Establishment of an experimental method for a grooved composite subjected to out-of-plane contact loading

A specimen and an experimental method to observe the behavior of a grooved composite subjected to out-of-plane contact loading is established and verified, and its response is examined. The specimen is designed so that the variability of stress-strain state is negligible across the width of the specimen. The dominant concept of the design is to isolate the response of the specimen around the groove from any other effects. Geometric parameters, stacking sequence (layup), and boundary conditions are determined for the specimen. With simply-supported boundary conditions, specimens fail in a simple beam shear mode as determined from the overall structural response of the specimen, thereby indicating that this configuration is not appropriate for the primary design goal. Thus, the rigid backface boundary condition is chosen and verified as the appropriate configuration. Contact, load transfer, and alignment issues arose in the first set of rigid backface tests and were solved by introducing finer machining, harder material for the indenter, and overall alignment with better accuracy. This resulted in the final test specimen configuration and associated test method, consisting of a specimen with a length of 56.00 mm, a width of 25.00 mm, an approximate thickness of 12.5 mm, and a maximum groove depth of 3.48 mm. The standard layup used for the tests is [F45/0/90]1os, while an alternate layup of [T30/0]13S was also used. In these tests, a number of key behaviors were observed: mode of failure, load-per-stroke slope, and "knee load".

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Aeronautics and Astronautics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2009

Author dc:creator

• Kobayashi, Yusuke, S. M. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Paul A. Lagace.

• Aeronautics and Astronautics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/54617

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/54617