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ppraf last won the day on October 30 2019

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About ppraf

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  1. Hello charansai Could you please try replacing the file "pathlib.py" at ~install\common\python\python3.5\win64\Lib with the one attached here ? You may rename the original so that you have a back up. where ~install default is C:\Program Files\Altair\2019 for a 2019 install. Regards Praful pathlib.py
  2. Hello - ModelExchange type of FMU is not supported for export from MotionView/MotionSolve currently. regards praful
  3. Hello Narasimhamurthy - Could you please share the version of MotionView you are using and also share the fem file if possible ? regards Praful
  4. Hi forestis - You could use the type "Expression" and have an expression something like this - `STEP(TIME, 1,0,1.1,100)+STEP(TIME,1.1,0,1.2,-100)` In this expression, the first STEP function increases the force to 100 from time 1 sec. until then it is 0. In the next STEP function, the force is being dropped down back to 0.0. (otherwise the force will remain at 100 for the remaining time of the simulation) You may also use a Curve that has the impulse profile of your choice and use TIME as the independent variable while using the type Curve. regards praful
  5. Hello SDB666 - By default, CAD and File graphics are positioned w.r.t Global Frame. You need to parametrize the CAD position with a movable Marker. And that marker has to be defined with respect to the angle parameter that you wish to change. It is doable but not a one click process. I'd be glad to take a look if you can share the model. Another approach would be to create a model with user defined mass properties and for visualization use primitive graphics (and not external graphics). Create a dataset for the angle parameter Create a Marker at the pivot about which the angle is measured. Align the Z axis of the marker along the axis of the pivot. Create points for the graphics using the "Parametric Points" tool using the Marker and cylindrical coordinates 4. Define the body and graphics Modify the angle to position as required. Attached is a sample that I created. points_in_cylindrical_coord.mdl
  6. Hi Laura - Defining revolute in all places will lead to model being over-constrained. That means, overall there are more constraints than the no. of degree of freedom. In reality, are all of these pin joints ? Or are there ball joints too. ? You may chose to work on a combinations of revolute and cylindrical/ball joints to avoid over constraining. Alternatively, you can define joints with compliance. (Turn on "Allow Compliance" check box while adding the joint). Then you'll get the option to toggle the joint from non-compliant to compliant. So then it is not really an idealized joint but a bushing with stiffness and damping property. Provide high stiffness values (1e6 or high) in all directions except Rotational Z. (leave it to zero). Provide some minimal damping (0.1% of stiffness is a good starting value). Regarding the out of plane rotation of 8 deg, you may want to model based on what exactly causes that rotation or what exactly limits the rotation to 8 deg. Is there some kind of a gap/play somewhere?). To begin with, you might want to ignore that out of plane rotation. regards praful
  7. Hi Sudhanshu - I see couple of problems with the current model. 1) Mass/Inertia for all the bodies are zero. You need to fix it. 2) Graphic h3d cannot be used as a flex body. You need to generate a flexbody h3d via Flexprep tool. regards praful
  8. Hello Sudhanshu - Importing an FEM or CAD only represents the body as a rigid body with the mesh in FEM or the geometry in CAD aiding as graphics for visualization only. For the initial study, it is generally sufficient. However, you may want to represent the flexibility of the frame by representing it as a flexible body. This is done by converting an FE model to a flex H3d. The Flexprep utility under FlexTools menu helps in doing that. Apart from a well formed FEM, you need to know the node numbers where the body will interface with other bodies through some joint, bushing or forces. Hope this helps Regards Praful
  9. Hello Tetoldini You should find a Coupler entity under the Rackpin Steering system where you can change the coupler ratio. regards Praful
  10. Hello yehoo if you can describe the problem in more detail, people in the forum could be able to guide you with the most appropriate solution. To answer your questions, 1) You can also define "contact" by using an ActionReaction Force and using solver function IMPACT or BISTOP. You can mimic a point to point contact or to a certain degree point to curve contact using this approach. Any reason why you do not want to use 2D or 3D contact ? 2) When you define an output - force on body, MotionView creates a <Post_Request statement in MotionSolve xml for the connected joints|bushing|spring-damper|force entities to the body. These forces can be plotted in Hypergraph. They should be available under the type "Marker Force" and request for each type of above connections would be listed. In HyperView, once you load a result H3D you can go to Vector Plot. Force/Moments should get listed under Result type and select the Body (Assembly in HyperView) and click Apply. Force Vectors should appear on the body selected. Hope this helps. Regards Praful
  11. Hello - To further add to Chris's description, the solver MotionSolve does not support applying displacement initial conditions on the joint. Hence it is not available for editing in MotionView. regards Praful
  12. Hi Adit - What this error says is that the model was created with one set of wizard and the current wizard is a different one. Usually, the assembly and task wizards work together. The tasks in the task wizard are or can be configured based on what was selected in the model wizard. If there is a mismatch, the task wizard won't appear. Regarding the events not appearing, could you go to File > Load > Preference File , select "MBD Vehicle Dynamics Tools" and click Load. ? Did that work ? regards praful
  13. Hello Adit - Are you able to run any other models ? Is this the only model that you have trouble ? Are you able to run a simple model, say from MotionView tutorial MV-100 ? regards praful
  14. Hi Yehoo - what kind of geometry is it.? Is it a CADGraphic in MotionView ? For contacts, from a solver perspective, the geometry needs to be clean and able to obtain a closed volume. Hypermesh and MotionView have some differences on handling CAD graphics. It is possible that MotionView shows something as free edges, while Hypermesh does not. You may adopt a different method of representing the graphics. If you are able to mesh the surfaces of the components in HM and export as an h3d, the same can be used as Graphics of type File. and that graphics can be used in contacts. regards praful
  15. Hello Pritish - I am the Program Manager for MotionView and I would be interested to look into your problem. You can share this model if possible via email to me. (my address is mentioned below). Please be assured that the files you share will remain confidential. Alternatively, in case the model still cannot be shared, I have another recommendation in order to circumvent this problem. You may replace the graphics that are being used (I believe those are CADGraphics) by using File Graphics (H3d format) instead. You may use the "Import CAD/FE using Hypermesh option available under Tools menu. You might want to use the 2nd radio option there (Import CAD or Finite Element model only) to import as graphics and not create bodies. Once imported, you would have to manually resolve the bodies of each graphics to existing bodies. You can then delete the original CADGraphics and make sure that the new set of graphics are selected in the Contact panel. Regards Praful ppraf@altair.com
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