The predictions of residual stresses are most critical on the machined aerospace components for the safety of the aircraft. In this paper, an enhanced analytic elasto-plastic model is presented using the superposition of thermal and mechanical stresses on the workpiece, followed by a relaxation procedure. Theoretical residual stress predictions are verified experimentally with X-ray diffraction...

In this paper, we present an interesting method to microfabricate a tilted micro air jet generator. We used the well-know deep reactive ion etching (DRIE) technique in order to realize in a silicon substrate a double side etching. For aircraft and cars, micro air jets will take an important place for fluid control. Micro air jets are characterized by their speed, frequency and tilt. Usually, th...

Concerning the feasibility of a future supersonic fleet, current market forecasts see a 60% chance of any launch of a supersonic business jet program in the next 8 years, and an 85% chance by 2020. Furthermore, different European projects like HISAC (www.hisacproject.com) or LAPCAT (www.esa.int/techresources/lapcat) deal with the development of supersonic aircraft. Airbus spent a lot of effort ...

Equipment and techniques employed in an airborne far ir (80-400 micro) spectral measurement of the solar brightness temperature are described, with particular attention paid to the scanning Michelson interferometer and the radiometric calibration. The airborne performance of several telescopic guiding systems, a liquid helium cooled bolometer, and golay cells are discussed, summarizing experien...

Foreign object damage (FOD) occurs when hard, millimeter-sized objects such as gravel or sand and even the pieces of the engine components are ingested into aircraft jet engines. Particles impacting blades produce small indentation craters which can become sites for fatigue crack initiation, severely limiting the lifetime of the blade. In this study, the impact on the edge of a thin plate is in...

Described is a method for determining a semi-empirical, equivalent simple-source model that accounts for the aeroacoustic sources in the jet plumes of high-performance military aircraft. The characteristics of the equivalent source are guided by previously reported observations of jet noise, including an asymmetric, partially correlated source distribution and known far-field peak directivity a...

One issue of interest pertaining to the development of a numerical model applicable to the nonlinear propagation of jet noise is the behavior of spectral predictions at large distances. In this study, a recorded noise waveform from a military jet aircraft is numerically propagated via a hybrid time-frequency domain solution to the generalized Burgers equation that incorporates spherical spreadi...

Vector acoustic intensity provides both the direction and magnitude of energy flow at the probe location and is, hence, more informative than acoustic pressure measurements. However, this important quantity has seen little application previously in aeroacoustics. In the present work, an intensity probe, consisting of four microphones, captured the radiated field to the sideline and aft of a tet...

General chemistry: an introduction to descriptive chemistry and modern chemical theory: Linus Pauling. Reviewed by J. S. Coles ................... .................... 49 Gas turbines and jet propulsion for aircraft. (4th ed.): G. Geoffrey Smith. Reviewed by Rob rt S. Ross ........................................ 49 Introduction to electron optics: the production, propagation, and focusing of e...

Problems that potential very light jet (VLJ) pilots of the future are having in the aircraft they currently fly, as evidenced in incident and accident reports, were analyzed. Significant problems identified include poor crew/single pilot resource management, low currency, inadequate preflight planning, avionics use difficulties, and cognitive performance issues, among others. Implications for t...