Improved Discrete Interval-Valued Stress-Strength Interference Model Based on Extended Universal Generating Function

In practical engineering,sometimes the probability density functions( PDFs) of stress and strength can not be exactly determined,or only limited experiment data are available. In these cases,the traditional stress-strength interference( SSI) model based on classical probabilistic approach can not be used to evaluate reliabilities of components. To solve this issue, the traditional universal generating function( UGF) is introduced and then it is extended to represent the discrete interval-valued random variable.Based on the extended UGF,an improved discrete interval-valued SSI model is proposed, which has higher calculation precision compared with the existing methods. Finally,an illustrative case is given to demonstrate the validity of the proposed model.

Reliability Assessment Method Based on Interference Variable for Stress-Strength Model

Stress-strength model is a basic and important tool for reliability analysis.There are few methods to assess the confidence limit of interference reliability when the distribution parameters of stress and strength are all unknown.A new assessment method of interference reliability is proposed and the estimates of the distribution parameters are accordingly given.The lower confidence limit of interference reliability with given confidence can be obtained with the method even though the parameters are all unknown.Simulation studies and an engineering application are conducted to validate the method,which suggest that the method provides precise estimates even for sample size of approximately.

Reliability Bounds based on Universal Generating Function and Discrete Stress-strength Interference Model

A method for estimating the component reliability is proposed when the probability density functions of stress and strength can not be exactly determined. For two groups of finite experimental data about the stress and strength, an interval statistics method is introduced. The processed results are formulated as two interval-valued random variables and are graphically represented component reliability are proposed based on the by using two histograms. The lower and upper bounds of universal generating function method and are calculated by solving two discrete stress-strength interference models. The graphical calculations of the proposed reliability bounds are presented through a numerical example and the confidence of the proposed reliability bounds is discussed to demonstrate the validity of the proposed method. It is showed that the proposed reliability bounds can undoubtedly bracket the real reliability value. The proposed method extends the exciting universal generating function method and can give an interval estimation of component reliability in the case of lake of sufficient experimental data. An application example is given to illustrate the proposed method

周期性随机应力强度退化下的SSI可靠性模型研究

在随机应力作用下强度随使用时间不断退化时,给出了一个周期性随机应力-退化强度干涉可靠性模型及其点估计方法,该模型考虑了应力与强度退化的相关性,最后利用算例验证了该模型的有效性.

Stress-Strength Structural Reliability Model with a Stochastic Strength Aging Deterioration Process

A stress-strength structural reliability model was proposed with a stochastic strength aging deterioration process. In structural engineering,the deterioration of structure's strength should be the total of the deterioration owing to continual wear, fatigue,corrosion,etc.,and the abrupt deterioration as a result of randomly variable loads. The deterioration of structure's strength should be influenced by both the internal deterioration owing to direct wear and the external deterioration due to randomly variable loads.Meanwhile,the load process was given as Poisson square wave process. The reliability was derived using stress-strength interference theory. In particular,the reliability was also given when random variables followed the normal distribution.

Reliability Analysis of Systems with Common Cause Failure Based on Stress-Strength Interference Model

Many mechanical systems have the characteristics of multiple failure modes and complex failure mech- anisms. On the basis of stress-strength interference （SSI） model, this paper takes the mechanical system with common cause failure （CCF） as the research object. The relationship between the stress distribution and the strength distribution is studied, and the failures of components are independent of each other under the determin- istic stress. Then, the concept of conditional reliability is introduced to build the system reliability models under the action of one-stress and multi-stress for both series and parallel systems. Finally, the corresponding properties of the DrODosed methods are discussed to show their advantages.

复合应力作用下强度退化的应力-强度干涉模型可靠性统计分析

在考虑随机复合应力作用下强度随使用时间不断退化时,研究了应力-强度干涉模型下的可靠性统计推断问题,给出了一个随机复合应力-强度退化干涉失效模型和模型未知参数的估计方法,该模型考虑了应力与强度退化的相关性,文章的最后利用算例验证了该模型的有效性。

考虑载荷作用次数的零部件可靠性模型

研究随机载荷多次作用时零件的失效过程,建立载荷多次作用下的零件可靠性模型。从载荷作用的统计学意义出发,根据顺序统计量的性质,建立载荷多次作用时等效载荷的累积分布函数和概率密度函数。运用应力—强度干涉模型建立零件在单一失效模式下载荷多次作用时的可靠性模型。最后,运用Monte Carlo方法对可靠性模型进行仿真实验,证明模型的正确性。

载荷粗糙度对可靠性的影响

研究随机载荷粗糙度和作用次数对系统可靠性的影响,运用应力—强度干涉模型和数理统计理论,建立随机载荷多次作用下的应力—强度干涉模型。在此模型下,通过理论分析和实例计算,找到载荷粗糙度、安全裕度和失效概率三者之间的关系,并建立一种新的零部件尺寸的计算方法。

FATIGUE RELIABILITY CALCULATION MODEL FOR COMPONENT UNDER RANDOM LOADING

in reliability design of fatigue under random loading, the influence of loading se-quence must be considered. In order to avoid the uneertain hypothesis in the Miner's rule, ie. thatthe sum of damage equals one represents failure, this paper proposes the probabilistic relativeMine's rule. This paper also presents a new method for calculating reliability, ie. the syntheticmethod of Miner's rule and interference model. This model considers not only the influence ofstress concentration, dimension and surface, but also the influence of stress amplitude and se-quence.

不确定气动干扰效应影响下并列大跨度桥梁颤振导数识别方法

将处于自然风中一前一后并列布置的大跨度桥梁相互之间可能存在的不确定相互气动干扰处理成随机气动干扰,并归入到紊流风随机激励中,采用基于模态参数识别的随机子空间识别方法,开发了桥梁断面颤振导数识别的专用程序,并以具有理论解的Theodorsen平板为例,通过系统响应数值仿真和颤振导数识别,验证了该方法的可靠性。针对实际大跨度桥梁,设计了并列节段模型试验悬挂系统,开展了紊流风和随机气动干扰效应下的并列大跨度桥梁节段模型风洞试验,将迎风、背风侧桥梁断面的颤振导数结果与均匀流、紊流风中单个桥梁断面颤振导数值进行了对比。结果表明:背风侧桥梁对迎风侧桥梁的颤振导数影响很小,而迎风侧桥梁对背风侧桥梁的颤振导数有较大影响;该研究方法为存在这种随机气动干扰的并列大跨度桥梁颤振导数识别提供了一个较为合理的途径。