The paper presents a proposition of the theoretical-experimental method of determination of power losses in the transversely vibrating rubber V-belt of continuously variable transmission. The article comprises the results of experimental tests conducted on a special test stand with a complete scooter drivetrain powered by a small two-stroke internal combustion engine. Such a configuration allows ensuring real CVT working conditions. A high-speed camera was used for the contactless measurement of belt vibrations and time-lapse image analysis was performed in dedicated software. An axially moving Euler–Bernoulli beam was assumed as the mathematical model. Longitudinal vibrations and nonlinear effects were omitted. Additionally, it was assumed that the belt material behaves according to the Kelvin–Voigt rheological model. Analysis of the damped free vibrations of the cantilever beam, made of the belt segment, allowed to determine the equivalent bending damping coefficient. The CVT power losses, due to bending in the rubber transmission belt, were obtained for the fixed working conditions after numerical calculations. The proposed methodology is a new approach in this research area, which allows to obtain results impossible to achieve with other measurement methods.
As the duration of a rock burst is very short and the roadway is seriously damaged after the disaster, it is difficult to observe its characteristics. In order to obtain the dynamic characteristics of a rock burst, a modified uniaxial compression experiment, combined with a high-speed camera system is carried out and the process of a rock burst caused by a static load is simulated. Some significant results are obtained: 1) The velocity of ejected particles is between 2 m/s and 4 m/s. 2) The ratio of elastic energy to plastic energy is about five. 3) The duration from integrity to failure is between 20 ms and 40 ms. Furthermore, by analyzing the stress field in the sample with a numerical method and crack propagation model, the following conclusions can be made: 1) The kinetic energy of the ejected particles comes from the elastic energy released by itself. 2) The ratio of kinetic energy to elastic energy is between 6% and 15%. This can help understand the source and transfer of energy in a rock burst quantitatively.
In the technical diagnostics and monitoring of high dynamic processes high-speed cameras are getting wider application. Recorded images sequence analysis of an object position makes possible to study also the oscillating movement. In this paper results of some exploratory research of test vibration signals are presented. The aim of the study was to examine the possibility of applying high-speed camera to vibration measurements in the frequency range up to 1000 Hz. The performed tests consisted in the simultaneous registration and analysis of vibration test signals using 4 alternative measuring systems. and then the determination of the frequency characteristics of vibration acceleration, total corrected (Wh characteristics) and uncorrected vibration acceleration values. The results of recorded image analyses of oscillating movement were compared with results of vibration acceleration measurements obtained using laser and piezoelectric transducers. Vibration acceleration spectra, the uncorrected and corrected (Wh characteristics) total vibration acceleration values were determined. Based on the achieved results, some limitations and conditions for the application of the high-speed camera used for vibration analyses have been identified. The test results confirmed the possibility of use of high-speed camera for research of low frequency vibration even at low displacements.
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The paper presents the possibilities of using a high-speed measuring camera in experimental tests of decompression of acetylene cylinders in a fire environment. Optical measuring technique was used in the tests. One of the main goals of the experiment was to calculate the energy that the fragments of an exploding cylinder would have during a fire that led to the explosion. In addition, the proposed solution was used to present the advantages and difficulties resulting from the use of measuring equipment in the planned experiment. On this basis, the research methodology was developed and verified. The values of the safety zone for the research team were determined, the manner and the rules of fracturing of this type of steel cylinders were determined.
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W artykule przedstawiono możliwości wykorzystania szybkiej kamery pomiarowej w badaniach eksperymentalnych dekompresji butli z acetylenem w środowisku pożarowym. W badaniach wykorzystano optyczną technikę pomiarów. Jednym z głównych celów eksperymentu było obliczenie energii, jaką posiadają odłamki eksplodującej butli podczas pożaru doprowadzającego do eksplozji. Dodatkowo, za pomocą zaproponowanego rozwiązania starano się przedstawić zalety, jak i trudności wynikające z użycia sprzętu pomiarowego w planowanym eksperymencie. Na tej podstawie opracowano i zweryfikowano metodykę badawczą. Wyznaczono wartości strefy bezpieczeństwa dla zespołu badawczego, określono sposób i zasady odłamkowania tego typu butli stalowych.
EN
The paper presents the possibilities of using a high-speed measuring camera in experimental tests of decompression of acetylene cylinders in a fire environment. Optical measuring technique was used in the tests. One of the main goals of the experiment was to calculate the energy that the fragments of an exploding cylinder would have during a fire that led to the explosion. In addition, the proposed solution was used to present the advantages and difficulties resulting from the use of measuring equipment in the planned experiment. On this basis, the research methodology was developed and verified. The values of the safety zone for the research team were determined, the manner and the rules of fracturing of this type of steel cylinders were determined.
Excavation, especially of hard rocks, using boom-type road headers is a source of strong vibrations of the boom in which they are equipped. These vibrations are transferred through construction nodes further to the turntable and the body of the road header. On the one hand, they are of great importance from the point of view of the durability and the reliability of the mining machine. On the other hand, they affect the variability of the parameters at which the process of cutting the heading face surface of a drilled roadway or tunnel is carried out. For the purpose of determining the vibration intensity of the boom of the road header a photogrammetry system based on two high-speed cameras Phantom Miro LC 120 was used. During the experimental investigations of the cutting process of a cement-sand block using the R-130 road header, the boom and turntable movements were recorded. The analysis of the time-lapse pictures of the recorded footage obtained from the high-speed cameras using dedicated TEMA 3D software allowed to determine the spatial trajectory of movement of the boom and the turntable during the cutting of the massive with specified mechanical properties with set values of the parameters of this process. Basing on the time courses of the coordinates of the boom and turntable characteristic points, the courses of the actual boom swinging speed and acceleration components of its vibrations were determined. The intensity of these vibrations was related to the conditions of the cutting process.
In order to identify the behavior of cutting picks during the process of mining with the use of a roadheader's cutterhead, an optic system has been employed. The main elements of the system were high-speed cameras. In conjunction with TEMA Motion 3D software (which is designed to analyze movement based on images registered in videos), this allowed for a detailed analysis of the trajectories of the boom, cutterheads, and cutting picks during the process of cutting. This article presents the process of conducting measurements as well as the results of a comparative analysis of the boom vibrations and movement trajectories of cutting picks on the cutterhead for selected cut types: progressive and degressive.
PL
Do identyfikacji ruchu noży w procesie urabiania głowicą urabiającą kombajnu chodnikowego wykorzystano zestaw optyczny, którego głównymi elementami były kamery szybkie. W powiązaniu z programem TEMA Motion 3D przeznaczonym do analizy ruchu na podstawie zarejestrowanego obrazu na filmach umożliwiło to szczegółową analizę torów ruchu wysięgnika, głowic urabiających i noży na głowicach w trakcie skrawania. W artykule przedstawiono proces prowadzenia pomiarów oraz wyniki analizy porównawczej drgań wysięgnika i torów ruchu noży na głowicy urabiającej dla wybranych skrawów: progresywnego i degresywnego.
Artykuł dotyczy problematyki eksperymentalnych badań dynamicznych zjawisk niebezpiecznych podczas obróbki drewna. Przedstawiono autorską metodę pomiaru prędkości odrzutu obrabianego materiału drzewnego z użyciem kamery szybkiej oraz programu komputerowego do analizy rejestrowanych obrazów. Metoda ta okazała się bardzo dokładna i niewrażliwa na zakłócenia wiórami i pyłami drewna, które stanowiły dotąd główną trudność w podjęciu eksperymentów naukowych. Nowa metoda może być również polecana do pomiarów prędkości innych gwałtownych i niebezpiecznych zjawisk występujących w procesach obróbki drewna generujących wióry i pyły.
EN
The article is devoted to problems in experimental testing of dangerous dynamic occurrences during wood working. An original method of measuring the speed of kickback of machined piece of wood as well as the new deploying the use of a high-speed camera and a specific computer program for evaluating registered images, were both described in the article. The new measurement method has proven to be very precise and insensitive to both wood chips and dust, which had been the main difficulty in earlier experiments. The new method can be also recommended to the measurements of speed of other violent and dangerous occurrences during woodworking processes which generate chips and dust.
Praca zawiera wyniki badań eksperymentalnych wyznaczania metodą wizualizacji parametrów ruchu mielników – kul w komorze laboratoryjnego młyna wibracyjnego. Wyznaczono drogi każdej z kul na podstawie analizy zbiorów obrazów ich położeń w znanym czasie. Obrazy rejestrowano kamerą o dużej szybkości zapisu. Identyfikację mielników ułatwiło oznakowanie ich rysunkami w postaci czarnych linii i figur geometrycznych. Prędkości i energie kinetyczne kul obliczono metodą analityczną.
EN
Experimental results dealing with the determination of grinding medium movement parameters made by visualization method in a laboratory chamber vibratory mill are presented in the paper. A path of each ball was specified on the basis of sets of positions at given time. Images were recorded with a high-speed camera. Grinding media identification was facilitated by labeling them with drawings in a form of black lines and geometric figures. Speed and kinetic energy of balls were calculated using analytical methods.
A method of high-speed camera recording for registration of dynamic crushing was presented. Energy-absorbing structures commonly used in the automotive industry were studied. Registered high-speed camera signal was compared with the signal obtained by integration of the crushing force.
PL
W pracy przedstawiono badania dynamicznego zgniatania profili cienkościennych o przekrojach: jednoomegowym (top-hat) i dwuomegowym (double-hat). Badania odbyły się na grawitacyjnym młocie spadowym. Proces deformacji struktury rejestrowany był za pomocą czujników udarowych siły umieszczonych pod podstawą próbki, co przy znanej masie bijaka pozwoliło na wyznaczenie przebiegu jego przyspieszenia. Wykorzystano także szybką kamerę, która pozwalała na bezpośrednie wyznaczenie przemieszczenia bijaka w czasie. Otrzymane sygnały — po ich scałkowaniu, bądź zróżniczkowaniu — zostały ze sobą porównane. W pracy wykazano wzajemną korelację przebiegów przemieszczenia bijaka w funkcji czasu otrzymywanych za pomocą opisanych metod. Różniczkowanie sygnału uzyskanego za pomocą kamery — bez użycia filtrowania — daje wyniki bardzo zaszumione. Sygnały przefiltrowane różnią się między sobą, w zależności od własności filtra. Nie dostrzeżono korelacji pomiędzy sygnałami przyspieszenia uzyskanymi za pomocą obu metod, szczególnie w pierwszych 10 ms procesu.
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The paper presents methodology of measurements and results of vibration research on a demolition hammer weighing 15.5 kg. The measurements of vibrations for the chosen measuring points have been carried out using a Photron FastCam 1024 PCI high-speed camera on a stand prepared for testing hand-held tools. To ensure signal stability and to reduce the influence of an operator the research was carried out with the hammer mounted in a special fixture enabling holding a tool with symmetric layout of handles. The measurement results are to be used for verification of a model assumed for a human being – tool system.
An optical measurement method of radial displacement of a ring sample during its expansion with velocity of the order 172 m/s and estimation technique of plastic flow stress of a ring material on basis of the obtained experimental data are presented in the work. To measure the ring motion during the expansion process, the Phantom v12 digital high-speed camera was applied, whereas the specialized TEMA Automotive software was used to analyze the obtained movies. Application of the above-mentioned tools and the developed measuring procedure of the ring motion recording allowed to obtain reliable experimental data and calculation results of plastic flow stress of a copper ring with satisfactory accuracy.
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W pracy zaprezentowano analizę procesów spalania materiałów wysokoenergetycznych zarejestrowanych przy pomocy szybkich technik wizyjnych. Badania przeprowadzono na przykładzie spalania zapłonników paliw rakietowych, mieszanin pirotechnicznych zawartych w petardach hukowych i próbek wykonanych ze stałego paliwa rakietowego. Wykorzystanym instrumentarium badawczym była kamera cyfrowa Phantom V310, której możliwości rejestracyjne sięgają do 0,5 mln klatek na sekundę. Na podstawie zarejestrowanych danych wyznaczono histogramy opisujące intensywność promieniowania świetlnego. W celu określenia granic zjawiska spalania wykonano binaryzację obrazów cyfrowych. Obszary wyznaczone na drodze binaryzacji umożliwiają precyzyjny pomiar propagacji oraz analizę kształtu płomienia. Przedstawiono metodę wyznaczania czasu spalania wykorzystującą analizę intensywność promieniowania świetlnego wyznaczoną za pomocą histogramów. Omówiono warunki prawidłowej rejestracji zjawisk z wykorzystaniem pomocy szybkiej kamery. Przedstawiono proces przetwarzania otrzymanych materiałów flmowych w celu efektywnego ich wykorzystania jako źródła informacji. Pokazano przykładowe możliwości komputerowej analizy obrazów w środowisku Matlab.
EN
The work presents the analysis of the processes of burning the high-energy materials with use of the high-speed vision techniques. The tests were conducted on the sample burning of the ignitors for the rocket propellants, the pyrotechnic mixtures used in the frework bangers and samples manufactured out of the solid rocket propellants. The research apparatus used was the digital camera Phantom V310, which is capable of recording up to 0.5 million frames per second. Based on the recorded data the histograms were calculated for the intensity of the visible radiation in the burning process. To determine the limits of the burning process the binarisation of the digital images was performed. The areas determined by binarisation allow precise measurement of the propagation and analysis of the shape of the fame. The method for determination of the burning time by analysis of the intensity of the visual radiation calculated from the histograms is presented. The conditions for the proper recording of the phenomena with use of high-speed camera are discussed. The processing of the motion materials for the effective use as the information source is presented. The computer analysis of the digital images was performed in the Matlab environment.
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