rctron's blog
How is this multiaxial relationship derived in this paper?
How did one arrive at the red-underlined part in the equation (2) from differentiating equation (1)? Please see the picture:
The paper referred here:
Chen, Y., Zhuang, W., Wang, S., Lin, J., Balint, D., & Shan, D. (2012). Investigation of FE model size definition for surface coating application. Chinese Journal of Mechanical Engineering, 25(5), 860-867.
CP model
I am new to crystal plasticity simulations and have been studying the concepts from "Introduction to Crystal Plasticity" in Mechanics of Microstructured Materials book.
Input file for the Single crystal plasticity subroutine Nonlinear Finite Elements for Continua and Structures by Ted Belytschko
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?
Input file for the CPFE VUMAT in Nonlinear finite elements for continua and structure
I am learning crystal plasticity and its implementation as VUMAT subroutine from the book Nonlinear finite elements for continua and structure. I am aiming to gain more insight about the implementation by studying the poly-slip, rate-dependent, single crystal plasticity subroutine provided in the solution manual.
However, I couldn't reproduce the example in the book successfully, as I believe I have made errors in defining the material properties in the Abaqus input file. So, can someone please provide the input file for the associated VUMAT subroutine?
Can someone post an example of UMAT and VUMAT for the same elasto-plastic problem?
I want to understand how the stress update algorithm is modified for the different definitions of stress rate in ABAQUS/Standard and ABAQUS/Explicit formulations. I know the relationships, I just want to see how it's coded in a subroutine.
Also, the Hughes-Winget algorithm is used to update the stress defined by the Green-Naghdi stress rate by using the Jaumann rate. How to implement that in VUMAT? Can someone please post an example to clarify these aspects?
How to include temperature effects on the shear rates in Dr. Huang's crystal plasticity code
I am using Dr. Huang's crystal plasticity code for an adiabatic process where temperature increase due to deformation need to be calculated. Dr. Huang's CP UMAT code does not consider the temperature effect of shear rate or hardening. Is there a way to include temperature effects in the current UMAT code?
http://www.columbia.edu/~jk2079/Kysar_Research_Laboratory/Single_Crysta…
When to use equation of state models in modeling high velocity impacts?
Equation of state models (Mie-Gruneisen equation of state etc) have been widely used to study hydrodynamic response of material during explosive deformation, ballistic impacts for a long time. As far as I understand, a hydrodynamic response is required to be incorporated in a model if the pressure of impact leads to an increase volumetric strength. That is the stress wave speed in the material exceeds the speed of sound in the material (v = sqrt(elastic modulus/density)). Ballistic impacts occur at strain rates close to 10^9 to 10^12/s.
How to combine VUMAT an VUEOS in Abaqus
Hi,
I have written a VUMAT for Johnson Cook Model. I would like to use subroutine VUEOS to define linear Mie-Gruneisen equation of state. The USUP type VUEOS subroutine can be found at Abaqus Documentation.
However, I am not able to figure out how to combine the two subroutines. What needs to be called from VUEOS into VUMAT?