Join us on Thursday for this FREE eSeminar and learn how Learn how Isight could be used to:
•Automate a series of functions to create a Sim-flow
•Add components to a Sim-flow
•Execute a Sim-flow
•Visualize Sim-flow results
•Assess the impact of the various design variables on the objectives
and identify significant interactions among the design variables
•Perform material model calibration
Register Today! http://bit.ly/IsightWeb
Hello,
I am having issues running an Eigen value simulation on a bridge model that I have developed. The model consists of a bridge super-structure supported by pinned connections on the ends of the bridge length and a roller support in the middle.
The model runs without errors when I do not request an Eigen value analysis, but aborts when I request an Eigen analysis. The message file sites the cause as a factorization error. Warnings also appear stating a zero pivot when releasing the 1st dof of the nodes associated with the roller connection.
I have attache the .inp file of my model. Do you know what may be causing this error?
Thanks,
Paula
Hello all,
For a project I want to model a cardboard package model. Basically I can even approximate a material responses, but I just want some material that can be used as packaging, such as cardboard. I am solving this problem in Abaqus. However I do not need to write a UMAT for that, any built in 'similar' model can work for me. Can you suggest some such materials in Abaqus?
Hi every body,
I'm a new user of UEL and have a questions. It would be very kind of you to help me with it.
I have a MATLAB code which gives me some big matrices. Is it
possible to save them as a file (.txt, .dat, etc) and call them inside
of the UEL? (It's almost impossible to change all of those codes to
FORTRAN or copy-paste them to UEL.)
Thanks in advance,
Best Regards,
-------------
Ashkan
Normal
0
21
false
false
false
DA
X-NONE
X-NONE
Hi
Sorry in advance, but this will be a long story...
Thank you for taking the time to look at it! :)
I have a 2D model that worked fine until a couple of
days ago where I tried changing the mesh a bit. Now when I try to run it aborts
calculation and gives some of the following errors:
- There are 14 unconnected regions in the model.
- There is zero MOMENT everywhere in the model based
on the default criterion. please check the value of the average MOMENT during
the current iteration to verify that the MOMENT is small enough to be treated
as zero. if not, please use the solution controls to reset the criterion for
zero MOMENT.
- The strain increment has exceeded fifty times the
strain to cause first yield at 5 points (reappears several times with various
numbers)
- The strain increment is so large that the program
will not attempt the plasticity calculation at 8 points.
Now, even if I try to go back to my original setting,
it still will not calculate. :(
A little bit about my setup (.inp file at: http://files.engineering.com/getfile.aspx?folder=7f9ccad1-9b8c-4375-a702... ):
It is a 2D deformable plate with 12 bolt holes at the
right side and 1 larger pin hole at the left side. The bolts and pin are
modeled as rigid circular wires, elements R2D2, and have a rigid body
constraint to its reference point in the center. The plate uses CPS6M elements.
Material is steel with E=216.5Gpa and v=0.3. I have
the yield and ultimate strength from tensile tests and also the final strain at
ultimate strength, so for the plasticity module I use: 274.5 MPa at 0 plastic
strain, 377.7 MPa at 0.35 plastic strain and set another point of 377.7 MPa
with 1.0 plastic strain just to ensure no stresses above the ultimate.
I use surface-to-surfacce contact between the rigid
bolts/pin and the respective plate holes. The rigid bolts/pin are set as the
master surface.
First fitting step: BCs are at each bolt for both main
directions and rotation. Initially I set a displacement of the plate of 0.5mm
to close the gap to the bolts and create contact. The pin is moved 1.0mm down,
also to create contact. Next step: Bolts are kept supported, plate displacement
is deactivated and the load is applied through displacement control of the pin.
I.e. the pin at the left hand side moves downwards causing the plate to bend,
but it is supported by the bolted connection at the right hand side.
I have tried both making a new mesh, using other
elements, utilizing stabilization through contact control, using small sliding,
reducing the displacement load, lowering step length and various other things.
I have even tried starting over with a former version of this file, using only
the geometry but resetting everything else. But nothing works... :(
I hope someone has an idea why this will not work. I
an completely out of ideas. Thank
you so much in advance! :)
Best regards,
Steen
P.S. A hint might be
that if I look at the result file, there are very large stresses at the end of
the fitting step, indicating that the plate might be pushed too much down?
However, if I reduce it contact will not be established.
/* Style Definitions */
table.MsoNormalTable
{mso-style-name:"Tabel - Normal";
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-priority:99;
mso-style-qformat:yes;
mso-style-parent:"";
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin-top:0cm;
mso-para-margin-right:0cm;
mso-para-margin-bottom:10.0pt;
mso-para-margin-left:0cm;
line-height:115%;
mso-pagination:widow-orphan;
font-size:11.0pt;
font-family:"Calibri","sans-serif";
mso-ascii-font-family:Calibri;
mso-ascii-theme-font:minor-latin;
mso-fareast-font-family:"Times New Roman";
mso-fareast-theme-font:minor-fareast;
mso-hansi-font-family:Calibri;
mso-hansi-theme-font:minor-latin;}
Hi everybody,
I have a UEL for truss element (T3D2). I'm calling and reading some .dat files inside of the UEL. I'm just reading these files inside of the UEL without doing anything to them or with them (It's just a test case). Here is an example:
OPEN(101, file="C:\Users\ak1070\Desktop\UMAT-UEL-UELMAT\UEL TEST\V1.dat", status='old',form='formatted',&
&action='read',position='rewind')
READ(101,*) AEVectors(1,:)
CLOSE(101)
.
.
.
OPEN(164, file="C:\Users\ak1070\Desktop\UMAT-UEL-UELMAT\UEL TEST\V64.dat", status='old',form='formatted',&
&action='read',position='rewind')
READ(164,*) AEVectors(64,:)
CLOSE(164)
I'm supposed to call and read 64 files. But it's just working for 38 files. When I'm calling 38 files it's working perfectly. I Mean:
OPEN(101, file="C:\Users\ak1070\Desktop\UMAT-UEL-UELMAT\UEL TEST\V1.dat", status='old',form='formatted',&
&action='read',position='rewind')
READ(101,*) AEVectors(1,:)
CLOSE(101)
.
.
.
OPEN(138, file="C:\Users\ak1070\Desktop\UMAT-UEL-UELMAT\UEL TEST\V38.dat", status='old',form='formatted',&
&action='read',position='rewind')
READ(138,*) AEVectors(38,:)
CLOSE(138)
But, when I'm calling 39 files the results change to sth weird. I thought maybe sth is wrong with data so, I called one of the previous files twice to make the total number of files 39 and still the results change to sth weird.
OPEN(101, file="C:\Users\ak1070\Desktop\UMAT-UEL-UELMAT\UEL TEST\V1.dat", status='old',form='formatted',&
&action='read',position='rewind')
READ(101,*) AEVectors(1,:)
CLOSE(101)
.
.
.
OPEN(138, file="C:\Users\ak1070\Desktop\UMAT-UEL-UELMAT\UEL TEST\V38.dat", status='old',form='formatted',&
&action='read',position='rewind')
READ(138,*) AEVectors(38,:)
CLOSE(138)
OPEN(138, file="C:\Users\ak1070\Desktop\UMAT-UEL-UELMAT\UEL TEST\V38.dat", status='old',form='formatted',&
&action='read',position='rewind')
READ(138,*) AEVectors(38,:)
CLOSE(138)
It would be very kind of you to let me have your advice.
Thanks in advance.
Best Regards,
Hi everyone,
I am performing FSI simulation under abaqus.
The simulation consists in a porous solid (elastic isotrope and homogeneous under Abaqus/explicit) filled by a non newtonian (viscous fluid under Abaqus/CFD). The whole is contained in a cubic shell in order to apply proper boundary condition.
The cube is pinned on one face and undergoes a compression displacement on the opposite face. I have defined an interaction condition between the solid surface and the fluid model surface so Abaqus can exchange information during Explicit and CFD simulation.
The simulation runs well until I diminish the element's size, then the simulation doesn't start and give me the following error message:
***WARNING: When performing co-simulation mapping from the partner code (the
source) to /Explicit (the target): search failed for the following
target elements:
These nodes are written to the output database (odb) in nodeset
COSIMULATION_ENGINE_SEARCH_MISALIGNED_NODES
I looked into the Abaqus documentation which gives the advise to put a skin on the solid geomtry in order to paste the mesh on the 2nd model geometry. This works only for a co-simulation between Abaqus/Standard and Explicit, but the skin option does't seem to exist for the fluid model.
I also tried to define exactly the same size of element in both solid and fluid model, but I still have the same error message. Also the explicit simulation performed alone works fine, so seems to indicate that the problems remains in the interface between the solid and the fluid.
Have you guys encountered the same kind of problem or could you give me some advice in order to solve this problem? I would very much appreciate.
Thanks in advance.
Romain
SIMULIA is more social than ever before, and the lines of communication are wide open! Join in the fun, tell your friends, and chat with us whenever/wherever! As they say, "The phone rings both ways," the same sentiment applies for social media. We want to hear from you! What do you want to see? What do you like? What do you want more of? Tell us!
We look forward to hearing from you!
https://www.facebook.com/3DSSIMULIA
Hi, i have a simple problem.
Suppose, one cube is there
with sides 10
units each.
Now,
m applying a pressure of 16 units on the top of the cube, applying
fixed B.C. at the bottom of cube.
The whole cube is meshed into 8
elements.
I want to find the nodal force at the
central node i.e at the
centroid. (linear elastic analysis)
RESULT : The central node i.e at centroid, it should give 400 units as nodal force. But it is giving only 100 units.
kindly help
me to solve the basic problem.
Hi everybody,
I'm working on UEL. The stiffness matrix (AMATRX) which I have
defined is consisting of complex numbers (real and imaginary part).
When I'm running it I'm getting this error message:
Abaqus Error: The executable standard.exe aborted with system
error code 1073741819. Please check the .dat, .msg and .sta files for
error messages if the files exist. ...
I checked the files and no error message was found.
When stiffness matrix is just real numbers, it's working perfectly.
Would you please let me know what should I do?
Thanks in advance.
Hello everyone!
I am trying to complete 2 separate analyses which i would love to get some advice on.
The first one is a CEL model in which i am aiming to test the dispersion of one fluid into another as one is slowly introduced into the other. I feel i understand what theory i need to know to model this problem and have the model ready to go, however when i try to solve it complains that one of my eularian components is not fully meshed, i have meshed and remeshed the component over and over to no avail. The component has a diffferent appearance in the mesh module from other components (see image), and is partitioned so as to assign initial material/void condition. To ensure that the unfull meshing wasnt being caused by the partitions i have tried multiple meshing approaches (bottom up meshing cell by cell or the instance as a whole) however the problem persists. One thing i have considered as a possible solution is the mesh-geometry association, however i do not know enough about this tool and this issue feels like a simple fix that i cannot seem to spot, has anyone else had a similar issue??
The second simulation is an acoustic model....this i am still in the theory phase and was hoping to gain some advice. I am simply trying to simulate the motion of a haptic feedback device (that is a linear resonance actuator) and model it's effect on a structure at different powers. It oscillates around 100 Hz. I am unsure what steps to use and wether acoustic elements are entirely neccesary. from what i understand the (linear peturbation-> frequency) step to apply a frequency and then linear perturbation ->steady state dynamics, direct) in order to analyse the effect on the structre. However, there is never any reference to applying the load to the set at which i hope to oscillate. can anyone offer a general workflow?
Hope this all makes sense, i know it's a very long post. Ive been going round in circles with these for a while so wanted to be very clear, any help is greatly greatly appreciated!
over and out,
Coz
I m doing Simulation of Impact of projectile on Polycarbonate plate , Can any one suggest what theory i used to design the Material in Abaqus CAE ,
Job Summary:
The postdoctoral research associate is expected to
provide research support within the frame of a multi-year engineering
research project undertaken by faculty from the departments of
Mechanical Engineering and Applied Math and Sciences at Khalifa
University. Limited teaching or other academic duties may be assigned to
the successful candidate under the supervision of the Advisor as
required by the University.
The successful candidate will be
expected to join as soon as possible. The duration of the appointment is until end of 2015.
Organization: Khalifa University
Job Location:
Abu Dhabi (Note: The University may periodically assign the employee to serve at any office or branch or to travel abroad on University business)
Description of Research Project:
The objective of this postdoctoral research project is to develop architectured smart materials with optimized microstructures for the purpose of maximizing strength-to-weight ratio and energy dissipation per unit volume for applications in the aerospace, automotive and civil engineering fields. The base materials are chosen to be Iron-based shape memory alloys (SMAs), which are emerging as less expensive alternatives to conventional SMAs such as Nickel-Titanium.
The envisaged research will focus on the following topics:
1. Elaboration and characterization of raw Iron-based SMAs (Fe-SMAs),
2. Modeling of monolithic and architectured Fe-SMAs,
3. Design optimization of the microstructure of architectured Fe-SMAs for optimal performance,
4. Fabrication and testing of optimized Fe-SMA samples/prototypes.
Duties and Responsibilities:
• Contributes to the research effort required for the successful completion of the research project.
• Participates in management and progress meetings relevant to the project.
• Regularly reports his progress and research findings to the Advisor, discusses technical approaches and difficulties, and maintains records of the work done.
• Acts in compliance with University policies with regard to the collection, use, and distribution of scientific data.
• Develops high quality research and participates in writing scientific articles suitable for publication in top-rated peer-reviewed journals.
• Undertakes a limited amount of teaching in relation to subject area and mentors graduate students and/or undergraduates under the supervision of the Advisor.
• Develops and delivers professional seminars and presentations in order to disseminate scientific results obtained by the project team in local and international conferences.
Education:
• PhD or equivalent in Mechanical Engineering or other equivalent area.
Experience:
• We are looking for candidates with experience in (i) Computational Solid Mechanics (ii) Finite element analysis (iii) Programming. (iv) Experience in materials characterization techniques
Computer Skills:
• Finite element analysis (Abaqus or similar)
• Scientific programming (Fortran, Matlab, and Python are preferred).
• Office software (Word, Excel)
Technical Skills:
• Numerical integration of nonlinear constitutive models for elastoplastic and similar materials.
Salary:
• The university offers internationally competitive salaries and allowance packages (75000 - 120000 USD per year)
Contact:
• Dr. Wael Zaki (wael.zaki [at] kustar.ac.ae)
Hi all,
I am looking for some reference on procedures for applying PBC in abaqus? I coud find some journal articles for the equation, but I am unaware of applying this into Abaqus under displacement laoding conditions..
any help in this regard would be appreciated greatly..
Thanks,
Bernad
Hi
I have a simple question. How could I model associative Tresca plasticity in ABAQUS?
I use Property module: material editor: Mechanical:Plasticity:Mohr Coulomb Plasticity
I know that In the case (friction angle=0) of the Mohr-Coulomb model reduces to the pressure-independent Tresca model with a perfectly hexagonal deviatoric section.
But I don't understand "dilation angle" & "deviatoric eccentricity" &"meridional eccentricity" & "cohesion yield stress" & "Abs Plastic Strain" .
For example if I want use Modeling Mises plasticity, Go to : Property module: material editor: Mechanical:Plasticity:Plastic
Yield Stress Plastic Strain
300 0
350 0.025
375 0.100
375 0.200
400 0.350
Now if I want use modeling associative Tresca plasticity,how its possible?
Thanks a lot for your kind help in advance.
Hi everyone,
I am trying to get the history output of
strain and stress tensor components at a node. However after analysis is
finished no such data are saved in the result section. I think Abaqus
only gives the stress and strain for elements and not at nodes. Any help
would be highly appreciated. Please consider that I am a new abaqus
use.
Thank you in advance
Hi Everyone
I have a question in using kinematic constraint to
model rigid diaphragm in ABAQUS? For example i define a RP(reference
point) at each story level and constraint three dof (U1,U2,UR2)(2
translational and 1 vertical rotational dof) of the Coupling Node to the
RP. However i think because of using the Kinematic constraint, The dof of
RP is now activated which means that the dof that i am not constraint
(U2,UR1,UR3) to can be free to translate and rotate, so i'm starting to
get error due to the singularity problems. I try to fix the problem by
providing a boundary condition to the unconstrained dof of the RP, however
my result start to get ugly because the extra boundary that i specified.
I was just wondering if you have any thought to my problems.
Many Thanks.
Peter
Hi,
I'm trying to model with abaqus a SSI between a axisymmetric concrete shell and soil (parameters are not too important right now). The main problem with the interaction is that in the edge area of the shell it is in tension and thus the foundation will rice from the soil in these areas. My question is what method would be the best to model this kind of behavior. I know that using spring elements the nonlinear behavior cannot be modeled. I read from the user manual that connectors could be used to model the nonlinear interaction between two nodes. Could it be possible to make a reference point for each node and connect the nodes to the reference points? Also the stiffness of the connector might be hard to determine in axisymmetric model...
Right now i've modeled the interaction by modeling the soil as an elastic block and creating a surface to surface interaction between the foundation and the soil. With this model i get 9 severe discontinuity iterations in the calculations and the foundation penetrates to the soil (Figure 1) so im not quite sure about the correctness of the model. I use hard normal behavior and frictionless tangential behavior
Any help would be appreciated.
With best regards
Matti Pirinen
Aalto-University
Hi every one,
Does Any one know the difference between Max. Principal values and Max.Principal(Abs) values in Abaqus ? I searched from there manual..but they have not mentioned in there manual too..could you please let me know the difference between those two parameters? Thank you very much.