On Numerical Modeling of Equal Channel Angular Extrusion of Ultra High Molecular Weight Polyethylene

2021 ◽  
Author(s):  
Kostiantyn Vasylevskyi ◽  
Kateryna Miroshnichenko ◽  
Stanislav Buklovskyi ◽  
Igor Tsukrov ◽  
Hannah Grover ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Numerical Modeling ◽  
High Molecular Weight ◽  
Equal Channel Angular Extrusion ◽  
Angular Extrusion ◽  
Ultra High Molecular Weight

On Numerical Modeling of Equal Channel Angular Extrusion of Ultra High Molecular Weight Polyethylene

2020 ◽  
Author(s):  
Kostiantyn Vasylevskyi ◽  
Kateryna Miroshnichenko ◽  
Stanislav Buklovskyi ◽  
Igor Tsukrov ◽  
Hannah Grover ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Numerical Modeling ◽  
High Molecular Weight ◽  
Plane Strain ◽  
Equal Channel Angular Extrusion ◽  
Constitutive Models ◽  
3D Models ◽  
Punch Force ◽  
Angular Extrusion ◽  
Ultra High Molecular Weight

Abstract Ultra high molecular weight polyethylene (UHMWPE) is widely used in biomedical applications, e.g. as a bearing surface in total joint arthroplasty. Recently, equal channel angular extrusion (ECAE) was proposed as a processing method to achieve higher molecular entanglement and superior mechanical properties of this material. Numerical modeling can be utilized to evaluate the influence of such important manufacturing parameters as the extrusion rate, temperature, geometry of the die, back pressure and friction effects in the ECAE of polyethylenes. In this paper we focus on the development of efficient FE models of ECAE for UHMWPE. We study the applicability of the available constitutive models traditionally used in polymer mechanics for UHMWPE, evaluate the importance of the proper choice of the friction parameters between the billet and the die, and compare the accuracy of predictions between 2D (plane strain) and 3D models. Our studies demonstrate that the choice of the constitutive model is extremely important for the accuracy of numerical modeling predictions. It is also shown that the friction coefficient significantly influences the punch force and that 2D plane strain assumption can become inaccurate in the presence of friction between the billet and the extrusion channel.

Finite Element Model of Equal Channel Angular Extrusion of Ultra High Molecular Weight Polyethylene

2021 ◽  
pp. 1-30
Author(s):  
Kostiantyn Vasylevskyi ◽  
Igor Tsukrov ◽  
Kateryna Miroshnichenko ◽  
Stanislav Buklovskyi ◽  
Hannah Grover ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Finite Element ◽  
Shear Strain ◽  
High Molecular Weight ◽  
Equal Channel Angular Extrusion ◽  
Dead Zone ◽  
Extrusion Force ◽  
Element Analysis ◽  
Angular Extrusion ◽  
Ultra High Molecular Weight

Abstract Ultra-high molecular weight polyethylene (UHMWPE) used in biomedical applications, e.g. as a bearing surface in total joint arthroplasty, has to possess superior tribological properties, high mechanical strength, and toughness. Recently, equal channel angular extrusion (ECAE) was proposed as a processing method to introduce large shear strains to achieve higher molecular entanglement and superior mechanical properties of this material. Finite element analysis (FEA) can be utilized to evaluate the influence of important manufacturing parameters such as the extrusion rate, temperature, geometry of the die, back pressure, and friction effects. In this paper we present efficient FEA models of ECAE for UHMWPE. Our studies demonstrate that the choice of the constitutive model is extremely important for the accuracy of numerical modeling predictions. Three considered material models (J2-plasticity, Bergstrom-Boyce, and the Three Network Model) predict different extrusion loads, deformed shapes and accumulated shear strain distributions. The work has also shown that the friction coefficient significantly influences the punch force and that the 2D plane strain assumption can become inaccurate in the presence of friction between the billet and the extrusion channel. Additionally, a sharp corner in the die can lead to the formation of the so-called “dead zone” due to a portion of the material lodging into the corner and separating from the billet. Our study shows that the presence of this material in the corner substantially affects the extrusion force and the resulting distribution of accumulated shear strain within the billet

Equal channel angular extrusion of ultra-high molecular weight polyethylene

2016 ◽  
Vol 67 ◽  
pp. 623-628 ◽  
Author(s):  
Steven D. Reinitz ◽  
Alexander J. Engler ◽  
Evan M. Carlson ◽  
Douglas W. Van Citters
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Equal Channel Angular Extrusion ◽  
Angular Extrusion ◽  
Ultra High Molecular Weight

Application of ultra-high molecular weight polyethylene in a hydraulic drive

2020 ◽  
pp. 77-78
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
High Molecular Weight ◽  
Hydraulic Drive ◽  
Control Valve ◽  
Hydraulic Control ◽  
Hydraulic Motor ◽  
Hydraulic Pump ◽  
Hydraulic Oil ◽  
Ultra High Molecular Weight

The use of ultra-high molecular weight polyethylene (UHMW PE) for the manufacture of various parts, in particular cuffs for hydraulic drives, is proposed. The properties and advantages of UHMW PE in comparison with other polyethylene materials are considered. Keywords ultra-high molecular weight polyethylene, hydraulic pump, hydraulic motor, hydraulic control valve, hydraulic oil, low temperature. [email protected]

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