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Chris Coker

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Chris Coker last won the day on March 16

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About Chris Coker

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  1. Most of your questions would be answered by reading the MF-Swift documentation. Your question #5 has been answered in a previous thread.
  2. I don't know if it's possible today with the drum road. What you can try: Create the graphic of the drum profile in a CAD package (or even Hypermesh). Import the CAD into Motionview, and attach the graphic to the Drum body in the MotionView model. This is the method we used for years to create graphics to attach to ground (before we had Road Tools). However, I don't know if it's possible to attach the graphics to the Drum in your case.
  3. A couple of suggestions: 1. Make sure your graphics card driver is up to date. This often fixes a lot of strange/random issues. 2. Make sure your HyperWorks installation is up to date. 3. Try installing the software on a different machine, and see if the issue still exists 4. As a last resort, re-install the software. FYI, this is not something I've seen in the past, so it's not a regular occurrence with our software. If you still have difficulties, we can work to get a developer in the loop and help diagnose.
  4. Not all road types are supported with Road Tools. For the drum road, you can create a simple cylinder graphic to represent the overall diameter of the drum. If you get the message "file type is invalid" then this likely means you have picked a road that the road tools doesn't support. Note, that the Road Tools are being constantly developed, and look for additional functionality in version 2020.
  5. MF-Tyre supports a drum type road profile. A sample is included in the default installation, inside the same folder with sample files for MF-Tire. The location of the directory will be similar to this: C:\Program Files\Altair\2019.1\hw\mdl\autoentities\properties\Tires\MF_SWIFT When you set up the model using AutoTire, you simply point the tire to use this drum road file. The properties of the drum itself can be modified by editing that road file.
  6. There is no specific tutorial for this. You can find the details about our Belt-Pulley tool in our MotionView help: Altair MotionView -> MotionView Panels -> MotionView Toolbars -> Subsystems Toolbar -> Create a Belt-Pulley Subsytem Further questions should be directed to our Multi-body dynamics forum. Note that modeling belt-pulley systems is rather challenging and can be computationally expensive.
  7. There is not a simple answer to your question. The general guidance is to reduce penetration between components as much as is reasonable, without making the stiffness so high that is results in computation difficulties. Sometimes you need to try different types of normal force calculation, sometimes it's the parameters themselves. In our help section, please read careful the section on Best practices for 3D contacts. Your wheel geometry does not have a uniform mesh, which is important for accurate contact forces. Just search the help for "Best Practices for Running 3D Contact Models in MotionSolve". There is a lot of important material there, that will save you a lot of time and headache if you will follows those best practices in setting up your problem.
  8. you can send files to me via this link: https://ftam1.altair.com/filedrop/~IoZSpU Chris
  9. 1. at this point, we'd need to take a look at the model, road and tire files you are using, if you are able to provide them. If not, I would suggest starting with a default model, and tire, and step by step adding the Fiala tire and road. It's really a simple workflow, with the only thing you typically have to pay attention to is the orientation of the Road Reference Marker 2. The output shafts are clearly not in line with the differential. I suspect you may have broken some of the parmeterization in the model. The axis of the half shaft doesn't have to be on the axis of wheel rotation. However, the outer CV joint must be on on the axis of wheel rotation. Similarly, the inner CV joint locations must lie on the same axis of rotation as the differential revolute joint. Since you are not a university user, it may make more sense for you to reach out to your account manager at Altair, and have him connect you with our support team, where they can provide you with more hands-on assistance.
  10. 1. The FIALA tire model does not have a USE_MODE code. Make sure you are starting with a Fiala tire dataset from the examples. Also try rotating the road reference marker 180 degrees as explained previously. Note, the .log file will tell you what road surface is being used. That's always a good first double check. If something is wrong with your road surface, it will default to a flat road. 2. It's likely that you have not defined the outer CV joint location correctly. It needs to be located along the rotational axis of the wheel. Otherwise you will see the behavior you seem to be describing.
  11. 1. "USE_MODE" 114 - This is part of the problem. 114 is for "smooth road contact" You are not going to be able to use certain types of road surfaces. Even then, this specifies a "point follower" road contact, which does not provide physically accurate results for short wavelength bumps. In order to use mode 4XX, TASS requires an additional 3rd party license, as do all of the other tire model companies (CD Tire, FTire). Per my previous post, you do not have the necessary licenses to use this tire model over a plank road surface. You might try a polyline, but again the physics are not going to be reasonable. Again, please talk a look at Altair's enhanced Fiala tire model. We support many different types of road surfaces, and there is no additional license cost. It utilizes elliptical cam contacts, which is better than point follower, but not quite as accurate as the brush contact used by tire models like FTire or CDTire. To use this tire model, all you have to do is point to the tire data in the sample file directory (it will say something like "fiala with elliptical cams" in the filename). It is also well documented in our help. The tire data files also have a smaller dataset, so they require less data to populate. This kind of tire model serves as a better starting point for users just starting out with bumpy roads.
  12. The model provided then is too simple for what you want to achieve. For a wiper mechanism, you typically will use MotionView, rather than InspireMotion, due to the need for flexbodies of the support structure, among other features. Also, I find it useful to model the wiper blades using polybeams, and then simple contacts between the polybeam and glass. There is a "snow blocking" test that needs to be set up and run on the wiper. Scripted simulation is helpful to set up the model here. Again, this is a feature currently found only in MotionView. Unfortunately, I don't have any models I can share, due to customer confidentiality.
  13. Did you check the USE_MODE flag in the .tir file? What values is given there? Another thing you may want to check is the orientation of the Road Reference Marker. Sometimes this needs to be rotated about the Z axis 180 degrees, depending on the tire model and road file you are using. Note there are probably two Markers, one for the front axle, and one for the rear axle.
  14. There are three possible sources of error here: 1. Your tire data needs to be able to support non-flat road surfaces. You have not indicated which tire model you are using (MF-Tyre, Fiala, F-tire, etc). Tip: look through the .log file, it will tell you what road file is being referenced, and what type of road contact. For example, there is a flag to set in MF-Tyre for the type of road contact you want to use. This has to be set correctly before the road file will be properly utilized. Research "USE_MODE" in the MF-Tyre docs, if that's the tire model you want to use. 2. non-flat road surfaces typically required additional licenses. Do you have the necessary license to run non-flat roads? (Important note: Our built-in enhanced Fiala tire model allows users to use non-flat road surfaces, for free. It doesn't have the same level of fidelity as tire model like MF-Swift, CD-Tire, FTire, that all require additional 3rd party licenses.) 3. in "road type" in the file above, you still list it as "flat". So, it's going to ignore any parameters you set. You should look at some of the many examples provided in the installation. There are also examples provided with documentation for the particular tire model you are using (F-tire, CD-Tire, MF-Tyre, etc). We currently do not provide tools for editing/modifying CRG files. However, there are some open source tools available on the OpenCRG website. If you want to create graphics for an analytical road surface like you are trying to use, what I normally do is create the geometry in Hypermesh, and put a simple mesh on it, and the export it as a .h3d file, which can then be loaded directly into MotionView as a graphical entity. Here is an example of a pot hole road, taken from our installation folder: $------------------------------------------------------------------COSIN_HEADER [COSIN_HEADER] FILE_TYPE = 'rdf' FILE_VERSION = 5.00 FILE_FORMAT = 'ASCII' (COMMENTS) {comment_string} 'pot_hole style road description' $--------------------------------------------------------------------------UNITS [UNITS] MASS = 'kg' LENGTH = 'mm' TIME = 'sec' ANGLE = 'degree' FORCE = 'newton' $-----------------------------------------------------------------------GRAPHICS [GRAPHICS] ROAD_INCR = 500 $--------------------------------------------------------------------------MODEL [MODEL] METHOD = '2D' ROAD_TYPE = 'pot_hole' $---------------------------------------------------------------------PARAMETERS [PARAMETERS] OFFSET = 0 ROTATION_ANGLE_XY_PLANE = 180 MU = 1.0 $ DEPTH = -50.0 START = 1000 LENGTH = 2000 Chris
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