The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump ari...The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump arises.The aims of this paper are,(1)to give fundamental explanations for the variability of Jump,and (2)to offer design factors to make the variability of Jump less.The model presented here was formulated in accordance with the transition of the system in reverse way commencing from the target impact stage to the chambering stage.Objects of the simulation are generic 120mm smooth bore and long rod system which are extremely simplified to the vibration of tube,the spring effect by sabot,and the free-ends beam of penetrator.Parametric calculations clarified that high Jump-variability is generated only when the last rebound is on the muzzle line.This particular state of rebound is achieved by many combinations of input-variable.Guide map named JV-Chart is proposed to show the high Jumpvariability zone.展开更多
The purpose of this study is to investigate and quantify some possible sources of dispersion of 120 mm APFSDS tank ammunition both experimentally and numerically.This paper aims to point out the most influential sourc...The purpose of this study is to investigate and quantify some possible sources of dispersion of 120 mm APFSDS tank ammunition both experimentally and numerically.This paper aims to point out the most influential source during In-Bore Balloting Motion phase as well as in External Ballistics phase of the ammunition and quantifies its effect on dispersion.Data obtained from flight trials is critically analysed and parameters affecting dispersion such as initial yaw/pitch rates,yaw/pitch dampening,plane start angle,launch spin,clearance,centre of gravity shift,dynamic imbalance angle,cross wind,etc.are observed and,later on,studied in detail by extensive External Ballistics Monte Carlo(EBMC)simulation and Six Degree of Freedom(6-DOF)trajectory analysis.In Bore Balloting Motion simulation shows that reduction in residual spin by about 5%results in drastic56%reduction in first maximum yaw.A correlation between first maximum yaw and residual spin is observed.Results of data analysis are used in design modification for existing ammunition.Number of designs are evaluated numerically before freezing five designs for further soundings.These designs are critically assessed in terms of their comparative performance during In-bore travel&external ballistics phase.Results are validated by free flight trials for the finalised design.展开更多
文摘The variability of projectile jump is the long-term issue to improve weapon accuracy.Nowadays we have many simulation codes to predict Jump.However,these codes cannot explain explicitly how the variability of jump arises.The aims of this paper are,(1)to give fundamental explanations for the variability of Jump,and (2)to offer design factors to make the variability of Jump less.The model presented here was formulated in accordance with the transition of the system in reverse way commencing from the target impact stage to the chambering stage.Objects of the simulation are generic 120mm smooth bore and long rod system which are extremely simplified to the vibration of tube,the spring effect by sabot,and the free-ends beam of penetrator.Parametric calculations clarified that high Jump-variability is generated only when the last rebound is on the muzzle line.This particular state of rebound is achieved by many combinations of input-variable.Guide map named JV-Chart is proposed to show the high Jumpvariability zone.
文摘The purpose of this study is to investigate and quantify some possible sources of dispersion of 120 mm APFSDS tank ammunition both experimentally and numerically.This paper aims to point out the most influential source during In-Bore Balloting Motion phase as well as in External Ballistics phase of the ammunition and quantifies its effect on dispersion.Data obtained from flight trials is critically analysed and parameters affecting dispersion such as initial yaw/pitch rates,yaw/pitch dampening,plane start angle,launch spin,clearance,centre of gravity shift,dynamic imbalance angle,cross wind,etc.are observed and,later on,studied in detail by extensive External Ballistics Monte Carlo(EBMC)simulation and Six Degree of Freedom(6-DOF)trajectory analysis.In Bore Balloting Motion simulation shows that reduction in residual spin by about 5%results in drastic56%reduction in first maximum yaw.A correlation between first maximum yaw and residual spin is observed.Results of data analysis are used in design modification for existing ammunition.Number of designs are evaluated numerically before freezing five designs for further soundings.These designs are critically assessed in terms of their comparative performance during In-bore travel&external ballistics phase.Results are validated by free flight trials for the finalised design.
