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Evaluating Component Fatigue Performance Under Programmed Random, and Programmed Constant Amplitude Loading
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English
Abstract
At the present time, it is generally conceded that testing for the evaluation of fatigue performance of materials subjected to variable loading in service, must contain variable loading as well. Single-level fatigue testing just will not provide an accurate answer.
Two methods of fatigue testing using variable amplitude have been advocated in the literature. The earlier method, developed by Gassner, involves the stratification of the service load spectrum into eight levels, from the maximum load to the minimum. The number of cycles at each level is developed from the load spectrum. The loads are then applied in a stepwise ascending-descending manner beginning with a mid-level.
The second method involves the use of a clipped random process, whose intensity (RMS) is varied throughout the test in a random stepwise manner, such that the final accumulation of loads is asymptotic to the desired load spectrum.
These two methods are examined in detail in this paper. A test program, involving automotive stub axles was developed, in which as many factors as possible were kept common to both types of tests. It is hoped that the results are a fair assessment of the two methods.
Authors
Citation
Swanson, S., "Evaluating Component Fatigue Performance Under Programmed Random, and Programmed Constant Amplitude Loading," SAE Technical Paper 690050, 1969, https://doi.org/10.4271/690050.Also In
References
- Gassner E. Schutz W. “Assessment of the Allowable Design Stresses and the Corresponding Fatigue Life” Paper presented at the 4th ICAF Symposium June 1965
- Jaeckel H.R. Swanson S.R. “Random Load Spectrum Test to Determine Durability of Structural Components of Automotive “Vehicles” 12th International Automobile Technical Congress Minneapolis, Minnesota May 1968
- Swanson S.R. Akaike H. “Load History Effects on Structural Fatigue” Paper to be presented at the 1969 Annual Meeting Session on Failure Mechanisms and Reliability Prediction in Structural Dynamics April 23 1969
- Swanson S.R. “An Investigation of the Fatigue of Aluminum Alloy Due to Random Loading” U.T.I.A. Report 84 February 1963
- Gassner E. Schutz W. “Evaluating Vital Vehicle Components by Programme Fatigue Tests” Ninth International Automobile Technical Congress May 4 1962
- Jacoby G.H. “Comparison of Fatigue lives under Conventional Program Loading and Digital Random Loading” ASTM Fall Meeting October 1968