Reliability Design Analysis Research Articles

Reliability analysis of bolt‐supported tunnels regarded as homogenized structures

AbstractThis paper presents a reliability analysis of deep tunnels reinforced by fully grouted bolts using a homogenization approach. From the constitutive viewpoint, the anisotropic elastoplastic behavior of bolted rock mass is formulated in the context of the homogenization method. Reliability design analysis is undertaken considering the configurations of both radial and face bolts used separately or in association. The combination of rock bolting associated with classical shotcrete lining is also addressed. Restricting to deep tunnels and axisymmetry conditions, a simplified analytical approach followed by finite element numerical modeling are developed in the framework of the homogenization method. Reliability analyzes are performed using the Monte Carlo simulation (MCS) and the first‐order reliability method (FORM). The response surface method (RSM) provides analytical approximations to enable reliability analyses without time‐consuming computational models. The results show excellent correlation between the obtained reliability parameters, which emphasizes the relevancy of the adopted reliability methods. Structural failure probabilities below or close to 1.0% were obtained in all cases studied for the best structural tunnel conditions.

Operational Safety Performance Assessment of a Special Valve Electric Drive

The paper considers the reliability design analysis stages that should be carried out at the blueprint stage of a special valve electric drive (SVED). It is shown that the key components affecting the SVED reliability are its radio-frequency components. The issue of developing a reliability test plan using the equivalence cyclic test method is considered. Experimental data resulting from reliability tests of four special valve electric drive samples are presented. A comparison is also given of the indicators obtained in the analytical calculation of the SVED reliability and the experimental data.

Data Sources for Reliability Design Analysis

Quantified reliability assessment is now employed by many organizations in the process industries. The objective is to identify critical areas in the plant where design changes are required to meet the safety or production specification. Mechanical system assessment is, however, frequently inhibited by the lack of representative equipment reliability data. Where these data are not available in-house recourse must be made to generic sources from the public domain. Members of the Process Industries Division's Mechanical Reliability Committee have recently completed a study to identify and evaluate the principal reliability data sources for use in process system assessments. This paper discusses the data requirements for reliability assessment and the use of these generic data to provide best-estimates of the reliability statistics for specific applications.