Diagnosis of the wear of gears in the gearbox using the wavelet packet transform

The paper presents research aimed at diagnosing early cases of wear of gears tooth surface in the gearbox based on measurements of vibration signals and their processing using the wavelet packet transform. Analysis concerned the vibration signals recorded in a test bench experiment, during which the wear of gears teeth increased (pitting and spalling). The studies allow conclusions to be drawn that the processing of vibration signals using the wavelet packet transform allows the detection of early cases of wear of the working surface of the teeth on the basis of an analysis of selected details of wavelet decomposition and vibration measures

A method for detecting damage to rolling bearings in toothed gears of processing lines

This paper presents a method of diagnosing damage to rolling bearings in toothed gears of processing lines. The research has shown the usefulness of vibration signal measurements performed with a laser vibrometer and of the method of denoising signals by means of a discrete wavelet transform in detecting damage to bearings. The application of the method of analysis of the characteristic frequencies of changes in the vibration signal amplitude made it possible to draw conclusions about the type of damage to the bearings

The influence of the hardening coolant agent on the properties of hot rolled bars of the steel 42CrMo4

In the work the influence results of two different hardening coolant agents on the basic mechanical proprieties and microstructure of the round hot rolled bars were presented. The bars of 42CrMo4 steel were exposed to analysis, and for those bars in the hardening process, water and modern pro-ecological polymer cooling agents Aqua Quench MK were used

A method for the selection of certain force and energy parameters of automatic sheet metal coiling machines

The paper concerns issues related to the sheet coiling process on processing lines. The industry’s needs and requirements for semi-finished products in the form of coil sheets are presented. The paper also discusses the results of the calculations of selected force and energy parameters of devices for coiling sheets made of a zinc-titanium alloy. The presented results were obtained based on calculations and a practical verification of the adopted assumptions using newly-designed devices introduced into operation

Knowledge transmission patterns at the border: ethnobotany of Hutsuls living in the Carpathian Mountains of Bukovina (SW Ukraine and NE Romania)

Background Cross-border research is a novel and important tool for detecting variability of ecological knowledge. This is especially evident in regions recently divided and annexed to different political regimes. Therefore, we conducted a study among Hutsuls, a cultural and linguistic minority group living in Northern and Southern Bukovina (Ukraine and Romania, respectively). Indeed, in the 1940s, a border was created: Northern Bukovina was annexed by the USSR while Southern Bukovina remained part of the Kingdom of Romania. In this research, we aim to document uses of plants for food and medicinal preparations, discussing the different dynamics of Local Ecological Knowledge (LEK) transmission among Hutsuls living in Ukraine and Romania. Methods Field research was conducted using convenience and snowball sampling techniques to recruit 31 Hutsuls in Ukraine and 30 in Romania for participation in semi-structured interviews regarding the use of plants for medicinal and food preparation purposes and the sources of such knowledge. Results The interviews revealed that, despite a common cultural and linguistic background, ethnobotanical knowledge transmission occurs in different ways on each side of the border. Family is a primary source of ethnobotanical knowledge transmission on both sides of the border; however, in Romania, knowledge from other sources is very limited, whereas in Ukraine interviewees reported several other sources including books, magazines, newspapers, the Internet and television. This is especially evident when analysing the wild plants used for medicinal purposes as we found 53 taxa that were common to both, 47 used only in Ukraine and 11 used only in Romania. While Romanian Hutsuls used almost exclusively locally available plants, Ukrainian Hutsuls often reported novel plants such as Aloe vera, Aronia melanocarpa and Elaeagnus rhamnoides. Knowledge related to these plants was transferred by sources of knowledge other than oral transmission among members of the same family. Therefore, this may imply hybridization of the local body of knowledge with foreign elements originating in the Soviet context which has enriched the corpus of ethnobotanical knowledge held by Ukrainian Hutsuls. Conclusions While ethnobotanical knowledge among Romanian Hutsuls is mainly traditional and vertically transmitted, among Ukrainian Hutsuls there is a considerable proportion of LEK that is transmitted from other (written and visual) sources of knowledge. This cross-border research reveals that despite a common cultural background, socio-political scenarios have impacted Hutsul ethnobotanical knowledge and its transmission patterns

Diagnosis of the wear of gears in the gearbox using the wavelet packet transform

The paper presents research aimed at diagnosing early cases of wear of gears tooth surface in the gearbox based on measurements of vibration signals and their processing using the wavelet packet transform. Analysis concerned the vibration signals recorded in a test bench experiment, during which the wear of gears teeth increased (pitting and spalling). The studies allow conclusions to be drawn that the processing of vibration signals using the wavelet packet transform allows the detection of early cases of wear of the working surface of the teeth on the basis of an analysis of selected details of wavelet decomposition and vibration measures

Diagnosing of valve clearance of the diesel engine

W pracy przedstawiono badania, których celem jest diagnozowanie zwiększonego luzu zaworowego silnika spalinowego z zapłonem samoczynnym. W eksperymentach stanowiskowych prowadzono pomiary przyśpieszenia drgań silnika spalinowego, w którym modelowano powiększony luz zaworu dolotowego i wylotowego. W celu poszerzenia możliwości diagnostyki ww. uszkodzenia wykonywano także pomiary i analizy hałasu, mierząc ciśnienie akustyczne w pobliżu silnika. Na podstawie zarejestrowanych sygnałów przeprowadzono ich analizę stosując uśrednianie i filtrację oraz wyznaczając energię, a także rozkłady czasowo-częstotliwościowe Wignera-Ville'a.The paper presents test results, whose aim is diagnosing of valve clearance increase in a combustion diesel engine. Acceleration of the engine vibration was measured in laboratory tests of the engine, in which clearence of intake and exhaust valves was increased. In order to widen diagnosis possibility of this valve clearence, noise was also measured and analysed by teaking acoustic preassure near the engine. On the basis of recorded signals, an analysis was made using average and signal filtration and as the next step energy was counted, as well as Wigner-Ville time-frequency decomposition

Diagnosing the engine valve clearance, on the basis of the energy changes of the vibratory signal

Celem badań jest diagnozowanie zwiększonego luzu zaworowego silnika spalinowego, który może być spowodowany uszkodzeniem hydraulicznych automatycznych kasowników luzu zaworowego lub nadmiernym zużyciem elementów głowicy. Do diagnozowania luzu zaworowego zaproponowano zastosowanie metody pomiaru i analizy drgań. W celu wykazania jej użyteczności przeprowadzono badania stanowiskowe, w których symulowano powiększony luz zaworowy silników z zapłonem iskrowym i samoczynnym. Następnie przeprowadzono przetwarzanie i analizę przyśpieszenia drgań silników, obliczając energię sygnału w oknie kroczącym i jego rozkłady czasowo-częstotliwościowe Wignera-Ville'a.The aim of the research is to diagnose the clearence of the valves in an internal combustion engine. The clearence may be caused by the damage of the hydraulic automatic reduction of the valve clearence or the excessive wear of the head elements. The measurement methods and the vibration analysis were proposed. In order to indicate their utility, workstand research was carried out. During the test, the enlarged clearence of the valve engine, both spark ignition and diesel was simulated. Afterwards, the transformation and the analysis of the engine vibration acceleration were carried out, calculating, in this way, the energy of the signal and its time-frequency Wigner-Ville decomposition

Analysis of the excitation forces change and their influence on the crankcase vibration of an internal combustion engine

Celem badań jest wyznaczanie drgań modelu kadłuba silnika spalinowego wywołanych zmiennymi siłami występującymi w układzie korbowo-tłokowym. Uwzględniając zależności kinematyczne układu korbowo-tłokowego określono wartości tych sił, przy założeniu zmian wartości ciśnienia nad tłokiem oraz zmian prędkości obrotowej silnika. Wyznaczone wartości sił wymuszających drgania zostały wykorzystane w modelu MES kadłuba do oszacowania prędkości drgań wybranego, przykładowego punktu kadłuba.The aim of the reaserch is counting internal combustion engine crankcase vibration caused by changing excitation forces in piston-crank system. The values of these forces were calculated taking into consideration kinematic equations of piston-crank system, assuming changes of cylinder pressure and engine rotation velocity values. The calculated excitating vibration forces were used in an engine FEM model to estimate vibration velocity of a choosen examplary crankcase point

The influence of vibration transmittance on diagnostics symptoms of tooth gear condition

W pracy przedstawiono wykorzystanie eksperymentalnej analizy modalnej do oceny wpływu transmitancji drgań na symptomy diagnostyczne stanu kół zębatych. Badania prowadzono na stanowisku mocy krążącej FZG. Stosując młotek modalny wymuszano drgania kół, wałów i obudowy przekładni jednostkowym impulsem siły. Na podstawie badań otrzymano charakterystyki transmitancji wzajemnej oraz własnej wybranych punktów pomiarowych wałów i obudowy przekładni. Wyniki badań porównano z rozkładami czasowo-częstotliwościowymi sygnałów drganiowych przekładni, które towarzyszą zużyciu powierzchni roboczej zębów i wykruszeniu zęba koła.The paper presents the use of experimental modal analysis in estimation of influence of vibration transmittance on diagnostics symptoms of tooth gear condition. The research was realized on power circulating gear testing machine FZG. Modal hammer was used to enforce gearbox element vibration. On the basis of the analysis characteristics of transmittance in different points of gearbox were received. The results of the experiment were compared to Wigner-Ville distribution of vibration signal, accompanying tooth surface and tooth local damages