Can anyone provide me with the input file for the example shown in the book Nonlinear Finite Elements for Continua and Structures by Ted Belytschko et al? The poly-slip, rate-dependent, single crystal plasticity VUMAT subroutine that is available publicly is attached in the following link. I have been trying to reproduce the results in Fig. 13.11 to Fig. 13.13. in the book, but am not successful in doing so. Can anyone please provide me with a working example input file for the problem?

https://gofile.io/d/xI9QSV

The ability to transform the crystal structure of metals in the solid-state enables tailoring their physical, mechanical, electrical, thermal, and optical properties in unprecedented ways. We demonstrate a martensitic phase transformation from a face-centered-cubic (fcc) structure to a hexagonal-close-packed (hcp) structure that occurs in nanosecond timescale in initially near-defect-free single-crystal silver (Ag) microcubes impacted at supersonic velocities. Impact-induced high pressure and high strain rates in Ag microcubes cause impact orientation-dependent extreme micro- and nano-structural transformations. When a microcube is impacted along the [100] crystal symmetry direction, the initial fcc structure transforms into an hcp crystal structure, while impact along the [110] direction does not produce phase transformations, suggesting the predominant role played by the stacking faults generated in the [100] impact. Molecular dynamics simulations at comparable high strain rates reveal the emergence of such stacking faults that coalesce, forming large hcp domains. The formation of hcp phase through the martensitic transformation of fcc Ag shows new potential to dramatically improve material properties of low-stacking-fault energy materials.

Download the paper here: https://authors.elsevier.com/a/1a0T34r9SUFFwe

Hello Everyone,

I am a new member of imechanica. I have started to learn UMAT of Abaqus to model my material behavior ( Cu6Sn5, HCP) using crystal plasticity finite element model. I found Dr. Huang's single crystal UMAT to start learning UMAT and I thought that it would be a great guide to start though it is written for FCC mat. But unfortunately I was not able to run the UMAT with it's input file.

It is showing error " Too many attempts were made for this increment". I have no idea where I went wrong as I just ran the UMAT with it's own physical model. Please can anyone provide me a running UMAT of Dr. Huang ? I think there is something I need to change. Also, guideline for learning UMAT will be a great help.

I have used the following code and devided into .inp file and .for file.

http://www.columbia.edu/~jk2079/fem/umatcryspl_mod.inp

Also , I am using Abaqus 6-12-1. Please help me on this issue.

Please mail me at soudchoudhury@gmail.com

Thank you so much.

We have recently published a paper on measurements of the density of geometrically necessary dislocations (GND) associated with wedge indentation of a single face-centered cubic crystal. The deformation field is two-dimensional and there are three effective in-plane slip systems that contribute to the plastic slip. We determine the lower bound on the total GND density with a three micrometer spatial resolution. We also show that in certain regions of the domain, the lower bound on total GND density corresponds to the exact total GND density. Therefore, in those regions we can determine the apportionment of the total GND density onto the individual slip systems. Among other things, this gives direct insight into the types of dislocation structures that are formed as a consequence of the wedge indentation.

The title, abstract and URL are below:

J.W. Kysar, Y. Saito, M.S. Oztop, D. Lee and W.T. Huh, Experimental lower bounds on geometrically necessary dislocation density, International Journal of Plasticity, 26, 1097-1123, 2010.

Abstract: A single nickel crystal is indented with a wedge indenter such that a two-dimensional deformation state with three effective plane strain slip systems is induced. The in-plane lattice rotation of the crystal lattice is measured with a three micrometer spatial resolution using Orientation Imaging Microscopy (OIM). All non-zero components of the Nye dislocation density tensor are calculated from the lattice rotation field. A rigorous analytical expression is derived for the lower bound of the total Geometrically Necessary Dislocation (GND) density. Existence and uniqueness of the lower bound are demonstrated, and the apportionment of the total GND density onto the effective individual slip systems is determined. The lower bound solution reduces to the exact solution under circumstances in which only one or two of the effective slip systems are known to have been activated. The results give insight into the active slip systems as well as the dislocation structures formed in the nickel crystal as a result of the wedge indentation.

http://dx.doi.org/10.1016/j.ijplas.2010.03.009

Simulation of crack bifurcation in single crystal nickel base superalloys under mixed mode conditions

PhD position available at the Centre des Matériaux , ParisTech , starting fall 2009.

This 3-year project is fully funded by Mines ParisTech, SNECMA and ONERA.

More details are given in the attached file.

Wanted skills: Applicants should possess a degree in Mechanical Engineering, Materials Science or a related discipline and have an outstanding academic track record. The candidate should have a solid understanding of mechanics of materials and continuum mechanics and be prepared to work on a mostly numerical project using non-linear finite element techniques.

Contact: Send a CV and a motivation letter to Samuel Forest.

Hi,

I truly appriciate if anyone can help me find mechanical properties and crystal structure of beta SiC single crystals. Any reference or link will be highly appriciated

Sincerely,

-Ashfaq Adnan