Natural Frequencies and Mode Shapes of Curved Rectangular Composite Panels with Interior Cutouts.
Abstract
A finite element computer code, STAGSC-1 and holographic interferometry were used to determine the effects of interior cutouts on the first five natural frequencies and mode shapes of curved Graphite Expoxy panels. The panels are a quasi-isotropic layup with a 12 inch chord and height. Both the finite element and holographic analysis were conducted using clamped-clamped boundary conditions. The vibration branch of STAGSC-1 is a energy technique based on small displacements and linear elastic stress-strain relationships. When compared with the time averaged holograms of the experimentally determined natural frequencies and mode shapes, the two techniques show a close correlation of both frequency and shape. It was found that for the 2 x 2 inch cutout, the mode shapes change very little while the natural frequencies displayed a small decrease for the higher modes. The 2 x 4 inch cutout retained the general mode shape of the solid panel for the first two modes. The third through the fifth mode shapes were changed by this cutout and the loss of panel stiffness was visible. The 4 x 4 inch cutout exhibit both a switch in symmetry of the first two modes and a general decrease in natural frequencies. (Theses)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1985
- Accession Number
- ADA165269
Entities
People
- Richard A. Walley
Organizations
- Air Force Institute of Technology