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Structural module, thin elastic layer with nonlinear forces, solver option for nonlinear systems

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Hi everyone!

I'm modeling a quite simple system of a composite material. Basically three cylindrical fibers embedded in a cuboid matrix.
All the materials are linear elastic. The numerical simulation aims to reproduce a quasi-static test so I use a parametric sweep over the imposed displacement with a relative small loading step.

Particularly I model the matrix/fiber interfaces, i.e., the external surface of the cylinders, as a thin elastic layer (TEL) with a nonlinear force of the type:

F= C [u]^3

in which C is a stiffness constant (the same for all three matrix/fiber interfaces) and [u] is the displacement jump.

Questions:

- Can I use a single TEL for all fibers? Or I must create a TEL for every cylinder?

- Using the TEL option on a cylindrical surface require some particular attentions?

- Finally, because of this modeling choice concerning interfaces I have to solve a nonlinear and implicit system of equations, moreover the interface stiffnesses are very high, as a result I have some convergence problems.
What is, in my case, the optimal choice for the solver configuration?


Thank you in advance.

0 Replies Last Post 28 juil. 2016, 07:26 UTC−4
COMSOL Moderator

Hello Maria Letizia Raffa

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