Dynamic Response of Doubly-Tapered Laminated Composite Beams Under Periodic and Non-Periodic Loadings PDF Download

Author: Pramod Kumar
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

Get Book

Book Description
Doubly-tapered laminated composite beams provide a great opportunity to enhance capabilities such as high strength-to-weight ratio, high modulus-to-weight ratio, and design flexibility. Due to design tailoring capabilities, the use of doubly-tapered composite beams has increased in the automobile industry and aerospace industry. In the present thesis, the free and forced vibration analyses of the width-and-thickness-tapered, called herein as doubly-tapered, laminated composite beams are conducted considering different boundary conditions, taper configurations, and loadings. The exact and closed-form solutions for the mode shapes and natural frequencies of doubly-tapered composite beams could not be acquired because of the complexity of the corresponding partial differential equations. Therefore, the classical laminate theory and the one-dimensional laminated beam theory in combination with the Ritz method are used in evaluating the stiffness and mass matrices of the composite beam. The natural frequencies and the corresponding mode shapes are determined by solving the eigenvalue problem obtained using the Ritz method. The forced vibration analysis of the doubly-tapered composite beams subjected to the transverse periodic and non-periodic loadings is carried out by representing the periodic loading as the superposition of the harmonic components of various frequencies using the Fourier series expansion and by expressing the non-periodic pulse excitation as the superposition of two or more simpler functions for which solutions are easier to determine. The maximum deflection of the doubly-tapered composite beam in spatial and time coordinates is determined. Numerical and symbolic computations have been performed using MATLAB® software. The solutions to the free and forced vibration analyses of the composite beams are compared, with the solution available in the literature and with the solution based on the Finite Element Method obtained using ANSYS®, to demonstrate solution accuracy. The Rayleigh damping is considered to model the viscous damping of the composite beam. A detailed parametric study is carried out to investigate the influences of the loading components in the Fourier series expansion, loading type, period of the periodic loading, the rise and fall times of the non-periodic loadings, taper angle, width ratio, thickness ratio, laminate length, stacking sequence, and taper configuration on the forced response of the doubly-tapered composite beam considering different boundary conditions.