Adams/Car 2005 and 2018 1

[bj7777]

hello

I'm using an MSC model called mini-Baja that has been built in Adams/Car 2005 and anlysing it in Adams 2018 . Mind you , the files are ready on MSC Adams official site .

problem is that I can't get the exact results from Adams/car 2018 Postprocessing …( Minute differences ) the parameters I want are vertical chassis acceleration and chassis longitudinal velocity

no matter what I did from changing units to changing solver integrators ( to the best of my knowledge ) was nigh on futile ...

can you explain how this happens ? is it a matter of changing Solvers Integrators because I have tried almost all of them ? was there something in Msc /Adams car back in 2005 that is changed in 2018 ? if so what can i do to get the exact results ?

my results are very similar to the results of the model in 2005 but with minute differences ? what is the reason of those minute differences ?????

FYI : i'm running the model in File Driven Events and the Baja vehicle model has post-made files for that ...

thank you very much

 

[GregLocock]

There are incremental changes in the way that templates are turned into adm files, which is what the solver actually runs. So if you build a model in 2005 and 2108 you will probably find slight differences. The solver also changes between releases. MSC support may be inclined to help you with that.

When each new version came out we used to run standard models through them and check that the results were reasonably similar. They were often different. That discipline seems to have faded away, but at least it means we can run the later versions (2013 in my case).

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[GregLocock]

We can check that. if you send me a link to the baja model I'll build the adm in 2013 and post it here. You can then use gdiff or whatever to explore the differences.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[bj7777]

thanks GregLocock for answering so fast , you clarified a lot with just a few sentences ...

i would really appreciate it if you check this model i will attach it here.

https://simcompanion.mscsoftware.com/infocenter/index?page=content&id=KB8017706

thank you very much

 

[bj7777]

and the movie in which the results of the previous version has been shown … is attached here …

mind you , it is "Slightly" different ... but still ...

 

[GregLocock]

There's the adm from the swingarm version.

I don't know if it runs, i don't have time to mess about with it.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[bj7777]

thanks anyway

so i have uploaded an image of my analysis(exact same model and tets File Driven 2018 ) and the result of the model itself in 2005

would you tell me if the diferences are normal ?
as you said the differences often happen so these minute diferences that i have circled with blue would be normal right ?

sorry to consume your time ...

also i detected that with the units being different in each model but resulting the same peaks in the gragh , the original model units might be wrong ( by the owner or builder of the model )

 

[GregLocock]

Hmm, if it was real world data I'd say that is excellent repeatability. yes, they are different. i suggest you do the adm comparison.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[bj7777]

what do I compare your file with ???

 

[GregLocock]

The adm from your model. adms are written in solver language, that pretty thing on your screen is no use to the solver. Export has several options for adams files, I think one is called adams solver dataset or something like that, you want a .adm file that looks similar to the one I posted.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

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[SomptingGuy]

With Greg here.

The model you are working with will be translated/exported to the form that the solver can understand. All it takes is for the MSC team to make some change in the the export scheme and you'll get a different result. As your GUI starts working with ever more abstract concepts, the direct mapping from GUI to solver disappears. You might find details in the release notes, if a subsystem's export method has been improved.

Steve

 

[bj7777]

thank you very much …

sorry for understanding your answer a bit late ...