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Reliability and variance-based sensitivity analysis of arch dams during construction and reservoir impoundment

M. Houshmand KHANEGHAHI, M. ALEMBAGHERI, N. SOLTANI

《结构与土木工程前沿（英文）》 2019年第13卷第3期页码 526-541 doi: 10.1007/s11709-018-0495-1

摘要： The static performance of arch dams during construction and reservoir impoundment is assessed taking into account the effects of uncertainties presented in the model properties as well as the loading conditions. Dez arch dam is chosen as the case study; it is modeled along with its rock foundation using the finite element method considering the stage construction. Since previous studies concentrated on simplified models and approaches, comprehensive study of the arch dam model along with efficient and state-of-the-art uncertainty methods are incorporated in this investigation. The reliability method is performed to assess the safety level and the sensitivity analyses for identifying critical input factors and their interaction effects on the response of the dam. Global sensitivity analysis based on improved Latin hypercube sampling is employed in this study to indicate the influence of each random variable and their interaction on variance of the responses. Four levels of model advancement are considered for the dam-foundation system: 1) Monolithic dam without any joint founded on the homogeneous rock foundation, 2) monolithic dam founded on the inhomogeneous foundation including soft rock layers, 3) jointed dam including the peripheral and contraction joints founded on the homogeneous foundation, and 4) jointed dam founded on the inhomogeneous foundation. For each model, proper performance indices are defined through limit-state functions. In this manner, the effects of input parameters in each performance level of the dam are investigated. The outcome of this study is defining the importance of input factors in each stage and model based on the variance of the dam response. Moreover, the results of sampling are computed in order to assess the safety level of the dam in miscellaneous loading and modeling conditions.

关键词： concrete arch dams reliability randomness improved Latin hypercube sampling variance-based sensitivity analysis exceedance probability Sobol′ index

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Choosing configurations of transmission line tower grounding by back flashover probability value

Dmitry KUKLIN

《能源前沿（英文）》 2016年第10卷第2期页码 213-226 doi: 10.1007/s11708-016-0398-6

摘要： There is a considerable number of works devoted to electrical characteristics of grounding. These characteristics are important in general. However, in application to grounding of transmission line towers they are not enough to determine what grounding construction is preferable in some particular case, because these characteristics are calculated or measured apart from the grounded object, and only limited number of current (or voltage) source waveforms is used. This paper indicates reasons in favor of the fact that to choose the optimum design of grounding, the calculation model should include the tower as it is. The probability of back flashover, which provides both qualitative and quantitative estimate of the grounding structure efficiency, can be taken as the criterion for the grounding design. The insulation flashover probability is calculated on the basis of engineering method, which evaluates breakdown strength of insulation for nonstandard waveshapes, and probability data on lightning currents. Different approaches are examined for identifying the back flashover probability, as not only amplitudes but also other parameters can be taken into account. Finite-difference time-domain method is used for calculations of transients. It is found that lightning current waveform can greatly influence calculated back flashover probability value.

关键词： grounding transmission line tower back flashover probability FDTD method

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Analytical method of capsizing probability in the time domain for ships in the random beam seas

LIU Liqin, TANG Yougang, LI Hongxia

《结构与土木工程前沿（英文）》 2007年第1卷第3期页码 361-366 doi: 10.1007/s11709-007-0048-5

摘要： The methods for constructing safe basins of ships and predicting their survival probability in random waves were studied. The nonlinear differential equation of the rolling motion of ships in random beam seas was established considering nonlinear damping, nonlinear restoring moment, and random waves. The random rolling differential equation was solved in the time domain by applying the harmonic acceleration method and by synthetically considering the instantaneous state of ships and the narrowband wave energy spectrum. The numerical simulation of random capsizing course was brought forward, the safe basins were constructed for safe navigation, and the survival probabilities of ships were calculated. As an example, the safe basins on the rolling initial value plane were constructed for a 30.27-meter-long fishing vessel according to different initial conditions and random wave parameters. The survival probabilities of the fishing vessel under different significant wave heights were predicted. Thus, the survival probabilities of ships in random seas can be predicted quantitatively by the proposed method.

关键词： different survival probability different significant nonlinear differential narrowband

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Transmission probability method based on triangle meshes for solving the unstructured geometry neutron

WU Hongchun, LIU Pingping, ZHOU Yongqiang, CAO Liangzhi

《能源前沿（英文）》 2007年第1卷第2期页码 158-166 doi: 10.1007/s11708-007-0020-z

摘要： The fuel assembly or core with unstructured geometry is frequently used in the advanced reactor. To calculate the fuel assembly, the transmission probability method (TPM) is widely used. However, the rectangular or hexagonal meshes are mainly used in the TPM codes for the normal core structure. The triangle meshes are most useful for expressing the complicated unstructured geometry. Even though the finite element method and Monte-Carlo method are well suited for solving the unstructured geometry problem, they are very time-consuming. Therefore, a TPM code based on the triangle meshes is developed here. This code was applied to the hybrid fuel geometry, and compared with the results of the MCNP code and other codes. The results of the comparison were consistent with each other. The TPM with triangle meshes can thus be applied to the two-dimensional arbitrary fuel assembly.

关键词： unstructured geometry assembly transmission probability TPM rectangular

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Evaluating effect of chloride attack and concrete cover on the probability of corrosion

Sanjeev Kumar VERMA, Sudhir Singh BHADAURIA, Saleem AKHTAR

《结构与土木工程前沿（英文）》 2013年第7卷第4期页码 379-390 doi: 10.1007/s11709-013-0223-9

摘要： Corrosion of reinforced concrete (RC) structures is one of the significant causes of deterioration of reinforced concrete (RC) structures. Chlorination is a major process governing the initiation and advancement of the injurious corrosion of steel bars. Now, several researches on the chlorination of concrete structures have been ongoing around the world. Present article reviews several recently performed chlorination studies, and from results of a field survey evaluates the effect of chloride content on the probability of corrosion and the influence of concrete compressive strength on the chloride content and penetration, also evaluates the effect of concrete cover over the chloride content of the RC structures at rebar depth and on the probability of corrosion.

关键词： concrete chloride reinforcement corrosion deterioration cover

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火灾引起的建筑物坍塌概率估算

孙金华,孙占辉,陆守香,范维澄

《中国工程科学》 2003年第5卷第11期页码 51-55

摘要：

为了研究不同防灭火安全措施下火灾引起的建筑结构整体坍塌的概率，对典型建筑物的火灾荷载进行了统计分析。利用建筑物火灾的规律及概率与统计理论，给出了典型建筑物的火灾荷载及火灾持续时间的概率分布函数。分析了由火灾引起建筑物坍塌的影响因素，并根据火灾统计结果，得到了写字楼在极端情况下由火灾引起的楼房坍塌概率与其耐火极限时间的关系，导出了一般建筑由于火灾引起的坍塌概率的简单估算方法。

关键词：建筑物火灾火灾荷载坍塌概率

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Nonlinear analysis and reliability of metallic truss structures

Karim BENYAHI, Youcef BOUAFIA, Salma BARBOURA, Mohand Said KACHI

《结构与土木工程前沿（英文）》 2018年第12卷第4期页码 577-593 doi: 10.1007/s11709-017-0458-y

摘要： The present study goes into the search for the safety domain of civil engineering structures. The objective is to show how a reliability-evaluation brought by a mechanical sizing can be obtained. For that purpose, it is necessary to have a mechanical model and a reliability model representing correctly the behavior of this type of structure. It is a question on one hand, to propose a formulation for the nonlinear calculation (mechanical nonlinearity) of the spatial structures in trusses, and on the other hand, to propose or to adapt a formulation and a modeling of the reliability. The principle of Hasofer-Lind can be applied, in first approach, for the reliability index estimation, scenarios and the probability of failure. The made check concerned metallic in truss structures. Finally, some structures are calculated using the method adapted by Hasofer-Lind to validate the probability approach of the reliability analysis.

关键词： modeling nonlinearity mechanical truss probability reliability response surface probability of failure

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Probability strength design of steam turbine blade and sensitivity analysis with respect to random parameters

DUAN Wei

《能源前沿（英文）》 2008年第2卷第1期页码 107-115 doi: 10.1007/s11708-008-0018-1

摘要： Many stochastic parameters have an effect on the reliability of a steam turbine blade during practical operation. To improve the reliability of blade design, it is necessary to take these stochastic parameters into account. An equal cross-section blade is investigated and a finite element model is built parametrically. Geometrical parameters, material parameters and load parameters of the blade are considered as input random variables while the maximum deflection and maximum equivalent stress are output random variables. Analysis file of the blade is compiled by deterministic finite element method and applied to be loop file to create sample points. A quadratic polynomial with cross terms is chosen to regress these samples by step-forward regression method and employed as a surrogate of numerical solver to drastically reduce the number of solvers call. Then, Monte Carlo method is used to obtain the statistical characteristics and cumulative distribution function of the maximum deflection and maximum equivalent stress of the blade. Probability sensitivity analysis, which combines the slope of the gradient and the width of the scatter range of the random input variables, is applied to evaluate how much the output parameters are influenced by the random input parameters. The scatter plots of structural responses with respect to the random input variables are illustrated to analyze how to change the input random variables to improve the reliability of the blade. The results show that combination of the finite element method, the response surface method and Monte Carlo method is an ideal way for the reliability analysis and probability strength design of the blade.

关键词： Probability sensitivity sensitivity analysis number cross-section statistical

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几率波与量子效应的扭率问题

欧阳首承,李智兰,袁东升

《中国工程科学》 2005年第7卷第6期页码 1-6

摘要：

按曲率空间的扭率，对含有三阶非线性变量导数的Schrödinger变形等价程进行了数值分析，发现几率波的几率性原来是扭率的疏密流在特定条件下的准规则流，并为势场强度和粒子体元密度的相互作用与量子扭率效应项综合作用的结果；纯量子效应作用为非规则流。

关键词：扭率几率量子效应非线性不稳定曲率空间

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基于适用概率匹配与多维情境驱动的设计知识推送技术 None

Shu-you ZHANG, Ye GU, Xiao-jian LIU, Jian-rong TAN

《信息与电子工程前沿（英文）》 2018年第19卷第2期页码 235-245 doi: 10.1631/FITEE.1700763

摘要：为了提高产品智能设计过程中设计知识的使用效率和质量，有必要向设计人员主动推送设计知识。知识推送主要包括知识匹配和匹配结果的合理推送两个方面。针对现有知识匹配通常缺乏智能性和匹配结果推送缺少个性化的问题，提出基于适用概率匹配和多维情境驱动的设计知识推送技术。构建包括设计知识表示向量、设计案例特征向量和映射布尔矩阵等的训练样本集，通过贝叶斯理论计算设计知识适用与不适用于设计内容的概率，即二者之间的匹配度，得到推送知识集。构建等级化设计内容模型对推送知识集进行过滤，通过设计知识、设计上下文、设计内容和设计人员等多维情境驱动，实现个性化的设计知识推送。在数控机床智能设计平台中的知识推送应用，证明了该技术的可行性和正确性。

关键词：产品设计；知识推送；适用概率匹配；多维情境；个性化

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基于火灾动力学和概率统计理论耦合的建筑火灾直接损失预估

褚冠全,孙金华

《中国工程科学》 2004年第6卷第8期页码 64-68

摘要：

以火灾成长概率和火灾发生后的过火面积为评价指标，探讨对建筑火灾过火面积的预估方法。依据火灾动力学和火灾发展过程中不同阶段的特点，将火灾由初期发展蔓延到整个防火分区的过程划分为4个阶段，采用概率论和事件树的分析方法，得到了每个阶段的火灾成长概率。根据不同阶段火灾的特点，求得了各阶段火灾的临界时间，并以此为基础对火灾发生后建筑物平均过火面积进行了预估。

关键词：建筑火灾火灾风险评估事件树概率过火面积

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Reliability design method for steam turbine blades

SHI Jinyuan

《能源前沿（英文）》 2008年第2卷第4期页码 363-368 doi: 10.1007/s11708-008-0073-7

摘要： Based on theories of probability and statistics, and taking static stresses, dynamic stresses, endurance strength, safety ratios, vibration frequencies and exciting force frequencies of blades as random variables, a reliability design method for steam turbine blades is presented. The purport and calculation method for blade reliability are expounded. The distribution parameters of random variables are determined after analysis and numerical calculation of test data. The fatigue strength and the vibration design reliability of turbine blades are determined with the aid of a probabilistic design method and by interference models for stress distribution and strength distribution. Some blade reliability design calculation formulas for a dynamic stress design method, a safety ratio design method for fatigue strength, and a vibration reliability design method for the first and second types of tuned blades and a packet of blades on a disk connected closely, are given together with some practical examples. With these methods, the design reliability of steam turbine blades can be guaranteed in the design stage. This research may provide some scientific basis for reliability design of steam turbine blades.

关键词： design reliability force probability purport reliability design

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High-order moment methods for LRFD including random variables with unknown probability distributions

Zhao-Hui LU, Yan-Gang ZHAO, Zhi-Wu YU

《结构与土木工程前沿（英文）》 2013年第7卷第3期页码 288-295 doi: 10.1007/s11709-013-0210-1

摘要： The reliability-based load and resistance factors design (LRFD) has been widely used in the structural design codes. In almost all of the current reliability methods for the determination of the load and resistance factors, the basic random variables are assumed to have known probability distributions. However, in reality, the probability distributions of some of the basic random variables are often unknown due to the lack of statistical data. In this paper, the high-order moment methods for LRFD including random variables with unknown probability distributions are proposed. From the investigation of the present paper, it can be concluded that: 1) The load and resistance factors can be determined even when the probability distributions of the basic random variables are unknown; 2) The present method is convenient and more effective in estimating the load and resistance factors in practical engineering since it needs neither the iterative computation of derivatives nor any design points; 3) In the applicable range of the high-order moment method, although the load and resistance factors obtained by the proposed method may be different from those obtained by first order reliability method (FORM), the target mean resistances obtained by both methods are essentially the same.

关键词： high-order moment methods applicable range load and resistance factors target mean resistance

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毫米波遥控弹道修正弹拦截机动反舰导弹命中概率的仿真研究

胡荣林,李兴国

《中国工程科学》 2007年第9卷第10期页码 65-70

摘要：

提出了修正拦截流的概念，建立了舰载毫米波遥控指令弹道修正弹（MMW-RCTCM）拦截机动反舰导弹空袭流的防空射击模型。研究了单发MMW-RCTCM对单一机动反舰导弹的命中概率、修正拦截流对单一机动反舰导弹的命中概率以及修正拦截流对机动反舰导弹空袭流的命中概率。根据当前的技术发展状况，分析了攻防双方的技术参数，并据此对各种典型攻防模式下的命中概率进行了仿真计算。计算结果表明，与无控弹丸相比，MMW-RCTCM对机动反舰导弹的拦截效率成倍提高，且能够有效防御超音速反舰导弹的高强度攻击。

关键词：遥控指令弹道修正弹毫米波修正拦截流反舰导弹命中概率

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Probability distributions of arsenic in soil from brownfield sites in Beijing (China): statistical characterization

Marina ACCORNERO,Lin JIANG,Eugenio NAPOLI,Marco CREMONINI,Giovanni FERRO,Federica BELLORO,Maosheng ZHONG

《环境科学与工程前沿（英文）》 2015年第9卷第3期页码 465-474 doi: 10.1007/s11783-014-0678-5

摘要： A probabilistic analysis was performed on soil arsenic concentration data from 4 brownfield sites at Beijing (Chaoyang and Haidian Districts), involved in environmental assessment studies. The available data sets were processed to provide a statistical characterization of the background populations and differentiate “anomalous data” from the natural range of variation of arsenic concentrations in soil. The site-specific background distributions and the existing wide-scale background values defined for the Beijing area were compared, discussing related implications for the definition of metal contamination soil screening levels (SSLs) in site assessment studies. The statistical analysis of As data sets discriminated site-specific background populations, encompassing 88% to 94% of the sample data, from outliers values, associated with either subsoil natural enrichments or possible anthropogenic releases. Upper Baseline Concentration ( ) limits (+ 2 level), including most of the site-specific metal background variability, were derived based on the statistical characterization of the background populations. Sites in the Chaoyang South District area had values in the range 10.4–12.6 mg·kg . These ranges provide meaningful SSL values to be adopted for As in local site assessment studies. Using the wide-scale background value for the Beijing area would have erroneously classified most of the areas in the subject sites as potentially contaminated.

关键词： upper baseline concentration site assessment arsenic probability plot