RELIABILITY PREDICTION OF HELICOPTER TRANSMISSION SYSTEMS USING STRESS-STRENGTH INTERFERENCE WITH UNDERLYING DAMAGE ACCUMULATION

摘要

This paper describes research into the development of reliability prediction models for rotor transmission systems in which component failure is caused by underlying aging processes such as fatigue, wear or corrosion. Reliability prediction is based on the stress-strength interference methodology, with stress related to surface damage and strength to the limit of allowable damage. The paper describes how damage accumulation and system failure logic is incorporated within the stress and strength functions. For fatigue-dominated processes, damage grows with number of cycles in response to applied load and environmental conditions. The concept of `operating state' is used to model statistical damage accumulation. Operating states describe load and lubrication conditions and associated statistical damage accumulation rate parameters. Growth rate variance is related to operating state transitions and can be modeled using stochastic techniques. Fatigue strength is obtained from S-N data. Formulated in this way, reliability can be predicted from design and operational parameters rather than historical failure data.