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Chris Coker

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  1. Part of the issue might be your file naming convention. "filename.mdl..xml" is likely going to create issues with the workflow. A MotionSolve run file should look like "filename.xml" Also you are using a very old version (13) of Hyperworks. I would recommending updating as our tools have improved a lot since version 13. Chris
  2. Yuvaraj, Just to add some more detail to Felipe's great advice. It appears that maybe you are using joint friction, as well as friction on your contacts? These are both very computationally complex, utilizing a LuGre friction model for joint friction, and in general it is common practice to leave these features turned off, unless we can answer two questions: 1) Is including this friction absolutely essential to capturing the required physics of my problem? In most cases, the answer is "no", or can be achieved using computationally more efficient methods like damping. Also, in the joint friction models, there are different levels of complexity that can be switched on and off. Only use the friction features that are required. For 3D contacts, static friction can add a lot of compute time to your runs. Ensure you need these feature before activating them. 2) Do I have all of the correct input data to populate the friction model correctly? The friction models required details about the size of the joint, friction properties, etc. Do not assume that you can simply turn on the joint friction model, and use the default values. Based on the size of your joints, and units of your model, the default values will usually not be a good starting point. If the answer to either of these questions is "no", but you need to damp your model's response to achieve a more physically accurate solution, a better choice is to add damping to the model. This can be easily accomplished by adding a bushing on top of an existing joint, but don't assign it any stiffness properties. Just give it some damping, in the desired directions of interest. This is computationally much more efficient that the LuGre model, and can be used with great success. It's also curious that you are using the VSTIFF integrator, and not DSTIFF. Also the integrator is taking a very, very small time step, with your max step size set to 1e-08. If this is required to get your models to run, there is likely some other issue with your model configuration. Chris
  3. It's also possible that the model didn't run at all. Did you get a message window pop up when launching the run? If not, then it's almost 100% you don't have the solvers installed or correctly installed. Note, MotionSolve does not write out an .xml file, that is the input to MotionSolve
  4. Sushanth- The parameters you are changing only influence the calculated parameters seen in the SDF outputs (for parameters such as anti-lift, anti-dive, etc). If you are running static ride analysis, and the vehicle weight changes, then your spring rate (and spring preload) will likely need to change, to account for the change in vehicle weight. Changing the preload will change the load into the suspension, which will change the displacement, stress, strain in the flexbody.
  5. Hi Abdullabh- To answer your second question, the math behind flexbodies is based off of linear deflection, and linear material properties. You will not get good results attempting to model a rubber component as a flexbody. If you need to model something like a rubber component, you should investigate using the non-linear finite element feature in MotionSolve (NLFE). For your first question: MotionSolve does not currently support 3D contact with flexbodies today. There is a workaround to this, where you attach many small rigid bodies to your flexible body with fixed joints. These small rigid bodies can then be used with 3D contact.
  6. Hi- The SDF file is created by a custom user subroutine, and is specific to vehicle suspensions. This is not quite what you want. You could go this route, but would be overly complex. A better approach would be to use the "TextView" client in HyperWorks, and some templex math to calculate your metrics. There should be tutorials in our help that guide you if you search for "TextView" "Report Templates" and "Templex" Regards, Chris Coker, Technical Manager - Altair
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