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Recent content by GMarsh

  1. GMarsh

    Johnson Cook model - flow stress match with UTS at ductility?

    Hi, I am trying to use Johnson Cook model for predicting equivalent flow stress. Just to check its validity at extremities, I input ductility as plastic strain, but I don't see it output stress close to ultimate tensile strength. I used ductility over 1 millisecond to calculate plastic strain...
  2. GMarsh

    Simulating HCF crack propagation using XFEM

    Thank you Mustaine3.
  3. GMarsh

    Simulating HCF crack propagation using XFEM

    Hi, I am thinking if it is possible to simulate crack growth under High Cycle Fatigue in Abaqus? All the tutorials I have come across on XFEM shows crack growth only with static load. Wondering if there is a way to simulate alternating stresses superimposed on static stresses. Thank you Geoff
  4. GMarsh

    Idealisation of weld joints

    Many thanks Corus. I will go through the paper suggested.
  5. GMarsh

    Idealisation of weld joints

    Just to add, my interest is to calculate the fatigue (HCF and LCF) life of the structure.
  6. GMarsh

    Idealisation of weld joints

    Hi, I am looking for various methods by which one can idealise a fillet weld joint in FE analysis. I searched through previous threads here and some general search on Google. Didn't find relevant info. Currently I use bonded contact between solid bodies which are welded. Then (as I get...
  7. GMarsh

    Thermal analysis using beam elements

    Apparently this is a bug in Ansys Workbench V14, which is corrected in V15. Workaround in V14 is to explicitly drop the midside nodes for beam / shell elements (for thermal analysis). Also for solid elements in the model, midside nodes should not be 'kept', but set to 'program controlled'.
  8. GMarsh

    Thermal analysis using beam elements

    Hi, I am doing a steady state thermal analysis in a model which has solid and beam elements (using Ansys Workbench 14). I get an error "Higher order elements are not valid for current analysis". But this problem is not there if I suppress the beam elements (even though the solid elements have...
  9. GMarsh

    Fatigue criteria for different materials

    Hi, Are certain fatigue criteria more relevant for certain type of materials? I heard that Gerber is good for ductile materials, etc. So can we use criterion based on material? Any particular reference on this? Thank you Geoff
  10. GMarsh

    Bushing joint for springs in 3-directions?

    Hi Orel, Thank you for the reply. I had a try with Bushing joint. It worked! I have not tried Matrix27, but my colleague said its function is similar to that of bushing joint as far as assignment of stiffnesses and damping are concerned. Geoff
  11. GMarsh

    Bushing joint for springs in 3-directions?

    Hi, I would like to connect surfaces of two bodies with springs in 3-directions (X,Y,Z) in ANSYS software. As the surface normals lie only along Y-direction and that a spring accepts stiffness only along its longitudinal axis, I am wondering if I can use Bushing Joint instead and define...
  12. GMarsh

    Stabilization damping factor in non-linear static analysis

    Hi, I am doing non-linear static analysis of a spring like structure. As the solution convergence is quite difficult, I would like to know what parameters for automatic stabilization - damping factor or dissipation energy fraction - should be given for convergence. And what are the criteria for...
  13. GMarsh

    Will rubber damping increase with compressive force?

    Thanks btrueblood. This answers the question! Yes, the structure is vibrating and loading is applied at an angle causing possible shear forces in the rubber. Kind regards
  14. GMarsh

    Will rubber damping increase with compressive force?

    Hi, I have a neoprene rubber sheet mounted on a structure. I am getting FRF using impact hammer testing and measuring damping through half power point method. When I compress this rubber sheet with two different loads I am getting different damping values. Higher compressive load gives more...
  15. GMarsh

    Viscoelastic material for damping high frequencies?

    Yes, but theoretically one should add damping also along with mass to damp out the split modes caused due to tuned mass. So I am looking to add damping tape which has highest loss factor in that frequency zone of 16kHz.

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