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1

Finite element analysis on prosthetic leg under different loads and flexion angles for medical applications

Konada Naresh Kumar, Koka Naga Sai Suman

Journal of Mechanical and Energy Engineering

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2022

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Vol. 6, No 2

1--12

EN

Prosthetic legs are mainly used to perform leg amputations more easily and sometimes the appearance is similar to a real leg. Different types of legs have been developed in recent days to be used in specific fields like running, cycling in sports and normal walking. The selection of materials and load bearing capacity of a leg determines its usage for any field of application. The behavior of prosthetic legs can be assessed properly by performing a finite element analysis on it with varying material properties and loads before it undergoes a designing and manufacturing stage. In the current study, Al alloy, Ti alloy, unidirectional Carbon fiber epoxy (UDCFE) and combined composite material which include (CF, UDCFE and Ti alloy) are used as materials for the prosthetic leg. A prosthetic leg model of C Type with its main parts being the sleeve, the rod and the base foot was designed initially by using the Solid Works 2010 software and the assembled file was imported to Ansys Workbench 2020 to perform a static and fatigue analysis. The static analysis was performed under four different load conditions, i.e. 60 kg, 70 kg, 80 kg and 90 kg, considering the different human weights of the body. A fatigue analysis was done by using the Soderberg method and applying a sinusoidal varying load for low cycle fatigue conditions. Theoretical calculations were also performed at various inclinations of foot 10°, 20°, and 30° with the ground and stresses were evaluated using finite element equations. The results obtained theoretically were compared with the analytical results. The best material which provided the lesser value of deformation and sustaining more loads with a lower value of the damage factor was selected for the design. Further experimental studies were suggested based on the results obtained from this work.

2

Microstructural and mechanical properties of CFC composite/Ti6Al4V joints brazed with Ag–Cu–Ti and refractory metal foils

Kang Yuhang, Feng Kaimin, Zhang Weitang, Mao Yangwu

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

487--496

EN

Carbon fiber-reinforced carbon composite (CFC)/Ti6Al4V alloy brazing has been performed with Ag–Cu–Ti braze and Nb (or W) foil. Satisfactory bonding is achieved at the interfaces among substrates, refractory metal layer and fillers. The joining region consists of filler I, refractory metal layer and filler II. The fillers I and II are composed of Ag-based solid solution, TiCu and Cu-based solid solution. A diffusion layer (comprising Ti-based solid solution and Ti2Cu) and a thin TiC reaction layer develop adjacent to Ti6Al4V and CFC substrates, respectively. Regarding the joining with Nb foil, slight dissolution and diffusion occur between Nb and Ti in the fillers upon brazing. However, neither inter-diffusions nor reactions between W and fillers are involved in CFC/Ti6Al4V joining with W foil. The average shear strengths of joints with Nb and W foils are about 200% higher than those without refractory metal foil, indicating that the thermal mismatch in the joint can be relieved by the introduced refractory metal foils with appropriate coefficients of thermal expansion. Moreover, Nb foil with high ductility is beneficial for the inhibition of both the micro-crack propagation and the brittle-phase formation in the joint. W foil can act as a hard barrier to adjust the joint stress distribution and to decrease the joint stress concentration.

3

Quantitative Analysis of Cryomilled Nanocrystalline Ti-6Al-4V Alloy Powder by X-Ray Diffraction

Oh M., Yu H. K., Lee J.-H., Oh M. C., Jung S.-H., Ahn B.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 3

1439--1442

EN

A nanocrystalline Ti alloy powder was fabricated using cryomilling. The grain size and lattice strain evolution during cryomilling were quantitatively analyzed using X-ray diffraction (XRD) based on the Scherrer equation, Williamson-Hall (W-H) plotting method, and size-strain (S-S) method assuming uniform deformation. Other physical parameters including stress and strain have been calculated. The average crystallite size and the lattice strain evaluated from XRD analysis are in good agreement with the result of transmission electron microscopy (TEM).

4

Effect of Fe Content on the Microstructure and Mechanical Properties of Ti-Al-Mo-V-Cr-Fe Alloys

Bae K.-C., Oak J.-J., Kim Y. H., Park Y. H.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 2B

1105--1108

EN

To investigate the effect of Fe content on the correlation between the microstructure and mechanical properties in near-b titanium alloys, the Ti-5Al-5Mo-5V-1Cr-xFe alloy system has been characterized in this study. As the Fe content increased, the number of nucleation sites and the volume fraction of the α phase decreased. We observed a significant difference in the shape and size of the α phase in the matrix before and after Fe addition. In addition, these morphological deformations were accompanied by a change in the shape of the α phase, which became increasingly discontinuous, and changed into globular-type α phase in the matrix. These phenomena affected the microstructure and mechanical properties of Ti alloys. Specimen #2 exhibited a high ultimate tensile strength (1071 MPa), which decreased with further addition of Fe.

5

Analiza zmian mikrostruktury odkuwki ze stopu Ti-6Al-4V wywołanych lokalnym nagrzaniem do temperatury występowania fazy β

Bała P., Krawczyk J., Pawłowski B., Lipski A.

Inżynieria Materiałowa

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2012

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Vol. 33, nr 4

280--283

PL

W pracy przedstawiono wyniki badań zmian mikrostruktury odkuwki rozwieracza ran (narzędzia używanego w chirurgii urazowej) wykonanego ze stopu tytanu Ti-6Al-4V. Zmiany mikrostruktury stopu zostały spowodowane lokalnym nagrzaniem odkuwki do zakresu temperatury występowania fazy β i chłodzeniem. W wyniku takich warunków odkształcania i chłodzenia badanego stopu uzyskano duże zróżnicowanie morfologii składników fazowych mikrostruktury. Badania mikrostruktury wykonano w celu ustalenia wpływu warunków lokalnego nagrzania (bez konieczności nagrzewania całej odkuwki) do formowania elementów wykonanych ze stopu Ti-6Al-4V. Określono zmiany mikrostruktury wywołane niejednorodnością odkształcenia w zakresie temperatury występowania α + β oraz drogę rozwoju pęknięć w mikrostrukturze stopu składającej się z fazy αʹ.

EN

In the paper the results of microstructure examination of Ti6Al4V alloy forgings used as surgery tools (weitlaner retractor) are presented. Changes in lowed by intensive cooling. As a result of local heating, a temperature gradient was obtained, which enabled the authors to achieve a wide range of microstructures of the investigated alloy. Study of the microstructure was done in order to verify the thesis that local heating (without heating whole forgings) up to the plastic deformation temperature, would not cause any adverse changes in the microstructure. Changes in the microstructure caused by inhomogeneous plastic deformation in the α + β range and the path of crack propagation in the αʹ phase, were described.

6

Development on diamond tool with forced cooling system for high speed cutting of aeronautic and astronautic parts

Tanabe I., Hoang T. B., Iyama T.

Journal of Machine Engineering

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2009

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Vol. 9, No. 1

58--65

EN

Recently titanium alloys and nickel alloys have become eminent for making aeronautic and astronautic parts. Since both nickel alloys and titanium alloys have a very small thermal conductivity, the being used tool will suffer from a huge damage by heat generated during cutting process. Therefore, there is a requirement for a durable tool with excellent cooling capacity. In this research, a new electro-deposited diamond tool for high speed cutting of nickel alloys and titanium alloys was developed and evaluated. The new tool is a cup shaped end mill, its body is made from copper (due to its superior heat conduction characteristics) and the platting layer for bonding the diamond grains #120 is nickel. The cooling system is an advancement of the former used heat pipe. Water is supplied from outside through a thin tube, that is integrated in the tool body. Thereby the effect of water evaporation, featuring a very large cooling capacity, could be applied. The assayed materials were Ti6Al4V and Inconel 718. The cutting conditions were investigated by some pre-experiments. It is concluded from the results that; (1) The cooling capacity of the new tool using water evaporation is very effective to maintain the grinding potential of electro-deposited diamond tools, (2) The new tool is effective for high speed grinding of nickel alloys and titanium alloys (3) The new tool and compulsory cooling system are economical and eco-friendly.

7

Skutki obróbki laserowej warstwy wierzchniej elementów ze stopów tytanu oraz aluminium

Wołyński A.

Journal of Research and Applications in Agricultural Engineering

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2004

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Vol. 49, nr 3

53-56

PL

W referacie przedstawiono efekty obróbki laserowej warstwy wierzchniej próbek ze stopu tytanu Ti6Al4V oraz stopu aluminium AlSi6Cu4. Obróbkę przeprowadzono przy użyciu lasera C02. W wyniku tej obróbki w próbce Ti6Al4V uzyskano wzrost twardości w warstwie przetopionej i w warstwie zahartowanej, natomiast w próbce AlSi6Cu4 uzyskano mniejsze przyrosty twardości, z równoczesnym powstawaniem pęcherzy gazowych w obszarze oddziaływania ciepła.

EN

Paper presents effects of laser treatment of surface layer of samples made of titanium alloy, Ti6Al4V and aluminium alloy, AlSi6Cu4. Laser treatment was carried out by means of a CO2 laser. In the titanium alloy Ti6Al4V, hardness increase in the zone melted by the laser beam is larger than in the zone that has only been hardened by the beam. Advantageous effects of laser treatment of the AlSi6Cu4 alloy have been obtained at a very low power density of the laser beam applied. Increase of the density causes formation of gas bubbles in the heat affected area.