Title page for ETD etd-05416181972480


Type of Document Dissertation
Author Humfeld, G. Robert Jr.
URN etd-05416181972480
Title Mechanical Behavior of Adhesive joints Subjected To Thermal Cycling
Degree Master of Science
Department Engineering Science and Mechanics
Advisory Committee
Advisor Name Title
Giurgiutiu, Victor
Ward, Thomas C.
Dillard, David A. Committee Chair
Keywords
  • thermal cycling
  • adhesive bond
  • polymer
  • residual thermal stress
  • viscoelasticity
  • fracture mechanics
  • thermal ratchetting
Date of Defense 1997-02-07
Availability unrestricted
Abstract
The effect of thermal cycling on the

state of stress in polymeric materials

bonded to stiff elastic substrates was

investigated using numerical

techniques, including finite element

methods. The work explored the

relationship between a cyclic

temperature environment,

temperature-dependent viscoelastic

behavior of polymers, and thermal

stresses induced in a constrained

system. Due to the complexity of

developing a closed-form solution

for a system with time, temperature,

material properties, and boundary

conditions all coupled, numerical

techniques were used to acquire

approximate solutions. Descriptions

of attempted experimental

verification are also included.

The results of the numerical work

indicate that residual stresses in an

elastic-viscoelastic bimaterial system

incrementally shift over time when

subjected to thermal cycling. Tensile

axial and peel stresses develop over

a long period of time as a result of

viscoelastic response to thermal

stresses induced in the polymeric

layer. The applied strain energy

release rate at the crack tip of

layered specimens is shown to

similarly increase. The rate of change

of the stress state is dependent upon

the thermal cycling profile and the

adhesive┬╣s thermo-mechanical

response. Discussion of the results

focuses on the probability that the

incrementing tensile residual stresses

induced in an adhesive bond

subjected by thermal cycling may

lead to damage and debonding, thus

reducing durability.

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