Meshing around a 10 micron wide crack

[psustudent]

Hello!
I am trying to refine the mesh around a 10 micron wide crack in a part. I want the mesh around the crack to be 1e-7 and the mesh in the rest of the part to be 3e-5. I have tried partitioning the crack and seeding the edges of the partition to be 1e-7; however, this continually results in Abaqus taking forever to mesh the part or the creation of several unreliable nodes highlighted in pink. The tip of my crack is rounded to be a half circle, so I want to refine the mesh here. I've attached some pictures for reference. I've tried following this video:

https://www.youtube.com/watch?v=vLQ4H5_QBAc

and this video:

https://www.youtube.com/watch?v=MtPQxfzR7n4&t=20s,

but am continually running into the problems I described above. I am using a free triangular mesh with plane strain, explicit, linear. I look forward to any advice.
Thanks!

 

[FEA way]

Some additional partitions (a few layers with different mesh densities) might be needed around the crack if the domain is large when compared with crack (or maybe you could reduce it).

 

[psustudent]

Around some of my partitions as I make the mesh smaller the mesh elements start to look larger and I get strange thin triangles at the boundaries. Do you have any idea what may be causing this?

 

[SWComposites]

Ugh, crummy auto mesher; mesh refinement in the wrong places.

You are probably going to have to create a partition right at the crack tip, and a series of partitions outside of that area.

But, why are you trying to model the crack with a fine mesh? why not use fracture/cohesive elements to analyze the crack?

 

[FEA way]

The transitions are wrong, you may need some horizontal lines to control the distribution in that direction (bias setting may help) or less rapid changes between the layers. You can apply local seeds also to faces instead of edges.