Browsing by Author "Allsop, Derek F."
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Item Open Access Ballistics of 17th century muskets(2010-10-12) Miller, David P.; Allsop, Derek F.This Project is an investigation to determine the position that a 17th Century musket ball was fired from a musket, when given the position it was found on the battlefield. Prior to this research the main concerns with making predictions were considered to be associated with the deformed shape of the musket balls affecting their drag coefficient and therefore, their distance to ground impact. The distance they would continue after impact due to bounce and roll was unknown. Previous research has been used and built upon to recreate the conditions of the English Civil War as accurately as possible. It was found that the average distance to ground impacts were in good agreement with predictions using the drag coefficient for a sphere showing that the distorted shape resulting from the firing process of the musket ball made little difference to its drag coefficient in the majority of cases. However, the distance travelled after the first ground impact greatly exceeded expectations, with the musket balls almost doubling the total average distance to their final resting positions - an increase of 81%. From these findings the initial factors thought to have had high relevance to the final resting position of the musket ball (velocity variation and drag co-efficient) become less significant and factors such as ground hardness become more prominent. The knowledge gained during this investigation will re-establish more accurate information to be obtained on the firing positions of opposing forces during conflicts in the English Civil War.Item Open Access From capability to concept: Fusion of systems analysis techniques for derivation of future(Cranfield University, 2007-03-27T09:11:22Z) Sparks, Emma S.; Couldrick, C. A.; Iremonger, M. J.; Allsop, Derek F.The intent of this thesis is to define a set of processes for use within UK Government dismounted soldier systems research that will provide stakeholders with auditable and traceable information to understand gaps in military capability and justify future procurement decisions. The need for this approach is linked to organisational shifts within the UK Ministry of Defence, and more specifically Government research with the move towards procurement of capability rather than equipment. In conjunction with reducing defence budgets and increased scrutiny, there is a need to prioritise spending to those areas that will provide the most significant enhancement to operational effectiveness. The proposed process suite provides underpinning data to support Government decisions, from definition of military need through to concept design and prioritisation of future research activities. The approach is grounded in the field of systems thinking and systems engineering providing the logical and systematic constructs required for highly complex systems where the human is a central focus. A novel fusion of existing systems tools and techniques enables both subjective data from domain experts and objective data in the form of operational analysis and field trials to be utilised for analysis across the five NATO capability domains, with output defining the relative importance of survivability, sustainability, mobility, lethality and C4I in the context of operational and strategic level military goals as well as wider challenges represented by the doctrinal defence lines of development. Future developments should include alignment with developing pan-MoD initiatives in the form of MODAF, if required by the customer organisation. This would enable generic versions of the process suite to be applied to any defence domain and problem.Item Open Access Investigations into the Optimisation of Sound Suppressor Geometry(Cranfield University, 2007-04-27T10:15:11Z) Lister, Aimee; Allsop, Derek F.Health and Safety regulations are becoming ever more stringent in order to protect us in all aspects of our daily lives to prevent noise pollution and damage to hearing. For those in the military and some areas of civilian life working with firearms there is a definite need to reduce the sound levels from them. In order to do this a working knowledge of sound moderators and suppressors is considered vital in order to assess their capabilities and optimise their performance. The project looks at a theoretical model of an integral suppressor for a modified 12 bore shotgun. The model was used to determine the area of holes through the barrel, allowing gas into the suppressor, has the greatest effect on the pressure within the suppressor. It was found that the volume of the suppressor and position of the hole through the barrel did not have such a significant effect on the pressure. The theoretical work was supported by experimental trials which confirmed the barrel hole size has a significant effect on the pressure. The experimental work also showed for the low pressure system the hole size through the baffles did not have a significant effect on the pressure. Work was carried out to establish whether current practice for proofing suppressors was sufficient. The results show that proof rounds give a lower pressure in an external suppressor than standard ammunition. Tests on improvised suppressors showed they are effective and allowed a visual analysis on suppressors. Baffles were shown to be advantageous in a suppressor configuration.Item Open Access Kinetic energy less lethal weapons and their associated blunt trauma injuries(2010-11-08) Tawell, Miles G.; Allsop, Derek F.A widely used class of Less Lethal Weapon is the kinetic energy projectile. This can cause blunt trauma to the targeted person and, under certain circumstances, its use can result in permanent injury or death. The low velocity at which Less Lethal projectiles are launched results in inaccuracy of use thus increasing the possibility that non targeted areas of the body susceptible to injury by blunt trauma will be hit. This research has been focused to investigate the impact characteristics of kinetic energy Less Lethal projectiles using different masses, materials, geometries and impact velocities and how they affect the criteria for injury to the head and the thorax. Computer based models for simulating impacts and possible injuries were investigated. Hydro codes were used to predict the effect of a range of projectile masses and impact velocities for a simplified human target. Physical models were built and tested to compare with the computer predictions. A correlation between projectile mass, velocity and skin penetration was found. Research was carried out on the impact process using an instrumented projectile to measure the acceleration experienced by the projectile and the duration of acceleration for a range of target materials. A simulated head model with a displacement transducer was used to investigate the impact properties of a range of projectile geometries with the objective of identifying the probable effect on blunt trauma and the level of injury that may be sustained. The introduction of air cavities into the projectile reduced the recorded displacement as well as its acceleration whilst extending the duration of the impact. High-speed video was used to investigate the impact process between the projectile and the target using a simulated thorax. The target used was a Behind Armour Blunt Trauma (BABT) test rig originally developed to investigate behind armour blunt trauma associated with combat body armour impacted by high velocity projectiles. A wide range of projectile geometries, materials and masses were investigated to examine the probable effect on blunt trauma and the level of injury that may be sustained. The introduction of air cavities and reduction of projectile mass was found to slightly reduce the rate of displacement in the BABT rig; however the maximum displacement remained similar because of the similar masses and velocities involved.