Perpustakaan Digital ITB

Composite materials are widely used in aerospace structures due to their high strength-to-weight ratio and directional stiffness control. This thesis investigates how fiber orientation and the presence of cracks affect the dynamic behavior and aeroelastic stability of a composite wing structure. The study focuses on both unidirectional and multidirectional layup configurations, analyzing the effects of crack location and crack length on natural frequencies, mode shapes, divergence speed, and flutter speed. Numerical simulations are conducted using the Finite Element Method (FEM) based on a shear-layer laminate modeling approach to accurately capture the dynamic behavior of multilayer composites. Aeroelastic analysis is performed using the Doublet Lattice Method (DLM) to evaluate fluid-structure interaction and predict instability thresholds. The simulations are implemented using MSC Patran and Nastran software to assess the structural and aeroelastic responses comprehensively. The results demonstrate that fiber configuration significantly influences the structural response, with multidirectional layups offering better balance and reduced sensitivity to damage. Certain fiber orientations provide enhanced performance under specific crack conditions, highlighting the potential of fiber arrangement to improve structural stability. These findings contribute to a deeper understanding of damage effects in composite wings and offer valuable insights into the design of more robust aeroelastic structures.