Date of Award

12-1991

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Aeronautics and Astronautics

First Advisor

Anthony N. Palazotto, PhD

Second Advisor

Shankar Mall, PhD

Abstract

To analyze the current Aircraft Battle Damage Repair (ABDR) techniques, a finite element model (FEM) of a curved composite panel with a center cutout section was developed and verified against previously obtained modal test results. The FEM was modified using different methods to exhibit the effects of riveting on an aluminum patch to repair the section. The different methods were contrasted against each other and previously obtained modal test results. The panel, a (0/-45/+45/90) sub s layup of AS4/3501 graphite epoxy measuring 12 inches in height and 12.19 inches across its arc length with a 2 by 4 inch cutout at a 0, +45, -45, or 90 degree orientation was modeled using MSC/NASTRAN QUAD4 elements. The first repair modeling method used a mixture of the aluminum and composite panel properties to represent the overlap region of the patch. The second method used ELAS2 and CONM2 elements to model the rivets, and modelled the panel and the patch separately. GAP elements prevented the patch from deforming through the panel. For the mixed properties, the mode shapes agreed with experimental data at lower frequencies but were distorted at the higher ones and were regularly 5-25% high. Modeling the rivets individually produced matching mode shapes and frequencies regularly within 5% of experimental values.

AFIT Designator

AFIT-GAE-ENY-91D-3

DTIC Accession Number

ADA243916

Comments

The author's Vita page is omitted.

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