Structural Analysis of Aircraft StructuresIntroductionAircraft are usually built from components such as wings, fuselages, tail units, engines, flight control surfaces, stabilizers, main rotor assembly , tail rotor assembly and landing gear with very few exceptions as designed. Each component has one or more categorical functions and must be designed to ensure that it can perform these functions safely. A fixed-wing aircraft has wings, fuselages, engines, flight control surfaces, stabilizers, and landing gear, and a rotary-wing aircraft has the main rotor assembly, tail rotor assembly, fuselages, engines, and landing gear. A good aircraft structure is one that provides all the strength and rigidity necessary to allow the aircraft to meet all its design requirements, but which does not weigh more than necessary. The important factors to be taken into consideration in aircraft structures are strength, weight and reliability which determine the requirements that the materials used in the construction or repair of the aircraft must meet. The cells must be light and resistant. All materials used in the construction of an aircraft must be reliable. Reliability minimizes the possibility of dangerous and unexpected failures. Many structural forces and stresses act on an aircraft both in flight and on the ground. When on the ground, gravity generates weight, which is reinforced by the landing gear. The landing gear absorbs the forces imposed on the aircraft by takeoffs and landings. Any maneuver that causes acceleration or deceleration during flight increases forces and stresses on the wings and fuselage. The stresses acting on the wings, fuselage and landing gear are tension, compression, bending, shear and torsion. The stress… at the center of the paper…) resulting stress is calculated for a given shell gauge pressure which is generally 12 psig. For the fuselage, the longitudinal bending moment distributions are examined from three load cases. Loads are calculated for a quasi-static pull-up maneuver, a landing maneuver, and a ride over runway bumps. Different structural fuselage geometries are available. There is a concept of simply stiffened shell using longitudinal frames. There are three concepts with Z-stiffened shells and longitudinal frames; one with structural material proportioned to provide minimal weight upon deformation, one with deformation efficiency compromised to provide lighter weight in minimal thickness, and one with a compromise on tip pressure. Likewise, there are three truss core sandwich designs, two for minimum weight under deformation with and without frames and one for a compromise between minimum caliber and deformation.