INVESTIGATION OF THE EFFECT OF ALTERNATIVE REFERENCE FIBER PATH DEFINITIONS ON DESIGN OPTIMIZATION OF FIBER-PLACED LAMINATES FOR IMPROVED FAILURE AND BUCKLING LOADS

Date

2025-2-28

Author

İnci, Hasan

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Advanced composite materials facilitate the customization of material properties, particularly through the implementation of curvilinear fiber paths to develop variable stiffness composites. The current designs are governed by curvature and Tsai-Wu failure index constraints, and the evaluation of global optima is conducted using two distinct metaheuristic optimization algorithms. Traditionally, reference curvilinear fiber paths are defined using various mathematical functions. This thesis introduces and systematically evaluates an alternative approach for defining reference fiber paths in three-dimensional structures and its applications. The proposed fiber path methodology is analyzed in the context of plates with holes and a wing torque box with an NACA 4412 profile, with the primary objectives of maximizing the buckling load factor and minimizing compliance. The findings indicate that the polynomial-based reference fiber path performs competitively, often achieving slightly superior results compared to established reference fiber path definitions. Two key outcomes are demonstrated in this study. First, the application of the polynomial reference fiber path to three-dimensional wingbox skins is achieved using analytical three-dimensional expressions, with buckling and compliance objectives remaining the focus. Second, the effects of single, dual, and triple region automated fiber placement on optimal buckling load and compliance are examined. The results reveal improvements, for buckling load factor, 37% compared to the optimal straight fiber case and 94% compared to the quasi-isotropic case and for compliance, 33% improvement compared to the optimal straight fiber case and 24% compared to the quasi-isotropic case. This approach highlights the potential to enhance optimization outcomes by increasing the number of skin panels between rib stations, each characterized by unique reference fiber path definitions.

Subject Keywords

Composite Structures, Optimization, Surrogate Model, Curvilinear Fiber Path, Aircraft Wing Torque Box

URI

https://hdl.handle.net/11511/113820

Collections

Graduate School of Natural and Applied Sciences, Thesis