Gasser-Ogden-Holzapfel model convergence

[cberggren]

Hello,

The Gasser-Ogden-Holzapfel model has been previously noted as having convergence issues under certain loading and fiber dispersion cases (see attached screenshot, from https://forums.febio.org/showthread....ight=holzapfel). Is this still the case?

Thanks,

Caleb

Annotation 2020-04-03 125329.png

[ateshian]

Hi Caleb,

The Gasser-Ogden-Holzapfel model is not being actively fixed. Prof. Holzapfel has told us that his finite element implementation of that model required some specialized numerical schemes to produce good convergence. He has offered to assist us in the process of fixing our implementation, but we haven't had the opportunity to work with him on this issue and don't have specific plans to do so in the immediate future.

Please note that this applies only to the model which was published in https://www.ncbi.nlm.nih.gov/pubmed/16849214. This model has a Mooney-Rivlin ground matrix and two fiber families with von Mises distributions. The fibers are either all in tension or all buckled when the strain along the principal direction of each distribution is either tensile or compressive.

We have previously provided an example of how FEBio may be used to implement the model of this paper: Holzapfel, G. A., Gasser, T. C., and Ogden, R. W., 2000, ‘‘A New Constitutive Framework for Arterial Wall Mechanics and a Comparative Study of Material Models,’’ J. Elasticity, 61, pp. 1–48.

Finally, in FEBio you can construct a model that reproduces all of the features of the 2006 GOH paper (uncoupled solid mixture with Mooney-Rivlin solid and two continuous von Mises fiber distributions), except that the determination of tension or compression is made for each fiber, not just the principal direction of the von Mises distribution. See Section 4.2 of the User's Manual 2.9.

Best,

Gerard

[cberggren]

Hi Gerard,

Sounds good regarding the Gasser-Ogden-Holzapfel model.

Thank you very much for the update and information regarding the options for implenting the various forms of this constitutive relation!

Have a great one,

Caleb