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Error in Multi-body simulation in OptiStruct

Altair Forum User

Hey guys,

I am running a multi-Body Simulation in OptiStruct 2017. The following error occurs:

INFO: Parsing XML file [D:/........

ERROR: not well-formed (invalid token) at line 1

ERROR: Error encountered in processing xml input file!

Error: Cannot open an MBD result file.

This error occurs in module 'mbddrv'.

Do you have any idea why this error is showing up?

Thanks already for your advice.

Cheers, Mike

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Altair Forum User

Hi Mike,

Do you have MBSIM for MBS parameters in your model?

Can you change the ITYPE to MSTIFF and check if that works?

Altair Forum User

I used VSTIFF. What's the difference between VSTIFF, DSTIFF, MSTIFF etc...? And what is the difference between using Craig-Chan and Craig-Bampton?

I changed the Input to MSTIFF. It doesn't help though.

However, I saw another error:

ERROR: Selected node [id=77468] not found for flexbody [id=1]!
ERROR: Failure in calculating invars for FlexBody [id=1]!

I don't know why this error occurs. The Point is at the end of a rigid that is connected to my flexible Body?!

Altair Forum User

They are integrators. The order of integrator is the order of equations for instance VSTIFF order is 5.

Can you share the model file with us?

You can use the File Transfer link in my signature below to share the file.

Altair Forum User

I sent the file. I hope you got it.

Altair Forum User

Mike,

Thank you, I am looking into it and will get back to you soon.

Altair Forum User

Hi Mike,

Can you explain the use case?

Since there are only two bodies why don't you use MotionView/MotionSolve directly instead of OS?

Altair Forum User

I want to use the model to conduct a topology optimization. Furthermore, I simplified the model significantly. Normally there are more and different components. I am not authorized to publish the original model data.

The error is pretty similar though and I don't know how to solve it.

Altair Forum User

Has anyone an idea why this problem occurs? Can it be related to alterations and bugs in the solver of HyperWorks 2017? Or might it be related to a MOTION defined by an unsupported Card? Or maybe a time step that is not well-chosen? I am glad about any hint. Cheers guys

Altair Forum User

I just included my Input and my Ouput-file. Maybe that helps in order resolve the problem. Thank you so much!!

Unable to find an attachment - read this blog

Altair Forum User

Hi Mike,

As suggested please model using MotionView and solve in MotionSolve. Extract the forces and use the same for optimization.

You can refer to these videos to learn about modelling, analysis and how to extract loads using MotionView/MotionSolve which are available @ http://www.altairuniversity.com/learning-library and search for motorcycle.

<?xml version="1.0" encoding="UTF-8"?>

Altair Forum User

Thank you Prakash