Effect of mesh size on simsolid result in conversion of implicit lattice geometry to triangle mesh

Hi there,

I wanted to do a simple static analysis using lattice structures produced as implicit geometry in the Altair Inspire program. After adding lattice to the inside of my model, I converted the geometry with the "Convert to triangle mesh" tool and performed the analysis with the Simsolid solver.

My problem in this part is that the analysis result changes a lot in different triangle mesh sizes and even if I did a few analyzes, I could not achieve convergence in the result. The contour appearances of the analysis results are similar, but there are big differences in the stress and displacement results. How can I get the correct result?

Additionally, I applied the mesh convergence method. I applied a much smaller mesh to the geometry, but even though the mesh size was very small, there was no convergence in the results. Errors such as 5%-10% in the results may be acceptable, but instead there were differences too high.

In the geometry I used, there are 2 flat plates of 24mmx24mmx5mm at the top and bottom and a 24mmx24mmx48mm lattice section in the middle. After the convert process, I combined the top and bottom plates and the lattice section with "Boolean".

F: 500 N (on the top plate)
Support: Fixed (on the bottom plate)
Material: PLA (E: 2865 MPa, Nu: 0.35, Density: 0.00124 g/mm3, Yield Stress: 56 MPa)
Lattice features:
Type: Hex Truss
Strurt Diameter: 1mm,
Cell Size: 2x2x4,
Visualization Quality: Very High

Another result with more triangle mesh size and better run options: