viscoplasticity

This paper describes the formulations for the viscoplasticity of metals based on the Chaboche and Delobelle model. The implementations of the viscoplastic models were detailed herein and then implemented via user subroutines for material models (UMAT) in ABAQUS. Two typical metals, i.e., 316 Stainless Steel and Zircaloy-4, were chosen as examples and their viscoplastic behaviors were captured. Numerical simulations are compared to reported experiments in order to validate the models and the UMAT codes.

Zheng Jia, Wing Kam Liu, Rate-dependent stress evolution in nanostructured Si anodes upon lithiation, Applied Physics Letters, 109, 163903 (2016) (DOI:http://dx.doi.org/10.1063/1.4964515)

Starting April 2016, we will have openings for two post-doctoral fellow positions in experimental and computational mechanics of advanced polymers. These positions will support a new research program between Singapore University of Technology and Design (SUTD) and National University of Singapore (NUS) funded by Agency for Science, Technology and Research (A*STAR). The project focuses on synthesizing, characterizing, modeling, and simulating the thermo-mechanical behavior of polymers with covalent adaptable networks (CANs), e.g. vitrimers.

Multiple Phd. positions are available in the area of computational solid mechanics with an emphasis on multiscale modeling of polymer nanocomposites, high strain rate characterization of novel nanocomposite materials,  in Mechanical Engg. Dept. in North Carolina A & T State University. Interested candidates are encouraged to communicate via email to tsain@ncat.edu and/or mannur@ncat.edu

 There are several graduate positions available in thermal fluid and control area also.

Thanks

The published version may be accessed at

https://www.researchgate.net/publication/251448926_Ductile_Fracture_by_V...

Since then, two other reviews were co-authored by me:

For Acta Materialia:

https://www.researchgate.net/publication/289140144_Failure_of_Metals_I_-...

And for IJF @ 50

https://www.researchgate.net/publication/305694679_Ductile_failure_modeling

Hi, I am a reserach fellow of mechanical engineering in Italy. I need to implement the elasto-viscoplastic model of Chaboche in a user subroutine in ANSYS accounting also for the plastic strain memorization and for the static and dynamic recovery. In a next step I sould also need to incorporate the damage variable of this model.

Classical plasticity models evolve state variables in a spatially independent manner through (local) ordinary differen- 

tial equations, such as in the update of the rotation field in crystal plasticity. A continuity condition is derived for the 

lattice rotation field from a conservation law for Burgers vector content—a consequence of an averaged field theory 

of dislocation mechanics. This results in a nonlocal evolution equation for the lattice rotation field. The continuity