AiMT Volume 7 (2012), Issue 2

Up-to-Date Tribo-Fatigue Test Possibilities and Methods

J. Stodola

This article deals with tribo-fatigue which is phenomena, situations, difficulties, and regularities related to the damage of fracture of tribo systems. Very often they could not be observed, comprehended, and described analytically, hence they could not expect proceeding from traditional views of solid mechanics, mechanics of fatigue damage and fracture, tribology, theory of dependability of mechanical systems and other disciplines of the mechanical and physical cycle. Tribo-fatigue involves special methods for wearfatigue test used to estimate experimentally the mutual and joint influence of the processes of friction and mechanical fatigue on the performance of materials and models of tribo-fatigue system under complex loading conditions.

Keywords: Tribology, fatigue, testing, mechanical systems, damage, modelling, deterioration, dependability.

Pages: 5-15

Resistance of IIR Barrier Materials against Selected Chlorinated Hydrocarbons

P. Otřísal and S. Florus

Information about quality assurance means insulating protection is very important. Their availability may be limited, and therefore in some cases will need to rely on the value of breakthrough times for basic hydrocarbons which are not substituted. The article describes how to test breakthrough times of the protective foil based on a polyamide carrier fabric coating butyl-rubber polymer mixture measured by the linear substituted saturated chlorinated aliphatic hydrocarbons.

Keywords: Chlorinated hydrocarbon, QCM detector, permeation rate, butyl-rubber (IIR), breakthrough time (BTT), chemical permeation resistance, permeation cell.

Pages: 17-22

Prediction of Vehicle Cabin Air Quality

Š. Čorňák, V. Horák and Z. Chládek

The quality of microclimate within the vehicle cabin substantially influences the driver and crew work performance and operational efficiency. One of the main factors of the microclimate quality is the carbon dioxide content in the vehicle cabin air, where the decisive source of increasing the CO2 concentration is the human breathing. The mathematical model for the unsteady state prediction of the CO2 content in the vehicle is closely described in the article. The model is validated for two examples of the CO2 concentration prediction: for varied number of persons in a vehicle and for various rates of vehicle ventilation. The method was verified by an experiment, where the measurement of the CO2 content was performed in a passenger vehicle for the combination of low and high rates of ventilation.

Keywords: Cabin air quality, vehicle microclimate, carbon dioxide, predictive model.

Pages: 23-32

Calibration Extension for Permeation Cell of PIEZOTEST Device

S. Florus and P. Otřísal

Measurement of permeation resistance of constructive materials against under interest volatile toxic compounds has a huge importance not only from the point of user’s view but also from commercial one. It is necessary to distinguish an amount of permeated under interest toxic compound through protective material within both approaches. The PIEZOTEST device is designed for measurement of resistance of square constructive materials used for body surface protection. Commercially delivered device was not able to be calibrated. The aim of this information is to present calibration solution of this device with the help of a calibration extension, available device for dosage. The knowledge of concentration of toxic substances penetrating trough material is needed to calculate to gain information concerning protective properties. Therefore, it is necessary to calibrate a QCM sensor.

Keywords: Permeation cell, calibration, permeation resistance, breakthrough time (BTT), normalization permeation mass, normalized breakthrough detection time, QCM detector, PIEZOTEST device.

Pages: 33-40

Attenuation of Acoustic Waves from Targets by Atmosphere

P. Melša

Acoustic detection of adversary land targets is interlinked with transmission of environment acoustic waves – atmosphere. The solution of this problem of acoustic exposure of target and acoustic transmission of information in atmosphere makes it possible to specify important dates about target of interest.

Keywords: Acoustic wave, wave attenuation, atmosphere, humidity, detection, target.

Pages: 41-47

Practical Experience with Distance Measurement Based on Single Visual Camera

A. de La Bourdonnaye, R. Doskočil, V. Křivánek and A. Štefek

The paper deals with the problem of distance measurement of stationary target by single visual camera in laboratory conditions. The paper describes the practical experiments performed in order to estimate the distance of a target using visual odometry. For the estimation of the distances, we used a camera and a target. For these estimations, photos were taken to obtain the coordinates of reference points on the target surface. The coordinates obtained were used in optical equations to estimate distances of the target in the space. The paper explains the procedures made for the experiment preparation, describes the experiments and finally analyses the results acquired. These practical experiments establish a basis for the implementation of the position algorithm into navigation subsystem of swarm robots.

Keywords: Single visual camera, distance measurement, error analysis, image analysis, optical properties.

Pages: 49-56

Comparison of Elevation Data of the Czech Republic for Designing Military Constructions

J. Sobotka

Current elevation database of the Czech Republic territory is obsolete and unusable for designing constructions. The paper deals with utilization of new elevation data of the airborne laser scanning for the designing of military buildings. The newly prepared digital elevation database will be the result of the airborne laser scanning of the Czech Republic (2009-2012). This paper compares the current elevation data (digital terrain model of 3rd generation) and new altimetric data (digital terrain model of 4th and 5th generations) with a geodetic measurement in situ.

Keywords: Elevation data, designing, digital terrain model, military construction.

Pages: 57-63

Spectral Angle Mapper as a Tool for Matching the Spectra in Hyperspectral Processing

F. Racek and T. Baláž

The article deals with analysis of Spectral Angle Mapper (SAM) as a tool for matching the separated endmembers with pure spectra from databases. The analysis of SAM is provided in three spectral regions: VIS, IR and VIS+IR together. Three kinds of available influences are analysed: additive noise, constant offset and slant offset.

Keywords: Hyperspectral imaging, noise, offset, spectral angle mapper.

Pages: 65-76

Differences in Barrel Chamber and Muzzle Deformation during Shot

S. Procházka and N. D. Ninh

The paper deals with mechanical parameters calculations of the barrel muzzle and barrel chamber. These calculations have been carried out for 30mm ballistic barrel. We aimed at elastic bore displacement, elastic tangential surface strain and powder gas pressure. Analytic and finite elements calculations were employed. The propellant gases and thermal load were considered together. There is temperature distribution at barrel muzzle which has been computed for experimental barrel.

Keywords: Barrel, chamber, muzzle, barrel bore, strain, stress, field of temperature.

Pages: 77-89

TECHNICAL INFORMATION
Response of Structure to Ballistic Load

P. Droppa, M. Vančo and V. Ferencey

The paper describes briefly the problem of elastic-plastic shock wave propagation in solids. Such waves originate by acting of explosion waves or by high velocity impact of solid parts on the structure. Computational simulations are applied to the problem of propagation of shock waves in composite material reinforced by fibres. The fibres are supposed to be much stiffer than the matrix. The shock wave in such material is influenced by reflexion and refraction on the interface between fibres and the matrix and by the interaction of the waves. The shock wave is strongly damped in such composites in this way.

Keywords: Ballistic load, shock wave propagation, fibre reinforced composite materials, shock wave damping, computational simulation.

Pages: 93-110

TECHNICAL INFORMATION
Analysis of Gas Flow in a Secondary Electron Scintillation Detector for ESEM with a New System of Pressure Limiting Apertures

J. Maxa, V. Neděla, J. Jirák, P. Vyroubal and K. Hladká

Environmental scanning electron microscopes offer wide possibilities for the exploration of various types of specimens, especially non-conductive and wet specimens containing different material phases. In this article the results of gas-pumping simulations are analyzed for the novel design of pressure limiting apertures in a secondary electron scintillation detector with usage of SolidWorks and Ansys systems.

Keywords: ESEM, SEs Scintillation Detector, CFD, CAE, SolidWorks, Ansys.

Pages: 111-116