Search Results

Hypersonic flight vehicles have potential applications in strategic defence, space missions, and future civilian high-speed transportation systems. ...Scramjet-powered air-breathing hypersonic vehicles experience extreme heat loads induced by combustion, shock waves and viscous heat dissipation.

Scramjet-based hypersonic airbreathers are needed for next-generation defense and space applications. Two scramjet configurations, namely, rectangular and axisymmetric, are primarily studied in the literature.

How Distributed Metal Additive Manufacturing Can Add a Surge to Military Supplier Strategies Ensure Aerospace Composite Quality with Force Measurement, Material Testing How Business Networks Can Help Stabilize the A&D Supply Chain A blueprint for modernizing the supply chain for greater connectedness and collaboration. Unlocking the Potential of 3D-Printed Polymers in Aerospace and Defense How to Select the Right Silicone for Space Applications Key Measurements to Maintain Performance of Critical Electronic Systems on Military Aircraft and Warships Physicists Develop a New Type of Antenna Towards Sustainable Recycling of Epoxy-Based Polymers: Approaches and Challenges of Epoxy Biodegradation Composites are especially important for the development and implementation of sustainable technologies such as wind power, energy-efficient aircrafts, and electric cars.

Abstract At hypersonic speed, severe aerodynamic heating is observed, and temperatures are too high to cool by radiation cooling; active cooling such as ablative cooling is helpful in this situation. ...A Computational Fluid Dynamics (CFD) simulation of a two-dimensional (2D) lifting body against thermally perfect air in a hypersonic region (Mach number, M > 5) is carried out for M = 5–9 to obtain a heat-transfer-minimized sweepback angle (ΛHT-min), at which heat transfer to the vehicle is minimum.

Why are Aerospace & Defense Companies Embracing Additive Manufacturing? Simplifying Power Design with Modular Architectures The Role of DevSecOps in Modern Edge Systems Making Machines Curious Designing Multi-Channel Microwave Radio Systems Using Optical Interconnects Solving Military Satellite, Radar and 5G Communications Challenges with GaN-on-SiC MMIC Power Amplifiers Advanced Airborne Defensive Laser for Incorporation on Strike Fighter Aircraft A technical and operational analysis of an airborne "hard-kill" Ytterbium fiber laser-based anti-missile system for use on strike fighters. Additive Manufacturing Utilizing a Novel In-Line Mixing System for Design of Functionally Graded Ceramic Composites Exploring the development of a direct ink writing system with multimaterial and in-line mixing capabilities for printing inks composed of high solids-loaded ceramic particulate suspensions.

Abstract At supersonic aircraft speeds, aerodynamically heated surfaces, e.g., nose, wing leading edges, are infrared (IR) signature sources from the tactically crucial frontal aspect. This study numerically predicts and then illustrates the minimization of IR contrast between the nose and background sky radiance by the emissivity optimization (εw,opt) technique, which has the least performance penalties. The IR contrast between the aircraft nose and its replaced background in 1.9-2.9 μm short-wave IR (SW-IR), 3-5 μm medium-wave IR (MW-IR), and 8-12 μm long-wave IR (LW-IR) bands are obtained. The IR contrast especially in LW-IR (i) increases with flight Mach number (M ∞) for a given flight altitude (H) and εw (ii) decreases with increasing H for a given M ∞ and εw. The εw,opt for a flight altitude of 5 km is found to decrease from 0.99 at M ∞ = 0.001 (low subsonic) in all three bands to 2 × 10−4 in MW-IR and 0.0213 in LW-IR bands at M ∞ = 3 (high supersonic).

This section presents the basic equations for computing ice protection requirements for nontransparent and transparent surfaces and for fog and frost protection of windshields. Simplified graphical presentations suitable for preliminary design and a description of various types of ice, fog, frost, and rain protection systems are also presented.

This section presents methods and examples of computing the steady-state heating and cooling loads of aircraft compartments. In a steady-state process the flows of heat throughout the system are stabilized and thus do not change with time. In an aircraft compartment, several elements compose the steady-state air conditioning load.

The fluid flow treated in this section is isothermal, subsonic, and incompressible. The effects of heat addition, work on the fluid, variation in sonic velocity, and changes in elevation are neglected. An incompressible fluid is one in which a change in pressure causes no resulting change in fluid density. The assumption that liquids are incompressible introduces no appreciable error in calculations, but the assumption that a gas is incompressible introduces an error of a magnitude that is dependent on the fluid velocity and on the loss coefficient of the particular duct section or piece of equipment. Fig. 1A-1 shows the error in pressure drop resulting from assuming that air is incompressible. With reasonably small loss coefficients and the accuracy that is usually required in most calculations, compressible fluids may be treated as incompressible for velocities less than Mach 0.2.

Together, the companies will develop customized lightweight material systems and advanced manufacturing processes, such as metal additive manufacturing – also known as 3D printing – to advance current and next-generation aerospace and defense solutions, including new structures and systems not currently in existence.

The fifth volume of this six-volume compendium publishes technical guidance and properties on ceramic matrix composite material systems. The selected guidance on technical topics related to this class of composites includes material selection, processing, characterization, testing, data reduction, design, analysis, quality control, application, case histories, and lessons learned of typical ceramic matrix composite materials. Volume 5, which covers ceramic matrix composites, supersedes MIL-HDBK-17-5 of June 17, 2002. The Composite Materials Handbook, referred to by industry groups as CMH-17, is an engineering reference tool that contains over 1,000 records of the latest test data for polymer matrix, metal matrix, ceramic matrix, and structural sandwich composites. CMH-17 provides information and guidance necessary to design and fabricate end items from composite materials.

This section presents the basic equations for computing ice protection requirements for nontransparent and transparent surfaces and for fog and frost protection of windshields. Simplified graphical presentations suitable for preliminary design and a description of various types of ice, fog, frost, and rain protection systems are also presented.

This section presents the basic equations for computing ice protection requirements for nontransparent and transparent surfaces and for fog and frost protection of windshields. Simplified graphical presentations suitable for preliminary design and a description of various types of ice, fog, frost, and rain protection systems are also presented.

This document summarizes types of heat sinks and considerations in relation to the general requirements of aircraft heat sources, and it provides information to achieve efficient utilization and management of these heat sinks. In this document, a heat sink is defined as a body or substance used for removal of the heat generated by hydrodynamic or thermodynamic processes. This document provides general data about airborne heat sources, heat sinks, and modes of heat transfer. The document also discusses approaches to control the use of heat sinks and techniques for analysis and verification of heat sink management. The heat sinks are for aircraft operating at subsonic and supersonic speeds.

The purpose of this section is to provide methods and a set of convenient working charts to estimate penalty values in terms of take-off fuel weight for any given airplane mission. The curves are for a range of specific fuel consumption (SFC) and lift/drag ratio (L/D) compatible with the jet engines and supersonic aircraft currently being developed. A typical example showing use of the charts for an air conditioning system is given. Evaluation of the penalty imposed on aircraft performance characteristics by the installation of an air conditioning system is important for two reasons: 1 It provides a common denominator for comparing systems in the preliminary design stage, thus aiding in the choice of system to be used. 2 It aids in pinpointing portions of existing systems where design improvements can be most readily achieved.

This section presents methods and examples of computing the steady-state heating and cooling loads of aircraft compartments. In a steady-state process the flows of heat throughout the system are stabilized and thus do not change with time. In an aircraft compartment, several elements compose the steady-state air conditioning load.

The fluid flow treated in this section is isothermal, subsonic, and incompressible. The effects of heat addition, work on the fluid, variation in sonic velocity, and changes in elevation are neglected. An incompressible fluid is one in which a change in pressure causes no resulting change in fluid density. The assumption that liquids are incompressible introduces no appreciable error in calculations, but the assumption that a gas is incompressible introduces an error of a magnitude that is dependent on the fluid velocity and on the loss coefficient of the particular duct section or piece of equipment. Fig. 1A-1 shows the error in pressure drop resulting from assuming that air is incompressible. With reasonably small loss coefficients and the accuracy that is usually required in most calculations, compressible fluids may be treated as incompressible for velocities less than Mach 0.2.

From concept to application, Fatigue and Durability of Metals at High Temperatures describes the method of strain-range partitioning for analyzing time-dependent fatigue. Creep (time-dependent) deformation is first introduced for monotonic and cyclic loading. Multiple chapters then discuss strain-range partitioning in details for multi-axial loading conditions and how different loading permutations can lead to different micro-mechanistic effects. The total-strain method of strain-range partitioning (SRP) is described, which is a methodology that sees use in several industries.

No other book provides the details of how to conduct tribotests, including their implications, how to avoid pitfalls, and which are most useful. This manual describes the many manifestations of friction wear and erosion and suggests specific tests that can be used to address problems. It gives guidance in determining if bench tests are appropriate for a problem and if so, which ones should be considered. Manual 56 is an excellent resource for newcomers to tribology and a useful reference for practicing tribologists.

It is found that control of heat transfer on a wing at hypersonic wing can act as a control device, comparable to that due a moderate flap deflection.