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Accession Number:
ADA280689
Title:
Effects of Thickness and Curvature on the Natural Frequencies of Cylindrical Composite Shells
Descriptive Note:
Master's thesis
Corporate Author:
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
Report Date:
1994-06-14
Pagination or Media Count:
100.0
Abstract:
An analytical study is performed to determine the dynamic response, natural frequencies and mode shapes, of deep composite cylindrical shells, including the effects of through the thickness shear strain. The DSHELL finite element program is used to predict the first four natural frequencies and the results are compared to a reference using the Galerkin technique. The program was extended to problems considering simply supported-free boundary conditions. The mode shapes are created by plotting a surface-contour plot of the eigenvector vector output from DSHELL. A linear free vibration analysis is performed on two graphiteepoxy panels. These panels have different ply orientation. Comparisons between the first panel used as a baseline using DSHELL, with previous analytical and experimentation studies were found to correlate well. For the second panel, the curvature and the span to thickness ratio were varied in order to measure effects on two ply orientations0 deg90 degs and -45 deg45 degs, under two boundary conditions. The results showed that, as the shell becomes deeper, the frequency becomes smaller. Also as the curvature increases, the Linear dynamics, Eigenvalue-eigenvector, Finite element.
Distribution Statement:
APPROVED FOR PUBLIC RELEASE
