Title page for ETD etd-093099-204411


Type of Document Dissertation
Author Rusovici, Razvan
Author's Email Address rrusovici@sti-tech.com
URN etd-093099-204411
Title Modeling of Shock Wave Propagation and Attenuation in Viscoelastic Structures
Degree PhD
Department Mechanical Engineering
Advisory Committee
Advisor Name Title
Inman, Daniel J. Committee Co-Chair
Lesieutre, George A. Committee Co-Chair
Ahmadian, Mehdi Committee Member
Cudney, Harley H. Committee Member
Robertshaw, Harry H. Committee Member
Saunders, William R. Committee Member
Keywords
  • Viscoelastic
  • Wave Propagation
  • Anelastic Displacement Fields
  • Mechanical Filters
  • Damping
  • Finite Elements
Date of Defense 1999-09-03
Availability unrestricted
Abstract
Modeling of Shock Wave Propagation and Attenuation in Viscoelastic Structures

Razvan Rusovici

(ABSTRACT)

Protection from the potentially damaging effects of shock loading is a common design

requirement for diverse mechanical structures ranging from shock accelerometers to

spacecraft. High-damping viscoelastic materials are employed in the design of

geometrically complex impact absorbent components. Since shock transients have a

broadband frequency spectrum, it is imperative to properly model frequency dependence

of material parameters. The Anelastic Displacement Fields (ADF) method is employed

to develop new axisymmetric and plane stress finite elements that are capable of

modeling frequency dependent material behavior of linear viscoelastic materials. The

new finite elements are used to model and analyze behavior of viscoelastic structures

subjected to shock loads. The development of such ADF-based finite element models

offers an attractive analytical tool to aid in the design of shock absorbent mechanical

filters. This work will also show that it is possible to determine material properties'

frequency dependence by iteratively fitting ADF model predictions to experimental

results.

A series of experiments designed to validate the axisymmetric and plane stress finite

element models are performed. These experiments involve the propagation of

longitudinal waves through elastic and viscoelastic rods, and behavior of elastomeric

mechanical filters subjected to shock. Comparison of model predictions to theory and

experiments confirm that ADF-based finite element models are capable of capturing

phenomena such as geometric dispersion and viscoelastic attenuation of longitudinal

waves in rods as well as modeling the behavior of mechanical filters subjected to shock.

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