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1

Analysis of Mechanical Properties of External Unilateral Fixation Device in the Case of Torque Load

Pervan Nedim, Muminović Adis J., Delić Muamer, Muratović Enis

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 3

31--39

EN

Analysis of mechanical properties of external unilateral fixation device „Ultra X“, in the case of torque load, is presented in this paper. Fixation device is applied on lower leg in the case of unstable fracture. Computer aided design (CAD) model and finite element model (FEM) are developed according to the dimensions and material properties of real fixation device. In the next step principal stress and deformation analysis is performed in CATIA V5 software. During numerical analysis values of stresses at critical places are monitored and analyzed. In addition, values of displacements are measured on important places on fixation device and bone fracture. Using values of displacements at the place of bone fracture, stiffness of the fracture is calculated. The same methodology is used to calculate stiffness of the fixation device. Using obtained results, several conclusions about the mechanical properties of the fixation device “Ultra X” are formulated at the end of the paper.

2

Stiffness Analysis of the External Fixation System at Axial Pressure Load

Pervan Nedim, Mešić Elmedin, Muminović Adis J., Delić Muamer, Muratović Enis

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 3

226--233

EN

The paper analyzes the stiffness of the Orthofix external fixation system at axial pressure load, applied to the lower leg in case of an unstable fracture. Based on the actual construction of the Orthofix fixator, its 3D model was formed, and then a structural analysis was performed in the CATIA V5 software system. The aim of this paper is to investigate the mechanical properties of Orthofix fixator. FEM analysis of the fixator revealed displacements at characteristic points of the structure and fractures. During the FEM analysis, it is possible to change the load values, all with the aim of obtaining the best possible information about the behavior of the fixator during installation and use by the patient. Based on the results obtained from the FEM analysis, it can be concluded that the Orthofix fixative shows very good stiffness, but also that it can be improved by using newer materials, such as composite or some alloys of titanium and aluminum.

3

Analysis of Mechanical Stability for External Fixation Device in the Case of Anterior-Posterior Bending

Pervan Nedim, Muminović Adis J., Mešić Elmedin, Delić Muamer, Muratović Enis

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 3

136--142

EN

Analysis of mechanical stability for external fixation device Orthofix in the case of anterior-posterior bending is carried out in this paper. Device is applied to the lower leg for the case of unstable fracture. Real device is measured and 3D CAD model is developed. CAD model is used for numerical structural stress analysis which is carried out using CATIA V5 software. Results for displacements are obtained for selected critical places on the device and for the place of fracture. In addition, values of principal and von Misses stresses are obtained and analyzed. Using obtained results, conclusions about mechanical stability of device are formulated.

4

Structural Size Optimization of External Fixation Device

Mešić Elmedin, Muminović Adil, Čolić Mirsad, Petrović Marin, Pervan Nedim

Advances in Science and Technology. Research Journal

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2020

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Vol. 14, no 2

233-240

EN

Structural size optimization of a device for external bone fixation within a formed iterative hybrid optimization algorithm was presented in this paper. The optimization algorithm was in interaction with the algorithms for generative design and FEM analysis and completely integrated within CATIA CAD/CAM/CAE system. The initial model, representing the current design of the bone external fixation device Sarafix, was previously verified by experimental testing. The formed hybrid optimization algorithm was created as an integration of the global (SA method) and local (CG method) algorithm. The constraints of the optimization model are the clinical limitations of the interfragmentary displacements and the material strength. The optimized design has less weight, greater rigidity and less transverse interfragmentary displacements at the point of fracture compared to the current design.

5

Określanie naprężeń pierwotnych w górotworze metodami hydraulicznymi – możliwości i zastosowania

Makówka Janusz, Myszkowski Jacek, Merta Grzegorz

Przegląd Górniczy

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2019

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T. 75, nr 7

27--36

PL

W artykule przedstawiono podstawy określania naprężeń pierwotnych w górotworze metodą hydroszczelinowania, w tym jej wersję najczęściej stosowaną w podziemnych kopalniach – metodę microfrac. Przedstawiono także opracowaną w Głównym Instytucie Górnictwa metodę NUHS wykorzystującą ukierunkowane hydroszczelinowanie skał. Metoda ta, w odróżnieniu do metody microfrac, umożliwia określenie pełnego tensora naprężenia. W artykule porzedstawiono przykład połączonego zastosowania obu metod w badaniach dla LW Bogdanka.

EN

The article presents the basics of determination of primary stresses in rock mass by hydro-fracturing, including its version most commonly used in underground mines - the microfrac method. NUHS method is also presented. The method, developed at Central Mining Institute, uses directed hydro-fracturing of rocks. This method, in contrast to the microfrac method, enables determination of the full stress tensor. The article presents an example of a combined application of both methods in research for LW Bogdanka.

6

Określenie przyczyny wysokoenergetycznych wstrząsów górotworu na podstawie parametrów mechanizmu ognisk

Stec K.

Zeszyty Naukowe Instytutu Gospodarki Surowcami Mineralnymi i Energią PAN

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2017

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nr 101

19--32

PL

Celem badań było określenie przyczyny występowania wysokoenergetycznych wstrząsów (energia E ≥ 1,0E+05 J) w rejonie ściany A położonej pokładzie 405/2 w znajdującej się w zachodniej części siodła głównego w Górnośląskim Zagłębiu Węglowym. W badaniach wykorzystano metodę inwersji tensora momentu sejsmicznego dającą w wyniku parametry mechanizmu ognisk (procentowy udział składowych: izotropowej, jednoosiowego ściskania lub rozciągania, składowej ścinającej; azymut i upad płaszczyzn nodalnych; kierunki osi naprężeń tensyjnych i kompresyjnych). Parametry te są wielkościami, które opisują procesy zachodzące w ogniskach wstrząsów i posiadają wyraźny związek z warunkami naprężeniowymi w danym rejonie. Na podstawie otrzymanych parametrów wyznaczono kierunki naprężeń głównych s1, s2, s3 oraz pozostałe parametry takie jak: parametr R = (s2 – s3)/s1 – s3); naprężenie normalne s i ścinania t przy założeniu, że s1 = 1 a s3 = 0; kierunek osi ściskania – rozciągana, kierunek naprężenia horyzontalnego. Przeprowadzone badania wykazały, że przyczyną występowania wysokoenergetycznych wstrząsów podczas eksploatacji ściany A w pokładzie 405/2 była dynamiczna destrukcja warstw stropowych, które uzyskały możliwość przemieszczenia się w kierunku przestrzeni powstałej po wyeksploatowaniu pokładu. Dodatkowym czynnikiem znacznie potęgującym ten proces był udział istniejących w górotworze naprężeń, które pochodziły od występujących w tym rejonie krawędzi i lokalnych uskoków. Wyniki badań stanowiły dodatkową informację dla określenia stanu zagrożenia tąpaniami w tym rejonie. Mianowicie, ze względu na niebezpieczne warunki (parametry naprężeniowe odpowiadające górotworowi o dużej wytrzymałości na ścinanie, w którym wstrząsy cechują się silniejszym oddziaływaniem dynamicznym) wykonane zostały w tym rejonie dodatkowe działania profilaktyczne – strzelania wstrząsowe.

EN

The aim of the research was to determine the cause of high-energy rock mass tremors (energy E ≥ 1,0E+05 J) in the area of longwall A located in seam 505/2, in the western part of the main saddle in the Upper Silesian Coal Basin. The research employed the method of seismic moment tensor inversion which provides parameters of focal mechanism (percentage share of its components: isotropic, uniaxial compression or tension, shear component; trend and dip of nodal planes, directions of tension axes and compression stress). The parameters describe processes occurring in focuses of tremors and they are clearly linked with stress conditions in a given area. Based on the obtained parameters, the directions of principal stresses σ1, σ2, σ3 were determined, as well as other parameters such as: parameter R = (σ2-σ3)/(σ1-σ3); normal stress σ and shear stress τ, assuming that σ1 = 1 and σ3 = 0; direction of Shortening/Extension axis; direction of horizontal stress. The research showed that the cause of the occurrence of high-energy tremors while exploitations longwall A mining seam 405/2, was the dynamic destruction of roof rocks which could displace towards the cavity created after mining the seam. An additional factor significantly magnifying the process was the share of stresses, which originate from the faults in the area, existing in the rock mass. The results of the research provided additional information to determine the degree of rockburst hazard in the area. Due to the very dangerous work conditions (stress parameters reflect the rock mass of high shear strength, where dynamic influence of tremors is stronger) additional preventive actions – distress blastings were made in this area.

7

Geomechanical modeling as a basic step in secondary reservoir stimulation treatment design

Słota-Valim M., Jędrzejowska-Tyczkowska H.

Nafta-Gaz

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2017

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R. 73, nr 1

3--13

EN

Unconventional reservoirs require a new approach at every level of the operation on the object, starting from exploration of reservoir formation, through well and drilling design and ending with well completion including reservoir development. Due to the specific nature of unconventional reservoir properties, the hydrocarbons bearing formation requires stimulation treatments like hydraulic fracturing, aiming to improve the pores connectivity and enabling the free flow of the gas into the well bore, which in the end brings production rates to economic levels. In the paper a geomechanical model of the synthetic object, allowing the analysis of many processes accompanying real hydrocarbons exploitation was presented. Special attention was paid to the demonstration of changes in the state of stress in the geological formation, due to the exploitation of hydrocarbons and the influence of the initial horizontal stresses relationship (σH/σh), on the effectiveness of stimulation treatments in unconventional formations.

PL

Formacje złożowe o charakterze niekonwencjonalnym do poprawy właściwości transportowych i uzyskania eksploatacji na poziomie uzasadnionym ekonomicznie wymagają stymulacji poprzez szczelinowanie hydrauliczne, którego efektywność uzależniona jest od panujących warunków mechanicznych, m.in. właściwości sprężystych szczelinowanego ośrodka i oddziałującego pola naprężeń. W pracy przedstawiono i omówiono wyniki modelowania geomechanicznego obiektu syntetycznego, pozwalającego na analizę wielu procesów towarzyszących wydobyciu węglowodorów. Specjalną uwagę poświęcono zmianom w rozkładzie naprężeń w górotworze będących skutkiem eksploatacji oraz wpływowi początkowego układu naprężeń poziomych na efektywność zabiegów udostępnienia niekonwencjonalnej formacji złożowej.

8

FEA of chrome-nickel composite in engine valve guides

Kailasam R., Yuvaperiyasamy M., Premkumar R., Dhanabal M.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 1

5--10

EN

In this journal paper an attempt has been made to increase the reliability of engine valve guide using chrome-nickel composites as an alternative material for the engine valve guides. chrome-nickel composites are finding increased application in automobiles, FEA of the chrome-nickel engine valve guide was design and analysis is done by using Ansys13 software. The temperature, thermal stress distribution amd structural analysis of the entire surface of the engine valve guide was analysised. The stress distributions were to be found even throughout the existing materials.

9

Geomechanical modelling of Paleozoic Shale Gas Formation: a case study from the Baltic Basin, northern Poland

Słota-Valim M., Sowiżdżał K., Jędrzejowska-Tyczkowska H.

Geology, Geophysics and Environment

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2017

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Vol. 43, no. 3

249--269

EN

The article presents the importance and position of geomechanical modelling workflow in reservoir characterization studies dedicated to unconventional shale reservoirs. We show the results of 3D geomechanical modelling carried out in an onshore area within the Baltic Basin, northern Poland, where the Silurian and Ordovician shale formations are the exploration targets. The fundamental elements of the methodology, processes, and available datasets used in the modelling are discussed. The petrophysical, elastic, and mechanic properties of the rock were applied in the modelling process, along with the principal stresses and pore pressure in the geological formation. Moreover, the main calculation methods and data requirements for the Mechanical Earth Model construction are discussed. A comprehensive 3D geomechanical model was constructed, providing important information to engineers and decision makers which allows them to optimize well placement, the direction of the horizontal section of the borehole and the parameters of hydraulic fracturing treatment. The model can identify zones of higher potential within the area of interest in terms of efficient stimulation treatment design.

10

Geomechanical conditions of causes of high-energy rock mass tremors determined based on the analysis of parameters of focal mechanisms

Stec K.

Journal of Sustainable Mining

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2015

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Vol. 14, iss. 1

55--65

EN

The aim of the research was to determine the cause of high-energy rock mass tremors (energy E ≥ 105 J) in the area of longwall H-2a located in seam 409/3 in Borynia-Zofiówka-Jastrzębie colliery, basing on the analysis of geological and mining conditions, seismic activity, focal mechanism and local stress field. The research employed the method of seismic moment tensor inversion which provides parameters of focal mechanism (percentage share of its components: isotropic, uniaxial compression or tension, shear component; trend and dip of nodal planes, directions of tension axes and compression stress). The parameters describe processes occurring in focuses of tremors and they are clearly linked with stress conditions in a given area. The conducted tests showed that the cause of occurrence of high-energy tremors and three rockbursts in lot H while mining seam 409/3 with longwall H-2a, was dynamic destruction of roof rocks which could displace towards the cavity created after mining the seam. An additional factor significantly magnifying the process was the share of stresses, which originate from the faults in the area, existing in the rock mass. Results of the research provided additional information to determine the degree of rockburst hazard in the area. Because of very dangerous work conditions (stress parameters reflect the rock mass of high shear strength, where dynamic influence of tremors is stronger) mining activity in longwall H-2a was terminated a few dozen metres earlier than it had been originally planned.

11

Stress distribution in anchoring regions of posts cooperating with overdentures

Chladek W., Chladek G., Krukowska J., Lipski T.

Acta of Bioengineering and Biomechanics

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2005

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Vol. 7, nr 1

35-45

EN

The paper presents the results of model research of mechanical compatibility of selected overdenture structures. The tests based on finite elements method were conducted on flat models reflecting the areas of posts anchoring m a sagittal piane. The reference point was the structure of a prosthesis seated on ball-and-socket joints secured in tooth roots. As altemative solutions, dentures placed on two cylindrical implants supporting ball-and-socket joints were compared with a denture attached to a joint which consisted of a straight axis bar and an elastic clip as well as with a denture supported by a joint of elevated retention, built of a doubly bent axis bar and three elastic bar clips. Taking advantage of the MES Algor program functions, the diverse materiał structures of the systems investigated were modelled. Next. the reduced stresses and principal maximum stresses generated m osseous tissues, in the implants anchoring area. were determined. The value of the mechamcal stimulator decisive to the osseous tissue remodelling was assumed as au evaluatiou criterion. It was assumed that making use of patient's own tooth roots to attach implants IS an optimal solution which, in terms of mechanics, IS practically identical to the alveolodental ligament of a healthy tooth. The application of the other methods of implanted prosthesis attachment always creates a risk of undesirable changes, mostly in the upper area of post insertion into the osseous tissue. The least favourably, in the light of stresses comparison, looks the joint of a doubly refracted axis, where the probability of adverse changes of the osseous tissue in a short time is high. This indicates the necessity to carry on words in order to improve this solution characterized by good retention.

12

O naprężeniach głównych

Grycz J.

Folia Societatis Scientiarum Lublinensis

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2002

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vol. 11

16-33

PL

Przedmiotem rozważań są dowolne ustroje odkształcalne, w których zachowana jest spójność cząstek struktury przy dowolnie dużych i dopuszczalnych deformacjach. Celem pracy jest wyprowadzenie wzorów do wyznaczania naprężeń głównych w dowolnym przestrzennym układzie naprężenia oraz w szczególnym przypadku płaskiego stanu napięcia.

EN

The topic of considerations are arbitary and deformable structures, which for arbitary and admissible strains remain continuous. The aim of analyses is to develop formuale for determination of principal stresses assuming an arbitary spatial stress distribution and in particular two dimensional tension.