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Application of Fatigue Crack Open Effect for Aircraft Structural Health Monitoring
No full textThe phenomenon of the Lamb wave interaction with fatigue crack in Al2024-T3 sheet was investigated at cyclic loading. Mentioned effect is associated with the crack open/close that change acoustic impedance of a crack. Analytical simulation of fatigue crack opening using the generalized Dugdale’s model of a crack in thin plate shows good accordance between the intensity of ultrasonic signal and a crack opening. The perspective of application for structural health monitoring (SHM) of aircraf
Electromechanical Impedance for Structural Health Monitoring
No full textSome problems of the electromechanical impedance method for structural health monitoring of aircraft are analyzed. The effect of structural damage to dynamic properties of a structure and piezoceramics transducer is considered. 1-D partial model of constrained PZT is developed and is given its generalization for any kinds of structural element. The example of model application for effect of crack estimation to dynamics properties and the EMI is presented
Possibilities of Heat Pump Integration for the Renovation of Dwelling Houses
No full textThe technical solutions for the installation of heat pumps in individual houses are well known, but its integration in the existing systems in dwelling houses is not common. Heat pump technology is referred to as renewable but would have technical, economic and environmental impact on the whole existing heat supply system in a dwelling house. The aim of this article is to investigate the possibility of using heat pumps for supplying heat to the existing residential buildings.
This article examines the possibilities to supplement the engineering systems with additional heat pumps. The smallest heat pump end-user group is the dwelling stairwell. The possibility to use heat pumps in a separate apartment has not been analysed.
This article analyses the integration of heat pumps for residential heat supply in the building. The primary heat source is the exhaust air or wastewater. All calculations have been made for several real existing dwelling houses in Birštonas town (Lithuania) within the framework of the CONCERTO Eco-Life project. The analysis also provides economic and environmental assessment of the alternatives.
This research was supported by EC FP7 CONCERTO program (‘‘Sustainable Zero Carbon ECO-Town Developments Improving Quality of Life across EU - ECO-Life’’ (ECO-Life Project) Contract No. TREN/FP7EN/239497/"ECOLIFE")
Adaptive Model of Wastewater Aeration Tank
No full textAbstract – The paper discusses the methodology of oxygen transfer virtual simulation in a wastewater biological treatment process, using the MATLAB/SIMULINK technology. A self-tuning adaptive model of a wastewater aeration tank, as a non-stationary object, with variable time dependent sensitivity and inertia indexes, as the functions of input variable - air pneumatic supply capacity Lg(t) (m3/min), output variable – dissolved oxygen concentration C(t) (g/m3) and oxygen expenditure, as a load – q(t) (g/min), required for wastewater complete purification, is expounded. Virtual models, applying Laplace transforms and SIMULINK blocks library, are composed in order to compare the transient processes of dissolved oxygen concentration in the simplified stationary model with constant sensitivity and inertia coefficients, and in the non-stationary model with variable sensitivity and inertia indexes. The simulation block-diagram for non-stationary model adoption to the variable parameters is developed, using informative links from input variable Lg(t), from variable load q(t) and feedback from output variable C(t) as inputs of calculation modulus, allowing to instantly re-calculate the variable indexes during simulation time. Comparison of the simplified stationary model and the non-stationary model shows that the simulation results of oxygen transfer differ up to 50%
Kompozīta materiāla izturības modelēšana
No full textDotajā darbā izskatītas svarīgas un aktuālas kompozītmatereāla izturības noteikšanas, sagrūšanas prognozēšanas un akustiskās emisijas signālu apstrādes problēmas, kas, ļauj noteikt drošas izstrādājuma izmantošanas robežas un konstatēt šīs robežas sasniegšanu
Determination of Stress-Strain Characteristics of Thin Polymer Films on Cylindrical Specimens
No full textBezpilota lidaparātu pielietošanas īpatnības lauksaimniecības lietojamplatību monitoringam
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Diagnostics of Fatigue Damage of Gas Turbine Engine Blades
No full textthe work contains the results of complex investigation related to the evaluation of condition of working blades of gas turbine engines during fatigue tests by applying the acoustic emission method. It demonstrates the possibility of estimating the fatigue damage of blades in the process of factory tests. The acoustic emission criteria for detecting and testing the kinetics of fatigue crack distribution were detected. It also shows the high effectiveness of the method for non-destructive testing of condition of solid and cooled working blades for high-temperature gas turbine engines
