Title page for ETD etd-51898-194938


Type of Document Dissertation
Author Jia, Hongyu
Author's Email Address hjia@vt.edu
URN etd-51898-194938
Title Impact Damage Resistance of Shape Memory Alloy Hybrid Composite Structures
Degree PhD
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Inman, Daniel J. Committee Chair
Kirk, R. Gordon Committee Member
Mahan, James Robert Committee Member
Reifsnider, Kenneth L. Committee Member
Robertshaw, Harry H. Committee Member
Keywords
  • Shape Memory Alloy
  • Impact
  • Damage
  • Composite
  • Super-elastic
Date of Defense 1998-05-26
Availability unrestricted
Abstract
The strain energy absorption of shape memory alloy (SMA)

bars and beams under tension and bending loading was studied.

A theoretical model is presented that can give quantitative

relations between the martensite fraction, the applied load,

and the strain energy absorbed in the shape memory alloy

(SMA). It was found analytically that the super-elastic SMA

demonstrates a high strain energy absorption capability. The

closed- form solution of the strain energy absorption

capability of SMA bars is a simple and useful tool in the

design of energy absorption applications of super-elastic

SMA. The nonlinear equations for SMA hybrid composite plates,

which can be used for low velocity impact or quasi-static

contact loading, are derived. The governing equations include

the transverse shear deformation to the first-order, large

deformation of the plates, and SMA/epoxy lamina. The

equations are derived in the general form with general

boundary conditions and general stack of angle ply. The

equations can be simplified to special forms in the

specific applications.

A theoretical study of the impact force and the strain

energy absorption of an SMA/graphite/epoxy composite beam

under a low-velocity impact has been performed. The contact

deformation, the global bending deformation, the transverse

shear deformation, and the martensitic phase transformation

of the super-elastic SMA fibers are studied. The energy

absorbed by the SMA hybrid composite is calculated for

each task of the absorption mechanisms: contact deformation,

global bending deformation, and The analysis methods and

models developed in this dissertation are the first reported

research in modeling SMA composite under low velocity impact

and quasi-static loading. The models and methods developed

here can be used for further study and design of SMA

composites for low velocity impact or quasi-static loading

in failure process.

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