Reliability Analysis of Wedge Slopes

The material parameters and geometric parameters of wedge slopes have high variability, and there are several failure modes for a wedge slope. It is necessary to carry out system reliability analysis for wedge slopes. We consider a wedge slope as a series system which is composed of four failure modes, and we consider each failure mode as a parallel sub-system with three components. Then, the reliability analysis is carried out by using the product of conditional marginal method and bound method of system reliability analysis. A new method for the linearization of nonlinear performance function is proposed for computing the coefficient of correlation between each failure modes in the parallel sub-system. Through the reliability analysis of a wedge slope, it is illustrated that a wedge slope can be considered as a series-parallel system, and the new linearization method can simulate the failure domain accurately. The failure modes computed from the reliability analysis and the deterministic method is different. Reliability analysis method is suitable for the design and management of wedge slopes.     

Research on Index of Reliability for Bearing Capacity of Rock - Socketed Single Pile in Chongqing

Based on the data from in-situ 102 rock-socketed test piles in Chongqing in recent 10 years and utilizing the limit state equation of the dimensionless random variables,the reliability analysis of the bearing capacity of rock-socketed single pile is made and the scope of the target reliability of rock-socketed piles in Chongqing is calculated with both JC method and Monte-Carlo method respectively.Furthermore,the target index of reliability is suggested.Finally,the concept of reliability coefficient(to replace the load partial factor and the resistance partial factor) is given and the bearing capacity of the single pile is determined by utilizing optimization method.Besides,the practical limit state design equation using reliability coefficient is put forward for its advantage of incarnating the simple and practical principle and being easy mastered and understood by the designers.     

Plastic upper bound theory reliability analysis of coal gangue hills

We established the plasticity limit analysis reliability limit state equation and the reliability calculating formula for gangue hills using the JC method. This work was based on the plasticity mechanics limit analysis upper bound theory and traditional slice methods. A reliability index of gangue hill stability was derived using this equation. It was found that the safety coefficient of gangue hills derived by the limit state equation risks failure if the variability of cohesion and internal friction angle are not considered. When the variability of the strength parameters rises, the reliability theory more consistently projects practicality than the limit state equation for gangue hill stability assessment.     

Plastic slip stability analysis of gangue granular media

This paper studies the landslide mechanism by the analysis of accumulation form, topography and geomorphology, self structure and natural river system of Weijiagou coal gangue hill. The limit state function is established based on plasticity mechanics limit analysis upper bound theorem and Bishop slices method, combining reliability theory. The safety coefficient and reliability index of Weijiagou coal gangue slope is calculated. The plasticity limit analysis upper bound theorem can consider the interior stress strain relation of soil, so the formula derivation process is stricter. It is the consideration of the variability of gangue parameters that making the evaluation result more reasonable.     

An ALgorithm of the Second Kind Fuzzy Reliability

Based on L.A.Zadeh's idea of fuzzy probability operation in his language probability which space is fuzzy probability,the concrete algorithm of the second kind fuzzy reliability of engineering structure/system is researched.The calculating equation of the fuzzy probabiliy of the second kind fuzzy reliability is given out by using the extension principle for fuzzy sets.The fuzzy set decompose theorem,which satesfies the closed probability operation,is given out and proved.The method calculating fuzzy reliability of that structure/system is studied,where the resistance and load effect of the structure/system have probability.The analysis indicates that the calculation of the second kind fuzzy reliability for a structure/system can be transformed into a series of solving optimum programming.The result of the example indicates the rationality of above algorithm.     

Reliability Analysis of Ultimate Bearing Capacity of Concrete Filled Tube High Piers

To deal with the contradiction between accuracy and time consuming, a model of reliability analysis of CFT was proposed based on the response surface and nonlinear finite element method, And Initial geometric imperfection was induced by consistent mode imperfection method.The reliability index and sensitivity coefficients of CFT high piers were invested by the proposed model.The effects of slenderness, eccentricity and diameter thickness ratio on reliability index of concrete filled tube high piers were studied by parameter analysis method.Meanwhile, the influence of geometric nonlinearity was also analyzed and the reliability of CFT high pier could be affected by factors mentioned above.Based on the analysis, several suggestions for improving the reliability of CFT high piers were proposed.     

Parameter uncertainty analysis for probability distribution of bulk power systerm reliability

Component reliability parameters are of uncertainty and are affected by the component type, operation time, and weather conditions. So do the reliability indices of bulk power systems. The calculation of its probability distributions and its alteration law affected by parameters uncertainty are researched to provide practical engineering reference with exploring the impact of the parameter uncertainty on reliability assessment. The point estimate method is firstly proposed based on the two-loop Monte-Carlo simulation, and then the improved Monte-Carlo simulation is presented to enhance the calculation efficiency further. Moreover, their theories, merits and faults are explained in detail. It can be seen from the evaluation results for the RBTS power systems that the accuracy of the three methods are similar but the improved Monte-Carlo simulation has the highest efficiency, followed by the point estimate method. The IEEE-RTS 79 power system is evaluated by using the improved Monte-Carlo simulation, and the results verify its validity.     

Analysis of salt rock underground deposit failure probability in operation period based on response surface method

For the safety of salt rock underground deposit, uncertainties and their influences are considered, and failure probability during operation period is analyzed. Based on finite element model, equation of limit state surface is transformed into explicit equation by response surface method. Combined with Monte Carlo method, computation efficiency is improved. The deposit could be simulated as a series-parallel system. The element with highest failure probability is determined first, then failure mode and system reliability are computed. Taking Jintan underground gas deposit as an example, the analysis indicates that as storage pressure increases, failure probability of middle part of deposit decreases firstly, then increases gradually when storage pressure accumulates to a certain extent. The failure probabilities of upper part and underside of deposit increase as storage pressure increases. During operation period, controlled failure mode is shear failure of upper part and underside of deposit under high storage pressure. In conclusion, the storage pressure during operation period should be controlled strictly.     

Nonlinear Finite Element Analysis of Reinforced Concrete Transferring Joints with Inclined Columns

A nonlinear finite element analysis using ANSYS is applied to the vertical mechanical behaviors of three specimens of reinforced concrete transferring joints with inchned columns, which are used in high - rise buildings. A comparison is made between the analytical achievements and the test results, including the mechanical behaviors, load - transferring path and the failure modes, and a good agreement is obtained. The reliability of the software ANSYS in the nonlinear analysis of such reinforced concrete structures is verified and developed.     

Synthetic Assessment of Power Transformer Condition Based on Matter-element Theory

Condition assessment on power transformer is an important approach to improve reliability of transformer and provide proper decision-making for condition-based maintenance. For long, static assessment method used in the past has already not adapted to the development of modem electricity transmission and distribution technology. So based on the deficiency of fuzzy synthetic assessment method, matter-element synthetic assessment method is introduced. The method can evaluate transformer condition not only in quality but also in quantity. Because each index weight can be given fairly and fast through improved analytic hierarchy process, which need not carry on consistency chec accuracy of assessment can be improved. Examples analysis has proved that assessment method of power transformer condition based on matter-element theory is rational and effective.     

Reliability Analysis of Reinforced Concrete Beams Strengthened with CFRP Sheets

The uniaxial load tests were conducted to investigate the material behavior of CFRP sheets. The results show that the probability distribution of CFRP tensile strength can be described by the three-parameter Weibull distribution. The design formulae for determining flexural capacity of reinforced concrete strengthened with CFRP sheet are proposed. The Monte Carlo procedure was applied to simulate the flexural capacity of reinforced concrete strengthened with CFRP sheet. By using the JC method, the reliability index was calculated based on the statistics of flexural capacity and load effect. After the analysis of the effect of the partial factor of CFRP sheet on the reliability index, the results reveal that the reliability index of all design points are the most close to target reliability index overall when the partial factor of CFRP sheet is 1.25,and in this condition the reliability index of three flexural failure modes achieve the target reliability index respectively. Therefore, the partial factor is suggested to be 1.25, which meets the requirement of reliability design.     

Progressive Collapse Analysis of RC Frame Using Vertical Nonlinear Dynamic Analysis

Progressive Collapse Analysis (PCA) is the base of quantitative assessment of progressive collapse-resisting capacity and progressive collapse-resisting design. There has been heightened interest among researchers of civil engineering in PCA. PCA of planar RC frame is carried on by vertical nonlinear dynamic analysis based on alternate load path method. According to responses of damage structure, progressive collapse-resisting capacity of remaining structure is evaluated. Two cases of removal of elements are analyzed, removal of columns at different stories on the same axes one by one and removal of all columns on the same axes at the same time. According to analysis of the effect of failure duration on structural progressive collapse, it is showed that the response of remaining structure is highly sensitive to failure duration of elements. The results indicate that vertical nonlinear dynamic analysis is an efficient method of progressive collapse-resisting design and progressive collapse-resisting capacity analysis.     

Application of GO methodology in reliability analysis of supply chain

To study the accurate calculation and fault mode diagnosis of supply chain, a new method-GO methodology is applied in reliability analysis of supply chain. Through analyzing every important factor leading to success of supply chain system and taking three-tier supply chain as the object, GO model of reliability analysis of supply chain is developed. The model can not only calculate reliability of supply chain system in detail, but also diagnose its failure mode and calculate its importance, which provides the way for improving and optimizing supply chain system. The example is presented to prove the method’s feasibility and validity.     

Analysis on the Quasi Monte-Carlo Method and its Application in the Slope Reliability

The critical reliability slip surface with minimum value of reliability index is difficult to be obtained by the Monte-Carlo method. The simplified Bishop method was adopted to calculate the factor of safety for given circular slip surface thereby defining the performance function in reliability analysis. Six variance values of random variables were designed and four sample ranges were assumed. A quasi-Monte Carlo method was defined with fow samples. One hundred and thirty-two potential slip surfaces were randomly generated. The reliability indexes regarding those slip surfaces were calculated by Monte-Carlo method and quasi-Monte Carlo method, respectively. The comparative results show that in the case of one random variable, the reliability index from Monte Carlo method is found to be linear with that from quasi-Monte Carlo method. In the similar conditions, the wider the sample range, the smaller the tangent value of line, and Vice versa. In addition, the bigger the sample number, the bigger the tangent value of line. The Quasi-Monte Carlo method is approved to be practicable for the determination of critical reliability slip surface for homogeneous slope.     

Analysis and synthesis of time-dependent reliability for integrated steering mechanisms

The steering performance of vehicle is directly affected by the kinematic accuracy of steering trapezoid mechanisms. Considering uncertainties that exist in steering mechanisms, the theory of kinematic time-dependent reliability is adopted to study the analysis and synthesis of the integrated mechanisms. A new method for high accuracy actual steering mechanisms design with the uncertainties is presented. Probabilistic model of kinematic error with dimension random variable is established, and analytical models of up-crossing rate and down-crossing rate for solving the time-dependent reliability of steering mechanisms are derived. A determination model and reliability model for mechanisms synthesis are built, and a numerical example are given to verify the effectively and robustness of time-dependent reliability synthesis method.     

Neutral point grounding mode decision algorithm for medium voltage distribution network

Different neutral point grounding modes have their own advantages and disadvantages,and the decision making of neutral point grounding mode for medium voltage distribution network needs to consider the power supply reliability,overvoltage and insulation coordination,relay protection,communication system interference,electrical safety and grounding device,which relate to the electric network reliability,security and economy movement aspect.A neutral point grounding mode decision method which comprehensively considers the reliability,safety and economy factors is proposed.The method combines the reliability evaluation,safety protection,construction and operation cost with the realization of distribution network for different neutral point grounding modes,and makes the optimal decision of neutral point grounding mode by calculating life cycle cost of different neutral grounding modes and coordinating the reliability index.An example is used to verify the feasibility and effectiveness of the decision method.     

Load Curtailment Strategy by Near in Bulk Power Systems Reliability Evaluation

In order to improve the existing method of electric network reliability evaluation, the basic concepts, for example, the flow through the failure events, the sent ends and received ends of these failure events, the load curtailment region of the received ends and the degree of the load curtailment, are defined. With these concepts, the connotation of LCSN (Load Curtail Strategy by Near) is enriched and algorithms of the load curtailment region are conducted. The theory foundation for further exploring LCSN is created. The results show that the algorithm can quickly and effectively make reliability assessment of power systems.     

Diagnosis approach based on failure mode importance of causality diagram

Causality diagram methodology is a probabilistic reasoning, which can be applied to fault analysis. However, it lacks analysis on the importance of failure mode. The importance of failure mode is introduced to develop causality diagram methodology, which is successfully applied in fault analysis of gas explosion in colliery. The study shows that causality diagram based on importance of failure mode is an effective qualitative and quantitative method to analyse faulty, evaluate system safety and provide feasible countermeasures to prevent accidents.     

Finite Element Reliability Analysis of the Stability of a Slope

The whole reliability index of a slope is derived through using the strength reduction method in the finite element analysis, which can make use of the former finite element program and can be used to both linear and nonlinear finite element analysis. The affection of the evaluation of derivative and the selection of reliability analysis methods is discussed, which shows that it is very important to select the type of limit state function of the slope stability. A new iterafive formula, which can consider the correlation of fundamental parameters, is proposed for FORM, and the convergence is very well.     

Effect-cause analysis for reliability evaluation of complex distribution system

The traditional distribution system reliability assessment model is mostly based on the failure mode and effects analysis,which is proceeding from a known cause to a necessarily related effect,i.e.enumerating fault events and then analyzing their effects