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  1. Hi Prakash, thanks for you answer. In my case the load type is LOAD for each card.
  2. Dear all, I'm analyzing the vibrational behavior of a sub-group into a Gear box. First of all I ran the modal analysis and I found that 3 and 4 vibrational mode are in a range of frequencies that could create some problems. Now I'm running a Transient analysis assigning to some nodes a sinusoidal force whose frequency corresponds to 3 and 4 vibrational mode. I observed that displacement are extremely low and, thinking that there was something wrong with assigned damping, I removed it from the params of the analysis. So, theoretically, I should expect very high displacement if system running at resonance frequency, but that does not happen. I've attached the Optistruct model. Please help me to understand how I'm wrong. To assign the force in TABLEID1 card I used a sampling rate equal to fi/10
  3. You should assign the required property (it depends from your kind of analysis) to the component which contains CQUAD4 elements
  4. Hi all, could someone explain me the difference between a Transient direct and a Transient modal analysis? Which may I use to analyze the vibrational behavior of a system? Thanks
  5. Dear all, I'm analyzing the effects of transmission errors over a gearbox in order to reduce noise and vibrations. I have the exitation forces linked to transmission error in the frequency domain and now I need to analyze the displacements of the gearbox caused by this force so I'm trying to do a transient analysis. So I would like to know if it's possible to assign in this kind of analysis a force in frequency domain and, if so, in which way should I procede. Thanks in advance for your support!
  6. Hi all, is there a way to collect multiple RLOAD card in order to process all of them in a single analysis? Thank you in advance!
  7. Hi Prakash, could you explain me in a few words how to use Beam in this case of study? Thanks!
  8. It works in Static linear or Modal Analysis? I read that they work only in Motion analysis or in Non linear...
  9. Hi all, I'm trying to run a modal analysis of a transmission. Being the first time I use Optistruct for this kind of analysis I've started with a simple case of a cylindrical gear fixed over a shaft, just in order to understand how the analysis must be configured. I would like to connect the gear over the shaft leaving free the axial movement, all other DoF must be fixed. I've created two RBE2 elements (one on the outer surface of the shaft and one on the inner surface of the gear). Now I want to connect this two element leaving free the Dof1, can someone explain me how to procede? Thanks!
  10. Hi Prakash, thanks for your support. I noticed that the mesher added this character during some process but I ignored about its importance! Regarding modelling issues, can you give me some examples? Thanks!
  11. Sure! I've just sent it to you. Thank you!
  12. Hi all, I'm analyzing the weldings in a beam of an earth moving machine. Some parts can be modeled as 2d shell while for some others I needed to create a 3d mesh. In a first tentative a created a 2d mesh for each element and I was able to run the analysis, but I noticed some inaccuracy in proximity of parts that can not be treated as 2d elements. So I improved the mesh treating this parts with 3d elements. Now I'm not able to run the analysis. During solving the log window prints this warning: *** WARNING # 1955 Static Loadcase 1 has zero static force vector. This typically produces zero solution and zero compliance. I linked the parts using spot weld connector (RIGID). In order to connect 3d elements with 2d shell I created a shell face upon each 3d element giving them a very thin thickness. I reassigned the nodes for each RBE3 element but this doesn't help me. I attached the .hm file if someone wants to have a look: https://www.dropbox.com/s/2v7fu0p4wd1msku/1_SIGMA_MAX_SEZ_4_MIDSURF_and_3D_1.hm?dl=0 Thanks for your support.
  13. Hi, I've made a simple dynamic analysis of two parts in relative motion. Now I would like to analyze stress in most critical regions. Which is the best way to procede? Thanks!
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