Hostname: page-component-cd9895bd7-hc48f Total loading time: 0 Render date: 2024-12-22T10:13:32.365Z Has data issue: false hasContentIssue false
  • English
  • Français

The contribution of fatigue usage monitoring systems to life extension in safe life and damage tolerant designs

Published online by Cambridge University Press:  04 July 2016

P. E. Irving ,
J. E. Strutt ,
R. A. Hudson ,
K. Allsop  and
M. Strathern
P. E. Irving
Affiliation:
School of Industrial and Manufacturing ScienceCranfield UniversityCranfield, UK
J. E. Strutt
Affiliation:
School of Industrial and Manufacturing ScienceCranfield UniversityCranfield, UK
R. A. Hudson
Affiliation:
School of Industrial and Manufacturing ScienceCranfield UniversityCranfield, UK
K. Allsop
Affiliation:
School of Industrial and Manufacturing ScienceCranfield UniversityCranfield, UK
M. Strathern
Affiliation:
School of Industrial and Manufacturing ScienceCranfield UniversityCranfield, UK
Get access Rights & Permissions [Opens in a new window]

Abstract

Fatigue usage monitoring systems (Fums) offer considerable potential for life extension of aircraft parts. In this work the life extension benefits of Fums is assessed by adopting a probabilistic approach. The roles of damage law type and of service usage variability is explored. It is shown by analysis that in the absence of cycle to cycle load interaction effects, load sequence has no effect on eventual life in either linear or non linear damage laws, provided that the function describing the rate of damage growth has separable variables of stress and damage. This condition includes fracture mechanics crack growth laws. Monte Carlo simulations have been conducted of fatigue life distributions in helicopter rotor components. Variability in manoeuvre damage, when summed over a large number of manoeuvres, has little effect on scatter in overall lives. A fixed manoeuvre usage spectrum will result in very small scatter in lives, whereas keeping the usage constant for each helicopter and allowing it to vary between helicopters, produces a significantly increased variability. The influence of load factors on life is also assessed. The extent of possible maintenance credits is discussed together with the use of Bayesian updating to make optimum use of both prior design data and current loads or damage information provided by Fums.

Type
Research Article
Information
The Aeronautical Journal , Volume 103 , Issue 1030 , December 1999 , pp. 589 - 595
Copyright
Copyright © Royal Aeronautical Society 1999 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Basehore, M.L. and Dickson, W. HUMS loads monitoring and damage tolerance: an operational evaluation, Paper 7 in Exploitation of Structural Loads/Health Data for Reduced Life Cycle Costs, RTO meeting proceedings RTO-MP-7 AC/323(AVT)TP/4, Brussels, May 1998.Google Scholar
2. Dickson, W., Cronkhite, J.D. and Summers, H. Usage and structural life monitoring with HUMS, in 52nd Meeting of the American Helicopter Society, AHS, 1996.Google Scholar
3. Azzam, H. The Use of Helicopter Flight Parameters for Damage Prediction, Unpublished MoD report 1993.Google Scholar
4. Barndt, G.L. and Moon, S. Development of a fatigue tracking program for Navy rotary wing aircraft, in 50th meeting of American Helicopter Society, 1994, pp 1359–1389.Google Scholar
5. Moon, S., , Menon, D. and Barndt, G. Fatigue life reliability based on measured usage, flight loads and fatigue strength variations, in 52nd meeting of American Helicopter Society, 1996, pp 366-389.Google Scholar
6. Carter, A.D.S. Mechanical Reliability, 2nd Ed, Macmillan Education, 1986.Google Scholar
7. Strutt, J.E. and Allsop, K. Probabilistic reliability analysis of pipelines: Part I Theoretical framework & Part II, Model Application; in International conference on life assessment and life extension of engineering plant, structures and components, Cambridge, September 1996.Google Scholar
8. Schutz, W. The significance of service loads for fatigue life analysis in VTT Symposium 130 on Fatigue Design, pub Technical research centre of Finland ESPOO, 1992, pp 11–35.Google Scholar
9. Dabayey, A.A. and Topper, T.H. Changes in crack opening stress after underloads and overloads in 2024-T351 aluminium alloy, Int J Fatigue, 1995,17, (4), pp 261–269.Google Scholar
10. Irving, P.E. and Hudson, R.A. The contribution of Health and Usage Monitoring Systems to calculations of damage state and future life of helicopter components under safe life and damage tolerant design Paper 7 in Exploitation of Structural Loads/Health Data for Reduced Life Cycle Costs, RTO-MP-7 AC/323/(AVT)TP/4, Brussels, May 1998.Google Scholar
11. Borgman, D. Helicopter fatigue methodology, AGARD CP297, 1981.Google Scholar