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Advances in Acoustics and Vibration
Volume 2008, Article ID 483857, 6 pages
Research Article

Dynamics and Stability of Stepped Gun-Barrels with Moving Bullets

Mechanical Engineering Department, British University in Egypt, El-Shorouk City, Cairo 11837, Egypt

Received 12 August 2007; Revised 16 November 2007; Accepted 20 January 2008

Academic Editor: Luc Gaudiller

Copyright © 2008 Mohammad Tawfik. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The stability of an Euler-Bernoulli beam under the effect of a moving projectile will be reintroduced using simple eigenvalue analysis of a finite element model. The eigenvalues of the beam change with the mass, speed, and position of the projectile, thus, the eigenvalues are evaluated for the system with different speeds and masses at different positions until the lowest eigenvalue reaches zero indicating the instability occurrence. Then a map for the stability region may be obtained for different boundary conditions. Then the dynamics of the beam will be investigated using the Newmark algorithm at different values of speed and mass ratios. Finally, the effect of using stepped barrels on the stability and the dynamics is going to be investigated. It is concluded that the technique used to predict the stability boundaries is simple, accurate, and reliable, the mass of the barrel on the dynamics of the problem cannot be ignored, and that using the stepped barrels, with small increase in the diameter, enhances the stability and the dynamics of the barrel.