Elastic Response of Acoustic Coating on Fluid-Loaded Rib-Stiffened Cylindrical Shells

dc.contributor.authorDoherty, Christopher Gillesen
dc.contributor.committeechairSouthward, Steve C.en
dc.contributor.committeememberAhmadian, Mehdien
dc.contributor.committeememberKurdila, Andrew J.en
dc.contributor.departmentMechanical Engineeringen
dc.date.accessioned2017-06-30T08:01:08Zen
dc.date.available2017-06-30T08:01:08Zen
dc.date.issued2017-06-29en
dc.description.abstractReinforced cylindrical shells are used in numerous industries; common examples include undersea vehicles and industrial piping. Current models typically incorporate approximate theories to determine shell behavior, which have limitations in terms of both thickness and frequency. In addition, many applications feature coatings on the shell surface that normally have thicknesses which must also be considered. To increase the fidelity of such systems, this work develops an analytical model of an elastic cylindrical shell featuring periodically spaced ring stiffeners with an acoustic coating applied to the outer surface. There is an external fluid environment. Beginning with the equations of elasticity for a solid, spatial-domain displacement field solutions are produced incorporating unknown wave propagation coefficients. These fields are used to determine stresses at the boundaries of the shell and coating, which are then coupled with stresses from the stiffeners and fluid. The stress boundary conditions contain double-index infinite summations, which are decoupled, truncated, and recombined into a global matrix equation. The solution to this global equation results in the displacement responses of the system as well as the scattered pressure field. Two distinct loadings are considered: a ring loading and an incident acoustic wave. Thin-shell reference models are used for validation, and the acoustic response of the system is examined. It is shown that the reinforcing ribs and acoustic coating have a considerable effect on system behavior.en
dc.description.abstractgeneralReinforced cylindrical shells are used in numerous industries; common examples include undersea vehicles and industrial piping. Current models typically incorporate approximate theories to determine shell behavior, which have limitations in terms of both thickness and frequency. In addition, many applications feature coatings on the shell surface that normally have thicknesses which must also be considered. To increase the fidelity of such systems, this work develops an analytical model of an elastic cylindrical shell featuring periodically spaced ring stiffeners with an acoustic coating applied to the outer surface. There is an external fluid environment. Beginning with elastic equations of motion for a solid, the displacements of the system can be found. These displacements are used to determine stresses at the boundaries of the shell and coating, which are then coupled with stresses from the stiffeners and fluid. Techniques are used to transform the stress boundary conditions into a large matrix equation, and the solution to this global equation results in the displacement responses of the system as well as the scattered pressure field. Two distinct loadings are considered: a ring loading and an incident acoustic wave. Thin-shell reference models are used for validation, and the acoustic response of the system is examined. It is shown that the reinforcing ribs and acoustic coating have a considerable effect on system behavior.en
dc.description.degreeMaster of Scienceen
dc.format.mediumETDen
dc.identifier.othervt_gsexam:10303en
dc.identifier.urihttp://hdl.handle.net/10919/78288en
dc.publisherVirginia Techen
dc.rightsIn Copyrighten
dc.rights.urihttp://rightsstatements.org/vocab/InC/1.0/en
dc.subjectReinforced cylinderen
dc.subjectacoustic coatingen
dc.subjectelasticityen
dc.subjectorthogonalizationen
dc.titleElastic Response of Acoustic Coating on Fluid-Loaded Rib-Stiffened Cylindrical Shellsen
dc.typeThesisen
thesis.degree.disciplineMechanical Engineeringen
thesis.degree.grantorVirginia Polytechnic Institute and State Universityen
thesis.degree.levelmastersen
thesis.degree.nameMaster of Scienceen

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