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Operation & support costs for military weapon systems accounted for approximately 3/5th of the $500B Department of Defense budget in 2006. In an effort to ensure readiness and decrease these costs for ground vehicle fleets, health monitoring technologies are being developed for Condition-Based Maintenance of individual vehicles within a fleet. Dynamics-based health monitoring is used in this work because vibrations are a passive source of response data, which are global functions of the mechanical loading and properties of the vehicle. A common way of detecting faults in mechanical equipment, such as the suspension and chassis of a ground vehicle, is to compare measured operational vibrations to a reference (or healthy) signature to detect anomalies.

Integrated health monitoring technologies are being developed for military ground vehicles to enable condition based maintenance in the short term and prognostic health management in the long term. Technical issues related to health monitoring of a military HMMWV are examined using a dynamic simulation model. Both free and forced vibration response analyses are conducted to examine the effects of damage and operational conditions on the vehicle response. The higher frequency modal properties are found to be sensitive to frame and cross member damage whereas the lower frequency sprung modal properties are not. Changes due to adding up armor are found to be much larger than those due to damage. In addition, cross member damage affects the higher frequency modes whereas damage to the left or right frames causes changes to the modal behavior across the entire frequency range making this type of damage most detectable.