Degree Type

Honors Capstone Project

Date of Submission

Spring 5-1-2009

Capstone Advisor

Dr. Barry Davidson

Honors Reader

Dr. Alan Levy

Capstone Major

Mechanical and Aerospace Engineering

Capstone College

Engineering and Computer Science

Audio/Visual Component


Capstone Prize Winner


Won Capstone Funding


Honors Categories

Sciences and Engineering

Subject Categories

Aerospace Engineering | Other Aerospace Engineering | Structures and Materials


Optimal use of laminated composite materials can only be achieved if its most common failure mechanisms are well understood. One of the most common modes of failure in laminates is delamination, or the separation of adjacent material layers. Therefore, there is a need to be able to predict a laminated composite’s resistance to delamination growth due to the complex real-world application loadings that it may experience. These complex loadings are made up of three primary modes of delamination growth, known as modes I, II, and III. Test fixtures for a new mixed mode I-II-III delamination toughness test were designed, built, and used to perform exploratory experiments. The test utilizes laminated composite test specimens that are similar to those used in other established toughness tests. The specimen is approximately 25 mm wide, 150 mm long and between 3 and 6 mm thick. The new test fixture may be installed in a standard uniaxial tension load frame, and includes two screw driven actuators. Three separate loads are applied to the specimen: one through the test machine’s hydraulic actuator and two using the screw driven actuators. The relative amounts of mode I, II and III loading may be adjusted by varying the relative magnitudes of these three loads. The new test set-up was used to perform a series of mode I, mode III, and mixed mode I-III delamination toughness tests on unidirectional T800S/3900-2B graphite/epoxy specimens. These tests yielded promising results, but a limited amount of fixture modifications were required to reduce frictional resistance. A set of proposed fixture modifications were therefore devised and are described herein.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.



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