Summary of Test Results for Aluminum Alloy Box Beam Fatigue Program, Test Phases I-IV
NAVAL AIR DEVELOPMENT CENTER WARMINSTER PA AIR VEHICLE TECHNOLOGY DEPT
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The results of a four-phase fatigue program for bending tests of 7075-T6 aluminum alloy box beams for positive loads only and for positive and negative loads for both constant-and variable-load amplitudes are presented. The relative damaging effect of four airplane flight-maneuver-loads spectra was determined, and the effects on fatigue life for variations in spectrum block size, stress level, stress direction, and load sequence were established and the results are discussed. When compared to full-scale aircraft structures of like material under constant-amplitude unidirectional loading on a percent of ultimate strength basis the beams represented the upper bound of those data for full-scale structures and exhibited similar fatigue characteristics. The beams were thus established as a suitable idealized structure for the investigation of those parameters which affect the structural fatigue life.
- Structural Engineering and Building Technology