Reliability Estimation for the Remained Stress-Strength Model under the Generalized Exponential Lifetime Distribution

A stress-strength reliability model compares the strength and stresses on a certain system; it is used not only primarily in reliability engineering and quality control but also in economics, psychology, and medicine. In this paper, a novel extension of stress-strength models is presented. The mew model is applied under the generalized exponential distribution. The maximum likelihood estimator, asymptotic distribution, and Bayesian estimation are obtained. A comprehensive simulation study along with real data analysis is performed for illustrating the importance of the new stress-strength model.

Reliability Assessment of Space Station Based on Multi-Layer and Multi-Type Risks

A space station is a typical phased-mission system, and assessing its reliability during its configuration is an important engineering action. Traditional methods usually require extensive data to carry out a layered reliability assessment from components to the system. These methods suffer from lack of sufficient test data, and the assessment process becomes very difficult, especially in the early stage of the configuration. This paper proposes a reliability assessment method for the space station configuration mission, using multi-layer and multi-type risks. Firstly, the risk layer and the risk type for the space station configuration are defined and identified. Then, the key configuration risks are identified comprehensively, considering their occurrence likelihood and consequence severity. High load risks are identified through risk propagation feature analysis. Finally, the configuration reliability model is built and the state probabilities are computed, based on the probabilistic risk propagation assessment (PRPA) method using the assessment probability data. Two issues are addressed in this paper: (1) how to build the configuration reliability model with three layers and four types of risks in the early stage of the configuration; (2) how to quantitatively assess the configuration mission reliability using data from the existing operational database and data describing the propagation features. The proposed method could be a useful tool for the complex aerospace system reliability assessment in the early stage.

Reliability Analysis on Domestic Special CNC Machine Tools Based on Weibull Distribution

Mean time between failures (MTBF), regarded as an important target to evaluate the performance of machine tool, is widely applied in analysis of reliability, especially in reliability model building. Taking Huazhong CNC HNC-848C Complex Machine Tool as research object, this paper conducted censored test to collect MTBF data during a period of 226 days. Based on the data and presupposed Weibull reliability model. Parameters of the model were estimated by least square method. Graph test Method and Kolmogorov-Smirnov Method are implemented to perform the hypothesis test on obtained parameters, which provides evaluation on MTBF of complex machine tool with theoretical basis and data reference.