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Escalators are now more and more widely used around the world. As escalator accidents occur from time to time, it is very important to analyze the structure and reliability of escalators. This paper studies the structure and reliability analysis methods of typical escalators. By applying parametric analysis methods, the efficiency and accuracy of escalator structure analysis are greatly improved. Because the failure of each structural member of the escalator truss system is dependent, this paper applies the dependent failure reliability modeling method and analyzes the reliability of the escalator truss system. The results show that the reliability analysis method of the truss system after considering the dependent failure is more reasonable. The above research work has certain reference significance for the design and analysis of escalators.

A new method based on Dynamic Bayesian Network (DBN) is proposed to assess the car engine reliability because of the limitation that the existing reliability analysis methods can only be used in static system reliability assessment. Firstly, define the failure mode and effect analysis table (FMEA) and the failure rates of the main components of the car engine and construct Bayesian network (BN) model. Secondly, combine the original BN model with time information and assess the reliability of the systems by using the advantages of BN in terms of the multi-state variables and uncertainly relations. The method is able not only to compute the reliability indices of car engine but also to carry out the fault detection easily to recognize the weakness of the system. This research is meaningful for reliability design and prediction of car engine.

Fatigue life corresponding to specific failure probability is much more significant than mean life, since fatigue fracture is a highly uncertain phenomenon. For a complex structural component with several damage sites, the contributions of the every damage site are stochastic in nature. Moreover, the damages or fatigue lives of the individual vulnerable sites are neither completely correlated nor perfectly independent of each other. The present paper develops a probabilistic fatigue life evaluation approach to predict the probabilistic fatigue life of complex mechanical or structural components containing multiple damage sites. By correctly dealing with the failure dependence of the every damage sites and characterizing the fatigue life random variable of a multi-site-damage (MSD) structure or component using the extreme statistic of the fatigue lives of the individual damage sites, probabilistic fatigue life of MSD structural component is reasonably predicted.

Aluminum alloy structural hangers are widely used in subway vehicle. The advantage of aluminum alloy is light weight and corrosion resistance. For different application fields, the structures of aluminum alloy components are very different. They are typically lighter for the same strength and provide better heat conduction. As we know that do FEA (finite element analysis) is necessary before and after the alloy structures have been made. In this paper, a detail analysis was done with FEM (finite element method), and the stress distribution of alloy structural hanger was obtained. Also the FEA results show that the maximum stress is less than the yield stress and the stress concentration of the slot is relatively high.

Hexagon socket head bolts are widely used in many engineering fields as fasteners and are common and important parts for engineering, but for some hexagon socket head bolts it is still tedious to build the 3D models and assess their reliability. It is important for a hexagon socket head bolt to do reliability assessment, especially for some hexagon socket head bolt that under complex load conditions. In order to improve the reliability and stabilization, a hexagon socket head bolt reliability assessment method is introduced and an example is given, and the example shows that do reliability assessment is useful and effective.

Bolt joints are widely used in all kinds of machines. The advantage of them is cheap and convenience. For different application fields, the structures of bolts are very different. They are typically lighter for the same strength and provide better heat conduction. As we know that do FEA (finite element analysis) is necessary before and after the bolts have been made. In this paper, a detail analysis was done with FEM (finite element method), and the stress distribution of bolt joint was obtained. Also the FEA results show that the maximum stress is less than the yield stress and the stress concentration of the thread is relatively high.

A gear transmission system such as a gear train is a series system in sense of reliability evaluation, while it is different from a traditional series system such as a chain. Therefore, the conventional series system reliability model is not appropriate for gear transmission system. Based on the time-dependent configuration and the time-dependent loading path of a gear train, system specific reliability modeling technique is presented, by which a gear train is taken as a time-dependent series system, consisting of different components (gear teeth) in different time intervals. To illustrate the application of the reliability analysis method, several time-dependent series system reliability models are developed for different types of gear trains, the reliability estimation results are compared with those obtained by traditional series system reliability model.

A component with multiple weak sites is widely used in practical engineering and the existence of multiple weak sites can significantly decrease the component reliability. On the other hand, only a few components bear static loading and most components bear dynamic loading. In this paper, a reliability model of isomorphic component with multiple weak sites is built based on an order statistics model and the influences of strength decentrality and loading decentrality on isomorphic component with multiple weak sites are discussed. Furthermore the influence of loading times is studied in detail. The results show that unlike a component with only one weak site, not only does the failure of a component with multiple weak sites have a relationship with the safety margin, but there also exist relationships with the number of weak sites, the loading roughness, and loading times. The work in this paper is of some guiding significance in reliability design and assessment of a component with multiple weak sites under complex loading.

The propulsion system, comprising four hydraulic cylinders, is an important power supply assembly in tunnel boring machine, and fatigue is the major failure modes to concern for the hydraulic cylinders. To evaluate the reliability of the propulsion system, i.e. the hydraulic cylinder assembly, a reliability model capable of completely reflecting the effects of stochastic load environment and material property degradation is required. For such a purpose, this paper presents a method to describe the uncertainty of random load history at two levels, i.e. the macro-level characterizing the variation in the whole load history intensity over individual load historys, and the micro-level describing the fluctuation of load peaks inside one load history. Starting from random load history expression, a multi-layer, multi-variate dynamic (time-dependent) reliability model is developed through system-level load-strength interference analysis. By the multi-layer configuration, the model hierarchically expresses the role of the uncertainty in the intensity of load history, the randomness in load peaks within a specific load history, the uncertainty of load action number, and the uncertainty of component strength. By utilizing discrete time variable (i.e. load action number), product property degrading with load cycles can be exactly incorporated in failure criterion. The model, taking on either the form of multi-layer integral or the form of multilayer summation, can synthetically reflect the effects of the uncertainty of random load environment including statistical risk over operation period, the dependence among component failures, the uncertainty of load action number in a specified time interval, the uncertainty of material strength and its deteriorating path. Besides, this model incorporates both fatigue criterion and ultimate tensile failure criterion uniformally, and is applicable to both mechanical component and series system. Since no assumption on the independence between component failures, the reliability model can naturally reflect the effect of failure dependence, and the (conditional) probability distributions of the individual variates involved in the models can be easily determined.

Reliability concepts, models and methods have been developed in different fields and applied to a variety of engineering cases from component, system to process. Besides the great amount of successive applications, challenges are everywhere including the understanding to the role of random load environment, especially its uncertainty in reliability estimation and experiment, the mechanism to produce the bathtub type failure rate curve, the modeling of component/system reliability under complex load environment and with multiple failure modes, and so on. Focused in the present paper are general load-strength interaction analysis method and related failure rate modeling approach, statistical dependence among component failures, characterization and expression of the statistical property of random load environment, and the incorporation of the factors describing time, space and failure mechanism to develop comprehensive reliability models capable of reflecting stochastic load environment and material degradation behavior.

Electronic systems are widely used in many engineer and civil fields, such as aviation, energy, communication, military and automatic etc. Usually the more the components that a system includes the poorer the system reliability is. But the failures of components are usually dependent. In this paper, a reliability model of dependent failure of electronic system is built and the influences of strength decentrality and load decentrality is discussed. The results of two examples prove the validity and superiority of the method in the application of the reliability modeling and assessment of system and the model that considered failure dependent is more reasonable than those conventional reliability models.

Acoustic emission(AE) of material is a common phenomenon; In fact, it has relation with the material states. In this paper, the acoustic emission test method is used and the characteristics of different phases of aluminum alloy cracks are analyzed. Artificial neural network(ANN) is used to recognize the pattern of AE of fatigue cracks. Practical test shows the above method could test the cracks that common method could not test. The result of pattern recognition is rather accurate, and is of practical engineering significance.

The plate specimen tensile test is a common material mechanical property test in practical engineering, but the gripping deviation of plate specimen will bring tensile test result an error. In this paper, a finite element model of aluminum alloy notched specimen is built and a static finite element analysis is carried on, the influence of the plate specimen tensile test gripping position deviation rightness of experiment to the test result is studied. The result expresses that the gripping deviation of plate specimen will bring tensile test result an error bigger. It is necessary to raise the accuracy request of the gripping position of plate specimen tensile test.