Trying to create a void in the mesh

Coreform Cubit Meshing
#1

Hi,

I’m trying to create a hole inside a model. Although I set the material properties of the medium to be the same, the results obtained with specfem3d are inconsistent with expectations (using the same material properties is only to verify that the model mesh is reliable).

But I didn’t get any error when creating the grid, and I didn’t get any error when running with specfem3d, but the result is that there is something wrong with the model grid (I have tried many times).

My ultimate goal is to create a multi-layer medium, and be able to arbitrarily set the shape and position of the inner cavity.

So I would like to ask if you have any suggestions on this issue. If there is any help, thank you very much!

the cubit code:


reset

brick x 100 y 30 z 30
brick x 20 y 10 z 30

subtract volume 2 from volume 1 keep
delete volume 1

volume 3 move x 50 y 15 z -15
volume 2 move x 50 y 15 z -15

webcut volume all with plane zplane offset -5



merge all
imprint all

volume all size 1
mesh volume all

block 1 hex in volume 2
block 1 name "elastic_1"
block 1 attribute count 7
block 1 attribute index 1 1
block 1 attribute index 2 475
block 1 attribute index 3 230
block 1 attribute index 4 2000
block 1 attribute index 5 9999
block 1 attribute index 6 9999
block 1 attribute index 7 0

block 2 hex in volume 3 4 5
block 2 name "elastic_2"
block 2 attribute count 7
block 2 attribute index 1 2
block 2 attribute index 2 475
block 2 attribute index 3 230
block 2 attribute index 4 2000
block 2 attribute index 5 9999
block 2 attribute index 6 9999
block 2 attribute index 7 0

export mesh "MESH_GEOCUBIT/mesh_file.e" dimension 3 overwrite
save as "MESH_GEOCUBIT/mesh_file.cub" overwrite

image
image931×536 286 KB

#2

Hello,

Welcome to the forum. You end up with two blocks that look like these in a cross sectional view. The commands to get this image are:

draw block all
graphics clip on plane x offset 50
graphics clip manipulation off

although I normally use the toolbar to manipulate the clipping plane.
image

The grid itself looks fine. Everything is merged correctly. The block definition is correct. Have you validated that the materials are defined correctly in specfem3d?

I have helped other specfem3d users in the past but I haven’t ever run the code. So, I’m not that much help with that. How are the results different than anticipated?

Thanks,
Karl

#3

Hi Karl,

Thank you! It gives me confidence to figure out the problem. Once I am sure that the model is alright, I went through every step and found the problem which is I should change the CPML condition.

So, thanks again!

Best,
Haiyang Liao