Application of virtual design tools to tube launched projectile systems

摘要

Virtual Design Tools (VDT) provide means for reducing product development cycles and minimising production costs. Supported by experimental validation, a Virtual Design Process (VDP) incorporating VDTs could potentially be used to perform the entire design process from conception through to design for manufacture. No evidence exists of a VDP for the development of advanced and novel weapons concepts. This thesis therefore presents a methodology which integrates Finite Element Analysis (FEA), Fluid-Structure Interaction (FSI) modelling and Shape Optimisation for the design and development of Tube Launched Projectile Systems. The resulting VDP provides the basis for designing weapon systems without the need for continual prototyping and physical testing. The VDP was first demonstrated through a historical case study of 16th Century Cannons. While the weapon itself was redundant, it provided a means by which the VDP could be used to thoroughly analyse and refine a primitive design. Methods of finite element analysis were first used to identify the nature of stresses inherent of the original cannon when fired. Explicit FE methods were found to be far more suitable for the analysis, revealing the dynamic interaction of the barrel and munitions over the entire Interior Ballistic (IB) cycle. FSI modelling was then introduced to analyse the impact of propellant performance on barrel/munition interaction. However, in the absence of an appropriate material model to describe propellant combustion, a detonation was simulated inside the cannon chamber instead. The analysis demonstrated the potential for FSI to integrate the properties of the propellant and structural system into a single analysis. Shape Optimisation was then applied to the cannon system to reach two design objectives. Optimisations of mass and system vibrations were successfully achieved. Subsequent to the 16th Century Cannon case study, an interior ballistic model was integrated into the MSC. Dytran Explicit Solver through a user subroutine. FSI modelling was then able to be used to study the structural behaviour of components subject to the dynamics of propellant combustion. Several simulations were performed to demonstrate this process. The VDP was then applied to the design and development of stacked kinetic energy rounds. More specifically, the design of a stacked High Velocity, Fin Stabilised, Discarding Sabot (HVFSDS) round was undertaken such that multiple rounds could be loaded into a single barrel with an aim of increasing the rate of fire. Explicit finite element methods were used to develop a wide variety of design ideas. Once the design concepts had been established, detailed explicit FE methods and Shape Optimisation were used to refine the design. Consequently, the developed stacked HVFSDS round concept was manufactured and subjected to physical testing. Experimental results were able to provide justification to both the design concept and the methodology employed in its development. Subsequent to testing, the VDP was again used to further refine the design. The developed VDP was therefore successfully able to integrate disciplines of structural mechanics, fluid dynamics and optimisation in providing a framework for designing novel concepts for tube lunched weapons systems.