Mariusz Żokowski, Marcin Chodnicki, Przemysław Krogulec and Norbert Sigiel
The article presented below is a prelude to the process of conducting sea bottom researches with autonomous underwater systems, focused on detection, classification and identification of objects causing possible threat for shipping and maritime environment. An article include guidelines and suggestions for the operators of autonomous underwater vehicles (AUV), mainly concerning preparations for the operation.
Michał Wachłaczenko, Radosław Przysowa and Mariusz Żokowski
The paper presents description of rotating bladed disk mathematical model. Correctly defined mathematical model of rotor allows creation of numerical simulation model which can be used to generate tip-timing data. First of all, the model is necessary to conduct a research on blade response due to input force in form of changing rotational speed. This enables the possibility to determine turbojet engine terminal operating conditions causing its failure
Jarosław Spychała, Mariusz Żokowski and Paweł Majewski
The article presents considerations concerning the construction of vibration reduction system using magnetic suspension technology. Presents the results of simulation, numerical and experimental the bearingless electric motor, for which successfully used this type of solution. Positive results of research and testing have become the basis for the development of the concept of building this type of active vibration reduction system , at the same time acting as a support for a technical object, which is a jet engine. Bearing failures are manifested by loss or distortion of their mass, which leads to a total destruction of the roller bearing, and thus reflected in the security. The article presents the concept of building active magnetic suspension to eliminate the bearing system of classical rolling bearing and replace it with magnetic bearing.
A diagnostic FDM-A method, based on the measurement of modulation of constituent frequency of direct current (DC) generator pulsation as well as FAM-C method, established on the measurement of frequency modulation of alternating current (AC) generator, were developed in the Air Force Institute of Technology [3, 9-10]. The essence of their accuracy lies in “natural” synchronizing of sampling with angular speed of the observed kinematic pair – if the dynamic processes of the observed object accelerate, the sampling becomes faster too [9-10]. At the same time, around the “synchronization points”, due to the clearance in the power transmission there is a certain natural oscillation between the observed kinematic pair and generator’s rotor − vibrations are created. These vibrations are called jitter [9, 23] and they constitute an additional supplement to this method, because they provide more information on resolution and accuracy. Moreover, the abovementioned method enables to define the level of subassembly abrasive wear and its location in the time of normal operation of the powerplant [9-10]. This method allows also detecting resonances of elements on the basis of observation of shape and relative position of characteristic sets, which i.e. enable to calculate the mechanical quality factor of kinematic pair − it is possible to establish the operation time of kinematic pair until entering the resonance degradation. Other numerous parameters associated with the assembly of power unit rotor were also outlined: rotor skew angle, level of frictional wear of bearing cage − lack of contact of bearing components, bearing assembly ovalisation.
Mariusz Żokowski, Paweł Majewski and Jarosław Spychała
The article discusses typical, operational systems for monitoring vibrations of jet engines, which constitute the propulsion of combat aircraft of the Armed Forces of the Republic of Poland. After that, the paper presents the stage of installing vibration measuring sensors in the direct area of one of the jet engine bearings, which is a support system for its rotor. The article discusses results of carried out analyses of data gathered during tests of the engine in the conditions a jet engine test bed. Results of detecting damages to the bear-ing, using sensors built in the direct area will be presented.
In this paper a results of a transient analysis of the linear actuator is presented. The linear actuator consist of the three cylindrical unmovable coils surrounded by a soft ferromagnetic case, a runner made from sequence of ferromagnetic and permanent magnet rings. The model of the linear actuator was implemented into two software: the Comsol Multiphysics and the Matlab-Simulink. Both environments are commonly used in simulation analysis, but the first one uses Finite Element Method (FEM) and the second one uses Ordinary Differential Equations (ODE). Moreover, the dynamic model was analysed in Matlab-Simulink software with value of electromagnetic phenomena implemented from Comsol Multiphysics. Comparison was made due to the time needed for calculation, accuracy of the simulation model as well as the as utility for further optimization process.