Damage evolution in composite materials under environmental ageing: a stochastic model with experimental validation

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dc.contributor Barkey, Mark E.
dc.contributor Roy, Samit
dc.contributor Wu, Zhijian
dc.contributor.advisor Haque, Anwarul
dc.contributor.author Rahman, Rezwanur
dc.date.accessioned 2017-02-28T22:22:31Z
dc.date.available 2017-02-28T22:22:31Z
dc.date.issued 2009
dc.identifier.other u0015_0000001_0000164
dc.identifier.other Rahman_alatus_0004M_10214
dc.identifier.uri https://ir.ua.edu/handle/123456789/670
dc.description Electronic Thesis or Dissertation
dc.description.abstract This work emphasizes on predicting probability density function of damages or "number density of damage" in graphite/epoxy polymer matrix composite materials (PMC) under hygrothermal aging condition. A coupled Forward-Backward Stochastic Differential Equation (FBSDE) is proposed as a mathematical model to predict number density of damages. The FBSDE consists of damage nucleation and annihilation rate in terms of Brownian motion. The uncertainty in damage nucleation and annihilation rate is noticed by proposing these two terms as "Brownian motion with drift". In order to verify the proposed model, a quantitative analysis was carried out on a limited number of graphite/epoxy specimens manufactured by VARTM process. The specimens were kept in a hygrothermal condition with room temperature cycling. A rigorous quantitative analysis of damages was done by optical microscopic inspection at different stages of aging period. The damages were classified based on the criteria of their size. Finally, the experimentally collected data for number density of damages were verified by using the proposed FBSDE. A detail parametric study was carried out using FBSDE and best possible predicted data was validated with the experimental observation. A reasonable estimation was observed from the model output.
dc.format.extent 87 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Engineering, Aerospace
dc.subject.other Applied Mechanics
dc.subject.other Applied Mathematics
dc.title Damage evolution in composite materials under environmental ageing: a stochastic model with experimental validation
dc.type thesis
dc.type text
etdms.degree.department University of Alabama. Dept. of Aerospace Engineering and Mechanics
etdms.degree.discipline Aerospace Engineering
etdms.degree.grantor The University of Alabama
etdms.degree.level master's
etdms.degree.name M.S.

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