• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.208-216
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• 2007

As the propellant mass is being accelerated out of the gun chamber along with the projectile, a continuous pressure gradient exists between the end of chamber and the base of the projectile. For this reason, the base pressure-travel curve is very important to design a conventional gun barrel in the interior ballistics, but it is not obtained briefly by empirical or theoretical method. In this paper, a simple relation between chamber pressure and base pressure was determined by the factor of base pressure(Cb) obtained from the experimental method. The simple relation gives a reasonable prediction for the reduction of pressure between the breech and the base of projectile owing to the axial gradient in the gun tube. The predictions have been validated by the infrared screen sensor and the PRODAS(PROjectile Design and Analysis System) for interior ballistic systems. Therefore, the base pressure-travel curve could be calculated from the chamber pressure measured by piezoelectric sensor. The base pressure-travel curve obtained from the simple relation offers initial information to gun barrel designer and is used for calculation of muzzle velocity.

• Transactions of the Korean Society of Mechanical Engineers
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• v.1 no.3
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• pp.125-130
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• 1977

This is a dimensionless analysis of interior ballistics for the design of gun tube. One of the characteristics of this analysis is to ues the .ETA.$_{j}$ number which means a relative quantity of virtual work to the kimetic energy of projectile at the muzzle. In order to apply the concept of virtual work, it is assumed that the projectile is moved from the beginning to the end of bore under constant pressure of the certain travel distance of projectile. The principle of the analysis is induced from the Le Duc equation, which expresses velocity as a function of projectile travel and is based on the translation of a hyperbolic curve. From this non-dimensional analysis, the optimum design parameters of pressure in the bore, velocity and acceleration of projectile can be obtained from the table of figure without computation. This method was verified by the experimental work.k.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.32-38
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• 2006

A clutch hydraulic system for automotive manual transmissions transfers hydraulic pressure generated by driver's pedal manipulation to the clutch mechanism. The foot effort when the clutch pedal is pushed is different than that when the clutch is returned. The effort or load difference, called hysteresis, is caused by the friction produced between rubber seal and inner wall inside the hydraulic cylinder. This clutch pedal travel foot effort hysteresis is essential for a clutch hydraulic system design and analysis. The dynamic model for a clutch hydraulic system is developed and a simulation analysis is performed to estimate the fiction coefficient as a function of the cylinder pressure. The simulation result is then compared to the measurements obtained from a clutch hydraulic system tester to ensure the reliability of the dynamic model and the coefficients estimated. Also the estimated friction coefficients at various pressure values are compared to those reported by an independent study.