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Thomas W. Eagar. Hohmann, Brian P. (Brian Patrick) Massachusetts Institute of Technology. Dept. of Materials Science and Engineering. Massachusetts Institute of Technology. Department of Materials Science and Engineering 2007-08-29T20:31:20Z 2007-08-29T20:31:20Z 2007 http://hdl.handle.net/1721.1/38585 156793852 Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007. "February 2007." Vita. Includes bibliographical references (leaves 158-160). An experimental study was carried out to determine the mechanical behavior of sandwich panels containing cellular cores of varying shape. Compression and four point bend tests were performed on sandwich panels with square and triangular honeycomb cores. These honeycombs were made of perforated aluminum sheet of repeating diamond and hexagonal patterns. The sandwich panel assemblies were joined via dip brazing. Defects were introduced into some panels to quantify the effect on strength and stiffness. Hybrid sandwich panels, consisting of foam material in the void spaces of the square and triangular cells were evaluated for the effect on the defect tolerance of the structures. The results showed that sandwich panels with diamond shaped cores had compressive strengths approximately four times greater than hexagonal shaped cores. In four point bending the diamond cores were approximately twice as stiff as cores made from hexagonal patterned sheet. The introduction of defects lowered strength by about 30% for diamond cores in compression, and about 15% for hexagonal cores. In four point bending this strength reduction was not as significant due to shear stresses damaging periodicity at a faster rate than in compression. (cont.) The use of foam within the cells resulted in higher absolute peak compression and flexure loads, however the Load/Density ratios demonstrated cases where the added weight of the foam did not result in a better panel. A difference of nearly an order of magnitude between the highest and lowest compressive and flexure loads is evident when the presence of defects and foam are taken into account. by Brian P. Hohmann. S.M. 161 leaves eng Massachusetts Institute of Technology 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. http://dspace.mit.edu/handle/1721.1/7582 Materials Science and Engineering. Mechanical behavior of dip-brazed aluminum sandwich panels Thesis application/pdf Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="f21e6dbf-fc59-43ce-ac19-201ed98041e1"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Mechanical behavior of dip-brazed aluminum sandwich panels</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2007</PublicationDate> <Authors> <Author> <DisplayName>Hohmann, Brian P. (Brian Patrick)</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Materials Science and Engineering.</Keyword> <Abstract>An experimental study was carried out to determine the mechanical behavior of sandwich panels containing cellular cores of varying shape. Compression and four point bend tests were performed on sandwich panels with square and triangular honeycomb cores. These honeycombs were made of perforated aluminum sheet of repeating diamond and hexagonal patterns. The sandwich panel assemblies were joined via dip brazing. Defects were introduced into some panels to quantify the effect on strength and stiffness. Hybrid sandwich panels, consisting of foam material in the void spaces of the square and triangular cells were evaluated for the effect on the defect tolerance of the structures. The results showed that sandwich panels with diamond shaped cores had compressive strengths approximately four times greater than hexagonal shaped cores. In four point bending the diamond cores were approximately twice as stiff as cores made from hexagonal patterned sheet. The introduction of defects lowered strength by about 30% for diamond cores in compression, and about 15% for hexagonal cores. In four point bending this strength reduction was not as significant due to shear stresses damaging periodicity at a faster rate than in compression.</Abstract> <Abstract>(cont.) The use of foam within the cells resulted in higher absolute peak compression and flexure loads, however the Load/Density ratios demonstrated cases where the added weight of the foam did not result in a better panel. A difference of nearly an order of magnitude between the highest and lowest compressive and flexure loads is evident when the presence of defects and foam are taken into account.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>