A Unified Reliability Modeling Approach for Mechanical System and Complex Component

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.

Reliability Model for Complex Mechanical Component Design

2013 ◽  
Vol 365-366 ◽  
pp. 28-31
Author(s):  
Li Yang Xie ◽  
Wen Xue Qian ◽  
Ning Xiang Wu
Keyword(s):  
System Reliability ◽  
Failure Modes ◽  
Statistical Dependence ◽  
Series System ◽  
Reliability Model ◽  
Component Reliability ◽  
Damage Site ◽  
Mechanical Component ◽  
Component Design ◽  
Element Failure

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.

scholarly journals System Reliability Design Analysis of Propulsion Structures

1993 ◽  
Author(s):  
S. Mahadevan ◽  
S. Mehta ◽  
R. G. Tryon ◽  
T. A. Cruse
Keyword(s):  
Failure Probability ◽  
Rational Design ◽  
Failure Modes ◽  
Quantitative Information ◽  
Reliability Estimation ◽  
Computational Method ◽  
System Failure ◽  
Turbine Engine ◽  
Reliability Design ◽  
The Individual

The reliability of a gas turbine engine structure is affected by the uncertainties in the operating environment (speed, temperature etc.) as well as in the structural properties (material properties, geometries, boundary conditions etc.). A computational method for accurate reliability estimation under such uncertainties is described in this paper. Reliability computation for individual failure modes (burst, LCF etc.) as well as overall system failure is addressed. System failure probability is computed through the union of individual mode failures. The method also provides precise sensitivity information about the effect of each uncertain parameter on the individual failure probabilities as well as on the system failure probability. Such quantitative information helps rational design decisions as well as risk assessment and certification.

Dynamic reliability analysis of mechanical system with wear and vibration failure modes

2021 ◽  
Vol 163 ◽  
pp. 104385
Author(s):  
We Wang ◽  
Gang Shen ◽  
Yimin Zhang ◽  
Zhencai Zhu ◽  
Changyou Li ◽  
...  
Keyword(s):  
Mechanical System ◽  
Reliability Analysis ◽  
Failure Modes ◽  
Dynamic Reliability

A Time-Dependent Reliability Estimation Method Based on Gaussian Process Regression

2018 ◽  
Author(s):  
Wang Han ◽  
Xiaoling Zhang ◽  
Xiesi Huang ◽  
Haiqing Li
Keyword(s):  
Machine Learning ◽  
Mechanical System ◽  
Physical Modeling ◽  
Learning Algorithm ◽  
Estimation Method ◽  
Gaussian Process Regression ◽  
Reliability Estimation ◽  
Time Dependent ◽  
Physics Of Failure ◽  
Gear Transmission System

This paper presents a time-dependent reliability estimation method for engineering system based on machine learning and simulation method. Due to the stochastic nature of the environmental loads and internal incentive, the physics of failure for mechanical system is complex, and it is challenging to include uncertainties for the physical modeling of failure in the engineered system’s life cycle. In this paper, an efficient time-dependent reliability assessment framework for mechanical system is proposed using a machine learning algorithm considering stochastic dynamic loads in the mechanical system. Firstly, stochastic external loads of mechanical system are analyzed, and the finite element model is established. Secondly, the physics of failure mode of mechanical system at a time location is analyzed, and the distribution of time realization under each load condition is calculated. Then, the distribution of fatigue life can be obtained based on high-cycle fatigue theory. To reduce the calculation cost, a machine learning algorithm is utilized for physical modeling of failure by integrating uniform design and Gaussian process regression. The probabilistic fatigue life of gear transmission system under different load conditions can be calculated, and the time-varying reliability of mechanical system is further evaluated. Finally, numerical examples and the fatigue reliability estimation of gear transmission system is presented to demonstrate the effectiveness of the proposed method.

scholarly journals Study on Chip Reliability Modeling Based on Mutually Dependent Competing Failure of Solder Joints in Different Failure Modes

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 204695-204708
Author(s):  
Longteng Li ◽  
Bo Jing ◽  
Jiaxing Hu ◽  
Xiaoxuan Jiao ◽  
Jinxin Pan ◽  
...  
Keyword(s):  
Failure Modes ◽  
Solder Joints ◽  
Reliability Modeling ◽  
On Chip

scholarly journals A Priori Assessment of Subgrid-Scale Models and Numerical Error in Forced Convective Flow at High Prandtl Numbers

2020 ◽  
Vol 105 (2) ◽  
pp. 377-392
Author(s):  
Lorenzo Sufrà ◽  
Helfried Steiner
Keyword(s):  
A Priori ◽  
Mixing Layer ◽  
Turbulent Pipe Flow ◽  
Numerical Error ◽  
Statistical Dependence ◽  
Special Focus ◽  
Subgrid Scale ◽  
Flux Divergence ◽  
Prandtl Numbers ◽  
The Individual

AbstractAn extensive a priori analysis has been carried out on data from Direct numerical simulation of fully developed heated turbulent pipe flow at high molecular Prandtl numbers $$Pr=10$$ P r = 10 /20, testing three popular modelling candidates for subgrid-scale closure in Large-Eddy simulation (LES). Aside from assessing the models’ capabilities to describe quantitatively the unresolved turbulent fluxes, a special focus is also put on the role of the numerical error, which arises from the discretization of the filtered advective fluxes on a coarse LES grid. The present analysis extends here previous studies on subgrid-scale momentum transport in a isothermal mixing layer and channel flow carried out by Brandt (J Numer Methods Fluids 51: 635–657, 2006) and Vreman et al. (J Eng Math 29: 299–327, 1995), respectively, to the subgrid-scale transport of heat at high Prandtl numbers. The statistical dependence between the individual contributions (resolved, subgrid-scale, numerical discretization error) constituting the filtered advective flux divergence in the LES formulation is investigated as well, in terms of corresponding cross-correlations. The sensitivity of the tested sgs-models to a grid refinement is further examined performing also a posteriori LES, where the basically more sophisticated candidates turn out to be more demanding in terms of required grid resolution.

scholarly journals Assessment of the Exposure of Turkey Farmers to Antimicrobial Resistance Associated with Working Practices

2019 ◽  
Vol 6 (1) ◽  
pp. 13
Author(s):  
Giorgio Franceschini ◽  
Marta Bottino ◽  
Ilary Millet ◽  
Elisa Martello ◽  
Francesca Zaltron ◽  
...  
Keyword(s):  
Direct Contact ◽  
Failure Modes ◽  
Individual Therapy ◽  
Human Consumption ◽  
Structured Interviews ◽  
Public And Private ◽  
Effect Analysis ◽  
Extended Spectrum Beta Lactamase ◽  
Working Practices ◽  
The Individual

The objective of the present study was the identification of farming practices in the production of turkeys for human consumption, and their ranking in terms of the occupational probability of exposure to antimicrobial resistant (AMR) bacteria, for farm workers. We gathered evidence and data from scientific literature, on risk factors for AMR in farmers, and on the prevalence of those hazards across farming phases. We administered semi-structured interviews to public and private veterinarians in Northern Italy, to obtain detailed information on turkey farming phases, and on working practices. Data were then integrated into a semi-quantitative Failure Modes and Effect Analysis (FMEA). Those working practices, which are characterized by direct contact with numerous animals, and which are carried out frequently, with rare use of personal protection devices resulted as associated with the greatest probability of exposure to AMR. For methicillin resistant Staphylococcus aureus (MRSA), these included vaccination and administration of any individual therapy, and removal and milling of litter, given the exposure of farmers to high dust level. Indeed, levels of occupational exposure to MRSA are enhanced by its transmission routes, which include direct contact with animal, as well as airborne transmission. Level of exposure to extended spectrum beta lactamase (ESBL) is more strictly associated with direct contact and the oral-fecal route. Consequently, exposure to ESBL resulted and associated with the routinely tipping over of poults turned on their back, and with the individual administration of therapies.

Risk Based Acceptance Criteria for Joints Subject to Fatigue Deterioration

2004 ◽  
Vol 127 (2) ◽  
pp. 150-157 ◽  
Author(s):  
Daniel Straub ◽  
Michael Havbro Faber
Keyword(s):  
Fatigue Failure ◽  
System Reliability ◽  
Failure Modes ◽  
Optimal Allocation ◽  
Influence Factor ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Revealed Preferences ◽  
Acceptance Criteria ◽  
The Individual

Different approaches to determine the acceptance criteria for fatigue induced failure of structural systems and components are discussed and compared. The considered approaches take basis in either optimization (societal cost-benefit analysis) or are derived from past and actual practice or codes (revealed preferences). The system acceptance criteria are expressed in terms of the maximal acceptable annual probability of collapse due to fatigue failure. Acceptance criteria for the individual fatigue failure modes are then derived using a simplified system reliability model. The consequence of fatigue failure of the individual joints is related to the overall system by evaluating the change in system reliability given fatigue failure. This is facilitated by the use of a simple indicator, the Residual Influence Factor. The acceptance criteria is thus formulated as a function of the system redundancy and complexity. In addition, the effect of dependencies in the structure on the acceptance criteria are investigated. Finally an example is presented where the optimal allocation of the risk to different welded joints in a jacket structure is performed by consideration of the necessary maintenance efforts.

Failure Prediction of Flip Chip Packages Using Finite Element Technique

2002 ◽  
Author(s):  
Abm Hasan ◽  
H. Mahfuz ◽  
M. Saha ◽  
S. Jeelani
Keyword(s):  
Finite Element ◽  
Flip Chip ◽  
Thermal Loading ◽  
Failure Modes ◽  
Element Model ◽  
Thermally Induced ◽  
Operational Life ◽  
Flip Chip Assembly ◽  
The Individual ◽  
Element Technique

Flip-chip electronic package undergoes thermal loading during its curing process and operational life. Due to the thermal expansion coefficient (CTE) mismatch of various components, the flip-chip assembly experiences various types of thermally induced stresses and strains. Experimental measurement of these stresses and strains is extremely tedious and rigorous due to the physical limitations in the dimensions of the flip-chip assembly. While experiments provide accurate assessment of stresses and strains at certain locations, a parallel finite element (FE) analysis and analytical study can complementarily determine the displacement, strain and stress fields over the entire region of the flip-chip assembly. Such combination of experimental, finite element and analytical studies are ideal to yield a successful stress analysis of the flip-chip assembly under the various loading conditions. In this study, a two-dimensional finite element model of the flip-chip consisting of the silicon chip, underfill, solder ball, copper pad, solder mask and substrate has been developed. Various stress components under thermal loading condition ranging from −40°C to 150°C have been determined using both the finite element and analytical methods. Stresses such as (σ11, σ12, ε12 etc. are extracted and analyzed for the individual components as well as the entire assembly, and the weakest positions of the flip-chip have been discovered. Detailed description of FE modeling is presented and the different failure modes of chip assembly are discussed.

Sign in / Sign up

Export Citation Format

Share Document