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Abaqus - INP file number precision

Submitted by neslon on
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ABAQUS
precision
significant digits
inp

Hi all!



I am working in a design optimization process MATLAB-ABAQUS and i need that abaqus writes the nodal coordinates in the inp file with at least 12 significant digits. If i change nodal output precision to full in the job manager i only get 9 digits.

I already changed numDigits in session.journalOptions.defaultFormat, session.journalOptions.fieldReportFormat and session.journalOptions.geometryFormat by submitting in the command line



nf = NumberFormat(numDigits=12, precision=0, format=ENGINEERING)

Vumat for Rousselier model (damage model)

Submitted by Sutham_eng on
research

Dear Everyone,

Now, I am writing Abaqus’s subroutine (Vumat) for modelling fracture and damage in Ferritic Steels.

The failure theory I have to use in my PhD research is the Rousselier’s Theory. 

 I try to write Vumat by following the procedure of Rousselier model integration in PhD thesis namely ‘3D CAFE modelling of transitional ductile - brittle fracture in steels’ that can see from http://seis.bris.ac.uk/~mexas/thesis.pdf (Appendix.B). 

Abaqus viscoelastic material time domain

Submitted by M.Goeke on
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TIME = FREQUENCY DATA

Hi,



i have a problem with the domain TIME = FREQUENCY DATA.

My test data is taken from a triaxial compression test wit constant
temperature and amplitude of the load, and ten preassigned frequencies.
The mastercurve from the data allows me to use any frequency of the
tested array.

The conversions from elastic modulus[E] to modulus of elasticity in
shear [G], and bulk modulus of elasticity [K] an their real and
imaginary parts are obvious.



The problem is that abaqus only accepts 50 per cent of the input data.

Warping function for 3D beams

Submitted by stan on
education

Dear All,

I am modeling 3D beams with arbitrary cross sections and for that purpose I need to calculate the warping function numerically. The warping function ψ(y,z) is defined as a solution of the following Laplace equation with Neumann boundary conditions:

∂2ψ/∂y2 + ∂2ψ/∂z2 = 0 in Ω,

∂ψ/∂n = z*ny - y*nz on Γ,

where Ω is the cross sectional area, and Γ is its contour. This system can be solved by different numerical methods, for example, finite element method, boundary element method, finite differences...

Numerically I obtain that

Reply--Abaqus quasi-static induced numerical damping

Submitted by Jiangping Xu on
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dynamic explicit

The damping ratio, used in quasi-static problems, such as sheet forming, stamping, forging, is that role, b, shown in the following equation

Ma+bCv=P-F

For the problems mentioned above, the value of b is about 0.1.  if dynamic explicit method is employed, the simulation may encounters steady problem, while convergence problem for implicit method employed.  I think, you can search some articles on damping in sheet metal forming, then you will understand the effect of this damping ratio.

experimental tests results of the propagation of cracks, to determine the characteristic parameters of the cohesive models

Submitted by A.Brick Chaouche on

Good mourning, it is well known that the cohesive forces models permet an easy and less combersome computation of the crack problems, these models formulated in term of stress are accompained with a scale effects because of the presence of a crachteristic lengths like the critical opening/sliding value, and the length of the cohesive zone at the begining of the propagation. In order to set the values of the characteristic lengths of the model used in the simulation for a given material, it is intressting to do that through an experimental tests like a compact tests.

stress at interfacial Guass point

Submitted by woshimaidi on
education
stress
extrinsic cohesive element
Guass point

hello,

     I have encountered a problem to calculate the stress at interfacial Guass point of each hexahedron element. Since the effective stress is needed to decide whether a cohesive element should be inserted when using the extrinsic cohesive element model, the stress at interfacial Guass point of each element is chosen to calculate effective stress. In the calculation process, the stress at Guass point of each hexaderon element can be obtained.Is there anyone who knows how to calculate the interfacial stress accurately? I would appreciate your comments.

passing away of Prof. Maurice Jaswon

Submitted by Mohsen Dashti on
research
Boundary Elements Method Group

Dr. Martin at Colorado School of Mines alerted us the unfortunate news of the passing away of Prof. Maurice Jaswon, a pioneer of boundary integral equation/boundary element method. An obituary is published by the London Daily Telegraph:
http://www.telegraph.co.uk/news/obituaries/technology-obituaries/897734…

non-convergence of result

Submitted by shijo_iitr on
research

i want to carry out a nonlinear static pushover analysis for a concrete dam, i'm using the concrete damage plasticity model for the above. i'm able to carry out the frequency analysis for the model, but after applying any kind of load the the job gets aborted in both static analysi and static riks analysis.

in static analysis it does not converge, whereas in  static riks analysis it says a zero displacement step ha been encountered and analysi cannot proceed..

can anyone please help me out tof this..

thanks in advance

shijo antony (IIT-R) 

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