(1998). Genetic Algorithms and Engineering Design. The Economist: Vol. 43, No. 4, pp. 379-381.

A problem-specific genetic algorithm (GA) is developed and demonstrated to analyze series-parallel systems determine the optimal design configuration when there are multiple component choices available for each of several k-out-of-n:G subsystems. The problem select components redundancy-levels optimize some objective function, given system-level constraints on reliability, cost, and/or weight. Previous formulations have implicit restrictions concerning type redundancy allowed, number...

This article proposes reliability models for devices subject to dependent competing failure processes of degradation and random shocks with a changing rate according particular shock patterns. The two are soft due continuous degradation, in addition sudden increases caused by shocks, hard the same process. In complex such as Micro-Electro-Mechanical Systems can change when system becomes more susceptible fatigue deteriorates faster, result withstanding shocks. considers four different...

For complex multi-component systems with each component experiencing multiple failure processes due to simultaneous exposure degradation and shock loads, we developed a new system reliability model, applied two different preventive maintenance policies. This model extends previous research, is from related research by considering an assembled of degrading components <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex...

Abstract A tabu search meta-heuristic has been developed and successfully demonstrated to provide solutions the system reliability optimization problem of redundancy allocation. Tabu is particularly well-suited this it offers distinct advantages compared alternative methods. While there are many forms problem, allocation generally involves selection components levels maximize given various system-level constraints. This a common extensively studied involving design, engineering operations...

Abstract A solution methodology is described and demonstrated to determine optimal design configurations for nonrepairable series-parallel systems with cold-standby redundancy. This problem formulation considers non-constant component hazard functions imperfect switching. The objective of the redundancy allocation select from available components an configuration maximize system reliability. For redundancy, other formulations have generally required exponential time-to-failure perfect...

Optimal solutions to the redundancy allocation problem are determined when either active or cold-standby can be selectively chosen for individual subsystems. This involves selection of components and levels maximize system reliability. Previously, could only found if analysts were restricted a predetermined strategy complete system. Generally, it had been assumed that was used. However, in practice both may used within particular design choice becomes an additional decision variable....

The application of genetic algorithms (GA) to constrained optimization problems has been hindered by the inefficiencies reproduction and mutation when feasibility generated solutions is impossible guarantee feasible are very difficult find. Although several authors have suggested use both static dynamic penalty functions for search, this paper presents a general adaptive technique which makes feedback obtained during search along with distance metric. effectiveness method illustrated on two...

This paper presents & evaluates composite importance measures (CIM) for multi-state systems with components (MSMC). Importance are important tools to evaluate rank the impact of individual within a system. For systems, previously developed do not meet all user needs. The major focus study is distinguish between two types which can be used evaluating criticality in MSMC respect system reliability. Type 1 that involved measuring how specific component affects A Monte Carlo (MC) simulation...

We present reliability and maintenance models for systems subject to multiple <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</i> -dependent competing failure processes with a changing, dependent threshold. In our model, two are considered: soft caused by continuous degradation together additional abrupt due shock process, hard the instantaneous stress from same process. These correlated or in respects: 1) arrival of each load affects both...

A custom genetic algorithm was developed and implemented to solve multiple objective multi-state reliability optimization design problems. Many real-world engineering problems are multi-objective in nature, among those, several of them have various levels system performance ranging from perfectly functioning completely failed. This uses the universal moment generating function approach evaluate different or availability indices system. The components characterized by having levels, cost,...

This article develops an optimum Condition-Based Maintenance (CBM) policy for continuously monitored degrading systems with multiple failure modes. The degradation of system state is described by a stochastic process, and maintenance alarm used to signal when the reaches threshold level. Unlike existing CBM models, this considers sudden failures that can occur during system's degradation. rate corresponding each mode influenced either age system, or both. A joint model constructed...

This article studies a system that experiences two dependent competing failure processes, in which shocks are categorized into different shock zones. These stochastic degradation process and random process, because arriving can cause instantaneous damage on the process. In existing studies, every causes an abrupt degradation. However, this may not be case when loads small within tolerance of resistance. proposed model, only larger than certain level considered to degradation, makes new model...

New reliability models have been developed for systems subject to competing hard and soft failure processes with shocks that dependent effects. In the new model, occurs when transmitted system are large enough cause any component in a series fail immediately, deteriorates certain threshold, affect both all components. Our research extends previous had processes, where dependency was only because of shared number shock exposures not effects associated individual shocks. Dependency sizes...

Based on reliability analysis for a system subject to s-dependent competing risks of internal degradation and external shocks, we propose condition-based maintenance policy considering imperfect repair complex systems. The (e.g., crack growth, erosion, or corrosion) can be modeled using stochastic deterioration process. External shocks arriving at random times are divided into two classes based their impacts the system: 1) fatal that cause fail immediately, if shock belongs any three classic...