A Method to Take Account of Inhomogeneity in Mechanical Component Reliability Calculations

The correct evaluation of reliability for the system or components is very important for high quality and security. The traditional models take stress and strength as the static random variable without considering the effect of strength degradation. The effect of strength degradation on the reliability of a gear was studied in this paper. With the conditional reliability introduced, a reliability calculation model of gear with multiple failure modes is developed by using the stress-strength interference model, without the assumption that there was independent failure mode of gear. The reliability model of a gear under the strength degradation is developed based on the model. And the dependence of gear reliability on the strength degradation is studied. The result shows that the gear reliability decreases with the strength degradation due to fatigue, corrosion, aging and other factors.

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“…Substitute the values and (5), (6) and (7) into (3), get the reliability of gears R(t) considering strength degradation:…”

Section: Calcula Non Examplementioning

confidence: 99%

Reliability calculation model of gears considering strength degradation

Liu

Zhang

et al. 2009

2009 16th International Conference on Industrial Engineering and Engineering Management

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“…Recently, the stochastic time-dependent characteristics of mechanical structure reliability draw more and more attention. The study considering load process to be Poisson Process has arisen [1,2], but the actual load process on structure is very complex and unpredictable. And with the passing of time during machine lifetime, the resistance of mechanical structure will degenerate too [3,4], e.g.…”

Section: Introductionmentioning

confidence: 99%

Calculation Method of Mechanical Structure Complex Time-Dependent Reliability with Blind Number Theory and its Implementation

Guo

Shi

Cheng

et al. 2009

AMM

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The basic ideas of expressing uncertain variables with blind number were introduced. The mechanical structure time-dependent characteristics variation in stochastic process was deduced. A time-dependent reliability calculation model was built with blind number theory. The numerical method based on blind number was applied to solve this complicated computing model. A LabVIEW program was compiled, and a frame beam’s time-dependent reliability was computed. The result shows the method based on blind number is very convenient and effective in solving the complicated reliability calculation model. In this method, the structure time-dependent reliability can be predicted quickly based on the historical data.

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“…To date, development of control schemes for MEMS is behind compared to their fabrication and structure design [1]. There is an enormous effort currently underway to mathematically model MEMS devices under different operating conditions and fault occurrence to identify their dynamics and enhance their reliability [2]- [5], [28]- [32]. Reliability enhancement techniques mostly address the structure reinforcement in thin-film depositions which are being evaluated under different conditions such as shock.…”

Section: Introductionmentioning

confidence: 99%

Reliability Enhancement of MEMS Lateral Comb Resonators Under Fault Conditions

Izadian

Famouri

2008

IEEE Trans. Contr. Syst. Technol.

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The delicate structure of microelectromechanical systems (MEMS) limits their reliability in cases of fault occurrence. Control systems can enhance their reliability of operation by providing fault robust systems. This paper illustrates a method for the safe operation of lateral comb resonators (LCR) under faulty conditions. Different types of fault are fabricated at chip level and experimentally tested in order to demonstrate the effectiveness of the reliability enhancement of operation in LCRs. Mass change and folded spring structural defects influence the device's behavior and reduce its reliability of operation. Here, model reference adaptive controllers (MRACs) are effectively used to enhance the reliability of faulty devices. Reliable operation of a +5% additional mass considering environmental conditions and asymmetries on the device, demand almost 80% higher control effort whereas +20% in case of broken trusses or +46% in case of adhesion point fault on a beam of folded springs. The simulation and experiment results demonstrate successful application of MRAC for reliable operation of LCRs by providing a fault-robust system.

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A Method to Take Account of Inhomogeneity in Mechanical Component Reliability Calculations

Cited by 14 publications

References 7 publications

Reliability calculation model of gears considering strength degradation

Reliability calculation model of gears considering strength degradation

Calculation Method of Mechanical Structure Complex Time-Dependent Reliability with Blind Number Theory and its Implementation

Reliability Enhancement of MEMS Lateral Comb Resonators Under Fault Conditions

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