Location

La Jolla ,CA

Start Date

1-1-1989 12:00 AM

Description

Until recently, the use of a finite element model (FEM) to simulate stress wave propagation has been limited to solutions where the number of degrees of freedom are kept to a minimum, because of hardware limitations on computer memory and computational speed. With the advent of a number of new supercomputers, numerical simulation becomes a reasonable approach to some simpler problems. Recently, Ludwig, et. at [1,2] have demonstrated the feasibility of such an approach for problems where materials are either isotropic or only slightly anisotropic. We extend this effort to unidirectional graphite/epoxy which has large variations in elastic properties. For this material the effect of elastic anisotropy on stress wave propagation has been studied both experimentally and analytically [3,4] and several interesting properties have been predicted and measured: mode transitions, sensitivity of flux deviations to small changes in anisotropy, and shear wave speeds exceeding longitudinal waves. With a FEM we can simulate and study some of these properties most effectively.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

8A

Chapter

Chapter 1: Fundamentals of Classic Techniques

Section

Elastic Wave Propagation

Pages

141-148

DOI

10.1007/978-1-4613-0817-1_18

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Finite Element Model of Stress Wave Topology in Unidirectional Graphite/Epoxy: Wave Velocities and Flux Deviations

La Jolla ,CA

Until recently, the use of a finite element model (FEM) to simulate stress wave propagation has been limited to solutions where the number of degrees of freedom are kept to a minimum, because of hardware limitations on computer memory and computational speed. With the advent of a number of new supercomputers, numerical simulation becomes a reasonable approach to some simpler problems. Recently, Ludwig, et. at [1,2] have demonstrated the feasibility of such an approach for problems where materials are either isotropic or only slightly anisotropic. We extend this effort to unidirectional graphite/epoxy which has large variations in elastic properties. For this material the effect of elastic anisotropy on stress wave propagation has been studied both experimentally and analytically [3,4] and several interesting properties have been predicted and measured: mode transitions, sensitivity of flux deviations to small changes in anisotropy, and shear wave speeds exceeding longitudinal waves. With a FEM we can simulate and study some of these properties most effectively.