مدل سازي پرنده و تحليل برخورد آن با لبه دم عقب هواپيما

چكيده انگليسي :

Bird Modeling and Investigation of its Impact to Horizontal Tailplane Reza Hedayati rezahedayati@gmail com Date of Submission 2 May 2011 05 02 Department Mechanical Engineering Isfahan University of technology Isfahan 84156 83111 Iran Degree Masters of Science Language Persian Supervisor Dr Saeed Ziaee Rad szrad@cc iut ac ir Abstract Impact between birds and an aircraft known as bird strike event is a common and dangerous phenomenon inaviation industry Experimental tests for bird strike certification are very expensive and time consuming In orderto decrease the number of costly sample tests a trustworthy analytical tool is necessary to precisely predict thestructural responses of bird and the target One of the most efficient methods in bird strike analysis is the finiteelement method In this study first three numerical methods namely Lagrange Smoothed ParticlesHydrodynamics SPH and Arbitrary Lagrangian Eulerian ALE have been used in order to investigate bird strikeincident The results have been compared with each other and also with experimental data In order to compare theresults obtained from three methods pressures at the center of impact and also deformation of bird models havebeen compared Results indicate that all the three methods are able to predict the pressure at the center of impactalmost accurately in both perpendicular and inclined impacts Next a bird model with geometry similar to a real bird Bufflehead Duck is introduced and compared totraditional bird models and also to experimental data Modelling a bird with a realistic body shape makes itpossible to investigate the effect of bird orientations in the bird strike on structures A bird can impact a part of anairplane from its head tail bottom or wings Any of these orientations can have a different effect on the responseand thus the integrity of an airplane part Since all birds do not have the same body shapes and sizes and since itis not always convenient to model a complex bird body four substitute bird models are introduced The modelsresults are then compared in order to determine the best substitute bird which can properly model the pressure andforce exerted by real birds when impacting from different orientations Based on the numerical simulations it canbe concluded that the impact from bird bottom side is the most damaging scenario while the tail side impact is theless dangerous one It was also found that for the tail side impact scenario a hemispherical ended cylinder showsthe best results while for the bottom side impact scenario an ellipsoid can be the best candidate for the birdsubstitute model In order to investigate the effect of orientation of bird more thoroughly a real mallard anatomy is numericallycreated from CT images and then used for analysis by SPH method The result produced by the real bird iscompared to that of the traditional bird models The effects of considering the cavities air and differentorientations at which a mallard strikes a target are also investigated In order to study the effect of orientation ofbird on bird strike events four impact scenarios were considered and simulated the impact from bottom head tailand wing sides It was found again that the impact from the bottom side is the most damaging scenario while theimpact from the wing side is the safest impact scenario Finally bird impact against an airplane tailplane is investigated Different tailplanes types i e with or withoutfoam core and different layup thicknesses have been considered and their results have been compared to eachother Keywords Bird Strike Tailplane SPH ALE Lagrangian Horizontal Stabilizer Finite Element Method

هدايتي، رضا

مدل سازي پرنده و تحليل برخورد آن با لبه دم عقب هواپيما

SPH , ALE , دم افقي هواپيما