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Recent content by dankoonFANTOMAS

  1. dankoonFANTOMAS

    Stress Concentration using USDFLD subroutine

    Hello everyone I am using USDLFD subroutine in FORTRAN to model a component with 2 materials and smooth transition btwn both. I based my work on the functionally graded structure and volume fraction. I used a sigmoid law in order to have a continous transition btw both materials. I subdivided...
  2. dankoonFANTOMAS

    Graded materials finite element modeling

    Alright thank you very much for your help Have a nice day
  3. dankoonFANTOMAS

    Graded materials finite element modeling

    Ok and I make the link with material properties in the input file with dependencies right? *Material, name=MAT *Depvar 1, *Elastic, dependencies=1 210000., 0.45, , 1. 1e+06, 0.45, , 10. *User Defined Field By a way it controls the interpolations in an element?
  4. dankoonFANTOMAS

    Graded materials finite element modeling

    Thk you for your advice. For the USDFLD program I came across a subroutine written by Emilio Martinez-Paneda for parameter transition between integration points. Here is the program: SUBROUTINE USDFLD(FIELD,STATEV,PNEWDT,DIRECT,T,CELENT, 1...
  5. dankoonFANTOMAS

    Graded materials finite element modeling

    Hello the community, I want to make a simple example of FGM (functionally graded materials) finite element model but with continuous variation in elements. Not by modeling each layer with a different property buy by displaying the continuous transition between MAT A and MAT B in an element. See...
  6. dankoonFANTOMAS

    FEA simulation of multi material printed component

    Hello, I want to model the mechanical behavior of a printed component with multi material subjected to static load. The thing is I do not know how to model the materials data in my fe model. I attached a picture of an example of multi material printed element. I use ALTAIR HYPERMESH to...
  7. dankoonFANTOMAS

    3D printed aircraft component

    Hello everyone, I recently bought a 3D printer at home and I discover the joy to create parts with complex geometry for the day life. So I was wondering what could be the application in aircraft design. In fact this technology is 30 years old and if I don't say anything wrong there is just few...
  8. dankoonFANTOMAS

    effect of ribs position on aerodynamic behavior

    Hello everyone, I was wondering what is the effect of ribs position on a wing on the aerodynamic behavior and especially on the aeroelastic behavior. Does the position of ribs can change the dynamic behavior for a flutter phenomena for example. I am not an expert in aircraft design so I do...
  9. dankoonFANTOMAS

    Different results between NASTRAN and ABAQUS

    Yes So adding a phase of 270 is right we are agree? My half sine shock is 0.011s long so the max is at 0.0055s, so a period of 0.022s.
  10. dankoonFANTOMAS

    Different results between NASTRAN and ABAQUS

    In order to have a positive input signal. I agree with you, I first put 90 deg but my input signal was negative and I had to apply a -1 factor to my shock in order to have the same input than the one in ABAQUS. I then tried 270 deg and I have a positive signal without adding my -1 factor. By...
  11. dankoonFANTOMAS

    Different results between NASTRAN and ABAQUS

    Of course I agree it is important in this kind of analysis my point was about the origin of the difference between results. Well in fact I am not sure it is the source of my problem here. I just run a sine sweep frequency on both codes and I obtained the same curve for the acceleration vs...
  12. dankoonFANTOMAS

    Different results between NASTRAN and ABAQUS

    The analysis is based on the same FEM model (made in Hypermesh and exported in .inp for ABAQUS and .dat for NASTRAN) so I have the same number of nodes, elements, materials. I made a previous modal analysis and I obtained the same frequencies, modes and effective masses with both codes. Yes...
  13. dankoonFANTOMAS

    Different results between NASTRAN and ABAQUS

    Hello everyone, I made the same analysis in NASTRAN and ABAQUS in order to compare their performance and results. It's a modal dynamic analysis (half sine shock), the shock is 0.011 s long and my analysis time is 0.22 s in order to see the behavior of the structure after the shock. In...
  14. dankoonFANTOMAS

    Damping coefficient definition for modal dynamics analysis

    Hey everybody I want to make a modal dynamic analysis and I have to define the damping coeff of my structure. I am new to ABAQUS and I used to make analysis on NASTRAN. Is the definition of this coeff is the same in both codes? Thk in advance!

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