AiMT Volume 4 (2009), Issue 1

Improvements in Simulation of Virtual Ant’s Behaviour

Z. Krupka, A. Štefek

This paper show some approach in simulation of virtual ant’s behaviour and results of many simulations. Presented system is revamped and adjusted to mechanical principles which are more generally. In simulation are applied Newton physic laws. Results of simulations confirm the success of selected approach.

Keywords: Ant behaviour, Flock intelligence, Simulation.

Page: 5 - 13

The New High Sensitive Variant of Nonlinear Ultrasound Spectroscopy for Nondestructive Testing

K. Hájek, J. Šikula

The nondestructive testing by ultrasound nonlinear modulation spectroscopy has two basic variants of realisation. The ultrasound excitation uses harmonic signals with relatively near or distant frequencies as using of mixing or modulation principle. This paper presents comparison of these two basic methods and it asks new possibilities for rising of sensitivity. Especially a necessary time for the exciting and sensing signals is compared. The second part discusses possibility of using of the burst-wave exciting mode for these methods. First, the excitation by phase coupled pulse signals is derived for obtaining of result long lime signal without waste of its useful energy. Nevertheless this output long time signal consists from time-separated pulses and therefore the analog prefiltration cannot be used for suppression of excitation signals. Therefore the new variant of mixing method is derived, where such exciting frequencies are used, that result signal with difference frequency has a relatively high frequency and a shorter period then the exciting signal. On the other hand, the frequency difference between this result component and exciting signal is sufficient for using of LC linear filters with sufficient attenuation of exciting signals.

Keywords: NDT, non-linear spectroscopy, modulation, ultrasound, cracks, pulse exciting

Page: 15 - 22

Microstructural Behaviour of Protective AlSi Coating under Thermal Load

M. Kianicová

Aircraft engine turbine blades are exposed to high temperatures, high static, variable stresses and strong cyclic thermal loads during their operation. The investigated blades originate from the engine DV2 which is appointed for light training combat aeroplane, where sudden changes of engine transition state are in progress mostly during flight manoeuvring. Under these conditions the engine is liable to suffer from unstable running as surging or failure of the fuel system for a several seconds. These undesirable features of engine cause that the critical value of the output gas temperature T4,C is exceeded and damage of the turbine blades is extensive owing to degradation or total loss of protective coating. A short-time (5 to 20 s) exceeding of the operating temperature T4C by up to several tens of degrees degrades the surface layers of the blades and reduces their service life compared to the planned service life of 1500 flight hours. This work deals with degradation of protective coating on rotor blade of the high pressure turbine (HPT) under condition that the temperature of blades would reach the temperature of outgoing gases. The blades were heated in the laboratory, the temperature of blades were admeasured by platinum-rhodium thermocouple. Degradation of coating was analysed by scanning electron microscope. The aim of the work was get new attainments of AlSi coating behaviour at high temperatures without corroding medium.

Keywords: Aircraft engine, protective coating, degradation, superalloys, rotor blades

Page: 23 - 29

Influence of the Breech Locking Clearance on the Automatic Weapon Function

L. Popelínský

The paper deals with the influence of breech locking clearance in the automatic weapon on its function. Small clearance is necessary for the correct function of the weapon. But in case of its increase this clearance may decrease the service life of the breech mechanism and negatively influence the function of the weapon automatics. The theoretical solution and the influence of the increase of the clearance are shown.

Keywords: Breech mechanism, breech locking clearance, gas operated drive

Page: 31 - 39

The Secondary Surveillance Radar Parameters Extraction by Using of SIF/IFF Responses Analysis

J. Veselý, P. Pouč

This article is focused on the possibility of extraction of Secondary Surveillance Radars parameters by using the responses SIF/IFF form planes. This extraction can be used for different goals as well as transponders location or interrogator testing. This article is focused especially on antenna rotation and pulse repetition interval extraction. For the posibility of these parameters extraction are used measured signal, i.e. received SIF/IFF codes and their time of arrival. The algorithms are tested by MATLAB.

Keywords: Secondary Surveillance Radar, Passive System, Parameters extraction

Page: 41 - 47

Man in the Aircraft’s Flight Control System

R. Jalovecký

The article deals with one of possible approaches how to create the alternate model of pilot behaviour in the process of aircraft flight control, especially in the situation when a repression of fast high oscillations of aircraft is eligible. Therefore the analysis and simulation of man behaviour with respect to automatic regulation view is introduced. Results of simulation of his response to the input pulse, and results of integration man-pilot to the circuit of absorbing high oscillations, are also presented.

Keywords: Aircraft automatic control, Autopilot, Oscillation damper, Aircraft, Matlab, Simulink

Page: 49 - 57

Technical Supervision of Investor-KFOR Mission Lesson Learned

E. Zezulová, J. Štoller

The article is focused on the technical supervision of the investor based on KFOR (Kosovo Force) mission lesson learned. Private local construction companies do the majority of constructional works during KFOR mission. In peace time, there is no difference between the content of work of the technical supervision of investor in the Czech Republic and on the mission in Kosovo. The main part of the article describes the supervision of constructional site with focus on the technical supervision of investor. The technical supervision of investor is the main part of the building process. He/she protects investor’s interests. There is no doubt that the careful technical supervision of investor may save financial resources and improve quality of building works. Contracted private local construction companies have had experiences with working for EU investors mainly in Germany and Austria. Regardless of their experience, the ignorance of basic knowledge of technical standards was a huge problem.

Keywords: Technical supervision of investor, technical supervisor of investor (TSI) KFOR mission, designer authorial supervision, government building control, regular inspector, private local company.

Page: 59 - 67