Mesh Improving

Question

Hi, 
 Can anyone give us some advice/tips to improve quality meshing for low angle interception surfaces. We have tried local refinements but even size elements got smaller mesh quality is not improving... thanks in advance. Here you have some images... 
 
 Regards, 
 
 Francesc

Rushan Gizzatullin · Answer

Dear Francesc , 
 It is quite difficult to estimate the problem without the project. Below you can find my assumptions: 
 1. 4.5&times;10^&minus;3 is a bad mesh quality, but not so critical. I think a minimum value of 0.0001 or less is more critical for the calculation. Moreover, I can assume that the volumes inside the pit will be deactivated, which means that bad elements will also be deactivated. Probably, you are not interested in the results in this area. 
 2. The yellow bar on the legend is at 0.1. It's more interesting to know where the bad red elements with mesh quality less than 0.001 are. 
 3. The average size of a element, and therefore the local size of a element, depends on the size of the entire model. This means that if you have a large model (large model diagonal), the average element size will also be large. I understand that the boundary conditions should not affect the results, but perhaps you can reduce the size of the model a bit. 
 4. Is it possible to change the volume of the "wedging" soil? Is this layer so important in terms of its parameters? Maybe you can combine it with neighboring soils. 
 5. I might suggest adding some vertical surfaces that intersect the bad elements. Alternatively, you can add some volume to this area and then refine the mesh in it. 
 I hope some of this helps. Good luck!

Stefanos Papavasileiou · Answer

Dear Francesc, 
 I agree with the comments from Rushan here. 
 Indeed, it seems that it is the intersection between the structures and the soil layer that causes these thin elements to be generated. Possibly consider keeping the thickness of that soil layer to a larger value to prevent these elements. Note that even with a small value the mesh generation can be improved without affecting the geotechnical behaviour. 
 Of course, it is always preferable to apply refinements and possibly partition the geometry at those locations. 
 In any case, as Rushan mentioned, clarify how big of an issue it is by adjusting the yellow slider on the legend and see if it is possible to adjust your geometry. 
 If you have problems, please let us know is a service request: https://apps.bentley.com/srmanager/ProductSupport

Mesh Improving

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