Wyniki wyszukiwania - BazTech

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Characterization of Fabric-to-Fabric Friction: Application to Medical Compression Bandages

Chassagne Fanette, Benoist Emilie, Badel Pierre, Convert Reynald, Schacher Laurence, Molimard Jérôme

Autex Research Journal

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2020

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Vol. 20, no. 2

220--227

EN

Fabric-to-fabric friction is involved in the action mechanism of medical compression devices such as compression bandages or lumbar belts. To better understand the action of such devices, it is essential to characterize, in their use conditions (mainly pressure and stretch), the frictional properties of the fabrics they are composed of. A characterization method of fabric-to-fabric friction was developed. This method was based on the customization of the fourth instrument of the Kawabata Evaluation System, initially designed for fabric roughness and friction characterization. A friction contactor was developed so that the stretch of the fabric and the applied load can vary to replicate the use conditions. This methodology was implemented to measure the friction coefficient of several medical compression bandages. In the ranges of pressure and bandage stretch investigated in the study, bandage-to-bandage friction coefficient showed very little variation. This simple and reliable method, which was tested for commercially available medical compression bandages, could be used for other medical compression fabrics.

2

Modyfikacja stanowiska do badania zjawiska tarcia występującego pomiędzy kołem jezdnym a nawierzchnią drogi

Pietruszewski R., Kopka J.

Autobusy : technika, eksploatacja, systemy transportowe

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2016

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R. 17, nr 12

1051--1057

PL

W artykule omówiony został projekt realizowany na Politechnice Łódzkiej, którego celem było zaadaptowanie istniejącego stanowiska badawczego, tak aby umożliwiało wykonanie pomiaru tarcia (przyczepności) opony przy poślizgu koła jezdnego 100%. Nawiązano do pojęć takich jak poślizg, siła tarcia (przyczepności) oraz współczynnik przyczepności. Zagadnienia te były kluczowe dla określenia warunków jakie zmodyfikowane stanowisko powinno spełniać. Omówiona została dotychczasowa konstrukcja stanowiska a następnie przedstawiono wykonane zmiany konstrukcyjne.

EN

Paper discussed the project realized at the Lodz University of Technology which aim was to adapt already existing test stand so that it enables measurements of the tire friction (tire adhesion) during 100% slippage conditions. Firstly, several terms connected directly with the topic of wheel (as the combination of tire and rim) and its kinematics were presented including slippage, friction force and adhesion (friction) coefficient of the tire. They were crucial from the point of view of the conditions that the rebuilt stand shall fulfill. Secondly, the already existing stand was described. This part of the work included description of three different configurations of the stand existing so far. Three different phases of the wheel’s motion together with the phenomena accompanying them that were tested on the stand were also presented. The last stage concerned the project part itself and included construction of the frame holding the electric motor and the balance frame holding the mass which reduces the wheel pressure force on the road. Finally, when the test stand in new configuration was ready, validating measurements were performed. As the result, it was concluded that rebuilt measuring construction enable one to examine the friction phenomenon between tire and road during 100% slippage. The obtained values of the friction coefficient were corresponding to the expected ones. Some interesting dependencies were also observed, for instance presumable influence of the increasing (over some value) tire temperature during measurement on friction coefficient. However, to validate it some modifications in the test stand construction are recommended for the future.

3

The possibility of determining the input parameters for the Discrete Element Method

Rozbroj J., Zegzulka J., Jezerska L., Necas J., Zurovec D.

Inżynieria Mineralna

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2015

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R. 16, nr 1

109--114

EN

This article describes measurements of mechanical-physical properties of a particular material, which can be used for validation or calibration of Discreet Element Method (DEM) and definition of basic input parameters or their extents. The validation can be executed by means of a real model of the equipment with which the DEM model is compared. It also explains potential measurement procedures for a real material to determine and verify the input parameter properties for the DEM. The validation material can be of plastic spherical particles, because this shape represents the basic particle for the DEM. Determination of the coefficient of restitution is executed by means of a high-speed camera and subsequent measurement of the particle's movement on a single XY plane. Collection of the measured data is used for identification and selection of suitable input friction parameters for the DEM. All procedures mentioned in this article can lead to clarification of validation or calibration, thus facilitating development and design of new equipment with application of DEM in the future.

PL

Ten artykuł opisuje możliwości pomiaru właściwości mechanicznych i fizycznych masy cząstek stałych, które mogą być wykorzystane do walidacji i kalibracji DEM, a służy również do definiowania podstawowych parametrów wejściowych, lub ich zakresów. Walidacja może być przeprowadzona za pomocą realistycznego modelu urządzenia, który porównuje się z modelu DEM. Dalej oto lista możliwych procedur pomiaru realistycznego materiału prowadzące do identyfikacji i weryfikacji właściwości parametrów wejściowych dla DEM. Jako materiał walidacji mogą być stosowane plastikowe kuliste cząstki, ponieważ ten kształt stanowi zasadniczą cząstkę dla DEM. Wyznaczanie współczynnika restytucji jest realizowany za pomocą kamery o wysokiej prędkości, a następ-nie mierzy się ścieżka ruchu cząstek w jednej płaszczyźnie XY. Zbieranie danych pomiarowych jest używany do identyfikacji i doboru odpowiednich parametrów wejściowe tarcia dla DEM. Wszystkie procedury wymienione w tym artykule może doprowadzić do wyjaśnienia problemów walidacji i kalibracji, i w ten sposób ułatwić rozwój i projektowanie nowych urządzeń w przyszłości przy użyciu DEM.

4

Stanowisko do badań tribologicznych w złożonym ruchu cyklicznym toczno-ślizgowym

Kowalewski P., Wieleba W., Leśniewski T.

Tribologia

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2007

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nr 2

303-311

EN

The concept of design of equipment for the tribological testing of materials and friction couple is described. Idea of equipment was created to build new, universal tribotester for investigation sliding materials in changing motion and load. Paper describes mechanical construction of new tribological tester also measurement and control system. Described machine should make easy investigation and testing friction of materials for different applications. New tribological tester is able to be run also in rolling and sliding motion in one time and to full control all applying loads and kinematics condition, such as normal force - Fn, rolling velocity - n and sliding velocity - vs. Those variables could be freely changing during a test. Value of variables can be depended on time and on themselves. It makes possibilities to doing investigation in special measurement programs. Paper also contains experimental results of demonstration investigation.