Innovative Approach to Full Scale Fatigue Testing using Hybrid Methodologies

The lack of adequate fatigue life verification for rotorcraft airframe structures leads to costly in service repairs being required in order to maintain structural integrity. The current established methodology does not test the airframe to the synergistically harmful combination of high cycle fatigue (HCF) vibratory load cycles superimposed on low cycle fatigue (LCF) caused by “g” maneuvers and airloads. This is due to the excessive time required to test items using conventional test methods.Dayton T Brown, Inc. (DTB), a leader in aircraft system engineering and testing services, has developed a comprehensive solution to improve structural testing methods by incorporating combined HCF and LCF testing. Our approach is based upon our successful Phase I demonstration test, combines simultaneous application of LCF and HCF fatigue loadings to conduct fatigue testing faster while using realistic loadings.. For Phase II, DTB will model, design and fabricate a High Speed Hybrid Fatigue Test (HSHFT) system and demonstrate it by testing two test items. One test will be run using conventional fatigue testing methods and the other will utilize HSHFT test methods. The results, time and costs for both methods will be compared to each other and to analytical predictions.