability theory, the reliability analysis and prediction are carried out on the laser large-caliber optical component in the laser system. The accelerated test and prediction method is suitable for theservice life testing field of the large-caliber optical component.
Owner:LASER FUSION RES CENT CHINA ACAD OF ENG PHYSICS

Pollution-flashover-caused trip probability calculation method of overhead lines in sand and dust environment

The invention provides a pollution-flashover-caused trip probability calculation method of overhead lines in a sand and dust environment. The method comprises: based on sandstorm weather information, building a deposit model of sand and dust particles on an overhead line insulator surface and calculates equivalent salt deposit density and equivalent dust deposit density on the insulator surface; by taking into account the feature that a dust-to-salt ratio in a sandstorm-prone area is high, building a transmission line pollution-flashover-caused trip probability model which comprehensively considers salt density and dust density on the insulator surface; combining relative studies on insulator probability statistics and line reliability theories, and assessing a overhead line pollution-flashover-caused trip risk in the sand and dust environment; and then, on the basis of relative humidity influence on insulator flashover leakage current, building a line pollution-flashover-caused trip model in wet weather after sandstorms, and assessing influence of relative humidity changes on the overhead line pollution-flashover-caused trip probability. According to the invention, possible overhead line trip faults are prevented, and a safe and stable operational level of a grid in sand and dust environment is improved.
Owner:HARBIN INST OF TECH +4
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