Calculation of Maintenance Cost Based on the Proportional Life Setback Model

Maintenance cost is one of the most difficult parts to calculate in variant-cost, for it s decided by the reliability of components. As an important factor of reliability, life is largely affected by maintenance. The proportional life prolonged model based on maintenance is presented firsdy. Based on this model, the function of Mainenance--Life--Cost is deduced. Which provides a new method for power plant to calculate maintenance cost more accurately.     

Multi-dimensional Life Cycle Economic Cost Assessment for Super Tall Building Structures

Super-tall building structures have the features of complex structural systems, diverse structural functions, long service life, massive investment and fixed owners. The life-cycle cost of super-tall building structures mainly contains initial cost, maintenance cost, failure cost caused by hazard and demolition cost. In order to achieve the minimization of the life-cycle cost of the super-tall building structure, a multi-dimensional life cycle economic cost assessment method is proposed in this study. The proposed method considers alternative design schemes, structural components and cost items. The overall cost management and optimization will be done at the initial phase of the structural project if this method can be employed. The proposed method is applied to a super tall building to illustrate its effectiveness and applicability.     

Experiments on heat loss characteristics in a fully opened cylindrical cavity receiver

The climate has a great impact on highway bridge rubber bearings than on building rubber bearings. In order to study the change of the mechanical properties during the life of the plain chloroprene rubber bearings of highway bridge under freeze-thaw cycle condition, the plain chloroprene rubber bearings were processed 25, 50, 75, 100 times by freeze-thaw cycle in the standard freeze-thaw chamber, then the axial compression tests were carried. The changes of the performance indicators in the bearing capacity , the ultimate compressive strength, vertical stiffness, elastic modulus under different freeze-thaw cycles were analyzed comparatively. The results show that the plain chloroprene rubber bearings are more prone to brittle failure after the freeze-thaw cycle, and the failure phenomena of steel plate exposing or cracks is more serious than the phenomena of the standard specimen. With the increase of the number of freeze-thaw cycle, the ultimate bearing capacity, ultimate compressive strength and compressive elastic modulus of the plain chloroprene rubber bearings decrease. The attenuation formula and decay curve in 50 years of ultimate compressive strength and elastic modulus of compression are analyzed by least square method, the trends of change are both in line with the exponential function. The mechanical properties of plain chloroprene rubber bearings of highway bridge significantly decreased under freeze-thaw cycle condition. therefore, the temperature ranges of plain chloroprene rubber bearings of highway bridge should be strictly controlled, and some suggestions, such as increasing its minimum applicable temperature, usng the natural rubber bearings as much as possible in cold regions, have been given.     

Effect of welding on high strain and low cycle fatigue behavior of hot-rolled H-beam

Low cycle fatigue(LCF)properties of H-beam as hot-rolled and welded are studied, and the cyclic stress-strain relationship and cyclic response characterization are determined. Based on the Coffin-Manson formula, the strain-fatigue life relationship is obtained. Finally, the cyclic toughness, which is the product of strain range at LCF life of 100 cycles and the stress amplitude, are calculated. The test results show that the cyclic toughness as welded H-beam is 62% of that as hot-rolled. Hot-rolled materials exhibit cyclic stability, and welded materials show cyclic softening followed by fracture. The scanning electron microscope(SEM) micrograph of fracture surfaces reveals that the fatigue crack initiates from the coarse grain area of welding joint, and the fine dimple is observed in the fracture surface, which indicates the welding joint remains a good ductility.     

浇筑式钢桥面铺装层推挤变形病害机理分析

以贵州省北盘江大桥钢桥面铺装层推挤变形病害为研究背景,采用凝胶渗透色谱法(GPC)和傅里叶变换红外光谱法(FTIR),从沥青分子尺度分析钢桥面铺装产生推挤变形的原因。分析结果表明:沥青老化并不是造成钢桥面铺装层推挤变形的主要原因;从现场调查可知,第2层粘层粘结能力的降低是造成钢桥面铺装层推挤变形病害的次要原因;通过级配分析发现,造成钢桥面铺装层推挤变形的主要原因是浇筑式沥青混合料(GA)级配偏细以及GA中集料颗粒的棱角性较差所致。     

Calculation of environmental cost in the structural optimization of super tall buildings

Chinese mainland has seen a rapid construction speed of super tall buildings in recent years. Due to its huge quantity material and energy assumption, the super tall buildings exert great impact on the environment. An innovative new life cycle model is proposed for assess and optimize the life cycle environmental cost of super tall buildings. The new life cycle model has two features. Firstly the space distribution of the building materials is considered besides the time dimension, and secondly the single life cycle concept is extended to multiple life cycles to investigate the carbon footprint from the perspective of more than one life cycle. A benchmark super tall building is established to illustrate the application of the proposed new life cycle model. According to the case study results, a remarkable difference would be made in carbon emissions if the life cycle environmental cost based structural optimization method could be applied.     

Statistical Analysis on High Strain and Low Cycle Fatigue Life of Rebars

High strain and low cycle fatigue(HSLCF)life of anti-seismic behaviors of rebars was investigaoted. Reliable theoretical basis was provided for data analysis on high strain and low cycle fatigue life of anti-seismic behaviors of rebars. The low cycle fatigue life of the HRB400 anti-seismic behaviors of rebars by quenching and self tempering (QST) process was tested. Because the low cycle fatigue life data was disperse, some kinds of mathematical statistics methods, such as Weibull double parameters probability function, normal distribution, lognormal distribution function and t-distribution function were used to statistically analyze the low cycle fatigue life data. The results indicate that in all of the probability functions, the low cycle fatigue life has the highest reliability by the t-distribution function method; the low cycle fatigue life has the lowest reliability by the normal distribution method; and the low cycle fatigue life has the highest safety by Weibull maximum likelihood method.     

Routing protocol of the wireless sensor networks for bridge health monitoring

By analyzing the reason that why the existing routing protocols cannot be applied to the wireless sensor networks for bridge health monitoring, a new routing protocol is proposed. Since the locations of the collecting modules are fixed, the proposed protocol exchanges the routing information between the neighbor nodes by adjusting the exchange cycle according to reliability of the modules. For the low routing security requirement, while to increase the routing efficient, the middle nodes replying the routing requirements with variable thresholds is introduced. In order to make full use of information in route discovering procedure, the backup routes mechanism is adopted. The proposed protocol can efficiently forward data and is suitable for the bridge health monitoring.     

Study on the Failure Distribution and Reliability Variation of the Equipment in Use

This thesis analyzes the factors which lead to the failure of equipment,the type of the failures and the reliability of the equipment.The distribution functions(such as exponential distribution and Weibuill distribution) of the failures are discussed and the reliability of equipment is estimated.Meanwhile,the methods of identifying the types of failures and the degree of the reliability of equipment are described by an actual example.The Failure Distribution and reliability of ZW-17/29 Series Air Compressors in use are obtained.It provides the ways to plan the technical and maintenance management of the equipment.     

Arrangement and design of main bearing for wind turbine

The wind turbine bearing runs under complicated loading and vibration condition and its design and analysis is a developing and crossing discipline. The typical main bearing arrangements for wind turbine are compared, including the 3-point arrangement with spherical roller bearing, double-row tapered roller bearing and cylindrical roller bearing, two single-row tapered roller bearings. The various factors including the wind turbine type, loading, cost and weight are considered in the design of wind turbine drive train. The influencing factor of bearing reliability and the relationship between wind load, drive train and bearing are studied. Based on an example of bearing reliability, the influence of complicated topography on wind load and bearing life is analyzed. The commonality of the wind farms with wind turbine failure is found, i.e. the topology and the wind condition of most wind turbine sites are very unfavorable, e.g. with sleep slope, not enough distance between adjacent wind turbines. Such factors can cause abnormal wind shear and turbulence, which can bring unexpected load onto the bearing. The key factors in the analysis procedure of topography and wind resource are discussed.     

Seismic Performance and Failure Process of Long-Span Bridge With High Piers

Based on OpenSEES platform, elastic-plastic structural model of long-span bridge with high piers is established. This paper utilizes time-history analysis method to analyze seismic responses of bridge under consistent or multi-support seismic excitation. Seismic performances and failure process for bridge with high piers are studied. Analysis results show that characteristics of seismic excitation and the way of excitation input have some effect on failure sequence and the occurrence or location of plastic hinge for bridge piers. The failure mode for high piers assumes bending failure, and the failure for top of pier is frequently prior to that of pier bottom, which should be paid enough attention.     

Modeling of UML in University Student Individual Credit Evaluation MIS

Unified modeling language(UML) is an object-oriented(OO) modeling notation standard,which could be used in various developing environment and software life cycle.The authors discuss how to the use the UML to complete the use-case modeling,static modeling and dynamic modeling of the university student individual credit evaluation management information system.They believe that the UML can improve the documentation,visualization and standardization of the system and ensure a better reliability and reusability.     

Fiber Fabry-Perot Sensor and Its Application for Monitoring Bridge Strain

The strain is an important parameter that reflects the bridge health status, the fiber Fabry-Perot sensor is embedded in the concrete structure as the intelligent sensing element for the bridge strain. The strain measuring system is made up of the fiber Fabry-Perot sensor,light switch,fiber strain gauge and the comput- er; it can be used to monitor automatically the bridge strain. At present,the system has been installed in the Dafosi Bridge over the Yangtze River in Chongqing. The monitoring data show that the fiber Fabry-Perot sensor has good stability and reliability; it can be used to monitor the bridge strain for a long time.     

柱失效方程中荷载相关特性对承载力抗震设计可靠度的影响

以竖向荷载和水平地震作用组合下的钢筋混凝土柱和钢柱为对象,研究了失效方程中荷载相关特性对柱承载力抗震可靠性的影响。根据现行《混凝土结构设计规范》和《钢结构设计规范》分析了不同柱弯矩轴力相关曲线的特性。结合多个框架结构实例,对比了柱失效方程中荷载相关曲线与规范考虑情形的异同。实例分析表明:水平地震和竖向荷载组合作用下,小偏压RC柱和工字型钢柱的荷载相关曲线与规范考虑的情形较为符合,均近似为负相关的直线;水平地震和竖向荷载组合作用下,大偏压RC柱的荷载相关曲线则与规范考虑的情形有较大出入,存在明显的正相关段部分。在此基础上,考虑失效方程复杂特性,依据已有的荷载和抗力变量概率模型,采用Monte Carlo法分析了水平地震和竖向荷载组合作用下柱的可靠性。结果表明:钢柱和小偏压RC柱的承载力抗震可靠度随轴压力荷载效应比值的变化幅度较小,与规范模式计算结果较接近;大偏压RC柱的承载力抗震可靠度随轴压力荷载效应比值的变化会有较大幅度波动,与规范模式计算结果差异较大;当轴压力荷载效应比值为负时,大偏压RC柱的承载力抗震可靠度会低于规范计算值较多,现行柱可靠性设计方法会偏于不安全。     

大攻角及桥面粗糙度对扁平钢箱梁涡振性能的影响

为探究大攻角及桥面粗糙度对扁平钢箱梁涡振性能的影响,对寸滩长江大桥主梁进行了风洞试验。应用Matlab软件模拟桥面粗糙度变化范围,根据模拟结果选取对应的砂纸在试验中模拟桥面粗糙度,分析了攻角及桥面粗糙度对扁平钢箱梁涡振区间及幅值的影响。试验研究表明:在大攻角下扁平钢箱梁的涡振振幅和范围明显增大,对桥址位于山区等容易发生大风攻角的地区的桥梁应进行大攻角试验。扁平钢箱梁的涡振响应随着桥面粗糙度增大而减小。正攻角范围内,桥面粗糙度对涡振响应的影响随着攻角减小而增大。桥面粗糙度发生变化时,扭转涡振响应更加敏感,变化幅度大于竖向涡振响应变化幅度。     

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.     

Continues software reliability demonstration testing scheme with decreasing function

The required testing duration of software reliability demonstration testing (SRDT) for the continuous safety-critical software is generally too long to endure. To solve this problem, a new continuous Bayesian-based SRDT scheme (CBSDF) for the safety-critical software is proposed by using the decreasing function method with the prior information. The representative decreasing function of the continuous reliability index (such as the failure rate) is selected to construct the prior distribution density function (PDDF). Then, the estimation values of the hyper-parameters of PDDF are calculated according to the prior information (i.e. the failure data collected in reliability growth testing) to obtain the posterior distribution and the detailed form of CBSDF. By selecting two failure data-sets as the source of prior information, the proposed CBSDF is compared with two existing Bayesian-based schemes (i.e. CBS1 without prior information and CBS2 with prior information). The experimental results show that with the same given reliability index, the proposed CBSDF is more effective than CBS1 and CBS2 by significantly decreasing the required testing time of SRDT and more suitable for the safety-critical software with high reliability.     

Innovation of Construction Projects Management Based on the Five-dimension Modeling

Nowadays,the computer technology is applied more and more widely in the architecture,engineering and construction industries(AEC).This paper introduces a methodology of construction project management based on the five-dimension modeling which integrates three-dimension building models,resources and schedules by the development of virtual construction technology.The application of this method also influences several aspects of project management such as range,time,cost,resource,communication and information management.Finally,the process of 5D modeling and the management practice are presented through a real life case in Beijing which proves to be a more efficient,productive and economy project.     

The Role of Product Planning in the Productinnovation Designing System

In the product life cycle, the product planning acts as a bridge between the customer demands and the product concept definition. So, it is the key factor of the success of the following new product designing and product sell. In other words, product planning level represents the competing ability of the enterprise and its new product. The paper introduces the operation flow, relative theory , and application technology involved in product planning by quoting consumed product designing process. In this way, we illuminate the role of product planning in the product innovation designing system. At the same time, the authors establish a completed strategy of NPD including marketing research, product concept definition, marketing opportunity identification and concept transformation.     

Approach on GBOM-based Accurate Quotation for Mass Customization Products

It is the trend to move to the case-based Mass Customization Products mode to fitthe customization needs in current business situation. It provides the customers the accurate cost and quotation by fast product configuration. To achieve this, the article brings out the accurate quotation based on the GBOM methodology in the case-based mass production mode, the product configuration model and the cost accumulation methodology. Finally, the whole methodology is applied to the real business and achieved good business results.