Perpustakaan Digital ITB

Modern aircraft, particularly military fighters, are designed to operate at high speed, high altitude and high mobility conditions while carrying equipment in the form of external stores. The external stores are carried with attachments under the aircraft wings, and these external stores may change the dynamic characteristic of the wing structure and alter the aeroelastic response. The installation and location of the wing stores changes the distribution of mass over the wing structure, which plays key role in determining the mode shapes and aeroelastic characteristic of the structure. Since the significant effect of store installation may cause changes in dynamic characteristic and aeroelastic response, dynamic structural analysis and dynamic aeroelastic analysis must be conducted to understand how installment location of these wing stores affects the aeroelasticity of the structure, to prevent structural failure. The dynamic structural analysis and dynamic aeroelasticity analysis utilizes finite element method (FEM) to model the wing, as an elastic body, with concentrated mass and rigid body as the wing store. The wing model is taken from Bae et al [1], reconstructed and then validated via the structural dynamic analysis and the aeroelastic analysis, with results showing validity of the reconstructed model boasting an error of less than 5% for both analysis. The dynamic structural and aeroelastic analysis results in the natural frequency of the structure and mode shapes, as well as critical flutter speed, respectively. The aeroelastic analysis uses the doublet-lattice method, to model the unsteady aerodynamic conditions, while the P-K method is used to obtain the flutter solution. The results pinpoint the parameters that affect flutter on an aircraft wing. The parameters that affect flutter significantly are the location of the store CG in the spanwise and chordwise direction, store model and store properties, such as geometrical and mass properties. When compared to the clean wing, the shifts of store CG in the chordwise to the trailing edge increases instability by 12%, for both store models. Meanwhile, shifts of the store CG in the spanwise direction show both instability and stability depending on the location of the store and the model of the store. The 0-D lumped mass store show stability increase of up to 35% depending on the store attached, while the 1-D beam element store shows both stability and instability increase of up to 6%. The implementation of inertia from the beam element affects the wing’s flutter behavior differently, than mere mass concentration from the lumped mass.