research
Lithium batteries--When mechanics meets chemistry
When I learned chemistry in college, the subject was presented to me with equations of chemical reactions. It took me some time to realize a couple of simple points: reactants need to meet to produce a product, and compounds take space.
The connection between chemistry and mechanics is made vivid to me in recent years in studying lithium batteries. As an example, here is a recent paper when chemistry is linked with plasticity, mass transport, and fracture—essential ingredients of solid mechanics.
Debugging standard user subroutines of ABAQUS
Hi,
I managed to find a way to debug UMAT step by step. I tested it on ABAQUS 6.9 using intel fortran 11.0 which is integrated with Visual Studio 2005 or 2008 running on Win 7/x64. The process is the same for other versions and other user subroutines (The same process should also work in linux, but with different debugger).
Using VGETVRM to compute strain in VUSDFLD ( abaqus explicit subroutine)
hi everybody.
I've used vgetvrm in vusdfld to calculate strain.
I have two question.
1- what's the differences between tensor strain and engineering strain?
I read user subroutine manual and it says"The shear strain components returned from utility subroutine VGETVRM are tensor components and not engineering components."
2-I want to calculate PE11 and PE22 with vgetvrm. but my results are strange.for example PE11 change between -11.14033 and 75.25797.
and PE22 change between -1.5974975E-04 and 4.7500171E-03
Hysteretic damping in modal analysis using ANSYS
Hello,
I want to do modal analysis of a structure with viscoelastic material. The viscoelastic
material has a complex youngs modulus E= E (1+i*g), where g is the loss factor. In ANSYS, modal analysis ignores all
nonlinearity, so how can I perform modal analysis with viscoelastic material?
OR
How can I perform modal analysis in ANSYS considering hysteretic damping (complex Young’s
modulus E= E (1+i*g) as input).
Cheers
J Plastic Calculation
Dear All:
I completed calculating my stress-intensity factors by modifying the verification test case in ANSYS
I need to calculate the J-plastic values for Ramberg-Osgood type material using isotropic hardening for various n values .
Does ANSYS have a Ramberg-osgood material model built in ?
The minimal nanowire
Advances in molecular assembly are converging to an ultimate in atomistic precision —nanostructures built by single atoms. Recent experimental studies confirm that single chains of carbon atoms —carbyne— exist in stable polyyne structures and can be synthesized, representing the minimal possible nanowire. Here we report the mechanical properties of carbyne obtained by first-principles–based ReaxFF molecular simulation. A peak Young’s modulus of 288GPa is found with linear stiffnesses ranging from 64.6–5 N/m for lengths of 5–64 ̊A.
STROH formalism or Lekhnitskii in MATLAB
Hi All,
I am a PhD student working with anisotropic elasticity to model T-stress. I understand the simplicity of derivation in Stroh formalism but am lost in the Matrix algebra whereas Lekhnitskii provides complex derivation for the formulation but on first glance, it seems more user friendly for numerical modelling.
Does someone have an experience in modelling the either one formalisms with MATLAB and could he share his experience?
Thanks for the sharing of information.
supports in Abaqus
Dear friends
I am modeling a
plate subjected to the vertical loading. the problem is, when the analysis goes
to the nonlinear part, the reactions in some nodes get negative value, while the
plate must be free to move upwards. so there must be no negative value
for reaction. i was wondering, if someone help me define the support in a way
that the plate would be free to move upward and constrain it for the downward
movwement.
Best Regards