Aeronautical Engineering: A continuing bibliography with indexes

This bibliography lists 512 reports, articles and other documents introduced into the NASA scientific and technical information system in April 1982

The failure of a tungsten carbide-cobalt cored projectile penetrating a hard target

Experimental results are presented from an investigation of the parameters of a ceramic-faced armour system that are required to induce damage in a tungsten carbide - cobalt (WC-Co) penetrator. A WC-Co material model has been successfully developed and implemented within the numerical hydrocode AUTODYN 2D. The understanding of penetration mechanisms was used to guide a parametric investigation, validating the WC-Co material failure model with experimental results. A series of experiments has been conducted firing the Russian 14.5 mm BS41 WC-Co cored projectile into various thicknesses and types of alumina (Al2O3) and silicon carbide (SiC), backed by aluminium alloy or mild steel semi-infinite witness blocks. Results demonstrated that SiC B out-performed standard monolithic armours and a selection of other armour ceramics including PS 5000 SiC and Sintox-CL. After comminution, the SiC B consisted of particles of closely interlocked grains. These appeared to provide considerable resistance to deviatoric stresses. Results suggest that it is not only increased hardness but also the nature of the fracture of the ceramic ahead of the penetrator that improves the armour’s ballistic performance at defeating WC-Co penetrators. If such superior ballistic response can be controlled and incorporated into practical armour systems, it will provide the basis for an advance in armour protective capability against WC-Co penetrators. In addition, a numerical material model derived from experimental data was developed to provide a preliminary tool to study the WC-Co failure. It was demonstrated that the numerical estimation of WC-Co behaviour using a shock Equation Of State (EOS), a piecewise linear strength model and a principle stress failure model provides a good method to estimate spall behaviour under dynamic loading in AUTODYN 2D. Successful numerical simulation of the material model used demonstrated the future potential of the technique

Fluid-Structure-Jet Interaction Effects on High-Speed Vehicles

This dissertation is focused on two design considerations for supersonic intercept missiles: (i) increased structural slenderness and (ii) attitude control jets. The resulting new designs have the potential to increase vehicle performance, but will lead to a coupled fluid-structure-jet interaction that has yet to be studied. Numerical results of the vehicle response across the design space and flight envelope can be used as guidelines for assessment of improved control effectiveness, maneuverability and agility. First, vehicle models are developed that include slender structures and attitude control jets to conduct flight simulations. The numerical analysis of fluid-structure-jet interaction using these vehicle models deleted{helps to fill the gap in the literature and} provides insight into how this interaction can be leveraged during the design to improve performance. Next, approximate methods for including jet interaction effects are developed for slender high-speed vehicles. These methods allow for more complex geometry, a range of flight conditions, and varying control inputs. The jet interaction models are developed for flight simulation to maintain accuracy without significant computational cost. A detailed computational model of the maneuverable vehicle with fluid-structure-jet interaction is created to study the sensitivity to changes in flight conditions. These steady and dynamic results of the nonlinear system identify the conditions that may be difficult to model as well as those that can be exploited for improved performance. Next, modeling methods for the fluid-structure-jet interaction dynamics in flight are developed and evaluated using aggressive maneuvers throughout the flight envelope. Previous methods are evaluated to identify their effectiveness and a new method is developed specifically to model the nonlinear vehicle response to aggressive maneuvers. Finally, fluid-structure-jet interaction effects introduced by a slender missile body and attitude control jets are modeled during flight simulations. Multiple vehicle configurations are considered and the simulation results demonstrate the corresponding design modifications can impact vehicle maneuverability and agility. Overall, this dissertation explores a new topic in fluid-structure-jet interaction that arises due to new design trends that seek to improve intercept missile performance. New modeling methods were developed to analyze the problem and numerical simulation results identify regions where the fluid-structure-jet interaction significantly affects the vehicle response.PHDAerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/147571/1/kitson_1.pd

A novel dual-spin actuation mechanism for small calibre, spin stabilised, guided projectiles

© Cranfield University 2022. All rights reserved. No part of this publication may be reproduced without the written permission of the author and copyright holderSmall calibre projectiles are spin-stabilised to increase ballistic stability, often at high frequencies. Due to hardware limitations, conventional actuators and meth ods are unable to provide satisfactory control at such high frequencies. With the reduced volume for control hardware and increased financial cost, incorporating traditional guid ance methods into small-calibre projectiles is inherently difficult. This work presents a novel method of projectile control which addresses these issues and conducts a systems level analysis of the underlying actuation mechanism. The design is shown to be a viable alternative to traditional control methods, Firstly, a 7 Degree-of-Freedom (DoF) dynamic model is created for dual-spin pro jectiles, including aerodynamic coefficients. The stability of dual-spin projectiles, gov erned by the gyroscopic and dynamic stability factors is given, discussed and unified across available literature. The model is implemented in a Matlab/Simulink simulation environ ment, which is in turn validated against a range of academic literature and experimental test data. The novel design and fundamental operating principle are presented. The actuation mechanism (AM) is then mathematically formulated from both a velocity change (∆V ) and a lateral acceleration (a˜) perspective. A set of axioms are declared and verified using the 7-DoF model, showing that the inherently discrete system behaviour can be controlled continuously via these control variables, ∆V or a˜. Control state switching is simplified to be instantaneous, then expanded to be generically characterised by an arbitrarily complex mathematical function. A detailed investigation, parametric analysis and sensitivity study is undertaken to understand the system behaviour. A Monte Carlo procedure is described, which is used to compare the correction cap abilities of different guidance laws (GLs). A bespoke Zero-Effort-Miss (ZEM) based GLis synthesised from the mathematical formulation of the AM, with innately more know ledge of the system behaviour, which allows superior error correction. This bespoke GL is discussed in detail, a parametric study is undertaken, and both the GL parameters and PID controller gains are optimised using a genetic algorithm. Artificial Intelligence (AI) Reinforcement learning methods are used to emulate a GL, as well as controlling the AM and operating as a GL, simultaneously. The novel GLs are compared against a traditional proportional navigation GL in a nominal system and all GLs were able to control the AMs, reducing the miss distance to a satisfactory margin. The ZEM-based GL provided superior correction to the AI GL, which in turn provided superior correction over proportional navigation. Example CAD models are shown, and the stability analysis is conducted on the geometry. The CAD model is then used in CFD simulations to determine aerodynamic coefficients for use in the 7-DoF dynamic model. The novel control method was able to reduce the 95% dispersion diameter of a traditional ballistic 7.62mm projectile from 70mm to 33mm. Statistical data analysis showed there was no significant correlation or bias present in either the nominal or 7-DoF dispersion patterns. This project is co-sponsored by BAE Systems and ESPRC (ref. 1700064). The con tents of this thesis are covered by patent applications GB2011850.1, GB 2106035.5 and EP 20275128.5. Two papers are currently published (DOI: 10.1016/j.dt.2019.06.003, the second DOI is pending) and one is undergoing peer review..PH

Aircraft armoring system for protection the aircraft crew from light firearms

Робота публікується згідно наказу ректора від 29.12.2020 р. №580/од "Про розміщення кваліфікаційних робіт вищої освіти в репозиторії НАУ". Керівник проекту: доцент, к.т.н. Закієв Вадим ІсламовичThe diploma work considers a design and layout of aircraft internal equipment to achieve aircraft modernization for providing protection for crew members. Aim of work is to develop aircraft armoring system for protection the aircraft crew. In this work was performed analysis of the structure and internal layout of the cockpit using NX software for modeling and strength analysis. It is shown that the aircraft can be equipped with this system without making changes in the basic structure

Aircraft armoring system for protection the aircraft crew from light firearms

Робота публікується згідно наказу ректора від 29.12.2020 р. №580/од "Про розміщення кваліфікаційних робіт вищої освіти в репозиторії НАУ". Керівник проекту: доцент, к.т.н. Закієв Вадим ІсламовичThe diploma work considers a design and layout of aircraft internal equipment to achieve aircraft modernization for providing protection for crew members. Aim of work is to develop aircraft armoring system for protection the aircraft crew. In this work was performed analysis of the structure and internal layout of the cockpit using NX software for modeling and strength analysis. It is shown that the aircraft can be equipped with this system without making changes in the basic structure

Application of virtual design tools to tube launched projectile systems

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

The visceral response to underbody blast

Blast is the most common cause of injury and death in contemporary warfare. Blast injuries may be categorised based upon their mechanism with underbody blast describing the effect of an explosive device detonating underneath a vehicle. Torso injuries are highly lethal within this environment and yet their mechanism in response to underbody blast is poorly understood. This work seeks to understand the pattern and mechanism of these injuries and to link them to physical underbody blast loading parameters in order to enable mitigation and prevention of serious injury and death. An analysis of the United Kingdom Joint Theatre Trauma Registry for underbody blast events demonstrates that torso injury is a major cause of morbidity and mortality from such incidents. Mediastinal injury, including those trauma to the heart and thoracic great vessels is shown confer the greatest lethality within this complex environment. This work explores the need for a novel in vivo model of underbody loading in order to explore the mechanisms of severe torso injury and to define the relationship between the “dose” of underbody loading and resultant injury. The work includes the development of a new rig which causes underbody blast analogous vertical accelerations upon a seated rat model. Injuries causes by this loading to both the chest and abdomen can be best predicted by the examining the kinematic response of the torso to the loading. Axial compression of the torso, a previously undescribed injury metric is shown to be the best predictor of injury. The ability of these results to translate to a human model is explored in detail, with focus upon the biomechanical rationale; that torso organ injuries occur through both direct compression and shearing of tethering attachments. Survivability of underbody blast could be improved by applying these principles to the design and modification of seats, vehicles and posture.Open Acces

AFIT School of Engineering Contributions to Air Force Research and Technology Calendar Year 1973

This report contains abstracts of Master of Science Theses, Doctoral dissertations, and selected faculty publications completed during the 1973 calendar year at the School of Engineering, Air Force Institute of Technology, at Wright-Patterson Air Force Base, Ohio