Abstract

A study on the optimization of tapered composite beams for vibration is conducted. Designers of tapered rotating structural components such as wind mill, helicopter or turbine blades are increasingly considering composite materials as an option to create lighter structures without compromising structural stiffness and to significantly increase their efficiency. In the design of composite material structures, a challenge arises due to a large number of design variables, therefore numerical optimization is required for a better design. Given this, the purpose of this study is to propose an optimization methodology for the design of a tapered beam, considering the vibration constrains present in rotating components. This is achieved by coupling a numerical model which considers the bending modes of vibration, with an optimization algorithm, both coded in MATLAB. Five optimization algorithms, heuristic and deterministic, are coded and compared and the most efficient method is selected. Because the ply orientation angles can assume an infinite number of possible angles, or follow the regular 0 / ±45 / 90 degrees approach, four possible tuning approaches are defined. The beam is optimized for the following design cases of boundary conditions and design requirements: the presence or absence of a tensile axial force, the presence or absence of a taper, three taper configurations, four proposed structural tuning approaches and four boundary conditions. Two of these structural tuning approaches are compared for its influence in the dynamic behavior of the structural component and in achieving better values of in-plane and out-of-plane stresses. The results demonstrate the Genetic Algorithm is an efficient method for optimization, a design analysis is an important step in optimization, and an appropriate tuning approach can improve the overall efficiency of the optimized structure.