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Structural optimization of composite and aluminum horizontal tail plane of a helicopter

Arpacıoğlu, Bertan
This thesis presents structural optimization studies of aluminum and composite material horizontal tail plane structure of a helicopter by using MSC.NASTRAN optimization capabilities. Structural design process starts from conceptual design phase, and structural layout design is performed by using CATIA. In the preliminary design phase, study focuses on minimum weight optimization with multiple design variables and similar constraints for both materials. Aerodynamic load calculation is performed using ANSYS and pressure distribution is used as the common loading for both aluminum and composite horizontal tail. Horizontal tail plane finite element model is created by using MSC.PATRAN. According to the characteristics of materials, design variables are chosen. For aluminum horizontal tail, thickness and flange areas are used as design variables; and for composite horizontal tail, attention is mainly focused on the ply numbers and ply orientations of the laminated composite panels. By considering manufacturability issues, discrete design variables are used. For different mesh sizes, initial values of the design variables, and design constraints, optimizations are repeated and the results of optimizations are examined and compared with each other. In the optimizations performed, constraints are taken as strength and local buckling constraints. It is shown that the optimization methodology used in this thesis gives confident results for optimizing structures in the preliminary design phase.