VIRTUAL TESTING OF METALLIC STRUCTURES FOR DAMAGE TOLERANT DESIGN UNDER FATIGUE LIFE ANALYSIS IN THE PRESENCE OF MSD

摘要

Computational simulation was used to generate virtual test data on the structural damage evolution characteristics under monotonically increasing loading, and cyclic spectra loading. The effort reported herein was undertaken to explore this capability by computational simulation of progressive probabilistic failure analyses in Integral Airframe Structure (IAS) panels lap joint and Crown Panel with and without DSD in the form of multi site damage (MSD). Virtual testing method generated much more information than is practical in actual testing. Coupon and component fuselage Tests were conducted after simulations and selected simulated data was compared with actual test results. The computational simulation is performed in two steps: 1) Deterministic and 2) Probabilistic. Agreement between virtual and actual test results was within ten percent for all simulations. The performances of stiffened metallic panels are compared with regard to structural durability under loading. Results show the damage progression sequence and the changes in the structural response characteristics during different degradation stages. Critical locations for damage initiation/progression are identified and compared to those produced during subsequent testing. A procedure is outlined for use of computational simulation data in the assessment of damage tolerance, determination of sensitive parameters affecting fracture and interpretation of experimental results with insight for design decisions.