scholarly journals Numerical Thermal Analysis of a T Jump System Used for Studying Polymer Behaviour

2019 ◽  
Vol 890 ◽  
pp. 155-161
Author(s):  
Sara Gomes ◽  
Paula Pascoal-Faria ◽  
Geoffrey R. Mitchell ◽  
Thomas Gkourmpis ◽  
Tristan Youngs
Keyword(s):  
Thermal Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Temperature Variation ◽  
Element Model ◽  
Maximum Temperature ◽  
Molecular Organisation

The processing of polymers is highly complex. The study of their crystallisation assumes an important role and needs to be carefully detailed. Scattering experiments can be used to study polymer molecular organisation. However these procedures are still very multifaceted leading to the need for planning all the details in the experiments that are to be performed. This manuscript presents a finite element model developed to study the temperature variation of a T Jump System, which has been used for studying polymer behaviour with the NIMROD instrument at the ISIS Neutron and Muon Source, UK. Results show that the variation across the sample was 2oC at a maximum temperature of 70oC and 1oC at a maximum temperature of 50oC.

Frictional heating of bearing materials tested in a hip joint wear simulator

1997 ◽  
Vol 211 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Z Lu ◽  
H McKellop
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Frictional Heating ◽  
Element Model ◽  
Maximum Temperature ◽  
Zirconia Ceramic ◽  
Chromium Alloy ◽  
Cobalt Chromium ◽  
Surface Temperatures ◽  
Ability To Act

In a hip simulator wear test using bovine serum as a lubricant, the heat generated by ball-cup friction may cause precipitation of the proteins from the lubricant. The resultant accumulation of a solid layer of precipitated protein between the ball and cup could artificially protect the bearing surfaces from wear, in a manner that does not occur in vivo. Alternatively, the gradual depletion of the soluble proteins could interfere with their ability to act as boundary lubricants on the bearing surfaces, thereby artificially increasing the wear rate. Because the rate of protein precipitation may depend on the maximum temperature at the bearing surfaces during sliding, rather than the mean temperature of the bulk lubricant, this study determined the transient surface temperatures using an array of thermocouples embedded in acetabular cups of GUR 415 ultra-high molecular weight polyethylene (UHMWPE) and femoral balls of metal or ceramic, in conjunction with a finite element model of the temperature distribution. The prostheses were tested at one cycle/s under a Paul-type, physiological load profile with 2030 N maximum force, with the load cycle synchronized to the motion cycle. The steady state temperatures of the bulk lubricant were 38°C for the zirconia balls, 36°C for the cobalt-chromium and 33°C for the alumina. However, the corresponding surface temperatures of the polyethylene, calculated with the finite element model, were 99°C with zirconia ceramic, 60°C with cobalt-chromium alloy, and 45°C with alumina ceramic. The rank order of the surface temperatures corresponded to the relative amounts of protein that were precipitated in the test chambers during wear tests with these materials.

Thermal Analysis of a Satellite Borne Instrument

2014 ◽  
Vol 536-537 ◽  
pp. 1397-1400
Author(s):  
Bo Chen ◽  
Ning Li
Keyword(s):  
Thermal Analysis ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Thermal Design

Thermal design and analysis of a satellite instrument is introduced in this paper. Some methods were adopted to help heat conduct and a finite element model was built. The analysis results showed that the temperature scopes of the main structures are from 45°C to 65.8°C and all of junction temperatures of the components are lower than the derated maximum junction temperatures themselves and leave enough design margins, which match the requirements of thermal analysis.

scholarly journals Thermal diagnostics of mechanical gear elements of combine harvester

2021 ◽  
Vol 845 (1) ◽  
pp. 012137
Author(s):  
A G Pastukhov ◽  
E P Timashov ◽  
I N Kravchenko
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Ambient Air ◽  
Element Model ◽  
Maximum Temperature ◽  
Mechanical Transmission ◽  
Friction Zone ◽  
Combine Harvester ◽  
Thermal Diagnostics ◽  
The Finite Element Model

Abstract The work carried out practical testing of the technology of thermal diagnostics of belt gear elements of the grating mill drive of the combine harvester. The basis of the technology is the principle of using the coefficient of the temperature ratio on the surface of the diagnosed unit and temperature in the friction zone, expressed through the coefficient of proportionality of the finite element model. The peculiarity of the thermal diagnostics, in this case, is to compare the temperature in the friction zone with the maximum allowable temperature for the direct contact zone in the mechanical transmission unit. The object of the study is the tensioning roller of the drive of the grating mill of the first stage of the CLAAS TUCANO 580 combine harvester with 6203-2RS TIMKEN bearings. The result of the numerical experiment showed a significant effect on the temperature in the friction zone of the operational parameters - radial force and rotational speed. The use of 3D-modeling made it possible to determine the key parameter of the proposed thermal diagnostics technology - the proportionality coefficient of the finite-element model k=0.489. The temperature of the bearing assembly of the tension roller was measured periodically, using a non-contact method during harvesting in the 2020 season. For the period of regular observations of 128 moto-hours, the value of the maximum temperature growth rate in the friction zone Vτ=0.025 °C/min and the maximum temperature in the friction zone 69.5 °C, taking into account the ambient air temperature, were determined. No failures of the diagnosed unit were found. In the process of application of thermal diagnostics technology, no errors of the first kind are recorded, which indicates the effectiveness of the proposed technology.

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