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1
Content available Strength Analysis Aspects of Psyllium/Thermoplastic Starch Films under Impact Loading Conditions
Beer-Lech Karolina, Kołodziej Paweł, Skic Anna, Branco Ricardo
Advances in Science and Technology. Research Journal
|
2024
|
Vol. 18, no 2
385--393
EN
Tensile test under quasi-static loads conditions is usually used to determine the mechanical strength of thermoplastic starch films. This kind of test does not fully illustrate the load conditions for packaging films, which, under the conditions of use, are succumb to dynamic loads. Thus, the aim of the study was to present the possibilities of using a patented soft tissues measurement testing station to analyze the mechanical strength of thermoplastic starch (TPS) films under impact loading conditions. Two groups of film specimens containing the addition of psyllium husks (TPS/PH) and psyllium flour (TPS/PF) were used for the measurements. The casting method was applied, and glycerol was used as a plasticizer. Microstructure of the specimen surface was analyzed by stereoscopic microscopy. Specimens with the addition of psyllium flour had a more uniform microstructure. The maximum breaking forces obtained during impact tests for these films were 5 times higher than specimens containing psyllium seed husk. The same behaviour was found with respect to stresses with average values of 48.6 MPa for TPS/PF and 20.2 MPa for TPS/PH. Moreover, research confirms usefulness of patented soft tissues measurement testing station to analyse the mechanical strength of thermoplastic starch films.
2
Content available Method of Measuring Frictional Resistance In Pendular Motion
Opałka Mariusz
Tribologia
|
2021
|
nr 1
15--19
EN
This paper presents a methodology for conducting tribological sliding tests based on decaying vibrations in pendular motion. The proposed method of determining the (averaged) coefficient of friction in pendular motion is based on measuring the potential kinetic energy. The method is characterized by a short measuring time and enables a quick comparison of the friction coefficients of different materials.
PL
W artykule przedstawiono metodykę prowadzenia badań tribologicznych materiałów ślizgowych na podstawie drgań gasnących w ruchu wahadłowym. Zaproponowana metoda wyznaczania współczynnika tarcia (uśrednionego) w ruchu wahadłowym opiera się na pomiarze energii potencjalno-kinetycznej. Zaproponowana metoda cechuje się krótkim czasem prowadzenia pomiarów oraz umożliwia szybkie porównanie współczynników tarcia dla różnych materiałów.
3
Content available remote Automated measuring devices for pendulum wire displacements
Kołodziejczyk M.
Geoinformation Issues
|
2015
|
Vol. 7, no. 1(7)
39--45
EN
The article describes the construction and principle of operation of two prototype devices: a laser device and an inductive device for measuring the pendulum wire displacement. A rotating laser beam and two inside detectors (fixed), as well as two external detectors were used in the first device. Falling on the detectors, the laser beam will cause them to generate electrical signals. The time differences between the signals generated by the internal (fixed) and external detectors are a function of the pendulum wire displacement. Inductive sensors mounted inside the measuring head, which is fixed to a cross-truck, moving along the perpendicular X and Y axes in the range of 50 mm, were used in the second device. The cross-truck is moved by stepper motors, and the inductive sensors placed in the X and Y axes search for the location of the pendulum wire. The number of steps of the stepper motors is a measure of the pendulum wire displacement along the X and Y axes. Such devices are used to control the deviation of verticality of tall hydro-technical facilities mainly due to the action of internal stresses and external factors such as temperature and the water level in the tank.
PL
W artykule opisano konstrukcję i zasadę działania dwóch prototypowych urządzeń: urządzenia laserowego i urządzenia indukcyjnego, służących do pomiaru przemieszczeń drutu wahadła. W pierwszym urządzeniu zastosowano wirującą wiązkę laserową oraz dwa detektory wewnętrzne (stałe) i dwa detektory zewnętrzne. Wiązka laserowa padając na detektory powoduje wygenerowanie przez nie sygnałów elektrycznych. Różnice czasowe wygenerowanych sygnałów przez detektory wewnętrzne (stałe) i detektory zewnętrzne są funkcją przemieszczenia drutu wahadła. W drugim urządzeniu zastosowano czujniki indukcyjne zamocowane w głowicy pomiarowej, która jest przytwierdzona do wózka krzyżowego, który przesuwa się wzdłuż prostopadłych do siebie osi X i Y w zakresie 50 mm. Wózek jest przesuwany silnikami krokowymi a umieszczone w osiach X i Y czujniki indukcyjne wyszukują położenie drutu wahadła. Liczba kroków silników krokowych jest miarą przemieszczenia drutu wahadła wzdłuż osi X i Y. Urządzenia takie są stosowane do kontroli odchyleń od pionu wysokich obiektów hydrotechnicznych głównie na skutek działania naprężeń wewnętrznych i czynników zewnętrznych jak temperatura i poziom wody w zbiorniku.
4
Content available Application of shape memory alloy in harvesto-absorber system
Kęcik K.
Acta Mechanica et Automatica
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2015
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Vol. 9, no. 3
155--160
EN
This paper presents a conception of the harvester-absorber system consisting of two parts. The first is the pendulum attached to the main system (oscillator), which is suspended on the linear damper and the nonlinear spring made of shape memory alloy. The spring is modelled as a polynomial function based on Landau–Ginzburg theory of phase transitions (similar as ferroelectric and ferromagnets). The obtained results show, that SMA element can increase harvesting energy level, while the absorber effect can be impaired (but not loss). Additionally, introducing SMA element causes changes in dynamics, introduces a new unstable solutions and bifurcations. The analysis was done by classical integration and continuation solution methods.
5
Content available remote Nonlinear Dynamics and Control of an Active Suspension of a Pendulum Vibration Absorber
Kęcik K., Mitura A.
Machine Dynamics Research
|
2014
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Vol. 38, No. 1
47-53
EN
The paper presents concept of an active suspension of an autoparametric pendulum system. The suspension consist of a magnetorheological (MR) damper and a shape memory alloy spring (SMA). The influence of non-linear damping and SMA stiffness on regular and chaotic vibrations and their stability, near the main parametric resonance has been analyzed. This active suspension allows control of position of periodic or chaotic regions. Additionally, the proposed suspension does not reduce the absorption effect.
6
Content available remote Energy harvesting of a pendulum vibration absorber
Kęcik K.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 7
169--172
EN
This paper presents the numerical results of a pendulum vibration absorber. The system composed of the pendulum attached to the Duffing’s oscillator. The harvester is mounted in the pendulum pivot structure and consists of a cylindrical permanent magnet mounted on rotor and of four windings fixed to the housing as a stator. The obtained results show the influence of system and electrical parameters on value of induced voltage for vibration absorption conditions.
PL
W pracy przedstawiono badania numeryczne wahadłowego tłumika drgań. Układ składa się z wahadła zamocowanego na oscylatorze Duffinga. Urządzenie indukujące prąd zamocowane jest w zawieszeniu wahadła i składa się z cylindrycznego magnesu zamontowanego na rotorze i czterech uzwojeń zamontowanych na stojanie. Otrzymane wyniki pokazują indukowane napięcie w warunkach dynamicznej eliminacji drgań.
7
Content available Efficiency analysis of an autoparametric pendulum vibration absorber
Kęcik K., Mitura A., Warmiński J.
Eksploatacja i Niezawodność
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2013
|
Vol. 15, no. 3
221-224
EN
This paper presents results of a study of a dynamic response of an autoparametric system consisting of the oscillator with an attached pendulum vibration absorber. The harmonic balance method is applied to get the autoparametic resonance conditions. The analytical full vibration absorption condition has been determined and verified by numerical simulations. Additionally, the influence of oscillator and pendulum damping on dynamics and the vibration absorption effect is presented.
PL
W pracy przedstawiono analizę dynamiki autoparametrycznego układu składającego się z oscylatora wraz z dołączonym eliminatorem drgań w postaci wahadła. W celu uzyskania obszarów rezonansu autoparametrycznego zastosowano metodę bilansu harmonicznych. Wyznaczono analitycznie,a następnie zweryfikowano numerycznie warunek pełnej eliminacji drgań. Dodatkowo, przedstawiono wpływ tłumienia oscylatora i wahadła na zjawisko eliminacji drgań oraz dynamikę układu.
8
Content available Gravimetry for geodesy and geodynamics - brief historical review
Krynski J.
Reports on Geodesy
|
2012
|
z. 1/92
69--86
EN
For last two centuries the role of gravity measurements in geodesy was continuously growing with the development of physical geodesy, growing needs for precise geodetic products and progress in technology. A very condensed historical review of gravimetric surveys with their uncertainty characteristics is given in the paper. It starts with single gravity measurements using simple pendulum through the application of reversible pendulum up to four-pendulum apparatus. Superiority of relative gravity survey over absolute gravity survey using pendulum has been highlighted. Further, the development of static spring gravimeters is briefly presented followed by precise ballistic gravimeters that provide more accurate gravity than relative gravity survey and become a valuable tool for geodynamic research. The concept of superconducting gravimeter and its role in geodynamic research is highlighted. Special emphasis is given to the portable free-fall gravimeter A10 designed for field survey. Also the achievements in the direction of developing atomic absolute gravimeters are briefly mentioned. The evolution of the concept and realization of the gravity control is discussed on the background of the progress in gravimetry, paying special attention on its scale and gravity level. It is illustrated with some examples of evolving Polish national gravity control. Finally an attempt to formulate the concept of modern gravity control is presented.
9
Content available remote Magnetorheological Damping of a System with a Pendulum Vibration Absorber
Kęcik K., Mitura A.
Machine Dynamics Research
|
2012
|
Vol. 36, No. 2
49-56
EN
This paper presents a numerical study of a nonlinear two-degrees-of-freedom system consisting of the Duffing oscillator with an attached pendulum absorber. The system is excited close to the principal parametric resonance. By applying numerical simulation we show the influence of viscous and a magnetorheological damping (MR) on the vibration absorption effect. The absorber can be highly efficient for slightly damped systems, if it is correctly tuned. A new element in this work is to use the MR damper, modelled with the effect of hysteretic loop in the nonlinear damper.
10
Content available Energy balance of two synchronized self-excited pendulums with different masses
Kapitaniak T., Czołczyński K., Perlikowski P., Stefański A.
Journal of Theoretical and Applied Mechanics
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2012
|
Vol. 50 nr 3
729-741
EN
We consider the synchronization of two self-excited pendulums with different masses. We show that such pendulums hanging on the same beam can show almost-complete (in-phase) and almost-antiphase synchronizations in which the difference of the pendulums displacements is small. Our approximate analytical analysis allows one to derive the synchronization conditions and explains the observed types of synchronizations as well as gives an approximate formula for amplitudes of both the pendulums and the phase shift between them. We consider the energy balance in the system and show how the energy is transferred between the pendulums via the oscillating beam allowing synchronization of the pendulums.
PL
Artykuł prezentuje analizę zjawiska synchronizacji dwóch wahadeł samowzbudnych o różnych masach. Pokazano, że jeśli takie wahadła zostaną zawieszone na wspólnej, ruchomej podstawie, zachodzi zjawisko ich (prawie) zupełnej lub (prawie) antyfazowej synchronizacji. Analiza bilansu energetycznego układu pozwala na określenie parametrów układu w stanie synchronizacji (amplitudy drgań i przesunięcia fazowe). Analiza bilansu energetycznego wyjaśnia także mechanizm synchronizowania się ruchu wahadeł: stały przepływ strumienia energii od jednego wahadła, via wspólna ruchoma podstawa, do drugiego wahadła powoduje, że ruch układu jest okresowy, a przesunięcia fazowe pomiędzy wahadłami przyjmują stałe, charakterystyczne wartości.
11
Content available remote Promieniowanie odpowiedzialne za ruch wahadełka w świetle teorii pola elektromagnetycznego
Tyrawa P.
Przegląd Elektrotechniczny
|
2011
|
R. 87, nr 3
341-345
PL
Promieniowanie, które wprowadza w ruch harmoniczny wahadło trzymane w palcach przez człowieka jest pochodzenia kosmicznego, dochodzi ono do powierzchni ziemi w okolicach biegunów magnetycznych, i tworzy zarówno nad powierzchnią ziemi jak i w jej wnętrzu rozkłady fal stojących. Sposób, w jaki ustalono cechy charakterystyczne tego promieniowanie i jego rozkłady fal stojących w sąsiedztwie ziemi, jest przedmiotem tego artykułu.
EN
The radiation which causes harmonic movement of a pendulum held by a man in his fingers comes from space. It reaches the earth's surface in neighbourhood of the magnetic poles. It creates distributions of standing waves over the whole surface of the earth, as well as in its interior. The object of this paper is the method by which that radiation's features, and its standing waves distributions in the earth's surroundings, have been confirmed.
12
Content available Zagadnienie tautochrony
Górecki H.
Automatyka / Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
|
2011
|
T. 15, z. 1
47-52
PL
W pracy przedstawiono rozwiązanie teoretyczne ruchu wahadła cykloidalnego. Czas wahań tego wahadła nie zależy od amplitudy wychylenia. Umożliwiało to konstrukcje zegarów bardzo dokładnych. Okazało się, że krzywa zwana tautochroną jest równocześnie krzywą najszybszego spadku w polu grawitacyjnym, to jest brachistochroną. Pokazano również narodzenie się krzywej, tak popularnej w elektrotechnice, to jest sinusoidę.
EN
In the paper, a theoretical solution for the motion of cycloidal pendulum is presented. The period of oscillations of such a pendulum is independent of the amplitude of oscillations. This enables construction of very precise clocks. It turns out that the curve called tautochrone is, at the same time, the curve of quickest descent in the gravitational field, that is, brachystochrone. The birth of the sinusoid curve, so popular in electrical engineering, is also described.
13
Content available Stabilization of pendulum in various inclinations using open-loop control
Ciężkowski M.
Acta Mechanica et Automatica
|
2011
|
Vol. 5, no. 4
22-29
EN
The paper presents the stabilization method of physical pendulum in various inclinations. The theory of the motion in a rapidly oscillating field has been applied to explain the phenomenon of stabilization and to set conditions for the stability of the pendulum. The paper shows results of computer simulations which confirm that the position control of the pendulum in the open-loop is possible.
14
Content available remote Effect of rotating during the pendulum motion
Jankowski J., Kędzia P.
Vibrations in Physical Systems
|
2010
|
Vol. 24
201--206
EN
The main contribution of this paper is to find the friction moments appear during the bar motion. The considerations are based on momentum and moment of momentum principles. The introduced friction is separated into rotating and sliding parts, where the rotating part is divided into rolling and whirling, as well.
PL
W pracy wyznaczany jest moment tarcia podczas ruchu belki. Rozważania są oparte na zasadach pędu i krętu. Rozważane tarcie jest rozłożone na część obrotową i część postępową, przy czy w tarciu obrotowym wydzielono składniki wirowe i toczne.
15
Content available Development of a Stabilized Wideband Pendulum-Type Gravity Direction Sensor Utilizing Electromagnetic Clutch and Brake for Anti-Swing
Okada T., Tsuchida A., Mukaiyachi T., Shimizu T.
Journal of Automation Mobile Robotics and Intelligent Systems
|
2008
|
Vol. 2, No. 4
45-51
EN
This paper proposes the usefulness of combining an electromagnetic clutch and brake with a pendulum for antiswing for developing a stabilized wideband pendulum-type gravity direction sensor. The pendulum-type sensor is high in response to direction change but liable to swing even when the change stops, in general. Therefore, anti-swing control without degrading sensitivity of direction measurement is important. Continuous damping of the pendulum motion causes an error in a stationary condition unless the pendulum is free from damping repetitively in an appropriate term. To develop a quick response direction sensor without error, we use a magnetic device. Based on motion analysis of a double pendulum, we simulate behaviours of the pendulum-type sensor by actuating the magnetic device by using different signals in form, frequency and magnitude. Also, we fabricate a motion simulator having two rotation joints to evaluate the anti-swing effect of the magnetic device. In the experiment we demonstrate that the device is beneficial for suppressing pendulum vibration over a wideband for measuring resultant direction of the acceleration compound with motion and gravity on such a platform moving randomly. Also, we show that a triangular signal is better than a sinusoidal signal for making the settling time short; however difference is within a narrow margin.
16
Content available remote Evolutionary design of interpretable fuzzy controllers
Hapke M., Komosiński M.
Foundations of Computing and Decision Sciences
|
2008
|
Vol. 33, No. 4
351-367
EN
This paper presents an approach that allows to evolve fuzzy controllers that can be expressed as fuzzy rules in human-readable form and interpreted. For comparison, the evolution is also performed on simple neural controllers. The control task considered here is a balancing problem, where a construct made of articulated elastic elements is equipped with sensors and actuators. The goal of the construct is to keep the top heavy part from touching the ground. Evolved controllers are evaluated using computer simulation. Control systems process signals from tilt sensors to actuators fixed in the construct. During evolution, fuzzy controllers (including their fuzzy sets and rules) are reconfigured by genetic operators in order to maximize fitness of the control. The article compares evolvability of neural and fuzzy controllers and demonstrates how additional, comprehensible knowledge can be gained which explains the work of the fuzzy controller. The representation for the fuzzy control system, evolutionary operators, various evaluation functions, and the best evolved control systems are presented. A sample evolved fuzzy control system is analyzed in detail to explain its behavior.
17
Content available remote Rolling friction influence onto physical pendulum vibrations
Jankowski J., Kołat P.
Vibrations in Physical Systems
|
2006
|
Vol. 22
149--154
18
Content available remote The dynamic of a coupled three degree of freedom mechanical system
Sado D.
Mechanics and Mechanical Engineering
|
2004
|
Vol. 7, nr 1
20-39
EN
In this paper, a nonlinear coupled three degree-of-freedom autoparametric vibration system with elastic pendulum attached to the main mass is investigated numerically. Solutions for the system response are presented for specific values of the uncoupled normal frequency ratios and the energy transfer between modes of vibrations is observed. Curves of internal resonances for free vibrations and external resonances for vertical exciting force are shown. In this type system one mode of vibration may excite or damp another one, and except different kinds of periodic vibration there may also appear chaotic vibration. Various techniques, including chaos techniques such as bifurcation diagrams and: time histories, phase plane portraits, power spectral densities, Poincare maps and exponents of Lyapunov, are used in the identification of the responses. These bifurcation diagrams show many sudden qualitative changes, that is, many bifurcations in the chaotic attractor as well as in the periodic orbits. The results show that the system can exhibit various types of motion, from periodic to quasi-periodic and to chaotic, and is sensitive to small changes of the system parameters.
19
Content available remote Experimental and Analytical Investigation of Rubber Adhesion
Kröger M., Popp K., Kendziorra N.
Machine Dynamics Problems
|
2004
|
Vol. 28, No. 1
79-89
EN
The total friction between tyre and road is based on hysteresis induced friction and adhesion induced friction. A pendulum test rig is designed for experimental investigations of the adhesion effect of rubber and the geometrical and material influences. Based on the Hertzian contact theory the hysteresis and adhesion is described by energy considerations.
20
Vibrational mechanics for the pendulum with oscillating pivot
Majewski T., Sokołowska R.
Elektronika : konstrukcje, technologie, zastosowania
|
2004
|
Vol. 45, nr 8-9
187-190
EN
A pendulum with vibrating pivot is analyzed. Vibration of the pendulum is presented as two component vibrations. A vibration forces appear and they change properties of the pendulum. The pendulum goes to a new position of equilibrium. The pendulum oscillates about it and the amplitude of vibration is determined. Stability of a new position is analyzed.
PL
Analizowane wahadło fizyczne z drgającą osią. Wykazano, ze istnieją dwie składowe jego drgań. Pojawia się siła wibracyjna, która zmienia jego własności. Wahadło drga wokół nowego położenia. Obliczono amplitudę tych drgania. Sprawdzono stabilność każdego z położeń.
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