Idalberto Mendoza (Prof.)Kirubeil Awoke2024-03-122024-03-122011-07https://etd.aau.edu.et/handle/123456789/2370Aircrafts and its airframes are subjected to various kinds of time dependent loadings; ranging from flight loads to ground maneuvering loads. In this thesis, the dynamic responses such as stress, strain or displacement near the crack tips on the all composite made fuselage structure when landing on various types of take off and landing pavement are assessed. Finite element modeling and analysis for all composite made fuselages is done using the layered shell element 4 node 63. A crack of significant parameter is generated on the outer top part of the shell for initiation of fracture. One leg model of the landing gear is used to drive the required mathematical formulations. The crack tips responses to random excitation caused by road roughness are determined. The excitation includes smooth, pastured and ploughed take off and landing strips. In all curves as the crack length increases the displacement and stresses response near the crack tips increases. We can see from the literature that the applied stress is directly proportional to the square root of the half crack length. This result was verified experimentally by Griffith for a wide range of crack length. This confirms both the analytical and experimental results obtained by Griffith’s and other similar researchers. From the curves we can observe that the shell responds relatively lowest stress and displacement response to class A than Class G and Class H pavement. Class H has the worst stress and strain response near crack tips and much affects and severs the thin structure. More over, stress and strain response to circumferential crack orientation is higher than the corresponding longitudinal one. This is probably due to the stress waves are perpendicular to the orientation of a crack, and which maximizes the local stress. Generally, the shell structure has higher strength to weight ratio and has higher stress and strain carrying capability, trends should look for using shells as their primary structure. Moreover, in the event of forced and emergency landing, the pilot has recommended to land as much as possible on Class G pavement than Class H pavement so that the applied stress is optimized.en-USCompositeShell fuselageCrackRandom vibration analysisPower spectral densityGround induced excitationspavement roughness data.Thesis