Effects of Wall Thickness on Frequencies of Flat Plates and Cylindrical Shells

Thin walled structures are utilized in multiple applications of engineering such as aircraft and spacecraft structures primarily to reduce weight. However, these engineering systems also experience complex dynamic loads such as torsional, axial, and buckling loads that can ultimately cause failures under dynamic environment. The purpose of this study is to better understand mode couplings resulting from the structural wall thickness reduction and to establish a critical thickness boundary. The case study is an empty cylindrical shell with uniform thickness and one open end. The cylindrical structure will be studied under various wall thicknesses for free vibration response using commercial finite element software MSC Software: Patran/Nastran. The finite element analysis results will be presented as a function of wall thickness, frequency and mode shapes. The results from computational simulations will be compared to experimental measurements from in house experiments being conducted by our DynaaTECC (Dynamics, Acoustics, Aeroelasticity, Theory, Experiments, Computations, Control) research group. Experimental and computational results will be compared in terms of frequency and mode shape values.