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Coupling matrix & Elasticity matrix of Silicon and Silicon dioxide

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Hi, I am working on Piezoelectric(AlN) simple cantiliver acuator, having my cantiliver composite 3-layer beam( Si, SiO2(buffer) and AlN on top as active layer). Physics that I am using is ''Piezoelectric devices'' and study is stationary. When I add materials to its respective layers, Si and SiO2 asks for the ''Coupling matrix and Elasticity matrix'' . I searched many online databasess and documents but didn't found these propeties, if anyone has these or can guide where I find it. Stay blessed



4 Replies Last Post 2020年3月11日 GMT-4 05:41
Dave Greve Certified Consultant

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Posted: 4 years ago 2020年3月3日 GMT-5 13:02

If you select silicon and silicon dioxide as Linear Elastic Materials you will find the problem goes away. Material parameters for these are built in to COMSOL.

(I assume that your SiO2 is not crystalline quartz, that is an entirely different can of worms).

If you select silicon and silicon dioxide as Linear Elastic Materials you will find the problem goes away. Material parameters for these are built in to COMSOL. (I assume that your SiO2 is not crystalline quartz, that is an entirely different can of worms).

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Posted: 4 years ago 2020年3月4日 GMT-5 13:18

Dear Dave Greve, Many thanks for your reply, yeah it works now but still shows the warning sign there. I wonder if it will affect my results?

Dear Dave Greve, Many thanks for your reply, yeah it works now but still shows the warning sign there. I wonder if it will affect my results?


Dave Greve Certified Consultant

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Posted: 4 years ago 2020年3月4日 GMT-5 14:10

Sorry, forgot to tell you to select these domains under Charge Conservation 1.

To calculate as piezo- a domain must be selected under Charge Conservation Piezoelectric (es), Piezoelectric Material (solid) and Multiphysics (piezoelectric).

To calculate as linear- select Charge Conservation (es), Linear Elastic Material (solid) and deselect under Multiphysics.

Sometimes this happens automatically, sometimes not. It depends on the order that you do things in. Just go through and verify selections under these three nodes.

Sorry, forgot to tell you to select these domains under Charge Conservation 1. To calculate as piezo- a domain must be selected under Charge Conservation Piezoelectric (es), Piezoelectric Material (solid) and Multiphysics (piezoelectric). To calculate as linear- select Charge Conservation (es), Linear Elastic Material (solid) and deselect under Multiphysics. Sometimes this happens automatically, sometimes not. It depends on the order that you do things in. Just go through and verify selections under these three nodes.

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Posted: 4 years ago 2020年3月11日 GMT-4 05:41

Many thanks Dave Greve, Your's guidence was really helpfull. God bless you

Many thanks Dave Greve, Your's guidence was really helpfull. God bless you

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