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FE modeling of dispersion in cylinders

Submitted by HSD83 on

As you may know wave propagation in circular cylinders is dispersive. As shown by Pochhammer, there

could be several different modes propagating in an infinite cylinder with

different wave speeds. I'm modeling wave propagation in a finite 3D circular cylinder in

LS-DYNA with solid elements and I'm applying a sinusoidal pressure along

the cylinder axis at one end while the other end is free. Based on

Pochhammer solution at a certain frequency there could be different

modes propagating in the cylinders with different speeds. I've observed

this in ultrasonic experiment. I apply sinusoidal pressure wave at one

end of a circular cylinder and receive the signal at the other end and I

can see different modes propagating with different speeds at different

frequencies. My question is why I dont see this effect in my 3D FE

model? All I see in my FE model is the 1st mode propagating in the

cylinder in all different frequencies.

Hello





I have something on the modeling of the SHPB. I cannot promise that you will find the answer to your particular problem in it.



Study these materials, available freely:





1) in the ABAQUS manual:



Getting Started with Abaqus: Keywords Edition     

9.1 Types of problems suited for Abaqus/Explicit



Getting Started with Abaqus: Keywords Edition     

9.4 Example: stress wave propagation in a bar





2) MODELING AND EXPERIMENTAL INVESTIGATIONS OF THE SHOCK

RESPONSE OF VISCOELASTIC FOAMS

by Richard J. Deigan

Dissertation submitted to the Faculty of the Graduate School of the

University of Maryland, College Park, in partial fulfillment

of the requirements for the degree of

Doctorate of Philosophy

2007





3) 2D Hopkinson bar simulation analysis

Al 6061-T6 specimens

A. Bouamoul

DRDC Valcartier

Defence R&D Canada – Valcartier

Technical Memorandum

DRDC Valcartier TM 2004-363

March 2006





4) Anthony D. Puckett:

Thesis

Fidelity of a Finite Element Model

for Longitudinal Wave Propagation

in Thick Cylindrical Wave Guides

Los Alamos National Laboratory

LA-13753-T





5) Army Research Laboratory:

Numerical Hopkinson Bar Analysis: Uni-Axial Stress and

Planar Bar-Specimen Interface Conditions by Design

by Bazle A. Gama and John W. Gillespie, Jr.

ARL-CR-553 September 2004

prepared by

University of Delaware

Center for Composite Materials

Newark, DE 19716

under contract

DAAD19-01-2-0005





6) find more on the Internet





Good luck



Frank

------------------------------------------
Ruhr-University
Bochum
Germany

Mon, 07/09/2012 - 19:27 Permalink