A review on the gun barrel vibrations and control for a main battle tank

We developed a new finite element formula for the barrel-projectile interaction.Then vertical tip displacement of the barrel was determined using Newmark's algorithm.We designed and optimized a passive vibration absorber to reduce the tip deflection of the barrel.For the optimization, we developed a new approach that combines the FEM and GA. The non-linear vibrations of a barrel, induced by the interaction with a high-speed moving projectile, negatively affect the shooting accuracy of a weapon. This study presents a new method that determines the non-linear behavior of the barrel with a passive vibration absorber and optimizes the absorber using the genetic algorithm (GA). Since both the barrel geometry and its coupling with the absorber are non-linear, a new finite element method (FEM) approximation has been developed for the interaction of barrel and projectile and combined with the classical finite element method. The final coupled equation of motion of entire system has been solved by a step by step integration, and for minimum tip deflection of the barrel, a GA has been then used in order to optimize the some parameters of the absorber. The results of analyses of the proposed FEM model were compared, and a good agreement was seen with the existing literature. In another example, the FEM-GA integrated optimization procedure was also used for the optimization of a passive vibration absorber, and a more accurate result (0.5% better) was obtained when compared to the experimental study given in literature.

Optimization of a passive vibration absorber for a barrel using the genetic algorithm

IN THIS STUDY, THE DYNAMIC INTERACTION BETWEEN A 120 MM SMOOTH-BORE TANK BARREL MODELED AS AN EULER-BERNOULLI CANTILEVER BEAM AND AN ACCELERATING PROJECTILE DURING FIRING IS PRESENTED. THE INTER-ACTION WAS MODELLED USING A NEW FEM APPROACH THAT TOOK INTO AC-COUNT THE PROJECTILEÂS INERTIA, CORIOLIS, AND CENTRIPETAL FORCES AND THE HORIZONTAL AND INCLINED POSITIONS OF THE BARREL. THE MASS, EXIT VELOCI-TY AND ACCELERATION EFFECTS OF THE PROJECTILE ON THE DYNAMICS OF THE BARREL WERE INVESTIGATED. THE EFFECTS OF THE PROJECTILEÂS INERTIA, AND CORIOLIS AND CENTRIPETAL FORCES WERE EVALUATED AS WELL. FURTHER-MORE, THE TIP DISPLACEMENTS AT DIFFERENT FIRING ANGLES WERE DETER-MINED BY TRANSFERRING THE MASS, STIFFNESS AND DAMPING MATRICES OF THE BARREL WITH THE ADDITION OF THE INSTANTANEOUS PROPERTY MATRICES OF THE PROJECTILE FROM A LOCAL COORDINATE TO THE GLOBAL CARTESIAN COOR-DINATE WITH THE AID OF TRANSFORMATION MATRICES. FINALLY, THE BARREL VIBRATIONS CAUSED BY THE SUCCESSIVE FIRINGS WERE EVALUATED UNDER DIFFERENT FIRING SCENARIOS. TO DEMONSTRATE THE VALIDITY OF THE CURRENT STUDY, COMPARISONS WERE MADE WITH THE RESULTS OF PREVIOUS STUDIES AND A GOOD AGREEMENT WAS ACHIEVED. BY USING THE METHOD RECOM-MENDED IN THIS STUDY, IT IS POSSIBLE TO DETERMINE THE ACCURATE DY-NAMIC BEHAVIOR OF ANY BARREL WITH SUFFICIENT SENSITIVITY, WITHOUT ANY COSTLY OR TIME-CONSUMING TESTS BEING NECESSARY.

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Dynamic response of a 120 mm smoothbore tank barrel during horizontal and inclined firing positions

FOR REALISTIC APPLICATIONS, DESIGN AND CONTROL ENGINEERS HAVE LIMITED MODELLING OPTIONS IN DEALING WITH SOME VIBRATION PROBLEMS THAT HOLD LOTS OF NONLINEAR CHARACTERISTICS SUCH AS NON-UNIFORM GEOMETRY, VARIABLE VELOCITY LOADINGS, INDEFINITE DAMPING CASES, ETC. FOR THESE REASONS NUMEROUS TIME CONSUMING EXPERIMENTAL STUDIES AT HIGH COSTS MUST BE DONE FOR DETERMINING THE ACTUAL BEHAVIOUR SUCH NON-LINEAR SYSTEMS. HOWEVER, USING ADVANTAGES OF MULTIPLE COMPUTA-TIONAL METHODS LIKE FINITE ELEMENT METHOD (FEM) TOGETHER WITH AN ARTIFICIAL INTELLIGENCE (ANN), MANY COMPLICATED ENGINEERING PROB-LEMS CAN BE HANDLED AND SOLVED TO SOME EXTENT. THIS STUDY, PRO-POSES A NEW COLLECTIVE METHOD TO DEAL WITH THE NONLINEAR VIBRATIONS OF THE BARRELS IN ORDER TO FULFIL ACCURATE SHOOTING EXPECTANCY. US-ING KNOWN ANALYTICAL METHODS, IN PRACTICAL, TO DETERMINE DYNAMIC BEHAVIOUR OF THE BARREL BEAM IS NOT POSSIBLE FOR ALL CONDITIONS OF FIRING THAT INCLUDE NUMEROUS VARIETIES OF AMMUNITION FOR DIFFERENT PURPOSES, AND EACH PROJECTILE OF DIFFERENT AMMUNITION HAS DIFFERENT MASS AND EXIT VELOCITY. IN ORDER TO COVER ALL CASES THIS STUDY PROPOS-ES A NEW METHOD THAT COMBINES A PRECISE FEM WITH ANN, AND CAN BE USED FOR DETERMINING THE EXACT DYNAMIC BEHAVIOUR OF A BARREL FOR SOME CASES AND THEN FOR PRECISELY PREDICTING THE BEHAVIOUR FOR ALL OTHER POSSIBLE CASES OF FIRING. IN THIS STUDY, THE WHOLE NONLINEAR BEHAVIOUR OF AN ANTIAIRCRAFT BARREL WERE OBTAINED WITH 3.5% ACCU-RACY ERRORS BY ANN TRAINED BY FEM USING CALCULATED ANALYSIS RESULTS OF AMMUNITIONS FOR A PARTICULAR RANGE. THE PROPOSED FEM-ANN COMBINED METHOD CAN BE VERY USEFUL FOR DESIGN AND CONTROL ENGI-NEERS IN DESIGN AND CONTROL OF BARRELS IN ORDER TO COMPENSATE THE EFFECT OF NONLINEAR VIBRATIONS OF A BARREL FOR ACHIEVING A HIGHER SHOOTING ACCURACY; AND CAN REDUCE HIGH-COST EXPERIMENTAL WORKS.

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Tip Deflection Determination of a Barrel for the Effect of an Accelerating Projectile Before Firing Using Finite Element and Artificial Neural Network Combined Algorithm

This study deals with analysis and design of active vibration control algorithm for the launcher of multiple launch rocket system (MLRS). The new method proposed is that guidance and control package are equipped on launcher, not rocket, to active control motion of launcher for the first time. It has interesting advantages as follows: (1) active vibration control is more competent, more pliable, and more realizable in engineering compared to passive vibration control. (2) The guidance and control package will not be destroyed. In this study, transfer matrix method of multibody system is used to build the controlled dynamic model of MLRS. This method does not need the global dynamic equations of system and has high computational rate. Independent modal space control method and optimal control theorem are applied to design control law with feedforward and feedback control loops. The modal filters are designed as the state estimator to obtain the modal coordinates and their derivatives. Modal disturbance forc...

Design of active vibration control for launcher of multiple launch rocket system

: Gun barrel vibrations lead to dispersion in the shot patterns Thus, reducing these vibrations should lead to increased accuracy. Since the muzzle is the anti-node for all vibration modes and its vibrations have the greatest effect on shot dispersion. it is the obvious location to attempt to dampen the vibrations A model of the gun barrel was created in MATLAB(registered) and verified by modal impact testing. Modal impact testing was done for the barrel alone and for three different muzzle brake vibration absorber configurations. Additionally the gun was fired with and without the absorber to determine its performance. Significant reduction in shot dispersion was observed.

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Gun barrel vibration absorber to increase accuracy

: The work reported herein details the operation, simulation, testing, and shortcomings of a direct fire weapon (105-mm M35) that has been modified to operate in a fire out-of-battery (FOOB) mode. In FOOB mode, the firing sequence is radically different than that for a conventional weapon. The gun is captured and preloaded in its out-of-battery position prior to firing. This position compares to a conventional system's maximum recoil location. When unlatched, forward momentum is imparted to the recoiling parts, which will eventually be opposed by the ballistic force imparted by firing a round. The ballistic impulse imparted to the gun reverses the momentum and returns the recoiling parts to their latched position ready for the next round. Although the total momentum imparted to the system is not changed, the FOOB approach could theoretically reduce the transmitted loads to the mount structure by 75 percent.

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Kenneth Olsen

Papers

Gun barrel vibration absorber to increase accuracy

Design, Testing, and Simulation of an Experimental 105-mm M35 Fire Out-of-Battery (FOOB) Direct Fire Gun