A Question about Chrono Validation Study

[xuanq...@gmail.com]

Hi all,

    I have a question about the Chrono Validation when I read the paper "Chrono: An Open Source Multi-physics Dynamics Engine".

    The fig.12 shows an experiment about the gravity-induced mass flow through a gap. From my opinion, if we want to validate a simulation, we'd better make all parameters in the simulation have same values with experiments, such as Young's modulus, poisson's ratio, CoR and friction effiecient.

    But in this validation case, I didn't see the author emphasize it. 

    So my question is, what is the standard procedure to validate the simulation? Do we need to make  all parameters in the simulation same with experiments? 

    If we just want to make simulation results match well with experiments, then we can tune the parameters to realize it. It seems not convincing. 

Thanks,

Qihan

[Dan Negrut]

Hi Qihan,

Thanks for your interest in Chrono.

 

The method called DVI doesn’t need a Young’s modulus since the way it models contact is via a rigid body assumption that leads to a DVI problem.

The value of the friction coefficient and the density of the material are within the physical range.

The PM simulation uses a value of K_N that is within the accepted range. See, for instance this paper that is cited more than 700 on google scholar:

https://journals.aps.org/pre/pdf/10.1103/PhysRevE.64.051302

Also, this paper (they all use values in the same range, usually three orders of magnitude than the actual value):

https://journals.aps.org/pre/pdf/10.1103/PhysRevE.74.021306

 

Finally, as shown in that plot, two different modeling and numerical solution methods; i.e., PM and DVI, give the same result, which is aligned with testing results.

A further discussion of Chrono and its validation is here:

https://journals.aps.org/pre/pdf/10.1103/PhysRevE.96.042905

 

I hope this helps but feel free to post follow up comments if you think we can assist.

 

Dan

-------------------------------------------------

Mead Witter Foundation Professor

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Department of Mechanical Engineering

Department of Computer Science

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