Temperature Dependence of the Yield Stress in α-Titanium Investigated with Crystal Plasticity Analysis

2018 ◽  
Vol 941 ◽  
pp. 1474-1478
Author(s):  
Yelm Okuyama ◽  
Masaki Tanaka ◽  
Tetsuya Ohashi ◽  
Tatsuya Morikawa
Keyword(s):  
Finite Element ◽  
Temperature Dependence ◽  
Yield Stress ◽  
Crystal Plasticity ◽  
Slip Systems ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Pyramidal Slip ◽  
Active Slip ◽  
Lattice Friction

The effect of the activated slip systems on the temperature dependence of yield stress was investigated in α-Ti by using crystal plasticity finite element method. A model for finite element analysis (FEA) was constructed based on experimental results. The displacement in FEA was applied up to the nominal strain of 4% which is the same strain as the experimental one. Stress-strain curves were obtained, which corresponds to experimental data taken every 50 K between 73 K and 673 K. The used material constants which are temperature dependent were elastic constants, and lattice friction stresses. The lattice friction stresses of basal slip systems were set to be higher than that of pyramidal slip systems at 73 K. Then, the lattice friction stresses were set to be closer as the temperature increases. It was found that the activation of slip systems is strong temperature dependent, and that the yield stress depends on the number of active slip systems.

Temperature Dependence of Deformation Behavior in Magnesium and Magnesium Alloy Single Crystals

2007 ◽  
Vol 345-346 ◽  
pp. 101-104 ◽  
Author(s):  
Shinji Ando ◽  
Naoharu Harada ◽  
Masayuki Tsushida ◽  
Hiromoto Kitahara ◽  
Hideki Tonda
Keyword(s):  
Magnesium Alloy ◽  
Temperature Dependence ◽  
Single Crystals ◽  
Yield Stress ◽  
Deformation Behavior ◽  
Pure Magnesium ◽  
Pyramidal Slip ◽  
Increasing Temperature ◽  
Zn Alloy ◽  
Active Slip

It is important to research activation of the slip systems in magnesium crystals to understand deformation behavior of magnesium. In this study, pure magnesium, Mg-7.0at%Li and Mg-0.1at%Zn single crystals were stretched in the [11-20] direction in the range of 77K to 573K to investigate the deformation behavior by non-basal slip. The active slip system was investigated by the observation of slip bands, etch pit bands and dislocations by TEM. {11-22} <-1-123> second order pyramidal slip is activated in all magnesium and magnesium alloy single crystals, and its yield stress shows anomalous temperature dependence in the range from 77K to 293K, however, the yields stress decreased rapidly with increasing temperature above 293K. The yield stress due to the pyramidal slip in Mg-Li and Mg-Zn alloy were lower than that of pure magnesium about 20MPa whereas the stress of Mg-Zn at 77K was about two times higher than pure magnesium.

Thermal-Electric Finite Element Analysis of Electrosurgical Cautery Process

2007 ◽  
Author(s):  
Robert E. Dodde ◽  
Scott F. Miller ◽  
Albert J. Shih ◽  
James D. Geiger
Keyword(s):  
Heat Transfer ◽  
Electrical Conductivity ◽  
Finite Element ◽  
Biological Tissue ◽  
Tissue Temperature ◽  
Temperature Dependent ◽  
Element Analysis ◽  
Temperature Dependent Thermal Conductivity ◽  
Insight Into ◽  
Good Agreement

Cautery is a process to coagulate tissues and seal blood vessels using the heat. In this study, finite element modeling (FEM) was performed to analyze temperature distribution in biological tissue subject to cautery electrosurgical technique. FEM can provide detailed insight into the heat transfer in biological tissue to reduce the collateral thermal damage and improve the safety of cautery surgical procedure. A coupled thermal-electric FEM module was applied with temperature-dependent electrical and thermal properties for the tissue. Tissue temperature was measured at different locations during the electrosurgical experiments and compared to FEM results with good agreement. The temperature-dependent electrical conductivity has demonstrated to be critical. In comparison, the temperature-dependent thermal conductivity does not impact heat transfer as much as the electrical conductivity. FEM results show that the thermal effects can be varied with the electrode geometry that focuses the current density at the midline of the instrument profile.

scholarly journals Temperature-Dependence of Rubber Hyperelasticity Based on the Eight-Chain Model

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 932 ◽  
Author(s):  
Xintao Fu ◽  
Zepeng Wang ◽  
Lianxiang Ma ◽  
Zhaoxuan Zou ◽  
Qingling Zhang ◽  
...  
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Natural Rubber ◽  
Temperature Dependence ◽  
Large Temperature ◽  
Chain Model ◽  
Element Analysis ◽  
Filled Rubber ◽  
Different Temperatures

Rubber-based materials are widely used in a variety of industrial applications. In these applications, rubber components withstand various loading conditions over a range of temperatures. It is of great significance to study the mechanical behavior of vulcanized rubber at different temperatures, especially in a range of high temperatures. The temperature dependence of the constitutive behavior of filled rubber is important for the performance of the rubber. However, only a few constitutive models have been reported that investigate the stress–temperature relationship. In this paper, based on an analysis of experimental data, the effects of temperature on the hyperelastic behaviors of both natural rubber and filled rubber, with different mass fractions of carbon black, were studied. The regulation of stress and strain of natural rubber and filled rubber with temperature was revealed. In addition, an eight-chain model that can reasonably characterize the experimental data at different temperatures was proved. An explicit temperature-dependent constitutive model was developed based on the Arruda-Boyce model to describe the stress–strain response of filled rubber in a relatively large temperature range. Meanwhile, it was proved that the model can predict the effect of temperature on the hyperelastic behavior of filled rubber. Finally, the improved Arruda-Boyce model was used to obtain the material parameters and was then successfully applied to finite element analysis (FEA), which showed that the model has high application value. In addition, the model had a simple form and could be conveniently applied in related performance test of actual production or finite element analysis.

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