Reliability analysis and modeling of the U. S. Marine Corps medium tactical wheeled vehicle in Operation Iraqi Freedom

Abstract

This thesis describes an analysis of the reliability of the Medium Tactical Vehicle Replacement (MTVR) cargo variant in Operation Iraqi Freedom (OIF), from March 1, 2004 to March 31, 2007. More than 870 MTVRs were fielded by the Marine Corps for OIF, of which 456 provided data for analysis. Analysis and modeling of this repairable system's failure modes are conducted at the MTVR variant, major unit, armored status, and subsystem levels to develop an understanding of the vehicle's usage and performance under field conditions. Reliability is measured by the frequency of occurrence of unscheduled maintenance events, with the number of days that a vehicle is not available due to these events ("deadlined days") used as a measure of severity. The challenges of using field maintenance and supply data are handled using various methods, including data verification, failure event aggregation, and odometer reading imputation. Nonparametric and parametric statistical methods are utilized, with system and subsystem failure mode recurrence data, to measure reliability throughout the period of observation and amidst the installation of system modifying vehicle armor kits. Reliability metrics are quantified to capture the effects of usage and armoring, taking into account that the MTVR is a repairable system.