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Scaling studies on the tensile strain rate sensitivity of laminated composites

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dc.contributor.advisor Raju, Keshavanarayana Suresh
dc.contributor.author Siddiqui, Md. Tareq
dc.date.accessioned 2012-06-21T15:28:13Z
dc.date.available 2012-06-21T15:28:13Z
dc.date.copyright 2011 en
dc.date.issued 2011-12
dc.identifier.other t11119
dc.identifier.uri http://hdl.handle.net/10057/5207
dc.description Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering. en_US
dc.description.abstract The stress-strain behavior and failure of composite materials are strain rate sensitive, and influenced by the dimensions of the structure. To elucidate the combined effects of scaling and strain rate on the strength of unnotched continuous fiber reinforced composites, an experimental investigation has been conducted on Newport NB321/7781 fiberglass/epoxy and Toray T800/3900-2B unitape/epoxy materials. The experimental results have been characterized in terms of failure strength, failure modes and the Weibull modulus m. A 2D-scaling approach has been followed and composite coupons were fabricated with [0]4 and [±45]s stacking sequences. The experimentation has been conducted at strain rates ranging from quasi-static (0.0002 s^-1) to high strain rate (50 s^-1), to study the mechanical responses and associated failure modes. Subsequently, the Weibull statistical model was utilized to characterize the scaling behavior at different strain rates. The average failure stress of [0]4 carbon, [0]4 fiberglass and [±45]s fiberglass specimens were observed to decrease with increasing specimen size at each strain rate. However, at high strain rate, the percentage of strength reduction was observed to be lower in comparison to the quasi-static strain rate. Owing to the free edge effects, the scaling effect was maximum for [+45/-45]s carbon unitape specimens. But unlike the other stacking sequences, the percentage of strength reduction at higher strain rates was higher compared to quasi-static strain rate, indicating increased scaling effects with strain rate. Weibull modulus m for the specimens tended to increase with increasing strain rate indicating diminishing scaling effects, while [+45/-45]s carbon specimens exhibited opposite trend. Failure at multiple locations was observed in larger coupons at high strain rate, which results in size and strain rate dependent fracture behavior. en_US
dc.format.extent xv, 123 p. en
dc.language.iso en_US en_US
dc.publisher Wichita State University en_US
dc.rights Copyright Md Tareq Siddiqui, 2011. All rights reserved en
dc.subject.lcsh Electronic dissertations en
dc.title Scaling studies on the tensile strain rate sensitivity of laminated composites en_US
dc.type Thesis en_US

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