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  1. ahkrit

    User subroutine DLOAD

    Hello, i am looking for a way to define DLOAD as field output variable. A simple line load is defined in user subroutine, which i would like to output on all the elements where defined. In abaqus documentation at subroutine dload it says it is not avialable for output. Is there maybe any...
  2. ahkrit

    Bolt pretension - axial force due to preload?!

    Hello. I am trying to model a simple preload of a screw in a double lap joint. As i apply the preload of 38kN for a M12 screw, it gives back an axial force at the end of app. 160N. I am wondering if it is realistic. Deformation and everything looks good, also tried with different contact...
  3. ahkrit

    Dynamic global - static local analysis of big structures

    Sorry if I was not clear but my question is if a given joint`s stiffness has to be included in the global model? I cannot use submodel as i have beam model(and it is not my goal nor my question). I am trying to solve the global model with beams and apply SF and SM values on local model. If you...
  4. ahkrit

    Dynamic global - static local analysis of big structures

    I have to correct myself. Node-based submodeling does work, even with Fiel import interface option, taking out one time step from a dnyamic simulation. So that works. Now my question is what i think @NRP99 you were also reffering to with "take out the global forces and moments at the cut...
  5. ahkrit

    Dynamic global - static local analysis of big structures

    This is a floating structure consisting of longer closed or open section profiles connected different ways at the ends (bolted, riveted or welded). Fully dynamic response is simulated and the joint (beam end connections) stresses i would like to calculate with local static analysis. Submodel...
  6. ahkrit

    Dynamic global - static local analysis of big structures

    Hello! I am looking for an efficient way of analysing bigger structures. The global analysis is a dynamic analysis, in which a local part, joint should be calculated in a local analysis in different time steps. What would be the most efficient way for such analysis? I tried submodeling...
  7. ahkrit

    Shell bolt model - Contact clearance

    @SWComposites how would you modell it in an efficient way? including preloading.
  8. ahkrit

    Shell bolt model - Contact clearance

    @FEA way This is the part where the article writes about the edge to surface contact (bolt clearance between shaft and hole): "For contact between the hole and the rigid surface, the classical node-to-surface contact search was used. Also a finite sliding tracking approach was used which means...
  9. ahkrit

    Shell bolt model - Contact clearance

    All BCs are according to the paper defined. The kin coup as well, so 3,4,5 DOFs are coupled between master nodes and hole nodes. In first step one end of the beam is fixed and the two end nodes of the plates.In 2nd step prescribed displacement applied in X direction.(see pics attached) The...
  10. ahkrit

    Shell bolt model - Contact clearance

    Hi! Based on my previous post (https://www.eng-tips.com/viewthread.cfm?qid=492174) I would like to have another question regarding this paper: https://files.engineering.com/getfile.aspx?folder=a89bf026-d899-4ce8-9a09-62fb984f5c66&file=edgetosurfacecontact.PNG It says at the contact definitions...
  11. ahkrit

    Shell edge contact

    Thanks for the comments. Actually i just found that with contact pair, with edge to surface options(hole edge nodes as node based surface and bolt rigid surface as element type surface) it works. You think that general contact would be still better to use?
  12. ahkrit

    Shell edge contact

    Hello. Does anyone know how is a proper shell edge contact can be defined in Abaqus? More precisely contact between shell edge and another shell surface. There is this paper attached about contact modelled in Abaqus. I mean the contact between the rigid bolt surface and the hole edge of the...
  13. ahkrit

    fatigue of complex riveted joint - bypass load

    @Ng2020 i think so as we that my problem.is not unique, still have not found any usefull information on the calculation procedure. I am working on floating structures, that is why the load can vary easily bith in direction and magnitude. Can you offer anyone who could provide individual...
  14. ahkrit

    Eurocode Fatigue - Aluminium and Steel for not common Detail categories (Rivet or bolt connection)

    Hello! I am trying to summirise the fatigue calculation steps for a joint based on Eurocode. As EC 1993.1.9 for steels says that with nominal stresses for the given Detail categories (FATCLASS-es?) one can make the calculation. How could one calculate a stress concentration factor for complex...
  15. ahkrit

    fatigue of complex riveted joint - bypass load

    The problem is, that in my case the direction and magnitude of the loads on the fastener (and the bypass load too) changes with time. Bending moment also occure on the beams which causes the kind of "circular" reaction pattern on the fasteners as posted above. How could one proceed with fatigue...
  16. ahkrit

    fatigue of complex riveted joint - bypass load

    @SW composites what would you suggest if you are modeling a joint where each connected beam has two axial bending and torsion, thus the distribution looks something like on the picture above posted? So all the fastener forces look in different directions. I would say net bypass load is...
  17. ahkrit

    fatigue of complex riveted joint - bypass load

    Thanks for the info. Well if it is "not perfect by any means" why would you suggest to do it that way? On the other hand then calculating all the other factors depending on simple geometry (like plate width W in Nius book) i have no idea how it could implemented for bended plate with complex...
  18. ahkrit

    fatigue of complex riveted joint - bypass load

    What i would be really interested in is still how to calculate a bypass load in different structures, where the members cannot be modelled as simple beam elements as Niu does in his book. For example on the shell model posted above, there is a bending load, which is transfered through the...
  19. ahkrit

    fatigue of complex riveted joint - bypass load

    Thanks Bragi for the links. Not bad documents indeed. However i would like to see the fatigue calculation process. As asked above for Niu`s method about the bypass load especially. Regarding rivets stiffness calculation there are many documents available. Unfortunately the rest of the...
  20. ahkrit

    fatigue of complex riveted joint - bypass load

    @Ng2020 yes, the loads are mainly in plane( meaning mostly shear loads are on the rivets) but i still would like to (probably have to) take axail loads into account as it can change the results at few joints. What does fbr/ft mean exactly? Boiling it down to 1d problem is also not clear. @Joe...

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