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1

Headframe modelling accuracy for finite element method analysis purposes

Biel D., Lipecki T.

Reports on Geodesy and Geoinformatics

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2018

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Vol. 106

19--24

EN

Nowadays, the growing popularity of terrestrial laser scanners (TLS) allows to obtain a point cloud of many industrial objects along with classic surveying. However, the quality and model’s accuracy in comparison to a real shape seem to be a question, that must be further researched. It is crucial especially for Finite Element Method (FEM) analysis, which, being a part of technical design, estimate the values of construction’s dislocation and deformation. The article describes objects such as headgear with steel support and 4-post headframe with steel sheers. Both supports and sheers were modelled basing on point clouds. All the models were compared to the point cloud. The differences in models’ shape were calculated and the maximal values were determined. The results’ usefulness in FEM analysis was described.

2

Inwentaryzacja szybowego zespołu wyciągowego z wykorzystaniem klasycznych metod mierniczych i skaningu laserowego

Jaśkowski W., Lipecki T., Matwij W., Jabłoński M.

Przegląd Górniczy

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2018

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T. 74, nr 1

8--14

PL

Szybowy zespół wyciągowy stanowi podstawę działalności każdego podziemnego zakładu górniczego. Jego sprawność i poprawne działanie podlega restrykcyjnym regulacjom prawnym, i jest na co dzień kontrolowane przez zespoły szybowe oraz energomechaniczne. Ponadto, w interwale wskazanym w przepisach, zespół szybowy podlega dokładnej inwentaryzacji, w której skład wchodzi określenie zależności geometrycznych pomiędzy maszyną wyciągowa a wieżą szybową oraz szybem i jego obudową. Do pomiarów inwentaryzacyjnych w przypadku szybów i wież wykorzystuje się znane od lat klasyczne metody geodezyjne, obejmujące pionowanie mechaniczne lub laserowe oraz pomiary tachymetryczne. Do pomiaru wałów maszyn wyciągowych i kół linowych wykorzystuje się dodatkowo niwelację precyzyjną. Ciągłe unowocześnianie technologii pomiarowych daje możliwość implementacji kolejnych metod do wymienionych powyżej celów. Autorzy dokonali porównania dokładności oraz ekonomiki wykonywania pomiarów w oparciu o wieloletnie doświadczenia z kompleksowych inwentaryzacji urządzeń wyciągowych z wykorzystaniem różnych technik badawczych.

EN

The shaft hoist assembly is the foundation of any underground mine. Its efficiency and correct operation are subject to restrictive legal regulations and are monitored on a daily basis by shaft and energomechanics units. In addition, at the regulatory interval, the shaft hoist assembly is subject to thorough inventory, which includes the determination of the geometrical relationship between the lifting machine and shaft and its housing. Inventory measurements for shafts and towers are performed with the help of conventional geodetic methods used for years, including mechanical or laser plating, and tachymetric measurements. For measuring hoisting machines and rope wheels transmission shafts precision levelling is also used. Continuous modernization of measurement technology gives the possibility to implement further methods for the abovementioned purposes. Based on many years of experience and measurements of the same object by use of classical methods and laser scanner, the authors have compared the accuracy and economics of performing comprehensive inventory of lifting equipment using the abovementioned research techniques.

3

Biomechanical analysis of asymmetric mesio-distal molar positions loaded by a symmetric cervical headgear

Kizilova N., Geramy A., Romashov Y.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 4

97--106

EN

Purpose: The plane 2d model and 3d finite element model of the headgear attached to two molars with different mesio-distal location are studied to show the asymmetric mechanical effects produced by symmetrically loaded headgear. In daily dental practice the asymmetrical location of molars is usually ignored. Methods: Six 3D finite element models of a symmetric cervical headgear were designed in SolidWorks 2011. The models showed symmetric molar position (model 1), 0.5 to 2 mm of anterior-posterior molar difference (models 2-5) and a significant asymmetry with 10 mm of difference in the locations (model 6). The head gear was loaded with 3N of force applied at the cervical headgear. The forces and moments produced on terminal molars are assessed. Results: It is shown the difference between the forces acting at the longer and shorter outer arms of the headgear increases with increase in the distance. The significant numeric difference in the forces has been found: from 0.0082 N (model 1) to 0.0324 N (model 5) and 0.146 N (model 6). These small forces may produce unplanned distal tipping and rotation of the molars around their vertical axes. The most important funding was found as a clockwise yaw moment in the system when is viewed superio-inferiorly. The yaw moment has been computed between -0.646 N•mm (model 1) and -1.945 N•mm (model 5). Conclusions: Therefore even small asymmetry in location of molars loaded by a symmetric cervical headgear will produce undesirable move-ment and rotation of the teeth that must be taken into account before applying the treatment.