Dynamic Reliability Analysis Method of Degraded Mechanical Components Based on Process Probability Density Function of Stress

Abstract

It is necessary to develop dynamic reliability models when considering strength degradation of mechanical components. Instant probability density function (IPDF) of stress and process probability density function (PPDF) of stress, which are obtained via different statistical methods, are defined, respectively. In practical engineering, the probability density function (PDF) for the usage of mechanical components is mostly PPDF, such as the PDF acquired via the rain flow counting method. For the convenience of application, IPDF is always approximated by PPDF when using the existing dynamic reliability models. However, it may cause errors in the reliability calculation due to the approximation of IPDF by PPDF. Therefore, dynamic reliability models directly based on PPDF of stress are developed in this paper. Furthermore, the proposed models can be used for reliability assessment in the case of small amount of stress process samples by employing the fuzzy set theory. In addition, the mechanical components in solar array of satellites are chosen as representative examples to illustrate the proposed models. The results show that errors are caused because of the approximation of IPDF by PPDF and the proposed models are accurate in the reliability computation.

Structural reliability analysis of automotive parts based on strength degradation and abrasion and correlation

“…where σ g is the function of 𝜌 𝑖𝑗 , 𝜎 𝑔 = 𝑓(𝑝 𝑖𝑗 ). According to Equation (11), reliability-based sensitivity with respect to correlation coefficients can be expressed as follows:…”

“…In the study of reliability, the study of strength degradation has become an important research direction. [9][10][11][12][13] At present, many scholars have proposed a variety of models to study the reliability of strength degradation. [14][15][16][17] Meanwhile, many scholars have proposed a variety of residual strength models to study the reliability of strength degradation.…”

“…Strength degradation is the process of fatigue strength decline of parts in the working environment. In the study of reliability, the study of strength degradation has become an important research direction 9–13 . At present, many scholars have proposed a variety of models to study the reliability of strength degradation 14–17 .…”

Dynamic fatigue reliability analysis of turbine blades under combined high and low cycle loadings

“…Generally, the gradual failure of aero-engine turbine blades is caused by material deterioration owing to the factors like creep, fatigue, corrosion, oxidation, etc. (Gao and Xie, 2014;Li et al, 2020). Due to the continuous decrease of remaining strength over the increasing of engine cycles, it is imperative to establish reliability models taking strength degradation into account for further reliability analysis under complex loading conditions.…”

Dynamic Reliability Analysis of Turbine Blades Under Combined High and Low Cycle Loadings

“…In fact, the strength of the components will continue to deteriorate with the number of applied cycles during operation, and the residual strength can be expressed by [18] ( ) ( )…”