Verification of rain-flow reconstructions of a variable amplitude load history

The suitability of using rain-flow reconstructions as an alternative to an original loading spectrum for component fatigue life testing is investigated. A modified helicopter maneuver history is used for the rain-flow cycle counting and history regenerations. Experimental testing on a notched test specimen over a wide range of loads produces similar lives for the original history and the reconstructions. The test lives also agree with a simplified local strain analysis performed on the specimen utilizing the rain-flow cycle count. The rain-flow reconstruction technique is shown to be a viable test spectrum alternative to storing the complete original load history, especially in saving computer storage space and processing time. A description of the regeneration method, the simplified life prediction analysis, and the experimental methods are included in the investigation.