Original Date: 03/08/1999
Revision Date: 01/18/2007
Best Practice : Condition Based Maintenance
Condition Based Maintenance (CBM) is a philosophy that uses sensors, algorithms, models, and automated reasoning to monitor the operations of machinery and equipment as well as determine appropriate maintenance tasks prior to an impending failure. Reducing life-cycle costs is the incentive for investing in CBM technology, and maintenance is the largest controllable cost in industry today. By understanding the workings of machinery and equipment, companies can control costs through efficient planning and effective maintenance. Sufficient warning of an impending failure provides an opportunity to maximize maintenance repair effectiveness and minimize resources, materials, and downtime. CBM technology also provides significant savings compared to traditional preventive maintenance based on time or run-to-fail maintenance. To be effective, CBM should operate as a system that detects and classifies an incipient failure; predicts the remaining life cycle of equipment; supports the operator’s decision for course of action; interfaces with the control system to take action; aids the maintainer in making repairs; and provides feedback to the logistics support and machinery design communities.
The Applied Research Laboratory at the Pennsylvania State University (ARL Penn State) instituted a systems approach for CBM by using a hierarchical architecture for developing and implementing health assessment systems. This hierarchy represents the decomposition of a system from the highest level at which the demand originates, the impact of the failure, down to the lowest level at which all failures originate. The hierarchy consists of six levels: material, element, component, subsystem, system, and plant platform. By decomposing a system, the ARL Penn State can apply diagnostic tools and sensors at the appropriate level to efficiently monitor and assess the health of a specific area. Collectively, individual health assessments at any level provide system health at the next higher level.
To support its expanding CBM efforts, the ARL Penn State also established four facilities: Mechanical Diagnostics Test Bed (MDTB); Ball and V-Ring Test Stand; Lubrication Test Loop; and Systems Integration and Technology Transfer Facility. These facilities provide the ARL Penn State with unique capabilities to advance the state of diagnostics and prognostics through the development, evaluation, and application of advanced sensing, reasoning, and modeling techniques. Of particular importance is the MDTB, which provides transitional failure data sets to characterize a fault.
The ARL Penn State recognizes the importance of CBM issues to its customers. Since 1994, the laboratory established itself as a leader in CBM mechanical systems, and continues to add to its portfolio of projects won through research contracts and grants. These projects cover various CBM issues from materials to decision support.
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