关键词: |
AIRCRAFT, AIRCRAFT PANELS, DAMAGE, RIVETS, TEST AND EVALUATION, AVIATION SAFETY, FATIGUE(MECHANICS), FATIGUE LIFE, AIRCRAFT MAINTENANCE, AIRFRAMES, AIRWORTHINESS, CRACKS, FABRICATION, FACILITIES, FAILURE, FATIGUE, FUSELAGES, LABORATORIES, LENGTH, LIGAMENTS, OPERATION, PANELS, PHASE, PRESSURE, RATES, REDUCTION, RESIDUALS, SITES, SPLICES, STRAPS, TAPS, TEST FACILITIES, DAMAGE CONTROL. |
摘要: |
This report presents data on (1) residual strength of aircraft panels containing Multiple-Site Damage (MSD) in tap splices, and (2) fatigue strength of panels subjected to cyclic pressure loading. The testing was conducted using the dedicated Aging Aircraft Test Facility previously built in the Foster-Miller laboratory. A previous report describes the work in the first phase involving the design and operation of the facility and the test data generated on residual strength of panels with longitudinal midday skin cracks. In the Phase II work presented here, several residual strength tests were conducted to develop a relationship between failure pressure and the lead crack length in the critical upper rivet line of the lap joint. In some of the panels multiple-site damage was also built in the rivet line during fabrication. The reduction in the residual strength due to MSD has been experimentally quantified. Conditions of crack arrest at tear straps and panel flapping were also investigated. Fatigue testing of the panel, with no initial damage in the tap splice except an unbonded lap joint area, was conducted to investigate the crack initiation at multiple sites, crack growth rates and eventual linkup of the ligaments and fracture failure. The ultimate life of the panel, and the damage in critical upper and lower skin rivet rows was determined. Conclusions of practical interest were drawn from the test data. Aging aircraft, Multiple-site damage, Fuselage fracture, Fatigue, Lap splice, Residual strength. |