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Element order of Gauss point data? How many integration point?

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Dear all,

I am going to use the Gauss point data to define a material properties. I am confused by the element order of the Gauss point data, say 0, 2, 4,6,8 ,10.... Does these number mean the integration point within an element? If not, how can I know the number of integration points?

Another question is what principles I should follow to select the element order. Now, my PDE is discretized by linear shape function. So, which element order for the Gauss point should I select to define the material properties?

Thank you so much for your help.

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Yu Zhang

1 Reply Last Post 2019年2月18日 GMT-5 08:28
Henrik Sönnerlind COMSOL Employee

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Posted: 5 years ago 2019年2月18日 GMT-5 08:28

Hi,

The number indicates the accuracy of the integration. In a 2D quad element this means

0 - 1 point 2 - 2x2 points 4 - 3x3 points etc.

For elements with other shapes, the locations are more complicated, but the integration accuracy is the same.

If you are using linear shape function order, the default integration rule is '2'. You can examine (and change) it by looking at the weak expression in Equation View.

If you work with own material models (as states in Gauss points) you should select the same order as is used for the integration of the weak expressions.

Regards,
Henrik

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Henrik Sönnerlind
COMSOL
Hi, The number indicates the accuracy of the integration. In a 2D quad element this means 0 - 1 point 2 - 2x2 points 4 - 3x3 points etc. For elements with other shapes, the locations are more complicated, but the integration accuracy is the same. If you are using linear shape function order, the default integration rule is '2'. You can examine (and change) it by looking at the weak expression in Equation View. If you work with own material models (as states in Gauss points) you should select the same order as is used for the integration of the weak expressions. Regards, Henrik

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