Date of Award

Fall 2020

Document Type


Degree Name

Master of Science (MS)


Mechanical & Aerospace Engineering


Aerospace Engineering

Committee Director

Oleksandr Kravchenko

Committee Member

Gene Hou

Committee Member

Miltos Kotinis

Committee Member

Andrew E. Lovejoy


Commercial and private aircraft have a need for strong yet light materials in order to have the most ideal performance possible. This study looks at the use of thin-ply composite materials to improve the performance of aircraft structures by means of weight savings and/or strength increase when compared to laminates that are composed of exclusively standard-ply materials. In order to perform an investigation based solely on finite element analysis, validation efforts were performed using test data from open hole tension, open hole compression, notched tension, and notched compression specimens. Once the models were validated sufficiently, the same modeling practices were used to compare laminates with varying ply angle orientations and various laminate stacking sequences. Initial investigations showed that for a one-to-one comparison of standard-ply laminates to hybrid laminates, there can be up to a 10% tensile load advantage, as well as an over 40% compressive load advantage when considering the final failure load of a small notched specimen. Secondary investigations showed that changing the ply angle orientation away from a more typical 45° ply to angles at various increments of 10° and 15° can yield both tensile and compressive advantages simultaneously. A final investigation determined that by adding or removing certain plies from the laminate, the previously mentioned tension and compression advantages can be expanded upon for failure load advantages up to 65% higher than baseline specimens, as well as the ability to potentially change failure modes. All of these load and damage mechanism advantages also come with the added benefit of weight savings between 10-25% of the baseline specimen original weight. The study presented herein shows initial successes in determining laminates that will reduce weight while increasing strength under various loading conditions.


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