Date of Award

3-1993

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Aeronautics and Astronautics

First Advisor

Anthony N. Palazotto, PhD

Abstract

The purpose of this thesis was to determine (both experimentally and analytically) the initiation and progression of failure, stress-strain response, and the failure loads of Graphite/Polyetheretherketone (Gr/PEEK) laminates, incorporating a centrally located circular discontinuity, loading in axial compression at room temperature. The laminates studied were (0°)16,(90°)16, (0°/90°)4S, (± 45°)4S, and (0°/±45°/90°)2S. The specimens were loaded within a Boeing Open Hole Compression Fixture. The micromechanical failure modes were identified using a Scanning Electron Microscope. The analytical progression of failure was predicted using a nonlinear finite element code developed by Dr. R.S. Sandhu of Wright Laboratories. The code utilizes a total energy method predicated upon the material properties curves obtained form experimentation to compute the stress-strain response of the material as well as the progression of failure within the model. Results were compared and conclusions were drawn. The comparison showed the the finite element code did a good job in predicting the behavior of the 0°,± 45°, 0°/90°, and 0°/±45°/90° laminates well, but did not model the nonlinear behavior of the 90°. The analytical failure loads could not be exactly determined, but estimation were made and the code predicted failure between 2% and 25% of the actual failure load...

AFIT Designator

AFIT-GA-ENY-93M-01

DTIC Accession Number

ADA262549

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