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EN
The paper presents the results of internal stress tests in rails and flash-butt welded rail joints. Stress patterns were tested in rail joints just after flash-butt welding, as well as after fatigue tests. Stress tests were performed using the destructive strain gauges based test method. Stresses emerging in rails and in rail joints were compared for the steel grades R260 and R350HT. Stress measurements were performed in accordance with the requirements of PN EN 13674 1:2011+A1:2017.
PL
Dokonano przeglądu dostępnych rozwiązań oraz przedstawiono propozycję układu badawczego do analizy – w czasie rzeczywistym – napięcia gumowej taśmy pracującej na przenośniku. Dzięki zastosowaniu czujników tensometrycznych w aparaturze badawczej możliwe jest uzyskanie danych, których interpretacja pozwoli na zdiagnozowanie stanu taśmy i przystosowanie procesu pracy przenośnika do wymogów Przemysłu 4.0.
EN
The review of existing solution and the proposal of the test equipment for belts tension detection on the conveyor in the real time is presented. Application of strain gauges made it possible to obtain the data, which would enable to make proper work condition diagnosis and to adapt the process to requirements of the Industry 4.0.
3
Content available Health monitoring in landing gears
EN
Every mechanical construction loses its properties in time due to the usage wear that leads to malfunctions and, in the end, to failure. Widely used method of failure time prediction base on extended laboratory tests where a device is tested against fatigue and wear. This method is well established but is expensive, time-consuming, and costly. Another way of failure prediction is to calculate it using advanced algorithms what is faster and cheaper but less accurate than actual tests. Furthermore, both methods are not optimal due to the principle of operation based on simplified assumptions. In such cases, it is common to make the lifespan of the safety wise devices for example landing gears much less than real in case of fatal failure not covered by the predictions. This can lead to much higher price and maintenance costs of the landing gear. Nowadays the worldwide trend is to monitor the behaviour of the devices in real time and predict failure using actual state. There are several methods of health monitoring, most of them including sensors, acquisition systems and computer software for analysis. In this article, authors describe possible landing gears health monitoring methods based on authors’ laboratory experience in sensor appliance and test data analysis. The authors also present their idea of adding health monitoring to existing landing gears where no dedicated infrastructure was initially designed.
EN
The proposed advantages of short stem hip arthroplasties are bone preserving strategies and less soft tissue damage. Bone preserving strategies do not only include a more proximal resection of the femoral neck, but especially for short stem hip arthroplasties with predominantly metaphyseal fixation a presumed more physiologic load transfer and thus a reduction of stress-shielding. However, the hypothesized metaphyseal anchorage associated with the aforementioned benefits still needs to be verified. Unfortunately, mid- to long-term clinical studies are missing. Methods: Therefore, the METHA short stem as a short stem with proposed metaphyseal anchorage and the Bicontact® standard stem were tested biomechanically in three pairs of cadaveric femora while strain gauges monitored their corresponding strain patterns. Results: For the METHA stem, the strains in all tested locations including the region of the calcar were similar to conditions of cadaver without implanted stem. The Bicontact stem showed approximately half of strain of the non-implanted cadaveric femura with slightly increasing strain from proximal to distal. Conclusions: Summarizing, the current study revealed primary metaphyseal anchorage of the METHA short stem and a metaphyseal-diaphyseal anchorage of the Bicontact stem.
5
Content available Strain gauge pin based force measurement
EN
In this article authors present force measurement method based on strain gauge measuring system installed inside pin, which is a part of light helicopter Main Landing Gear Shock Absorber. Strain gauges in full bridge configuration were installed inside the mounting pin (upper one – fuselage side). Placement and type of strain gauges were selected during the preliminary tests, which verified the validity and conditions of the force measurement. Preliminary tests allowed verification and selection of an optimal measurement system by testing two types of them. The impact on force according to the angle of force vector direction was also verified. Preliminary tests of the strain gauges equipped pin were performed using quasistatic tests stand – 40 T hydraulic press for applying force acting on shock absorber and pin. Whole measuring system is planned to be used in real time analysis of shock absorber force acting on fuselage mounting node. The strain gauges allows measurement of force in any place of the structure, the article presents the advantages of the system located inside pin. Additionally, the installation technologies of strain gauges in hard-to-reach places are presented. The article is summed up with an analysis of the problems, which arise during the installation and measurement process using strain gauges installed in such a specific place.
6
Content available Strain gauge measuring plate for dynamic tests
EN
In dynamic tests, especially landing gears, it is necessary to measure and record load levels. In this article, authors present measurement methods used in the landing gear tests on the 10-Ton Drop Test Machine, which is capable of simulating conditions similar to real landing in landing energy dissipation tests. Possible test objects include dampers, shock absorbers, and crash structures and devices. In described case load measurement can be done by several methods where one of them is strain-gauge plate based load measurement. This type of measurement is weighting system under the test object where all forces acting on it are measured. Strain gauge plate is usually tailormade measurement system, which is composed out of mechanical device (plate itself) equipped with strain gauge force sensors, strain gauge amplification system and recording system. In addition, differences between static and dynamic measurements are described as well as influence of dynamic test conditions on strain gauges behaviour. In the article, authors describe general layout of the system, advantages and disadvantages of the test stand and problems that may appear during measuring. Authors also emphasize how the accuracy of the design affects to the quality of measurement. At the end of the article, advantages and disadvantages of the test stand and problems that may appear during measuring are described.
EN
The boom of BWE is a very complex structure, dictated by its functions in operation of the excavator. In the simplest approach, it can be considered as an arm of an R-R robotic manipulator, having at distal extremity the working element, i.e. the bucket wheel, being fixed at proximal extremity by a joint to the turret, which, at its turn is articulated to the infrastructure which includes the undercarriage (travelling mechanism). In order to reduce the weight/stiffness ratio and to include the on board conveyer, the boom is generally embodied as a lattice – truss structure. The constitutive elements i.e. the members and joints are subject to severe loads, which due to their cyclical variable character with a high random component, lead to failures which are caused by overloading and/or fatigue. The actual paper deals with the field measurements performed in past years on several BWEs from CEO open pits, including acceleration measurements and stress measurements using strain gauges. Both kind of sensors-accelerometers and strain gauges were mounted on several critical points of the boom, and the measurements were performed both in normal operation and in some loading-operating scenarios. The recorded data were postprocessed in order to obtain spectral graphs in order to obtain information about the influence of different excitation sources on the boom elements behaviour.
PL
Wysięgnik wielonaczyniowej koparki kołowej jest złożoną strukturą definiowaną przez technologię pracy koparki. W celu zmniejszenia stosunku waga/sztywność oraz występowania przenośnika taśmowego wysięgnik jest zaprojektowany jako konstrukcja kratownicowa. Jej elementy są poddawane silnym obciążeniom, które ze względu na ich cykliczny charakter z wysoką składową losową prowadzą do awarii spowodowanych przeciążeniem lub zmęczeniem konstrukcji. Niniejszy artykuł przedstawia pomiary terenowe wykonane w ostatnich latach na wielonaczyniowych koparkach kołowych pracujących w kopalniach CEO za pomocą tensometrów oraz akcelerometrów. Pomiary te zostały zamontowane w krytycznych punktach wysięgnika, a pomiary zostały wykonane zarówno podczas normalnej pracy koparki jak i podczas realizacji scenariuszy obciążenia. Zarejestrowane dane zostały poddane obróbce w celu uzyskania wykresów widmowych.
8
Content available remote Three point bending of hand laminated fiber composites
EN
The article describes the course and results of research on a composite laminate. Specimens were made from glassreinforced epoxy resin using the hand lamination technique with the fibres arranged unidirectionally along the specimen. The dimensions were selected on the basis of DIN EN ISO 14125. Strain gauges were placed on the surface of every specimen, then testing was conducted - three point bending. The specimen was placed so that the strain gauge was at the stretched side during bending in order to measure the strain. The stress was also calculated analytically, based on the process parameters. As a result, the theoretical stresses were compared with the experimental ones.
PL
Opisano przebieg i wyniki badań laminatu kompozytowego. Materiałem, z którego wykonano próbki, była żywica epoksydowa wzmocniona włóknem szklanym. Próbki do badań zostały przygotowane w technologii laminowania ręcznego. Włókna ułożone były jednokierunkowo, wzdłuż próbki. Wymiary zostały dobrane na podstawie normy DIN EN ISO 14125. Na powierzchni próbki umieszczono tensometry. Następnie przeprowadzono badania - zginanie trójpunktowe. Próbkę umieszczono tak, aby tensometr był od strony rozciągania podczas zginania, dzięki czemu mierzone było odkształcenie. Naprężenia były obliczane również w sposób analityczny, na podstawie parametrów procesu. W wyniku uzyskano porównanie naprężeń teoretycznych z doświadczalnymi.
PL
W artykule przedstawiono wyniki badań naprężeń wewnętrznych w szynach oraz połączeniach szyn kolejowych, wykonanych metodą zgrzewania oraz spawania termitowego. W badaniach naprężeń zastosowano metodę niszczącą tensometryczną. Porównano zależności naprężeń w szynach oraz złączach szynowych wykonanych z gatunku R260 oraz gatunku R350HT. Metodę pomiaru naprężeń oparto na wymaganiach zawartych w normie PN EN 13674-1:2011.
EN
The paper presents the results of internal stress tests in rails and rail joints, carried out applying the welding method and the termite welding. Stress tests were used as destroy strain gauges tests. The stress ratios in rails and rail joints made of R260 and R350HT were compared. The stress measurement method is based on the requirements of PN-EN 13674-1+A1:2017 standards.
EN
The article presents the potential use of magnesium alloys in the aerospace industry. In this project the static strength analysis of magnesium alloy AZ31 of the control – system lever of the ILX-27 unmanned helicopter was carried out. Control-system levers are located between the swash plate and an actuator. The aim of the tests was to confirm the strength properties of the magnesium alloy control-system lever for their implementation on the ILX-27 unmanned helicopter. Strain gauge sensor was used during the tests. Strain gauges installation on easily corrodes surface requires special method. The laboratory tests were proceeded by the lever static strength calculations in the computing environment ANSYS Inc. Additionally, a geometry measurement of the control-system lever at CMM equipped with a laser scanner head was made to compare with the lever CAD model to assess the quality and method of conformance. Unmanned helicopter ILX-27 is being developed through the introduction new materials and technologies. Tests of control system lever have shown if it is possible to use lighter materials than aluminum alloy to provide sufficient strength properties while reducing the mass of the object. Analysis of the available materials used in aerospace engineering allowed selecting the best of magnesium alloy.
EN
Purpose: The number of primary total hip arthroplasties (THA) is steadily increasing. Over the last decade numerous so-called short stem hip arthroplasties were introduced on the market. The aim of these implants with a predominantly metaphyseal anchorage is to reduce stress shielding and thereby the risk of aseptic loosening. One of the short stem arthroplasties with predominant metaphyseal fixation is the METHA® short stem (Aesculap, Tuttlingen, Germany). In order to reconstruct the biomechanics the METHA stem is available in different sizes with different centrum-collum-diaphysis-angles (CCD-angle). In this study, we want to address the research question of how the size of the implant and different CCD-angles influence the strain patterns of the proximal femur. Methods: Three different stem sizes (size 2, 3 and 4 – CCD-angle 130°) and three stems with different CCD-angles (size 3 – 120°, 130° and 135° CCD-angle) were successively implanted in a synthetic femur. Eight strain gauges monitored the corresponding strain patterns of the proximal femur. Results: Independent of stem size and CCD-angle only small changes in the strains were recorded around the distal part of the METHA stem when compared to the intact femur. However, all stems increased the strains in the region of the calcar. This was most pronounced by smaller CCD-angles and major sizes. Conclusion: The stem size and CCD-angle primarily influence the region of the calcar. Greater sizes and smaller CCD-angles lead to increased strains at the calcar. The other regions are hardly influenced by the stem size and CCDangle of the femoral component.
EN
Purpose: Previous biomechanical studies have estimated the strains of bone and bone substitutes using strain gages. However, applying strain gages to biological samples can be difficult, and data collection is limited to a small area under the strain gage. The purpose of this study was to compare digital image correlation (DIC) strain measurements to those obtained from strain gages in order to assess the applicability of DIC technology to common biomechanical testing scenarios. Methods: Compression and bending tests were conducted on aluminum alloy, polyurethane foam, and laminated polyurethane foam specimens. Simplified single-legged stance loads were applied to composite and cadaveric femurs. Results Results: Showed no significant differences in principal strain values (or variances) between strain gage and DIC measurements on the aluminum alloy and laminated polyurethane foam specimens. There were significant differences between the principal strain measurements of the non-laminated polyurethane foam specimens, but the deviation from theoretical results was similar for both measurement techniques. DIC and strain gage data matched well in 83.3% of all measurements in composite femur models and in 58.3% of data points in cadaveric specimens. Increased variation in cadaveric data was expected, and is associated with the well-documented variability of strain gage analysis on hard tissues as a function of bone temperature, hydration, gage protection, and other factors specific to cadaveric biomechanical testing. Conclusions: DIC techniques provide similar results to those obtained from strain gages across standard and anatomical specimens while providing the advantages of reduced specimen preparation time and full-field data analysis.
EN
This article presents a way of calibration of an unconventional two-current circuit, named 2J+2R, which consists of two current sources and two referential resistors connected to the circuit mass. This bridge was used to measure the beam deflection and the temperature increase simultaneously with the use of a pair of metal strain gauges. This paper contains theoretical and corrected (after calibration) processing characteristics of the measurement circuit. Calibration coefficients of both inputs, responsible for measurement of the measured values in the places where the strain gauges are attached, were calculated. Moreover, the standard combined and expanded uncertainties of both calibration coefficients were calculated and an uncertainty budget was made.
EN
This paper presents selected cases of inapplicability of theory based methods of determining critical loads in thin – walled, composite tubes. 8th layered composite tubes with square cross-section were being subjected to static compression and in order to register experimental data two measuring equipment were employed: strain-gauges and Digital Image Correlation system ARAMIS R. When measurement data were collected five different theory based methods were applied in order to determine critical loads. Cases where it was impossible to apply certain methods or some doubts about correctness of the results occurred were presented and analyzed. Moreover in cases where it was possible, the theory was equivalently transformed, in such a way to fit experimental data and calculate the critical loads.
15
Content available remote Ring-shaped strain gauges and their application
PL
W artykule przedstawiono zaprojektowany i skonstruowany tensometr pierścieniowy. Jest on przeznaczony do pomiaru odkształceń poprzecznych betonowych kolumn wsporczych, w celu monitorowania ich stanu. Elektryczne uzwojenie oporowe tensometru jest starannie zahermetyzowane, przez co może on być zalewany płynną mieszanką betonową i użytkowany w środowisku wilgotnym. W artykule umieszczono również wyniki przykładowego zastosowania tensometru pierścieniowego w warunkach laboratoryjnych.
EN
This paper provides a description of a designed and constructed ring-shaped strain gauge. Such a gauge, intended for measuring transverse strain of a concrete supporting column, can be used for monitoring the state of the latter. The electric resistance element of the gauge is thoroughly sealed in a watertight manner, thereby making it possible to flood it with poured concrete and then use in a humid environment. The paper also discusses the effects of an exemplary application of ring-shaped strain gauges under laboratory conditions.
EN
An understanding of the load transfer within spinal posterior column of lumbar spine is necessary to determine the influence of mechanical factors on potential mechanisms of the motion-sparing implant such as artificial intervertebral disc and the dynamic spine stabilization systems. In this study, a new method has been developed for evaluating the load bearing of spinal posterior column by the surface strain of spinal pedicle response to the loading of spinal segment. Six cadaveric lumbar spine segments were biomechanically evaluated between levels L1 and L5 in intact condition and the strain gauges were pasted to an inferior surface of L2 pedicles. Multidirectional flexibility testing used the Panjabi testing protocol; pure moments for the intact condition with overall spinal motion and unconstrained intact moments of +-8 Nm were used for flexion-extension and lateral bending testing. High correlation coefficient (0.967-0.998) indicated a good agreement between the load of spinal segment and the surface strain of pedicle in all loading directions. Principal compressive strain could be observed in flexion direction and tensile strain in extension direction, respectively. In conclusion, the new method seems to be effective for evaluating posterior spinal column loads using pedicles' surface strain data collected during biomechanical testing of spine segments.
PL
W artykule przedstawiono metodę i sposób pomiarów tensometrycznych w modelu laboratoryjnym ściany wagonu kolejowego. Artykuł ten jest pierwszym etapem działań prowadzonych w celu potwierdzenia możliwości zastosowania materiałów kompozytowych jako materiałów do budowy zespołów i podzespołów wagonów towarowych. Przedmiotem badań jest ściana wagonu towarowego. W ramach przyszłych badań proponuje się zastąpienie wybranych elementów materiałami kompozytowymi, między innymi: włóknami szklanymi i węglowymi. Takie działanie prowadzić moSe do zmniejszenia masy pojedynczego wagonu, czego następstwem jest redukcja masy całego składu kolejowego. Prezentowane wyniki są częścią działań prowadzonych w Instytucie Automatyzacji Procesów Technologicznych i Zintegrowanych Systemów Wytwarzania Politechniki Śląskiej w ramach projektu badawczo rozwojowego o numerze rejestracyjnym PBR-8/RMT-2/2009.
EN
This article presents the method and way of measuring strain gauge in a laboratory model of a wall of a railway wagon. The article is the first step in the research leading to confirming the possibility of using composite materials as construction materials of assemblies and subassemblies of wagons. The subject of the research is a wall of a wagon made of standard materials. As part of future research, replacing selected elements with composite materials such as glass fibres, carbon fibres and others is proposed. Such action can lead to lowering the weight of a single wagon, resulting in reducing the weight of the whole set of wagons. The results presented are part of the research conducted at the Institute of Process Technology and Integrated Manufacturing Systems of Silesian University within the research and development project with registration number PBR-8/RMT-2/2009.
PL
W pracy opisano budowę dynamometru przeznaczonego do badań postępu procesu rehabilitacji. Dynamometr, dzięki radiowej transmisji danych pomiarowych do komputera, umożliwia rejestrację przebiegu ćwiczeń i wykonywanie analizy przebiegu rehabilitacji. Budowę dynamometru oparto na nowoczesnym mikrokontrolerze jednoukładowym ADuC845. Opracowano program w środowisku LabVIEW, który umożliwia analizę rejestrowanych danych.
EN
The construction of the push-pull dynamometer dedicated for the investigation of the rehabilitation process is described in the paper. The application of the wireless data transmission between the dynamometer and computer allows users to record and make analysis of rehabilitation process. The dynamometer circuit is based on the ADuC845 microconverter. Application in LabVIEW was carried out for analysis of data from dynamometer.
PL
Opisano czterozaciskowy (4T) układ mostka rezystancyjnego zasilanego niekonwencjonalnie z dwóch źródeł prądowych i o dwu wyjściach z obu jego przekątnych, nazwany mostkiem dwuprądowym (2J). Podano napięcia wyjściowe niezrównoważonego mostka jako funkcje rezystancji jego gałęzi lub ich przyrostów od równowagi mostka w wartościach względnych. Przedstawiono przykład realizacji dwuparametrowego (2D) przetwornika do równoczesnego pomiaru odkształcenia i temperatury wykorzystującego ten mostek i omówiono wybrane wyniki pomiarów eksperymentalnej jego weryfikacji.
EN
A four-terminal (4T) bridge circuit unconventionally supplied by two current sources connected in parallel to opposite arms, named double current bridge (2J) is presented. It has two different outputs from both diagonals. The output voltages described as functions of arm resistances or their increments from bridge balance in relative units are given. Example of its application is proposed. Signals conditioning formulas of the two-parameter (2D) measurement - of strain and temperature are discussed in details. Some results of experimental verification of instrumetation circuit, designed for this bridge are shortly presented.
PL
Ekstensometry i tensometry są instrumentami wykorzystywanymi w próbnych obciążenaich statycznych, służącymi zarówno weryfikacji nośności pali jak i optymalizacji rozwiązań projektowych fundamentów głębokich. Te nowoczesne metody pozwalają niejednokrotnie na zaprojektowanie pali krótszych o nośności wystarczającej do przeniesienia projektowanych obciążeń. Znakomitym tego przykładem są badania wykonane przez polskich inżynierów na budowie ekskluzywnych apartamentowców w jednym z najbardzie zaludnionych miast świata - Karachi w Pakistanie. W atykule opisano technologię wykonania pali i program badań.
EN
Ekstensometry i tensometry są instrumentami wykorzystywanymi w próbnych obciążeniach statycznych, służącymi zarówno weryfikacji nośności pali jak i optymalizacji rozwiązań projektowych fundamentów głębokich. Te nowoczesne metody pozwalają niejednokrotnie na zaprojektowanie pali krótszych o nośności wystarczającej do przeniesienia projektowanych obciążeń. Znakomitym tego przykładem są badania wykonane przez polskich inżynierów na budowie ekskluzywnych apartamentowców w jednym z najbardziej zaludnionych miast świata - Karachi w Pakistanie. W artykule opisano technologię wykonania pali i program badań.
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