Variation in cutting forces with cutting parameter selection, tool geometry, and wear status plays an important role for milling process evaluation and modeling. While piezoelectric force measurement is commercially available, it is often considered a precise but expensive method. This paper presents a novel solution for vector-valued cutting force measurement. The table-mounted, flexure-based kinematics provide three degrees of freedom that are used to measure the in-process milling force vector components in the working plane by low-cost optical sensors. Based on analytical models and FEM analysis, an appropriate design was derived. The assembly and testing of the developed dynamometer are presented. A test setup based on a machining center was used for the system evaluation and the data are compared to the forces measured by a commercially available, piezoelectric cutting force dynamometer.
W niniejszej pracy skupiono się na analizie zmiany niwelety mostu. Do tego celu wykorzystano wyniki pomiarów geodezyjnych. Z uwagi na złożony kształt wykresów ugięć konieczne było stosowanie korekty, w której korzystano z pomiaru sił w wantach. Jest to jeden ze stosowanych algorytmów wygładzania funkcji ugięcia uzyskanych z pomiarów geodezyjnych. Do analizy skuteczny jest globalny model konstrukcji 2D z wykorzystaniem elementów prętowych. Jest on szczególnie efektywny w zastosowaniu MRS, gdy występuje regularny układ punktów pomiarowych. Zaletą algorytmu jest wybór dowolnego wycinka przęsła i niezależność od warunków podporowych.
EN
The alterations of bridge gradeline is a main subject of the paper. For this purpose, the results of geodetic survey were used. Due to the complex shape of the deflection lines, it was necessary to apply a correction procedure, using the results of measurement of forces in the stays. This is one of the algorithms used to smooth the deflection function obtained from geodetic measurements. A global 2D numerical model with bar elements is effective for the analysis. It is especially effective in MRS applications when there is a regular arrangement of measurement points. The advantage of the algorithm is the selection of any section of the span and independence from the support conditions.
This paper presents how forces are perceived in a racing simulator based on a Stewart Platform. By retrieving calculated forces in a racing game by its physics engine and comparing them to real-life measurements during the platforms motions it is possible to evaluate the platforms immersiveness. Virtual values extracted from the game engine are deemed satisfactory to their real life counterparts and serve as a baseline. In order to evaluate forces created by the simulator, a lap around a virtual test track is recorded and played back while an accelerometer and gyroscope record its movements. Overall, accelerations recorded in the direction of X and Y axis along with angular speed of rotation around the aforementioned those axis. To accurately comparing every derived force, the recorded virtual lap is divided into sections representing the five most common manoeuvres during racing. These comparisons serve as an evaluation method to measure the immersiveness of the simulator.
The analysis of natural hazards, including gas-geodynamic phenomena, requires study of the basic physical processes that take place at each stage of an event. This paper focuses on analysing the transport of fragmented rock material during rock and gas outbursts. Our theoretical considerations and experiments have allowed us to specify and verify the significant forces acting on fragmented rock during its transport, thus determining the speed of grains of each grain class in the stream of expanding gas. The above study may serve as a preface to a wide-ranging quantitative and qualitative energy analysis of the movement of material ejected during Gas-geodynamic phenomena.
This study analyses the performances of various path controlling strategies for a 3-degrees of freedom wrist exoskeleton, by comparing key indicators, such as rise time, steady-state error, and implementation difficulty. A model was built to describe both system’s kinematics and dynamics, as well as 3 different controllers (PID, PD+, and a hybrid force/position controller) that were designed to allow each joint to perform smooth motions within anatomic ranges. The corresponding simulation was run and assessed via Matlab (version 2020a). In addition to the performance comparison, remarkable characteristics could be identified among controllers. PD+ showed higher response speed than the other controllers (about 4 times), and PID was reinforced as the technique with the easiest implementation due to the smallest matrices. The study also allowed to greater potential of the hybrid controller to interact with its environment, i.e., the robotic device.
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Efektywne zabezpieczenie logistyczne wojsk, wymaga posiadania odpowiedniego potencjału. Planowane do użycia siły i środki muszą zostać tak skalkulowane, aby w każdych warunkach usługi logistyczne, a w tym dostawy środków bojowych i materiałowych docierały w odpowiednie miejsce, w odpowiednim czasie oraz w odpowiedniej ilości i jakości. W 1999 roku, w odpowiedzi na wyzywania współczesnej logistyki wojskowej powstała 10 Opolska Brygada Logistyczna. Była to pierwsza w Wojsku Polskim jednostka wojskowa, przeznaczona do wsparcia logistycznego Polskich Jednostek Wojskowych wykonujących zadania w kraju i poza jego granicami. Autor postawił na wstępie hipotezę, że najprawdopodobniej 10 Opolska Brygada Logistyczna odegrała znaczącą rolę w aspekcie realizowanych zadań zabezpieczenia logistycznego Sił Zbrojnych Rzeczypospolitej Polskiej. W toku prowadzonych badań hipoteza ta została zweryfikowana pomyślnie. Celem artykułu było również znalezienie odpowiedzi na pytanie czy podjęte w 1999 roku rozwiązanie organizacyjne utworzenia 10 Opolskiej Brygady Logistycznej sprawdziło się w aspekcie realizowanych zadań zabezpieczenia logistycznego Sił Zbrojnych. Cel główny został zrealizowany poprzez przedstawienie 10 Opolskiej Brygady Logistycznej, jej roli i przeznaczenia, aktualnie posiadanego potencjału oraz głównych zadań realizowanych w kraju jak i w misjach poza jego granicami na rzecz Polskich Kontyngentów Wojskowych. Ukazano również wysiłek brygady włożony we wsparcie administracji publicznej w walkę z pandemią koronawirusa SARS-CoV-2 oraz współpracę w tym obszarze i wsparcie logistyczne jednostek wojsk operacyjnych oraz innych służb mundurowych. Podjęcie tej problematyki wynikało z potrzeby uzupełnienia wąskiego katalogu dostępnych opracowań na temat funkcjonowania opolskiej jednostki. Do przeprowadzenia badań wykorzystano literaturę oraz dokonano analizy aktualnych danych uzyskanych z poszczególnych sekcji Pionu Logistyki, Szefa Sztabu oraz Pionu Szkolenia 10 Opolskiej Brygady Logistycznej.
EN
The effective logistic support to military requires the possession of adequate potential. Forces and means planned to be used have to be calculated, so in all conditions logistic services to include delivery of ammunition and other material means arrive at the right time, at the right place, at the right quantity as well as the right quality. In 1999, as a response to then requirements of military logistics the 10th Logistic Brigade was founded. It was the first military unit in Polish Armed Forces designated to provide logistic support to Polish military units in and outside the country. The author formulated the hypothesis that most probably the 10th Opolska Logistic Brigade played an important role in providing logistic support to Polish Armed Forces. The indicated hypothesis was confirmed right during the study. Another reason of this article was to find an answer to the question if the decision of founding of the 10th Logistic Brigade in 1999 was pertinent taking into consideration performing logistic tasks in favor of Polish Armed Forces. The article showed the role, the purpose and the up to the date potential of the 10th Logistic Brigade. It also presented a wide range of tasks performed by personnel of this military unit in as well as outside the country where providing logistic support to Polish Military Contingents. In the article author introduced the picture of effort that was performed by soldiers and civilian personnel of the 10th Logistic Brigade during the fight against SARS-CoV-2 pandemic. This part of the article also presented the cooperation with local authorities as well as other uniformed services. This study addressed the above mentioned issues because there was a very small amount of available works concerning the subject of military unit from Opole. In the study the up to date data of the Logistics Department, the Training Department and the Chief of Staff of the 10th Logistic Brigade was used.
In this paper we consider the processes of dynamic interaction between the boiling particles of the dispersed phase of the emulsion leading to the large droplet breakup. It is indicated the differences in the consideration of forces that determine the crushing of non-boiling and boiling drops. It is determined the possibility of using the model to define the processes of displacement, deformation or fragmentation of the inclusion of the dispersed phase under the influence of a set of neighboring particles. The proposed method allows us to determine the main energy parameters of the homogenization process by boiling the emulsion.
PL
W tym artykule rozważamy procesy dynamicznej interakcji między wrzącymi cząsteczkami zdyspergowanej fazy emulsji, prowadzące do rozpadu dużych kropel. Wskazano na różnice w uwzględnianiu sił, które determinują kruszenie kropli niewrzących i wrzących. Określono możliwość wykorzystania modelu do zdefiniowania procesów przemieszczenia, deformacji lub fragmentacji włączenia fazy rozproszonej pod wpływem zestawu sąsiednich cząstek. Proponowana metoda pozwala określić główne parametry energetyczne procesu homogenizacji podczas ogrzewania i wrzenia emulsji.
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The paper presents a well known idea of using permanent magnets as a source of energy in an industrial transport system (for instance maglev). The idea of this paper is to present computation and simulation for a transport system in 2D space using the Ansys environment. An idea for a system which starts to operate only at the very moment when a worker needs help and is moving a heavy object, and is using it with a minimum amount of energy has become an idea about saving energy. When gravity is eliminated by magnetic fields forces, for moving heavy object, we only need to overcome the moment of inertia. All resistance practically disappears, because there is almost no friction in this system. In the paper the use of magnetic field concentration in Halbach array system for eliminating gravitational forces during a load movement has been presented.
PL
W pracy przedstawiono dobrze znaną ideę wykorzystania magnesów trwałych, jako źródła energii w przemysłowym systemie transportu (na przykład maglev). Ideą tego artykułu jest prezentacja obliczeń i symulacji transportu systemu w przestrzeni 2D za pomocą środowiska Ansys. Pomysł na system, który działa tylko w momencie, gdy pracownik potrzebuje pomocy i porusza ciężkim przedmiotem i używa go przy minimalnej ilości energii, staje się pomysłem oszczędzania energii. Kiedy grawitacja jest eliminowana przez siły pola magnetycznego, do przemieszczania ciężkich obiektów wystarczy jedynie pokonać moment bezwładności. Cały opór praktycznie znika, ponieważ w tym układzie prawie nie ma tarcia. W artykule przedstawiono zastosowanie koncentracji pola magnetycznego w układzie macierzy Halbacha do eliminacji sił grawitacyjnych podczas ruchu ładunku.
W artykule przedstawiono założenia i szczegółowe cele projektu oraz aktualny stan wiedzy i możliwości uzyskania postępu w zapewnieniu spójności pomiarowej w europejskim i światowym przemyśle w zakresie siły statycznej, ciągłej i dynamicznej. Omówiono także zakres uczestnictwa GUM oraz potencjalny wpływ założonych w projekcie przedsięwzięć na środowisko, metrologię i użytkowników. Przedstawiono wzorce GUM o najmniejszej niepewności pomiarowej, na których zostaną wykonane badania siły statycznej i ciągłej.
EN
The article presents the assumptions and detailed objectives of the project as well as the current state of the art and the possibilities of achieving progress in ensuring traceability in European and global industry in the field of static, continuous and dynamic force. The scope of GUM participation and the potential impact of the design assumptions on the environment, metrology and users were also discussed. GUM standards with the lowest measurement uncertainty, on which static and continuous force tests will be performed, are presented.
Projektując stężenia połaciowe poprzeczne [1], zaleca się przyjmować zastępcze obciążenie od imperfekcji geometrycznych dźwigarów dachowych. Obciążenie to można bezpiecznie oszacować [1] przy założeniu stałej na długości elementu stabilizowanego siły ściskającej i imperfekcji w kształcie paraboli o strzałce e0. W pracy, dla różnych kształtów imperfekcji geometrycznych elementów stabilizowanych, wyznaczono obciążenia imperfekcyjne oraz siły w prętach tężnika połaciowego i porównano je z siłami wyznaczonymi wg [1]. Wyniki analiz przedstawiono w tabeli i sformułowano syntetyczne wnioski.
EN
During designing transverse roof bracing, [1] recommends taking into account equivalent stabilizing load from geometrical imperfections of roof girders. This load can be safely estimated [1] assuming a constant compression force along the length of the stabilized element and initial parabolic imperfection with maximum amplitude e0. In the paper, for different shapes of geometrical imperfections of stabilized elements, imperfect loads and forces in the roof bracing were determined and compared with the forces determined according to [1]. The results of the analyzes are presented in the table and synthetic conclusions were formulated.
This study investigates the automotive magnetorheological (MR) shock absorber behaviour in conditions of changing temperature. Its temperature-dependent behaviour was quantified between ambient and maximal operating temperatures of the device. Aspects addressed include the temperature dependence of the control coil resistance in the absorber, the influence of operating current level on control coil temperature and the temperature dependence of the absorber force response and energy dissipation in the system. The results of experiments enabled us to evaluate the mechanical performance of the absorber at varied temperatures.
The article is devoted to solving the fundamental and applied problem of nonlinear structural me-chanics of machines by introducing into the drum two additional stop cylinders with supporting rollers at the end and adjustable length, providing a given elliptical or circular shape of a flexible shell with a smoothly variable geometry in the area of its contact with compacted pavement material. Compaction of soil, gravel and asphalt concrete in the sphere of road is not only an integral part of the technological process of the roadbed, road foundation and surface construction, but it is actually the main operation to ensure their strength, stability and durability. The quality, cost and speed of road construction, the possibility of using fundamentally new technologies, structures and materials is largely determined by the availability of modern road machinery.
This experimental study investigated the effects of a conventional cutting fluid during drilling cylindrical holes on workpiece materials made of the AISI 1040 steel. Drilling responses were compared between dry and wet (in presence of the cutting fluid) cutting conditions with respect to drilling force, roundness deviation and taper of the hole, and chip morphology. High production machining and drilling with high cutting speed, feed, and depth of cut were found to be inherently associated with the generation of a large amount of heat and high cutting temperature. In a dry condition such high cutting temperature not only reduces dimensional accuracy and tool life but also impairs the roundness deviation and taper of the hole. The use of a conventional cutting fluid, in such a situation, was very effective to reduce the cutting temperature. In a dry cutting condition, numerous tool-wears were found on the drill bits. Drilling in such a dry condition seriously affects roundness of the hole, and chip shape and color. Contrastingly, use of a traditional cutting fluid reduced temperature as well as improved roundness and taper of the hole. It also acted as a lubricate at the tool tip–work surface interface. Overall, the conventional cutting fluid enhanced the quality of the machine work and potentially can increase machine life of drill bits.
The main purpose of this research was to analyse the distribution of plantar pressures and foot characteristics during walking between weeks 27 and 36 of pregnancy. The secondary purpose was to test the effect of the customized orthopaedic shoes that were worn by the experimental group. Methods: Pregnant women (n = 73) were divided into 2 groups, control group (n = 38) and experimental group (n = 35) which completed 5 gait trials on a walkway (1.55m) at a self-selected velocity of gait, where force, pressure and remaining foot characteristics were sampled and displayed by Novel database pro m (version 25.3.24). Results: Analysis of foot characteristics did not reveal important changes. Analysis of the distribution of plantar pressures revealed few changes in the pre- and post-measurement of the experimental and control groups between weeks 27 and 36 of pregnancy. In the last measurement, there is a significant increase of peak pressure only in the midfoot area of the left foot (151.1 ± 41.2 kPa) and in the hindfoot area of the right foot (346.3 ± 104.1) of the experimental group. The control group exhibits similar pressure development for both of foot. Conclusions: Monitored parameters demonstrated in certain areas notably development of force and contact area. Results of foot characteristics did not reveal a significant changes. As both groups registered similar values in certain areas in a comparison of pre/post measurement characteristics, the influence of specific orthopaedic shoes cannot be conclusively demonstrated in the experimental group.
In the case of bucket wheel excavators, the cutting process is influenced by the forces opposing the working elements and cutting tools. These forces determine the choice of machines and their parameters as well as the operating method [1, 2]. Studies conducted on the failure causes of mechanical parts show that the cutting and loading systems cause the highest rate of failure – about 32% of all recorded mechanical failures [3]. In this paper, we will use the Finite Element Method (FEM) to analyze the deformations and stresses acting on the cutting teeth mounted on the rotor of BWEs. For this, Solid- Works® software was used, both as a CAD tool to design the teeth as well as to model and simulate the phenomena.
This study investigates the behaviour of MR fluids in the oscillatory compression squeeze mode. Experiments were performed on commercially available MR fluids in the purpose-built experimental set-up. The influence of MR fluid’s properties and magnetic flux density on the force generated during the squeeze mode was investigated.
According to the scaling laws for nanomechanical resonators, many of their metrological properties improve when downscaled. This fact encourages for constant miniaturization of MEMS/NEMS based sensors. It is a well known fact, that the laws of classical physics cannot be used to describe the systems which are arbitrarily small. In consequence, the classical description of nanoresonators must break down for sufficiently small and cool systems and then the quantum effects cannot be neglected. One of the fundamental question which arises is, how one may investigate quantum effects in MEMS/NEMS sensors and what is the influence of quantum effects on the performance of such systems. In this paper we would like to raise those issues by presenting the results of our work related to our estimations and calculations of MEMS/NEMS dynamics. The first and second sections are of theoretical character. In the first section (Classical modeling), we describe the classical methods for describing the resonator dynamics and the classical limit on the resolution of MEMS/NEMS based force sensors, which is set by the thermomechanical noise. In the second section (Quantum aspects), we concentrate on the quantum description of micro and nanoresonators and the influence of quantum effects, such as zero-point motion and back-action, on their performance (quantum limits). The third section is devoted to the presentation of our experimental methods of MEMS/NEMS deflection metrology, i.e. Optical Beam Deflection method (OBD) and fibre optics interferometry.
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W artykule przedstawiono wyniki pomiarów sił w rozporach głębokiego wykopu oraz ich analizę i porównanie z wartościami obliczonymi w projekcie zabezpieczenia. Wykorzystano inżynierski system pomiarowy złożony z oprogramowania i jednostki pomiarowej współpracującej z układem sensorów. Jako czujniki zastosowano mostki tensometryczne naklejane na odpowiednio przygotowaną powierzchnię rozpór wykopu. Obserwowano różne etapy pracy obudowy wykopu w zależności od stanu robót ziemnych oraz odpowiadających im oddziaływań. Zastosowanie częściowych współczynników bezpieczeństwa typowych normowych parć na ściankę szczelną zapewniło bezpieczne zaprojektowanie rozpór wykopu.
EN
The article presents the results of measurements of forces in the struts of deep excavation and the analysis and comparison with values calculated in the project. Engineering measurement system consisting of software, measuring unit, which operates together with the strain gauges was used. Strain gauges were glued to the prepared surface of the struts of the sheet pile. Measurements take into consideration different stages of earthworks and the corresponding loading. The use of partial safety factors for typical earth pressure of code on the wall ensured safe design struts excavation.
In this article, a new mathematical representation of the sinusoidal alternating velocity, force and power by means of some complex quantities, termed ‘holors’ is proposed. The word holor is a term to describe a mathematical entity that is made up of one or more independent quantities, and includes complex numbers, scalars, vectors, matrices, tensors and other hypernumbers. Holors, thus defined, have been known for centuries but each has been developed more or less independently, accompanied by separate nomenclature and theory.
The main aim of the study was to design a new system to measure punching and kicking forces as well as reaction times in combat sport athletes. In addition, the study examined whether there were any intergender differences in the force of punches thrown by boxers and kicking forces delivered by taekwondo athletes. Boxers (male, n = 13; female, n = 7) were examined for the force of single straight punches and taekwondo athletes (male, n = 14; female, n = 14) for force of single Apdolio and Dwit Chagi kicks. The punching bag was equipped with acceleration transducers and gyroscopes embedded in a cylinder covered with a layer to absorb shock as well as a set of colour signal diodes. Value of the punching bag’s acceleration was used for calculating: strike force; the punching location on the bag; and time of a strike. The relative error of force calculation was 3%; the relative error in acceleration measurement was less than 1%. The force of a straight rear-hand punch was greater than the force of a lead-hand punch among male and female boxers. The force of Apdolio kick delivered with a rear leg was greater compared to a lead leg among female and male taekwondo athletes. Significant gender differences were noticed in the force in both types of kicks. In boxers, intergender differences were reported only for the force of a punch thrown with the rear hand. Based on these findings, it was concluded that the modified punching bag is a good diagnostic tool for combat sports.
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