Monday, 11 October 2004 - 3:30 PM

This presentation is part of : Graduate Student Competition

Theoretical Study Of The Dynamic Response Of Bars

Roman Krashanitsa, University of Arizona, University of Arizona, Aerospace and Mechanical Engineering Department, 1130 N Mountain, Tuscon, AZ 85721

This study is focused on one-dimensional wave propagation in bars composed of a series of connected rods made of dissimilar materials. The initial boundary value problem is formulated and the governing system of nonlinear equations is derived for an arbitrary nonlinear elastic law of the materialís behavior. Linear elastic and nonlinear elastic materials have been considered. A numerical iterative scheme is developed based the finite difference method. Effects of nonlinearity in material equation of state have been investigated. Numerical results for benchmark problems prove the accuracy and computational effectiveness of the proposed algorithms. Numerical results were compared to the results of simulation using finite element method. Finite element solution has been obtained with the help of LS-DYNA. Difficulties in designing benchmark problems and issues of accessing results of calculations using commercial software are reported. A parametric analysis of the Split Hopkinson Pressure Bar is undertaken in order to simulate an experiment for dynamic response of ceramic materials using the proposed method. A numerical study was performed and stresses and strains were computed in the modified split Hopkinson pressure bar subjected to a sequence of two loading impulses. Results of the numerical simulation demonstrated the limitations of the conventional method of data analysis based on Kolskyís method. The extension of the presented approach to other constitutive laws of material behavior is discussed in the present study. The present method can also be used for deriving the stress-strain histories in the specimen from the signals measured at the strain gauges in bars.

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