Accession Number:

ADA151580

Title:

The In-Flight Estimation and Indication of Cumulative Fatigue Damage to Helicopter Gears,

Descriptive Note:

Corporate Author:

AERONAUTICAL RESEARCH LABS MELBOURNE (AUSTRALIA)

Personal Author(s):

• Fraser,K. F.

Report Date:

1984-03-01

Pagination or Media Count:

120.0

Abstract:

Estimates of the safe fatigue life of helicopter transmission components may be made if in-service load data together with transmission fatigue data, represented as the number of cycles to failure as a function of tooth load, are available. Instrumentation has been developed to provide in-flight estimation and indication of the proportion of safe fatigue life expended for critical gears in single or twin-engine helicopter transmission systems. In addition, basic transmission load data in the form of totalized times spent in a number of continuous torque bands are continually updated and stored during flight. The basic load data together with values of life expenditure for critical gears for the current flight can be automatically printed out after flight. This technique opens the way towards fatigue life monitoring of individual transmissions. The special demands of the life estimating system are evaluated and in particular the very significant effects of errors in mean torque estimation are assessed. Originator supplied keywords include Fatigue life Gearboxes Gears Helicopters Transmissionsmechanical Microcomputers Computer programming Computerized simulation computer printouts Australia. Author.

Descriptors:

• *ESTIMATES
• *HELICOPTERS
• *INFLIGHT
• *TRANSMISSION GEARS
• *TRANSMISSIONS(MECHANICAL)
• COMPUTERIZED SIMULATION
• LIFE EXPECTANCY(SERVICE LIFE)
• FATIGUE LIFE
• COMPUTER PROGRAMMING
• MICROCOMPUTERS
• AUSTRALIA
• FATIGUE TESTS(MECHANICS)
• COMPUTER PRINTOUTS

Subject Categories:

• Helicopters
• Computer Programming and Software
• Computer Hardware
• Machinery and Tools

Distribution Statement:

APPROVED FOR PUBLIC RELEASE