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Study of Contact Parameters in Metal-On-Plastic Hip Endoprosthesis with the Analytical-Numerical Method of Contact Mechanics

Chernets Myron, Zubrzycki Jarosław

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 3

145--153

EN

The purpose is to analyze the influence of the elastic characteristics of the materials of the tribological pair: acetabular–femoral head on the maximum pressures in the hip joint endoprosthesis. Based on the proprietary calculation method of hip joint endoprostheses, an analysis of the impact of UHMW-PE elasticity characteristics (Young's modulus and Poisson's ratio) on the contact parameters was carried out: maximum contact pressure, and contact angle. The study determined the value of contact pressures depending on the changes in the elastic characteristics of UHMW-PE and changes in the geometry of the tribological pair (variable radii of the Grade2TDN head and the UHMW-PE acetabulum). It was found that increasing Young's modulus of UHMWPE increases its stiffness, which causes a noticeable increase in contact pressures in the endoprosthesis. The quantitative and qualitative regularities of this impact were determined. The developed method allows for earlier estimation of contact pressures depending on the external load (patient's body weight), and geometric parameters of the artificial hip joint (diameter of the endoprosthesis head and the acetabulum). This allows you to make a personalized endoprosthesis resistant to damage. It is very important in modern medicine because life expectancy in developed countries is longer and the durability of endoprostheses should be 10–12 years. Hospital statistics show that the need for total hip replacement concerns even younger people. Implantation of a hip joint prosthesis is an invasive and costly procedure, hence the need to produce prostheses with a long service life (over 15-20 years) before re-arthroplasty. The obtained test results showed that the use of an endoprosthesis cup made of UMHW-PE with higher stiffness (high E1 value and low ν value) results in an increase in maximum contact pressures p(0). Increasing the Poisson's ratio in the tested range causes an increase in the contact pressure p(0) even 1.1 times. Increasing the diameter of the head of the D2 endoprosthesis decreases the contact pressure by an average of 2.32 times. On the other hand, a change in the radial clearance  in the tribological pair of the hip endoprosthesis from 0.1 mm to 0.2 mm causes an increase in contact pressures by an average of 1.35 times.

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Wyznaczenie temperatury na styku pary tribologicznej

Bogdan-Chudy M.

Zeszyty Naukowe. Mechanika / Politechnika Opolska

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2015

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z. 105

17-20

EN

This paper presents a method to measure the temperature at the interface of tribological pair. The contact temperatures measurement was performed using the thermocouple type K and pyrometer.

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Wpływ wymuszeń zewnętrznych na cechy użytkowe warstwy wierzchniej w tocznym węźle tribologicznym

Musiał J., Muślewski Ł., Bojar P., Troszyński A.

Logistyka

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2014

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nr 6

7706--7712

PL

W pracy przedstawiono rozważania dotyczące oceny wpływu obciążenia i czasu pracy węzła tribologicznego oraz chropowatości współpracujących powierzchni (będącej wynikiem procesu technologicznego) na opory ruchu. Badania przeprowadzone na maszynie zużyciowej AMSLER wykazały, że zmiany oporów ruchu podczas eksploatacji pary kinematycznej z tarciem tocznym zachodzą w sposób ewolucyjny, ze zmienną intensywnością. Wyniki badań empirycznych pozwoliły na opisanie modelami matematycznymi zmian momentu tarcia, zachodzących w wyniku oddziaływania wymuszeń zewnętrznych.

EN

In the paper there were presented deliberations on dependance of loading and working time of a tribological pair as well as on cooperating surfaces' roughness (being a result of a technology process). Tests conducted with the usage of a AMSLER wear testing machine have demonstrated that movement resistance changes (during opertating of a kinematic pair with rolling friction) happen gradually with variable intensity. Empirical test results enabled to describe the changes of a frictional moment (undergoing as a result of external loads) with mathematical models.

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Operational evaluation of piston ring wear in large marine diesel engines

Adamkiewicz A., Drzewieniecki J.

Journal of Polish CIMAC

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2012

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Vol. 7, no 1

9-17

EN

This article presents operational evaluation of piston ring wear in large marine diesel engines based on inspection through cylinder liner scavenge ports. It contains a description of verification methods of piston rings based on visual inspections, clearance measurement of piston rings in piston grooves and piston rings gap measurement. Moreover, it is indicated that piston ring gap measurements can lead to an evaluation of piston ring wear and by calculating into running hours can be treated as a reference parameter at next inspections and a parameter determining wear trends. Furthermore, application of chromium layers on working surfaces of piston rings enforces the need to control chromium layer wear by measuring the layer thickness by induction and eddy current methods. Concluding, the authors discussed constructional – operational methods of improvement between tribological pair – liner and piston rings in working conditions .

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Analiza procesu tarcia i efektów zużywania się żeliwa szarego oraz kompozytu AK7-SiC podczas bezsmarowej współpracy ze stalą.

Przetakiewicz W., Czujko T., Iwan T.

Inżynieria Materiałowa

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2001

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R. XXII, nr 6

1036-1041

PL

Przedmiotem badań były próbki żeliwa perlitycznego wycięte z nowej tarczy hamulcowej samochodu oraz próbki kompozytu z osnową w postaci siluminu Al-7%Si zbrojonego cząstkami SiC, o udziale wagowym 21%. Przeprowadzono testy tribologiczne w układzie krążek (próbka)-klocek za pomocą maszyny Amslera w warunkach tarcia suchego. Określono wartości zużycia masowego i liniowego próbek oraz stalowej przeciwpróbki, przy dwóch wartościach nacisku jednostkowego: 1 MPa i 2 MPa. Wyznaczono też sumaryczne, względne zużycie każdej pary tribologicznej. Zbadano zmiany temperatury i momentu tarcia w funkcji czasu pracy skojarzenia ciernego. Opierając się na analizie mikroskopowej zmian stanu powierzchni zidentyfikowano dominujący mechanizm zużywania się obu materiałów. Zaobserwowano intensywne zużycie ścierne żeliwa. W przypadku kompozytu przeważało utlenianie osnowy i nierównomierne złuszczanie się produktów tego procesu. W przyjętych warunkach badań zużycie żeliwa było ponad 100-krotnie wyższe niż kompozytu.

EN

The domain of the research consisted of the pearlitic cast iron samples cut from a new car break disc and also composite samples with silumin matrix (as Al-7%Si) reinforced by SiC particles (21 % wt.). Tribological tests in configuration of a roller (sample) and antifriction block with the help of Amsler machine in conditions of dry friction have performed. The values of mass and linear abrasive wear of samples and steel anti-friction block sample determined in presence of two units pressure values (1 MPa and 2 MPa), have been defined. Consequently, the summary relative abrasive wear of each tribological pair has been assigned. The changes of temperature and the moment of friction have been investigated as a function of work time. Based on microscopy analysis of the surface changes, the dominating mechanism of abrasive wear of both materials has been defined. The intensive abrasive wear of grey cast iron has been observed. As far as composite is concerned, matrix oxidation and irregular abrasive wear of the products in this process have been prevailed. Under the accepted research conditions the abrasive wear of grey cast was over 100 times higher than the one of the composite.