Masters Theses

Abstract

"Finite element modeling techniques for studying mechanical properties of nonlinear viscoelastic structural adhesives are presented here. Long term mechanical properties of the Ashland Urethane and Araldite Epoxy adhesive systems have been studied. The stress and strain based modified free volume theories developed at the University of Texas-Austin are verified by using them to model the nonlinear material properties of the aforementioned viscoelastic adhesives. The modified free volume theories work on the fundamental assumption that all viscoelastic material nonlinearities are dependent on free volume and that they can be captured entirely in a nonlinear shift factor definition. These shift factor definitions incorporate parameters to model the nonlinearities observed in shear dominated loading. Ashland Urethane and Araldite Epoxy were modeled using the stress and strain based approaches respectively. The modified free volume theories were incorporated into the NOVA-3D finite element analysis code, which was then used to simulate uniaxial tensile tests and biaxial Arcan tests. In an effort to analyze the effects of such adhesives on the overall mechanical properties of bonded structures, the effect of cohesive crack growth within a finite thickness adhesive layer was studied. Strain energy release rates for stationary cracks in double cantilever beam (DCB) specimens were modeled for the purpose of comparison with published data. Strain energy release rates for a DCB specimen made out of viscoelastic urethane and epoxy adhesives were computed for comparison with exact solution"--Abstract, page iii.

Advisor(s)

Roy, Samit

Committee Member(s)

Dharani, Lokeswarappa R.
Nanni, Antonio

Department(s)

Mechanical and Aerospace Engineering

Degree Name

M.S. in Mechanical Engineering

Publisher

University of Missouri--Rolla

Publication Date

Summer 2000

Pagination

viii, 80 pages

Note about bibliography

Includes bibliographical references (pages 77-79).

Rights

© 2000 Sreesh Kumar Inguva, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Thesis Number

T 7767

Print OCLC #

44651123

Electronic OCLC #

1110184973

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