Aircraft structures, whether metallic or composite, are subject to service damage which requires their periodic inspection and maintenance. While taking the aircraft out of service is quite costly, the assurance of structural integrity requires such inspection – and possible repair work based on the inspection results obtained. If damage is detected from an inspection, the decision whether to r...

Introduction Safe disposal of nuclear waste is a difficult problem. Long-term plans are to house nuclear waste permanently in underground facilities. In the near-term however, nuclear waste is stored in temporary storage facilities at various sites around the country. Federal and state regulations require periodic inspection of these storage facilities to insure storage vessel integrity and ver...

Nondestructive evaluation methods are widely used in quality control processes for critical components in systems such as aircraft engines and nuclear power plants. These same methods are also used in periodic field inspection to assure that the system continues to be reliable while it is in service. This paper describes a detection algorithm to automatically analyze vibrothermography sequence-...

One of the most challenging scientific industrial problems in recent years is automatic defect detection and characterization. Automatic defect detection can replace human operators who locate and identify defects. Detection of defects in the steam generating tubes through periodic inservice inspection is one of the most significant issues of the fast breeder reactors. Among various pipeline in...

Techniques for automatic monitoring of faults in machinery are being considered as a means to safely simplify or dispense with expensive periodic fault inspection procedures. This paper presents results from an ongoing investigation into the feasibility of using Acoustic Emissions (AEs) for automatic detection of microcrack formation/growth in machine components.

Inspection is always an important preventive maintenance (PM) activity and can have different depths and cover all or part of plant systems. This paper introduces a two-level inspection policy model for a single component plant system based on a three-stage failure process. Such a failure process divides the system′s life into three stages: good, minor defective and severe defective stages. The...