i am working on autofrettage process in a cylinder with end caps . and i have problems with it. which material model is better to be used , what is the proper element to model it . what is the best number of substeps ? and there are errors when i am trying to apply pressure load.
my question is about the history data storage in FEAP.
I am writing element subroutine (elmt01) in FEAP 8.3 for a history dependent problem (crystal plasticity).
I have written the stiffness
matrix subroutine (stiff01), but it needs the data from the previous
solution steps (previous strains, stresses, plastic strains, dislocation
densities .... nh1,nh2=30 per point).
My co-organizers and I invite you to submit an abstract to the upcoming symposium “Multiscale Perspectives on Plasticity in Metals” at the ASME 2012 International Mechanical Engineering Congress & Exposition (IMECE), to be held November 9-15, 2012 in Houston, Texas. This symposium will explore the unique challenges to understanding plastic deformation in metals and formulating material models that can accurately predict thermo-mechanical deformation. Presentations will cover experimental and modeling investigations of the physical mechanisms that control plasticbehavior in metals, and insight gained on incorporating these mechanisms into high-fidelity models and simulations.
We anticipate the opening of four postdoctoral positions in 2012 to work on statistical aspects of fracture and plasticity, and in particular on size effects in the fracture of disordered media and in microplasticity. The positions will be funded by the ERC Advanced Grant 2011, SIZEFFECTS.
We look for candidates with a strong background in one or more of the following areas:
- statistical mechanics (scaling, critical phenomena, disordered systems)
- numerical modeling fracture
- dislocation dynamics simulations
- molecular dynamics simulations of mechanical properties of solids.
I've recently had the opportunity to take another look at plasticity in the large deformation context. I've avoided going into geometric and other issues involved with multiplicative deformations (points stressed in earlier blog posts by Giovanni (http://imechanica.org/node/11545), Arash (http://imechanica.org/node/11623) and Xiabo (http://imechanica.org/node/11599). Attached are some old notes that I'd prepared some years ago to help me with the details. I hope they're of use to other students of mechanics.
EXTENDED ABSTRACT SUBMISSION: Nanobrücken II: A Nanomechanical Testing Workshop, March 22-23, 2012, INM Saarbrücken, GermanySubmitted by Oden Warren on Fri, 2012-01-13 15:18.
You are cordially invited to attend Nanobrücken II: A Nanomechanical Testing Workshop, jointly presented by INM - Leibniz Institute for New Materials and Hysitron, Inc., with co-sponsorship from the JEOL company. This is the second workshop in the Nanobrücken series. The workshop's scope has been broadened, and the abstract submission deadline is now February 19, 2012.
There is an immediate opening for a postdoctoral research position in the Advanced Computational Research Lab at RPI, Troy NY to work on Crystal Plasticity Finite Element Methods. Currently we are working on interesting advances in the areas of radiation damage and high strain rate loading conditions. Encouraged to apply are creative, self-motivated individuals with a sound baclkground in computational mechanics, CPFEM and materials science. RPI is home to the CCNI, one of the most powerful university-based supercomputational research facilities in the world.
1. PhD in Computational/Applied Mechanics/ Computational Materials Science or related field.
I am familiar with the flow theory version of the plasticity theory but still quite confused with the deformation theory version of the same.
When a material is modeled using a non-linear elastic model to predict its plastic behavior with no distinction between the elastic and the plastic strain, is it a deformation theory in that case?
Any elaboration in this regard would be really helpful.
Thanks in advance.
Concurrent reaction and plasticity during initial lithiation of crystalline silicon in lithium-ion batteriesSubmitted by Kejie Zhao on Sat, 2011-11-26 19:32.
Surface dislocation nucleation mediated deformation and ultrahigh strength in sub-10-nm gold nanowiresSubmitted by Yang Lu on Thu, 2011-10-27 21:33.
I am working on the simulation of ring rolling. I have written the subroutine for the plasticity part in the subroutine VUHARD and have set the PLASTIC part in material definition to USER.
I dont have HARDENING PROPERTIES so i have set it BLANK. i have set the path of the subroutine in the job defintion part too. But abaqus crashes whenever i try to do DATA CHECK
It says ABAQUS KERNEL EXITED WITH AN ERROR.I dont know why this problem arises?. I am stuck.
The curve i want to define is yieldstress=K*plasticstrain^m*plasticstrainrate^n
Designing copper–zirconium based nanowires for improving yield strength and plasticity via configuring surface atomsSubmitted by Vijay Kumar Sutrakar on Wed, 2011-10-19 16:52.
Following our previous work on Cu-Zr nanowire system, in this paper we have shown improvement in various thermo-mechanical properties of nanowire via manipulating the surface atoms. The paper titled "Designing copper–zirconium based nanowires for improving yield strength and plasticity via configuring surface atoms" by Vijay Kumar Sutrakarand D Roy Mahapatra has been published in Journal of Nanoparticle Research. The paper can be downloaded from
The Abstract of the paper is given below:
(This paper is to appear in the IUTAM Procedia on "Linking scales in
computations: from microstructure to macro-scale properties," edited by
Amit Acharya, S. Jonathan Chapman
With a view towards utilization in macroscopic continuum models, an approximation to the root-mean-square of the driving force field on individual dislocations within a "representative volume element" is derived. The plastic flow field of individual dislocations is also similarly averaged. Even under strong simplifying assumptions, non-trivial results on the origin and nature of anisotropic macroscopic yielding, plastic spin, and the plastic flow rule (for single and polycrystalline bodies) are obtained. A particular result is the dependence of the plastic response of a material point of the averaged model on the presence of dislocations within it, an effect absent in conventional theories of plastic response (e.g., J2 plasticity). Also noteworthy is the explicit geometric accounting of the indeterminacy of the slip-plane identity of the screw dislocation that appears to lead to some differences with conventional ideas.
I would like to run a tensile test under ls-dyna of a mild steel and
apply a 7000 N load to the dog bone specimen on a explicite scheme.
have wild deformations ( and an error) on the nodes on edges where the
load is applied, so can you please tell me what are the importants
constants (like time termination, mass scale,...) and how to perform a
Have a good day,
As one of the biggest Departments of its kind in the UK, the Wolfson School of Mechanical and Manufacturing Engineering has an international reputation for being at the forefront of technological innovation and for maintaining extensive links with industry.
Can someone please guide me to comprehensive literature for implementing multi-yield surface plasticity in numerical codes. I am not sure if I, properly, understand the algorithm.
Thanks in advance
My system got shutdown while running a job in Abaqus.15 Gb odb file was generated and now I am not able to open the odb file.It is saying some error about the format.Have anyone came across such a problem.
Pls help me
Abstract deadline extended: August 15. ISCM III, Taipei, December 2011, Minisymposium of "Multiscale Methods in Plasticity"Submitted by Zhiqiang Wang on Wed, 2011-07-27 15:40.
Abstract deadline extended to August 15, 2011 for ISCM III-CSE II in Taipei, Taiwan, December 5-7, 2011. Please submit your abstract to the minisymposium of "Multiscale methods in plasticity".
We invite the submission of abstracts for a Minisymposium of Multiscale
Methods in Plasticity at the Third International Symposium of
Computational Mechanics (ISCM III) in conjunction with the Second
Symposium on Computational Structural Engineering (CSE II), which will
be held in Taipei, Taiwan, December 5-7 2011. Abstract submission
deadline is now August 15, 2011. Please check the conference website for more
In general for incremental plasticity problems it is well known that one has to use an iteration scheme (Newton-Raphson, modified Newton-Raphson or Quassi Newton etc.) in order to achieve a converged solution for finite element equations. Is it also neccessary to have an iteration scheme for an incremental viscoplastic problems ? I am also attaching a paper where the authors have implemented an equilibrium correction scheme in the principle of virtual work, which is supposed to ensure convergence. I am not able to comprehend how it takes care of the convergence without any iterations. Any help would be highly appreciated.
I am M.Sc. sutdent in Istanbul Technical University and my research subject is comparision of several ductile damage models both computationaly and experimentally.
I am trying to compare ductile damage models such as Freudenthal,Cockroft,Ayada ,Brozzo etc. computationally using ABAQUS and seeking a way to implement these damage models in ABAQUS.
To obtain each models damage result individually should damage model be implemented in ABAQUS or can a regular tensile test results be used for calculation of damage values.
Could you please advise me for methodolgy to run a simulation to obtain ductile damage values accordng to models mentioned above.
Thanks in advance for your help.