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Magnetorheological Elastomer Issues: Rotation Matrix and Hyperelasticity

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Greetings,

I am working on a project that uses magnetically active elastomers(MAE) being subjected to external magnetic fields (H). The internal magnetization of the elastomer (M) is oriented in the x-axis direction while the magnetic field (H) applied to the MAE is in the y-axis direction. This causes the magnetic elastomer to rotate in such a way that the magnetization of the elastomer (M) tries to line up with the external magnetic field (H).

With that explained, I am trying to verify my model by tracking the remanent flux density (RFD) within the elastomer. When I track the remanent flux density, I come across graphics that are askew to what should be happening. Instead of the RFD rotating with the elastomer, it follows an arbitrary path. I am currently using Ampere's Law on the elastomer to apply the Remanent Flux Density within the Magnetic Field section of the Ampere's Law. The X and Y components of the Br are as follows:

X: M*cos(solid.curlUZ/2)
Y: M*sin(solid.curlUZ/2)

I have also tried using solid.rotxZ etc. to simulate a rotation matrix but I haven't had any luck. Could you help point me in the right direction when it comes to functions that deal with the rotation of objects. I've been using dynamic help within comsol but couldn't find anything that has worked yet.

**If this makes it simpler: imagine an arrow within a rectangular box. I rotate the box but the equation governing the arrow within the box does not incorporate the rotation of the box so it remains stationary as the box moves. I want this arrow to move with the box using functions such as solid.curl or whatever works best for this type of scenario. (Hope that helps simplify my problem)**

A second issue I am having is incorporating hyperelasticity into my MAE. When applying the hyper elasticity model within the solid mechanics module to the MAE, I begin to experience solver issues. The values within the hyper elasticity model are just ball-park values due to the fact that experimentation of our material's values is not complete. I suspect that may be an issue as to why the solver will not converge but I feel it may be due to settings within the MUMPS solver setting. Any ideas as to why either of these issues are arising?

[model attached]

Thanks in advance, I really do appreciate any advice.
Rob S.


0 Replies Last Post 18 nov 2012, 17:01 GMT-5
COMSOL Moderator

Hello Robert Sheridan

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