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Everything posted by lambefr

  1. Thanks Hyperman and Andy for the edited model and the pointers to changing the PROP parameters. I had missed the comments. Thank you for your help.
  2. I am trying to model a rubber material that has 300%+ elongation capacity. I don't need to model the rupture mode, just the fact that it can deform elastically and return to its original shape. I tried with LAW2 and LAW42 but my solid elements (BRICK) just seem to explode when I reach close to 100% elongation. I tried different ISOLID (1,14,24), but I always get the same result. Any advices welcome, thanks. Images of model and .rad, .out below. Law2_finer.zip
  3. Greatly appreciated, Thanks Hyperman!
  4. Thanks for your input Hyperman. I was hoping to be able to pull it off with shells but was expecting the large h/L ratio of my elements to be a problem. Spin off question for rubber in Radioss; how can I introduce damping in the material? As it is 100% elastic with Law2, it just "flaps" around indefinitely, which my real part does not do! Can damping be introduced "directly" in the material properties with another material law? Or must it be externel (ex. Rayleigh, DYREL, etc.)? If external, which is best to use? Keep in mind that I will have many rubber plates like this one moving at relatively high speed (100+km/h) impacting stationnary objects. I don't want the external damping to affect the overall correctness of the simulation but I need to properly represent the "internal" damping of the rubber. I would have access to a physical test to calibrate the damping of my model. Thanks
  5. Hello, I am trying to model the correct bending stiffness and rebound and damping behavior of a rubber plate. My plate is meshed with 3mm shells adn 6mm P1 property. I tried with Mat Law2 and Law69 and in both cases my model "explodes" on the rebound. See images below and both model files attached. Any help in figuring out what I'm doing wrong? Thanks! law69.zip law2.zip
  6. Hello, I tried those two options already (/ANIM/VECT/FINT and /ANIM/VECT/FEXT), and they do not seem to output what I am looking for. To be honest, I don't fully understand what these options output exactly. But I do know that they do not have the correct order of magnitude nor orientation at the node/element I am interested in. /FINT gives me order of magnitude of 10N force and /FEXT gives me 10e-6N where from my /TH/SPRING I know I am looking for 10e4N force. Any other option? Thanks
  7. Found out how to retrieve the /ANIM/SPRING/FORC in the contour tab. But I can't plot it as a vector so my question still stands!
  8. Hello, I have a suspension arm with a ball joint modeled in Radioss. My ball joint is modeled as a beam element connected to a zero length SPRING2N with very high translation rigidity and 0 torsional rigidity. I would like to be able to show the reaction force acting in my SPRING2N as a vector to appreciated visually and in one glance its orientation in space. I can use an output block /TH/SPRING to plot the magnitude but this does not provide the orientation. I tried /ANIM/VECT but none of the options seem to offer what I am looking for. I also tried /ANIM/SPRING/FORC, but I can't find "where" this result is plotted (vector, contour?). Any help on how I can do what I want? Thanks
  9. Hi, thanks for the answer but it does not answer my question. I know how a sperical joint is suppose to behave... all rotations are free! No need to explain that to me. What I am pointing out is that I want to limit the angular articulation of my srping in a certain way and although the moving skew /MOV that I created are visually moving correctly (i.e. their Z axis are always coaxial - see gif image above), the spring does not seem to follow my skews correctly. Why is my kjoint2 not behaving as I would expect?
  10. Ok thank you! I was trying to us the printout info to debug my kjoint2 problem and was getting confused because of the contradicting angle between the *_0000.out and the /TH. I will concentrate on the /TH info.
  11. I am trying to trouble shoot a problem I am having with a kjoint2 in Radioss. Can you help me understand the way the initial angle is outputed in the starter file? I use two node reference systems (skew_ID1 and skew_ID2 in kjoint2 card) that have a rotation between their Z axis (see image below). The rotation can be seen in the TH/spring (~0.5rad) when I plot it in Hyperview but I can't seem to understand how it is showed in the starter file (all numbers below "initial angle" are 0?). Can you help me understand the starter file info please? Also see my other post:
  12. Long story and potentially many questions in the same post but all related to the same issue and I ned help! I can't seem to understand how my kjoint2 spherical connection between 2 RBODY is behaving. What I am trying to model is a suspension ball joint in Radioss and I want the rotation to be limited to a certain maximum angle in ANY direction from vertical (creating a conical shaped limit envelop). I created a simple problem to resolve my issues but it doesn't seem to work. I cerated 2 node reference systems in such a way that they move together and that their Z axis is always coaxial. I then limited my kjoint2 in Saz- and Saz+ to ±1 rad but it does not behave as desired. When I plot my TH/spring, I can see that RZ of my spring DOES respect the 1 rad angle limit. But this does not make sense with the visual behavior and the true angle that I can plot in Hyperview that cleary goes over 1 rad. Also Rx and Ry are showing rotation which again does not make sence with the visual behavior. Any help to resolve this is appreciated! Thanks All my simple model files: Radioss_BJ_angle_V19.zip
  13. Thanks for your answers! @Prakash Pagadala: When I load the .H3D for both model and results, the "systems" tab icon is simply not in the model entity tree? So I can't hide or unhide them?... BUT, when I load the 0000.rad as my model and the .H3D as my results, the systems do appear and I can see them move. Thank you Q.Nguyen-Dai for this answer! Any reason why I don't see them when I load the .H3D in the model also? Thanks for your support
  14. Hello, I tried a quick search but did not find my answer; sorry if it is trivial but it is causing me a hard time! I created node reference systems in Hypermesh. I solve my non linear problem with Radioss and my coordinate defining nodes move during the simulation (hence my coordinate systems *should* follow them). My qyestion is: how can I make my systems visible in Hyperview 2017 so that I can see how they moves and behaves in time during the simulation? Thanks
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