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Carbon Fiber Hyperelasticty Problem

Carbon Fiber Hyperelasticty Problem

Carbon Fiber Hyperelasticty Problem

(OP)
Hello

I am attempting to model a carbon fiber tow in Abaqus. The ends of the fiber tow are ovals with major axis 12.5 and minor axis 0.3136. The tow is oriented along the x-axis. The variables I'm using are for the Holzapfel model of hyperelasticity and are the following:

C10: .00382
D: .0024
k1: 100000000
k2: .00000001
kappa: 0.333

I have used these same values on the same model but with the face of the tow being a 1x1 square.

There is also a mass density of 1.77e-6

A gravity load is applied along along the -y axis.

I'm using element type C3D20R: A 20-node quadratic brick, reduced integration

I don't think my problem is a poorly refined mesh, as I've tried the problem with an excessively refined mesh, and I still receive an error.

The error that I'm receiving occurs on the first increment and is:
THE COMPRESSIBILITY OF THE ANISOTROPIC HYPERELASTIC MATERIAL WILL BE IGNORED IF USED IN COMBINATION WITH ELEMENTS WITH PLANE-STRESS FORMULATION. Abaqus ASSUMES FULLY INCOMPRESSIBLE BEHAVIOR IN THIS SITUATION.

4138 elements are distorted. Either the isoparametric angles are out of the suggested limits or the triangular or tetrahedral quality measure is bad. The elements have been identified in element set WarnElemDistorted.

Excessive distortion at a total of 101740 integration points in solid (continuum) elements

Excessive distortion at a total of 94933 integration points in solid (continuum) elements

Excessive distortion at a total of 80342 integration points in solid (continuum) elements

Excessive distortion at a total of 48702 integration points in solid (continuum) elements

Excessive distortion at a total of 15767 integration points in solid (continuum) elements

Thank you for any help you can prvide!

RE: Carbon Fiber Hyperelasticty Problem

Some context will help.

What is the application? Why are you assuming anisotropic hyperelasticity? HGO material law is typically assumed by the soft tissue biomechanics community. I am not familiar with carbon fiber tows (?) and do not know what they have to do with biomechanics.

Also, why are you not starting with a coarse mesh and building on it?

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