Reliability Model for Complex Mechanical Component Design

Taking into account the uncertainty in material property and component quality, a complex mechanical component such as a gear should be treated as a series system instead of a component when evaluating its reliability, since there exist many sites of equal likelihood to fail. Besides, conventional system reliability model is not applicable to such a system because of the statistical dependence among the failures of the every element (damage site). The present paper presents a model to estimate complex mechanical component reliability by incorporating order statistic of element strength into load-strength interference analysis, which can deal with multiple failure mechanisms, reflect statistical dependence among element failure events and that among different failure modes.

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A Unified Reliability Modeling Approach for Mechanical System and Complex Component

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.308-310.1416 ◽

2011 ◽

Vol 308-310 ◽

pp. 1416-1419

Author(s):

Li Yang Xie ◽

Shao Ze Yan

Keyword(s):

Mechanical System ◽

Failure Modes ◽

Reliability Estimation ◽

Statistical Dependence ◽

Reliability Modeling ◽

Damage Site ◽

Complex Component ◽

Element Failure ◽

Failure Dependence ◽

The Individual

With the scenario of reliability estimation, a geometrically complex mechanical/structural component with multiple damage sites should be treated as a system, since there are many links (damage sites) of similar failure probabilities on any of such a component and the failures of the individual damage sites are not perfectly dependent of each other. Conventional system reliability model is not applicable to such a system because of the statistical dependence among the element (damage site) failures. To estimate the reliability of a mechanical system (or a complex component) in which element (damage site) failure dependence plays an important role, a model capable of reflecting the effect of element failure dependence is necessary. The present paper develops models which can deal with multiple damage sites and multiple failure mechanisms, reflect the dependence among element failure events and that among different failure modes. Such models are applicable to both typical mechanical systems and various components.

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Study on the Stability of the Coal Seam Floor above a Confined Aquifer Using the Structural System Reliability Method

Geofluids ◽

10.1155/2018/9580271 ◽

2018 ◽

Vol 2018 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Haifeng Lu ◽

Xiuyu Liang ◽

Nan Shan ◽

You-Kuan Zhang

Keyword(s):

Coal Seam ◽

System Reliability ◽

Failure Modes ◽

Water Inrush ◽

Series System ◽

Mechanical Parameters ◽

Structural System ◽

Key Strata ◽

Structural System Reliability ◽

The Stability

A quantitative method of structural system reliability was proposed to study the influence of random rock mechanical parameters and loads on the stability of the coal seam floor above confined aquifers. To obtain the reliability probability of the floor, two modes of water-resistant floor failure were suggested as follows: (1) mining completely removed the water-resistant key strata of the floor. In this case, the failure modes were of three main types: mining failure, confined water intrusion, and combined mining failure and intrusion. (2) Failure modes included shear and tensile failures when the thickness of the key strata was greater than 0. On the basis of the elastic thin plate theory, the performance function that calculates the reliability probability of all modes could be obtained. The failure modes were regarded as the series system. The Monte Carlo method was employed to calculate the reliability probability of each failure mode and series system. The results showed that the random rock mechanical parameters and loads of the key strata significantly influence the antiwater inrush capacity of the floor. In addition, the water inrush coefficient and reliability probability can be simultaneously used as the evaluation indexes of water inrush risk. Both these indexes could improve the assessment of the reliability of the floor.

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Reduction of System Reliability Model Uncertainty by Considering Dependent Components With Stochastic Process Loading

Volume 1A: 36th Computers and Information in Engineering Conference ◽

10.1115/detc2016-59260 ◽

2016 ◽

Cited By ~ 1

Author(s):

Yao Cheng ◽

Xiaoping Du

Keyword(s):

Model Uncertainty ◽

System Reliability ◽

Epistemic Uncertainty ◽

Shared Environment ◽

Reliability Model ◽

Design Component ◽

Operation Conditions ◽

Component Design ◽

Wide Range ◽

Stochastic Load

When component dependence is ignored, a system reliability model may have large model (epistemic) uncertainty with wide reliability bounds. This makes decision making difficult during the system design. Component dependence exists due to the shared environment and operation conditions. It is difficult for system designers to model component dependence because they may not have access to component design details if the components are designed and manufactured by outside suppliers. This research intends to reduce the system reliability model uncertainty with a new way for system designers to consider the component dependence implicitly and automatically without knowing component design details. The proposed method is applicable for a wide range of applications where the time-dependent system stochastic load is shared by components of the system. Simulation is used to obtain the extreme value of the system load for a given period of time, and optimization is employed to estimate the system reliability interval. As a result, the epistemic uncertainty in system reliability can be reduced.

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Study on the System Reliability of Steel-Concrete Composite Beam Cable-stayed Bridge

The Open Civil Engineering Journal ◽

10.2174/1874149501609010194 ◽

2016 ◽

Vol 10 (1) ◽

pp. 418-432 ◽

Cited By ~ 1

Author(s):

Buyu Jia ◽

Xiaolin Yu ◽

Quansheng Yan ◽

Zhen Yang

Keyword(s):

Mechanical Behavior ◽

System Reliability ◽

Composite Beam ◽

Degrees Of Freedom ◽

Failure Modes ◽

Limit State ◽

Element Model ◽

Differential Method ◽

Component Reliability ◽

Cable Stayed Bridge

Steel-concrete composite beam cable-stayed bridge is a complicated system consisting of a composite beam, tower, and stayed cables. And the composite beam is composed of a steel beam, bridge deck and connectors, which has a different mechanical behavior from the general beam structure. In a word, the steel-concrete composite beam cable-stayed bridge is characterized by specific mechanical behavior and has many influencing factors. Thus, its safety analysis often cannot be easily implemented. This paper aims to study the component reliability of the steel-concrete composite beam based on the stochastic finite element method (SFEM) and the recognition of main failure modes in the system reliability of the cable-stayed bridge. For the component reliability of the steel-concrete composite beam, a nonlinear element model with 10 degrees of freedom (DOF) is adopted, which can consider the particular longitudinal slip effect between the steel and concrete. And the direct differential method (DDM) is used to deduce the response gradient of the element model. Meanwhile, the tower and the composite beam are considered as beam-column members to establish their limit state functions in the form of interaction equations. For the recognition of main failure modes in the system reliability, this paper proposes the concept of uniformity of the reliability index and the refinement strategy to improve theβ-unzipping method, which can identify the main failure modes or neglect the unnecessary non-main failure modes. Finally, a certain steel-concrete composite beam cable-stayed bridge is used to verify the effectiveness of the proposed method.

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Mechanical Component’s Dimension Design With Required Reliability by the Monte Carlo Method

Volume 14: Safety Engineering, Risk, and Reliability Analysis ◽

10.1115/imece2020-23050 ◽

2020 ◽

Author(s):

Xiaobin Le

Keyword(s):

Monte Carlo ◽

Monte Carlo Method ◽

Failure Mode ◽

Failure Modes ◽

Limit State ◽

Design Parameters ◽

Mechanical Component ◽

Component Design ◽

The Monte Carlo Method ◽

State Functions

Abstract Since the main design parameters in a mechanical component design have some uncertainties and should be treated as random variables, the reliability of a component is a better measurement of the safe status of a component. A component will not be reliable unless it is designed with specified reliability. Therefore, the mechanical component design should be a dimension design with the required reliability. The fundamental concept of the Monte Carlo method is to plug-in randomly generated numerical values into the governing equation of a design problem to get a trial result. The Monte Carlo method has become so powerful numerical simulation approach in almost every field such as optimization, numerical integration, and reliability calculation. But for reliability engineering, most of the literature shows how to use the Monte Carlo method to calculate the reliability of a component. This paper will propose the modified Monte Carlo method to determine a component dimension with required reliability. This paper first discusses and establishes typical limit state functions of a component under static loads. These limit state functions cover two failure modes including the failure mode due to strength and the failure mode due to excessive deformation. Then, the procedure and the flowchart of the modified Monte Carlo method will be explained in detail. The provided procedure and the flowchart are easy to be followed for compiling a MATLAB program to conduct a dimension design with required reliability. Two examples will show how to implement the proposed new method for conducting a dimension design with required reliability.

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Mechanical Component Reliability Calculation through Multi-Plane Combination Method

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.423-426.1636 ◽

2013 ◽

Vol 423-426 ◽

pp. 1636-1639

Author(s):

Hai Tao Lu ◽

Yu Ge Dong

Keyword(s):

System Reliability ◽

Combination Method ◽

Component Reliability ◽

Performance Function ◽

Reliability Calculation ◽

Mechanical Component ◽

First Order Second Moment ◽

Estimate System ◽

Second Moment Method ◽

Probable Failure

For the performance function with high nonlinearity around the most probable failure region, stress-strength interference model and advanced first-order second-moment method (AFOSM) can cause huge errors in the computation results. The multi-plane combination method is presented to calculate reliability of the mechanical component, in which the component reliability calculation is first transformed into a relatively simple system reliability problem, and then the equivalent calculation method is applied to estimate system reliability. The example application shows the accuracy and efficiency of the multi-plane combination method.

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Computational Structural Reliability Analysis of a Turbine Blade

Volume 3A: General ◽

10.1115/93-gt-237 ◽

1993 ◽

Cited By ~ 5

Author(s):

H. R. Millwater ◽

Y.-T. Wu

Keyword(s):

Reliability Analysis ◽

Turbine Blade ◽

System Reliability ◽

Structural Reliability ◽

Failure Modes ◽

Component Reliability ◽

Importance Sampling Method ◽

Creep Stress ◽

Analysis Methodology ◽

Computational Implementation

A system reliability methodology has recently been developed to determine accurately and efficiently the reliability of structures with multiple failure modes. This paper explores the computational implementation and application of the methodology through the structural system reliability calculation of a turbine blade subject to randomness in material properties. Failure due to creep, stress overload, and vibration is considered. The methodology consists of a probabilistic system reliability analysis methodology integrated with finite element methods. The failure paths and failure modes are organized using a fault tree. An efficient method for assessing the reliability of a single failure mode, i.e., component reliability, is implemented as well as an efficient adaptive importance sampling method to assess the system reliability. A probabilistic structural analysis program, NESSUS, is used for the calculations.

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Time-Dependent Series System Reliability Analysis Method and Application to Gear Transmission Systems

International Journal of Reliability Quality and Safety Engineering ◽

10.1142/s0218539317500140 ◽

2017 ◽

Vol 24 (03) ◽

pp. 1750014 ◽

Cited By ~ 1

Author(s):

Liyang Xie ◽

Enjun Bai ◽

Wenxue Qian ◽

Ningxiang Wu

Keyword(s):

Reliability Analysis ◽

System Reliability ◽

Gear Transmission ◽

Gear Train ◽

Time Dependent ◽

Series System ◽

Reliability Model ◽

Analysis Method ◽

Gear Transmission System ◽

Dependent Series

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.

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