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  1. kribri

    Rotational stiffeness in node

    Hi, I have a challenge with modeling rotational stiffness of my model. Attached is a picture of the model. I want to change the rotational stiffness for the z-rotation in the joint between the four shells/panels. How can I do this in Abaqus? kind regards K
  2. kribri

    How to Core Failure in Composite FEA?

    Hi, I'm modeling a room subjected to a uniform pressure applied instantaneous (blast). I have modeled 1/4th of the model due to symmetry. I know from testing that the core material of the panels fail a distance from the corner, while the faces still are intact. My question is how can I model...
  3. kribri

    Equivalent sandwich thickness

    Thank you for all the response. This helps a newbie alot. To explain: I'm comparing a SPS panel with a stiffened steel panel. What I want to find out is what thicknesses for the steel-faces and the polymer-core can be used for the SPS panel to get equivalent flexural rigidity as the stiffened...
  4. kribri

    Equivalent sandwich thickness

    The figure to the right is a composite sandwich plate. Steel-polyurethan-steel. I am very greatful for you help. Krish
  5. kribri

    Equivalent sandwich thickness

    desertfox: sorry for causing all this trouble with the double posting. I have looked at the approach of using a Uneven I-beam (http://www.efunda.com/designstandards/beams/UnevenIbeam.cfm). If you can I would we very greatful if you could take a quick look at the calculation in the excel sheet...
  6. kribri

    Equivalent sandwich thickness

    Sorry, forgot to write that. I need to compare the bending stiffness (flexural rigidity).
  7. kribri

    Equivalent sandwich thickness

    Hi, I'm trying to calculate the equivalent thicknesses of the elements in a composite sandwich compared to a steel plate with steel stiffeners (three types of stiffener: flatbar, tbar and angle) How do I do this? Krish
  8. kribri

    Laminated glass

    The constraints are simply supported with pull in. And the loading is 2.5kN/m2 (uniform pressure) Conventional shell elements(S4R in abaqus) and solid elements (C3D8R) will not provide a reliable result. Should this be modelled with continuum shell elements? Krish
  9. kribri

    Laminated glass

    Hi Rob, thank you for responding. The modulus of the PVB is an debatable value. Research presents values from 0.5MPa to 0.95GPa(!!!). I chose a value based on a Shear Modulus equation which depends on temperature (G=1.1GPa) and used Hooke's law(-> E=3.78MPa). The window size I've been looking...
  10. kribri

    Laminated glass

    Hi, I hope someone can help me with this. I'm analysing Monolithic glass vs Laminated glass. I'm looking at a window of the size 800x1600mm. The monolithic is 8mm thick. The laminate consists of glass faces and is glued together with PVB. The laminate is 4+0.76+4mm. Isotropic Glass material...
  11. kribri

    Script for writing node coord list

    Hi, I need a script that writes x,y and z coordinates for each node into a .txt file. I would like it to write it like this: 1, x, y, z 2, x, y, z Can anyone help me with this? Krish
  12. kribri

    FEA of welds, shell vs solid

    Thanks for the quick feedback. I see that I was a bit quick when posting this, sorry for the incon. I'm not interested in the peak stress in the actual weld, but peak and nominal stresses in the surrounding structure in combination with studying mean stress in the weld. The question is, based...
  13. kribri

    FEA of welds, shell vs solid

    I have a question regarding the use of shell elements vs solid elements in the FEA of welds. Some say that the shell elements don't give as good results for the peak stress as the solid elements. But shell give okay results for the nominal stress. Any comments/experience on this? K
  14. kribri

    Section Modulus of almost rectangular sandwich beam

    Hi SWComposites, thanks for the quick reply. I know how to calculate the section modulus for a homogeneous material section. But this beam/girder is a bit different, so I'm a bit confused. I need the section properties to check the FE model with my hand calculations. There are some deviation...
  15. kribri

    Direction of S11 for a composite layup

    Hi, I'm modelling a beam in Abaqus with conventional shells and the properties are set with Composite Layup. The faces are 45/-45 plies with a core material. When viewing the stresses or strains in a composite material ie. S11 or S22 they are presented in the same direction as the material...
  16. kribri

    Section Modulus of almost rectangular sandwich beam

    Hi guys, thanks for the help. SWComposites: It would be great if you could expand on your method. Panelguy: The beam is loaded with a vertical load. It is modeled in abaqus with a uniform pressure over the whole top surface. How would you model it in FEA? I have modelled it as a conventional...
  17. kribri

    Section Modulus of almost rectangular sandwich beam

    Hi, I'm trying to calculate the Section Modulus for the beam cross-section presented in the attachment. Can anyone please assist? krish
  18. kribri

    Sandwich beam properties

    Hi, I'm modelling sandwich beams in Abaqus. I have these material properties for the: - face: E1,E2, E3, G12, G31, G23, nu12, nu13 and nu23 - face: density, volume fraction, thickness, area mass - core: E1,E2, E3, G12, G31, G23, nu12, nu13 and nu23 How do I model this in Abaqus? I believe I...
  19. kribri

    xml.parsers.expat.ExpatError

    Hi, What does this error message mean? Traceback (most recent call last): File "Python/monitorMechanism.py", line 437, in __processCB xml.parsers.expat.ExpatError: xml declaration not at start of external entity: line 2, column 0 Traceback (most recent call last): File...
  20. kribri

    Weight output in Abaqus

    Hi, I am wondering it is possible to get abaqus to write the weight of a structure or even better a weight distribution of a structure in a output file?

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