MULTI-SCALE MECHANICS OF COMPOSITE SANDWICH STRUCTURES WITH BIOLOGICALLY INSPIRED FIBER REINFORCED FOAM CORES: A POTENTIAL TEMPLATE FOR DEVELOPING MULTIFUNCTIONAL STRUCTURES

Simple item page
dc.contributor.advisorBruck, Hugh Aen_US
dc.contributor.authorHaldar, Sandipen_US
dc.contributor.departmentMechanical Engineeringen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2013-10-10T05:31:19Z
dc.date.available2013-10-10T05:31:19Z
dc.date.issued2013en_US
dc.description.abstractThis dissertation describes a novel multi-scale characterization and modeling approach for developing bio-inspired composite sandwich structures. The source of bio-inspiration was chosen to be Palmetto wood, a naturally occurring porous composite material with macrofiber reinforcement. Characterization of Palmetto Wood at multiple length scales revealed that the mechanical behavior is dominated by the stronger and stiffer macrofibers, while the porous cellulose matrix controls load transfer and failure between macrofibers. Shear dominated debonding and pore collapse mechanisms have been identified as the leading modes of failure mechanism. The role of macrofiber volume fraction and strain rate on macroscale response and damage evolution has been evaluated through experiments. It is seen that increase in macrofiber concentration increases the stiffness of the Palmetto wood, leading to a higher concentration of macrofiber in the outer region of the wood by evolution. A damage model has been developed to decouple the effect of the plastic strain and pore collapse on damage evolution. Using Palmetto wood as a template, prototype bioinspired sandwich composite structures have been fabricated using carbon fiber reinforcement in the foam core to translate the mechanics principles of Palmetto wood. The sandwich composite structures with bioinspired foam core and standard foam core have been characterized under quasi-static and dynamic three-point bending load. The model developed to study damage evolution in Palmetto wood has been applied to the behavior of bioinspired sandwich to quantify the parameters. The enhancement in mechanical behavior has been achieved by reinforcement of the carbon rods in the core like the macrofibers in the Palmetto wood. An increase in macroscale reinforcement in the core led to the behavior that tunes the material response to a better combination the flexural stiffness, energy absorbance and damage evolution characteristics. A Finite Element Analysis (FEA) model has been developed to numerically study the effects of reinforcement in the foam core on its flexural behavior as observed in the experimental characterization. The simulations performed using homogenized, isotropic properties from simulations of the bioinspired core affirm the experimental observations. The viability of developing multifunctional sandwich structures from the multiscale characterization and modeling of the bioinspired foam cores has also been investigated. Prototype sandwich battery structures were fabricated using copper coated fiberglass and Zn plate facesheet, a carbon foam core, and an adhesive of NH4Cl and ZnCl2 bound by HTPB and epoxy polymers. Very low power generation was demonstrated using the prototype batteries, however it was determined that the mechanical strength and energy absorbing capability were compromised, as expected from the model, indicating that the use of macrofiber reinforcement could potentially enhance multifunctional behavior.en_US
dc.identifier.urihttp://hdl.handle.net/1903/14612
dc.subject.pqcontrolledMechanicsen_US
dc.subject.pqcontrolledMechanical engineeringen_US
dc.subject.pqcontrolledEngineeringen_US
dc.subject.pquncontrolledComposite Materialsen_US
dc.subject.pquncontrolledDigital Image Correlationen_US
dc.subject.pquncontrolledExperimental Mechanicsen_US
dc.subject.pquncontrolledFinite Element Analysisen_US
dc.titleMULTI-SCALE MECHANICS OF COMPOSITE SANDWICH STRUCTURES WITH BIOLOGICALLY INSPIRED FIBER REINFORCED FOAM CORES: A POTENTIAL TEMPLATE FOR DEVELOPING MULTIFUNCTIONAL STRUCTURESen_US
dc.typeDissertationen_US

Files

Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
Haldar_umd_0117E_14350.pdf
Size:
15.26 MB
Format:
Adobe Portable Document Format
Download

Collections

UMD Theses and Dissertations
Mechanical Engineering Theses and Dissertations