Use of Material Tailoring to Improve Axial Load Capacity of Elliptical Composite Cylinders
dc.contributor.author | Sun, Miao | en |
dc.contributor.committeechair | Hyer, Michael W. | en |
dc.contributor.committeemember | Patil, Mayuresh J. | en |
dc.contributor.committeemember | Case, Scott W. | en |
dc.contributor.committeemember | Cramer, Mark S. | en |
dc.contributor.committeemember | Librescu, Liviu | en |
dc.contributor.department | Engineering Science and Mechanics | en |
dc.date.accessioned | 2014-03-14T20:18:50Z | en |
dc.date.adate | 2006-12-01 | en |
dc.date.available | 2014-03-14T20:18:50Z | en |
dc.date.issued | 2006-11-16 | en |
dc.date.rdate | 2006-12-01 | en |
dc.date.sdate | 2006-11-20 | en |
dc.description.abstract | This study focuses on the improvement of the axial buckling capacity of elliptical composite cylinders through the use of a circumferentially-varying lamination sequence. The concept of varying the lamination sequence around the circumference is considered as a viable approach for off-setting the disadvantages of having the cylinder radius of curvature vary with circumferential position, the source of the reduced buckling capacity when compared to a circular cylinder with the same circumference. Post-buckling collapse behavior and material failure characteristics are also of interest. Two approaches to implementing a circumferential variation of lamination are examined. For the first approach the lamination sequence is varied in a stepwise fashion around the circumference. Specifically, each quadrant of the cylinder circumference is divided into three equal-length regions denoted as the crown, middle, and side regions. Eight different cylinders designs, whereby each region is constructed of either a quasi-isotropic or an axially-stiff laminate of equal thickness, are studied. Results are compared to the baseline case of an elliptical cylinder constructed entirely of a quasi-isotropic laminate. Since the thickness of the quasi-isotropic and axially-stiff laminates are the same, all cylinders weight the same and thus comparisons are meaningful. Improvements upwards of 18% in axial buckling capacity can be achieved with one particular stepwise design. The second approach considers laminations that vary circumferentially in a continuous fashion to mitigate the effects of the continuously-varying radius of curvature. The methodology for determining how to tailor the lamination sequence circumferentially is based on the analytical predictions of a simple buckling analysis for simply-supported circular cylinders. With this approach, axial buckling load improvements upwards of 30% are realized. Of all the cylinders considered, very few do not exhibit material failure upon collapse in the post-buckled state. Of those that do not, there is little, if any, improvement in bucking capacity. Results for the pre-buckling, buckling, post-buckling, and material failure are obtained from the finite-element code ABAQUS using both static and dynamic analyses. Studies with the code demonstrate that the results obtained are converged. | en |
dc.description.degree | Ph. D. | en |
dc.identifier.other | etd-11202006-124553 | en |
dc.identifier.sourceurl | http://scholar.lib.vt.edu/theses/available/etd-11202006-124553/ | en |
dc.identifier.uri | http://hdl.handle.net/10919/29693 | en |
dc.publisher | Virginia Tech | en |
dc.relation.haspart | submit-11-29.pdf | en |
dc.rights | In Copyright | en |
dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
dc.subject | Buckling | en |
dc.subject | Material Tailoring | en |
dc.subject | Elliptical Cylinder | en |
dc.subject | Composite | en |
dc.subject | Material Failure | en |
dc.subject | Stability | en |
dc.subject | Post-buckling | en |
dc.title | Use of Material Tailoring to Improve Axial Load Capacity of Elliptical Composite Cylinders | en |
dc.type | Dissertation | en |
thesis.degree.discipline | Engineering Science and Mechanics | en |
thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
thesis.degree.level | doctoral | en |
thesis.degree.name | Ph. D. | en |
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