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• Two-kind combined reliability systems are introduced in terms of two reliability systems: (n , f , k) and < n , f , k >. • Some important concepts such as irreducible structure and structure equivalence are introduced. • We present an important criterion: four-class combined reliability systems are needed to be considered in essential. • A coordinate system is introduced for representing the working and failure regions for the combined reliability systems. • A procedure for calculations of the combined reliability systems is given. In the paper, two-element (f , k) and < f , k > combined systems are developed, and two-kind combined reliability systems and some related new concepts such as irreducible structure and structure equivalence are introduced, which can be used not only in real practical situations, but also enrich the reliability contents. We proved that four-class combined reliability systems need to be considered actually, which facilitates the handling of these combined reliability systems. Meanwhile, a coordinate system with two axes, the number of total failed components and the number of maximal consecutive failed components, is introduced in the paper for representing the working and failed areas for the combined reliability systems, which brings out a useful tool for understanding the working and failure mechanisms, and system state transition ways, for the combined reliability systems. To summarize the reliability calculation, a procedure for calculations of the combined reliability systems is presented, which is an efficient guidance for these reliability computations. Finally, two numerical examples are given to illustrate the computation procedure in which the detailed steps, special on using Finite Markov Chain Imbedding Approach (FMCIA), are shown. We believe that the present paper can shed light on researches on combined reliability systems. [ABSTRACT FROM AUTHOR]

A warranty product often has an interval structure, resulting in different warranty periods for each component due to their distinct degradation paths. From the manufacturer's perspective, it is reasonable to establish appropriate warranty periods for each part to achieve cost savings. This paper introduces a dependent series configuration consisting of a main component and an auxiliary component. The failure of the main component leads to system failure, while the failure of the auxiliary component only causes a random damage to the main component. These two components follow different Wiener degradation paths, and then their first passage times (FPTs) follow disparate inverse Gaussian distributions. Assuming a pre-deterministic warranty period, W , for the main component, and η W , 0 < η < 1 , for the auxiliary component, the warranty period can be divided into two stages: [ 0 , η W ] and [ η W , W ]. In this context, the paper proposes warranty claim policies for replacement, objective-oriented imperfect repair (OOIR), and refund. The corresponding warranty costs sustained by manufacturer and consumer within these two stages are considered. Finally, a numerical example is presented to illustrate the warranty costs sustained by manufacturer and consumer under different scenarios, as well as the total warranty costs. • The degradation paths, warranty periods and warranty costs of the series system is analyzed. • The warranty costs sustained by manufacturer and consumer under different scenarios is analyzed. • The interdependence between various components is considered. [ABSTRACT FROM AUTHOR]

Multi-state system models are more practical and valuable when describing complex engineering structures than binary-state system models. Modelling of linear consecutive- (k , l) -out-of- n : F systems with shared components under non-homogeneous Markov dependence is discussed in this work. The proposed model is an extension of both "consecutive- k -out-of- n : F system" and "consecutive- k -out-of- n : F system with shared components between adjacent subsystems". All the components in the system are assumed to have three states and are non-homogeneous Markov-dependent. Using the method of sum of disjoint products (SDP), the system reliability formula is derived by summing the reliability values for all disjoint cases. The well-known finite Markov chain imbedding approach (FMCIA) is used for deriving the reliability formula for each disjoint case. For the special cases of systems with homogeneous Markov-dependent or independent components, the corresponding results are deduced. Finally, some numerical examples are presented to illustrate all the results developed here. • Consecutive-(k,l)-out-of-n: F systems with shared components are modelled. • Using the method of SDP and FMCIA, the system reliability formula is derived. • The method is also fit for homogeneous Markov-dependent or independent cases. • Numerical examples demonstrate the efficiency of the proposed method. [ABSTRACT FROM AUTHOR]

Reliability analysis for k -out-of- n systems has received much attention in the field of reliability due to its practical importance. In this work, models for linear and circular k -out-of- n : F systems with shared components, consisting of m subsystems, are discussed. The finite Markov chain imbedding approach cannot be used directly to derive reliability of the considered systems because of the common area existing between adjacent subsystems. For this reason, we first derive the probability that the number of failed components is a given value in the m common areas. Then, all disjoint cases, each of which is regarded as a series system consisting of m subsystems with different initial state probability distributions, are obtained, with which the n i th step transition rate matrix is calculated by using the Markov chain technique, for i = 1 , 2 , ... , m. Finally, the reliability of the system is obtained by summing the reliabilities of all cases along with the finite Markov chain imbedding approach. Some numerical examples are presented to illustrate the efficiency of the proposed reliability evaluation method. • Linear and circular k -out-of- n : F systems with shared components are modelled. • A method combining the finite Markov chain imbedding approach with some theoretical analysis is proposed. • Reliability calculation rules for both two considered systems are described based on our method. • Numerical examples are presented to illustrate the efficiency of the proposed reliability evaluation method. [ABSTRACT FROM AUTHOR]

Consecutive- k systems have well known for outstanding developments and extensive applications. In this paper, we propose consecutive- k -out-of- n : F systems with shared components between adjacent subsystems which extend the consecutive- k -out-of- n : F linear and circular models and the consecutive- k r -out-of- n r : F linear zigzag structure and circular polygon structure. They are referred to as an extension of linear zigzag structure and an extension of circular polygon structure respectively. The idea of computation for reliability is to cut the system into m subsystems and to get the reliability of every subsystem, then to obtain the system reliability in terms of reliabilities of all subsystems, the probability of occurrence of each event and the system structure. Based on this view, we obtain the reliability for the above two structures by combining the sum of disjoint products with finite Markov chain imbedding approach (FMCIA). A numerical example demonstrates the efficiency of the proposed method for our new models. • The consecutive- k -out-of- n : F systems with shared components between adjacent subsystems considering linear and circular structure are modelled. • A method combining sum of disjoint products with finite Markov chain imbedding approach is proposed. • Reliability calculation rules for both two models are given based on our method. • Numerical examples demonstrate the efficiency of the proposed method for our new models. [ABSTRACT FROM AUTHOR]