Optimal solutions to the redundancy allocation problem are determined for systems designed with multiple k-out-of-n subsystems in series. The objective is to select the components and redundancy levels to maximize system reliability given system-level constraints. The individual subsystems may use either active or cold-standby redundancy, or they may require no redundancy. Previously, optimization methods for this problem either pertained to k-out-of-n systems consisting of a single subsystem or to series–parallel systems (k=1). Additionally, it had generally been assumed that only active redundancy was to be used. In practice design problems can vary appreciably from these restrictions and the design process may consider more complex system configurations. Unfortunately, available optimization algorithms are inadequate for many of these design problems. The methodology presented here is specifically developed to accommodate the case with k-out-of-n subsystems. Optimal solutions to the problem are found b...

SYSTEM RELIABILITY OPTIMIZATION WITH k-OUT-OF-n SUBSYSTEMS

Reliability of imperfect switching of cold stanby systems with multiple non-critical and critical errors

In various critical applications of many systems, economic use has been an essential architectural attribute for achieving high performance. A k-out-of-n system, which consists of n components and fails if at least 
$$n-k+1$$

 of the n components fail, is one of the most important systems in practice. Several researchers have shown that, there is an optimal design of such a system, so that the expected total cost of the system is minimized. The present paper aims to find the best compromise between age replacement and system configuration to design a k-out-of-n system when replacement first and last are applied i.e. the system undergoes preventive maintenances before failure at a planned time T or at a random working cycle Y whichever occurs first or last. Expected cost rates for the first and last replacement are formulated. Case studies are provided to illustrate the applications of the theoretical results developed and a numerical algorithm is made to obtain optimal k-out-of-n system configuration.

Optimal design of k-out-of-n system under first and last replacement in reliability theory

A.A. Chari

Papers

Reliability analysis in the presence of chance common cause shock failures

Availability and frequency of failures of a system in the presence of chance common-cause shock failures

Optimal redundancy of K-out-of-n:G system with two kinds of CCFs

Availability and frequency measures of a non-identical two component system in the presence of common cause shock failures