Date of Award

3-23-2017

Document Type

Thesis

Degree Name

Master of Science in Systems Engineering

Department

Department of Systems Engineering and Management

First Advisor

John M. Colombi, PhD.

Abstract

Attritable systems trade system attributes like reliability and reparability to achieve lower acquisition cost and decrease cost risk. Ultimately, it is hoped that by trading these attributes the amount of systems able to be acquired will be increased. However, the effect of trading these attributes on system-level reliability and cost risk is difficult to express complicated reparable systems like an air vehicle. Failure-time and cost data from a baseline limited-life air vehicle is analyzed for this reliability and reparability trade study. The appropriateness of various reliability and cost estimation techniques are examined for these data. This research employs the cumulative incidence function as an input to discrete time non-homogeneous Markov chain models to overcome the hurdles of representing the failure-time data of a reparable system with competing failure modes that vary with time. This research quantifies the probability of system survival to a given sortie, S(n), average unit flyaway cost (AUFC), and cost risk metrics to convey the value of reliability and reparability trades. Investigation of the benefit of trading system reparability shows a marked increase in cost risk. Yet, trades in subsystem reliability calculate the required decrease in subsystem cost required to make such a trade advantageous. This research results in a trade-space analysis tool that can be used to guide the development of future attritable air vehicles.

AFIT Designator

AFIT-ENV-MS-17-M-172

DTIC Accession Number

AD1051581

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