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 StructuresRazvan 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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