Bin Wu
During firing, a large amount of heat is transferred into the gun bore. Many heat-induced problems, such as erosion of the gun-bore surface and barrel overheating, significantly limit gun performance. Barrel cooling, including passive cooling and active cooling, is an effective approach to diminish these adverse thermal effects. Passive cooling technologies, such as chromium plating and wear-reducing additives, are adopted to reduce the thermal energy input by setting up a thermal barrier between the hot propellant gas and the steel of the barrel. Active cooling technologies, such as finned-barrel cooling and forced liquid/air cooling, reduce the temperature increment of each round fired by increasing the thermal dissipation rate. Finite element analysis (FEA) results have shown that active liquid cooling is effective in controlling the barrel temperature, thereby preventing barrel overheating and increasing barrel life.
David J. Purdy and J. Rajesh Kumar
Battlefield mobility is one of the fundamental requirements of tracked military vehicles. The suspension provides the necessary ride, handling, and traction for the vehicle when traversing over either paved roads or on unprepared terrain. The Hydro-gas Suspension Unit (HSU) is one current state-of-the-art suspension technology with a huge potential for improvement in the future. In this work a mathematical model is developed and simulated using Matlab and Simulink. The model incorporates the compressibility of the fluid and expansion of other components using an effective bulk modulus and the damper valve characteristics. A novel method of modelling the flow through the damper valve using a lookup table is presented to overcome a problem with algebraic loops. Results from the model are discussed for different damper valve characteristics and input frequencies. The HSU model is incorporated into a simulation of a six-wheel station tracked vehicle having eight degrees of freedom, in order to study the ride quality of the vehicle and to propose a method for selecting the damper valve characteristics.
M.A. Rajesh
MAPCHAT is a system for on-line capture and dissemination of tactical and terrain information among geographically separated users. It has a distributed, multi-server, multi-client architecture that enables the users to capture and communicate spatial and non-spatial data, in the form of overlays, to other users in the LAN, or WAN, or to mobile users in field locations, connected through a wireless interface. The MAPCHAT system consists of Windows PCs, loaded with MAPCHAT software, and a back-end repository of maps and overlays (Windows PC with Oracle Database Server), all connected via a LAN, WAN or wirelessly using GPS-fitted receivers for mobile subscribers. MAPCHAT works on the principle of normal Chat software with one significant difference: in addition to the textual chat messages, it handles geographic data encoded as textual data in XML format. MAPCHAT software consists of two components—the server and the client. The server component is a normal Chat server implemented using TCP/IP socket programming in Java2. The MAPCHAT client is a powerful GIS tool, capable of display and analysis of geographic data in various formats, with an added XML parser and a communication module.
James W. McCulloch and Bob Walters
Ultra wideband (UWB) is an emerging communications technology that offers high data rates over short distances with a low probability of intercept. UWB is defined by the Federal Communications Commission (FCC) in terms of the amount of bandwidth used, not the way it is used, and three different technological approaches have emerged: short-pulse UWB; OFDM-UWB and DS-UWB. OFDM and DS are being developed commercially for use in the home networking market. Short-pulse UWB remains a developmental technology with some potential benefits to the military in addition to the low probability of intercept, such as good resistance to multipath fading and the ability to locate an emitter precisely. With the move towards to a Network-Equipped Capability (NEC) and the associated need to pass increasing amounts of data between battlefield entities, there is a requirement for a short-range data bearer. This paper looks at UWB as a whole and considers a number of potential military applications where UWB may be suitable for this short-range data-handling role. Other roles such as wireless links on and around a soldier, remote sensors, and logistic tracking by the use of transmitting ‘tags’ are also suggested.
Alfred Kaufman
This article is a first cut at quantitatively exploring the conditions under which the fundamental tenets of the Network Centric Warfare doctrine might be valid. It is based on a somewhat more extensive study of the subject published by the author [1] and covers three related topics: the situational awareness that is made possible by networking of battlefield sensors, the onset of cohesive behaviour amongst the human actors involved in operating networked systems, and the limits of human proficiency. The paper shows that the situational awareness obtained through the network is not automatically better than that obtained from individual sensors and identifies the conditions under which it might be; it shows how the cohesive behaviour is increased by the size of the networked community, by the quality of leadership controlling that community, and by the degree of individual proficiency with which members join the community; and it shows how recruiting, training, retention, and the quality of life will affect that individual proficiency. In the end, the article summarizes the various factors which must be addressed before the promise of networking can be realized.
Alan C. McLucas and Michael J. Ryan
Expert system dynamicists are those who have developed the skills to perceive structure—that is, they have ability to recognise that dynamics appearing to be very different on the surface are actually caused by fundamentally similar mechanisms. They then use these skills very effectively to build models of complex problems. Desire to exploit knowledge of fundamental structures in system dynamics models has led to the formulation of molecules of system dynamics structure. But there is more we can do to facilitate learning about, and recognition of, structure as well as improve system dynamics modelling methodology. This paper argues that aspects of systems engineering practice can be integrated with system dynamics to produce a methodology which exploits knowledge of structures, utilises top-down model formulation and bottom-up construction of models, thereby enabling management of the complexity encountered during model building. The proffered methodology enables all modellers, even the least experienced, to quickly and reliably build robust models of complex problems. How this is achieved is explained and demonstrated.
