A non-equilibrium thermodynamic framework for viscoplasticity incorporating dynamic recrystallization at large strains

2021 ◽  
pp. 102988
Author(s):  
Rolf Mahnken ◽  
Hendrik Westermann
Keyword(s):  
Dynamic Recrystallization ◽  
Large Strains ◽  
Equilibrium Thermodynamic ◽  
Thermodynamic Framework ◽  
Non Equilibrium

A study on deformation-induced degradation of the compressible polymeric pressurized vessel through a non-equilibrium thermodynamic framework

2021 ◽  
pp. 108128652110429
Author(s):  
M. Kazemian ◽  
A. Moazemi Goudarzi ◽  
A. Hassani
Keyword(s):  
Dissipation Rate ◽  
Parametric Design ◽  
Material Model ◽  
Energy Dissipation Rate ◽  
Maximum Energy ◽  
Equilibrium Thermodynamic ◽  
Hill Model ◽  
Thermodynamic Framework ◽  
Proposed Model ◽  
Non Equilibrium

The present paper investigates the degradation of compressible polymers based on the proposed model on strain-induced degradation of incompressible polymers. In a non-equilibrium thermodynamic framework, constitutive equations and evolution laws are derived using the principle of maximum energy dissipation rate and specifying how energy can be stored and dissipated. As a computational model, the governing equations are applied to the pressurized polymeric vessel subjected to the Ogden–Hill compressible hyperelastic material model. To analyze the axisymmetric plane-strain degradable vessel, programming in ANSYS Parametric Design Language (APDL) and the Standard Galerkin Finite Element Method (SGFEM) are applied. The results show that the degradable compressible Ogden–Hill model can also predict the degradation of incompressible polymers subjected to the neo-Hookean model. Results also reveal that the highest dissipation rate and material softening occur at the inner radius of the inflated degradable vessel. Creep-like and stress-relaxation-like responses of the polymeric vessel with time-position-dependent material properties are examined. ANSYS coding indicates good accuracy and efficiency in studying the compressible vessel subjected to inhomogeneous degradation.

Non-equilibrium thermodynamic analysis of adsorption carbon capture: Contributors, mechanisms and verification of entropy generation

Energy ◽  
2020 ◽  
Vol 208 ◽  
pp. 118348
Author(s):  
Zhihao Guo ◽  
Shuai Deng ◽  
Yu Zhu ◽  
Li Zhao ◽  
Xiangzhou Yuan ◽  
...  
Keyword(s):  
Thermodynamic Analysis ◽  
Entropy Generation ◽  
Carbon Capture ◽  
Equilibrium Thermodynamic ◽  
Non Equilibrium

scholarly journals Microstructural Evidence for Grain Boundary Migration and Dynamic Recrystallization in Experimentally Deformed Forsterite Aggregates

Minerals ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 17
Author(s):  
Caroline Bollinger ◽  
Billy Nzogang ◽  
Alexandre Mussi ◽  
Jérémie Bouquerel ◽  
Dmitri Molodov ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Dynamic Recrystallization ◽  
Grain Boundaries ◽  
Driving Forces ◽  
Electron Backscatter Diffraction ◽  
Boundary Migration ◽  
Large Strains ◽  
Grain Boundary Migration ◽  
Mapping Techniques ◽  
Von Mises

Plastic deformation of peridotites in the mantle involves large strains. Orthorhombic olivine does not have enough slip systems to satisfy the von Mises criterion, leading to strong hardening when polycrystals are deformed at rather low temperatures (i.e., below 1200 °C). In this study, we focused on the recovery mechanisms involving grain boundaries and recrystallization. We investigated forsterite samples deformed at large strains at 1100 °C. The deformed microstructures were characterized by transmission electron microscopy using orientation mapping techniques (ACOM-TEM). With this technique, we increased the spatial resolution of characterization compared to standard electron backscatter diffraction (EBSD) maps to further decipher the microstructures at nanoscale. After a plastic strain of 25%, we found pervasive evidence for serrated grain and subgrain boundaries. We interpreted these microstructural features as evidence of occurrences of grain boundary migration mechanisms. Evaluating the driving forces for grain/subgrain boundary motion, we found that the surface tension driving forces were often greater than the strain energy driving force. At larger strains (40%), we found pervasive evidence for discontinuous dynamic recrystallization (dDRX), with nucleation of new grains at grain boundaries. The observations reveal that subgrain migration and grain boundary bulging contribute to the nucleation of new grains. These mechanisms are probably critical to allow peridotitic rocks to achieve large strains under a steady-state regime in the lithospheric mantle.

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