Learning Forum

[rileylau0913]

Hi all,

I'm using Autodyn's SPH-FEM to simulate a hypervelocity impact analysis. And I notice that both strucutred solvers and unstructured solvers have the same variable type (eg. X, Y, X-velocity, etc.). What's the difference between these two solvers? And if I would like to output only the position, mass and velocity of the SPH particles which solver should I choose? 

[Chris Quan]

The terminology “structured” vs. “unstructured” refers to the mesh topology, i.e., structured mesh versus unstructured mesh.

A structured mesh is I–J–K based, where the grid indices run from
I=1 to Imax⁡
J=1 to Jmax⁡, and
K=1 to Kmax.​
for three-dimensional models. Mesh connectivity is implicit through the index ordering.

An unstructured mesh is indexed by a one-dimensional array, running from 1 to the total number of elements (or nodes), with connectivity explicitly defined through element–node relationships.

Typically, the Multi-Material Euler (Euler–Godunov) solver, Ideal Gas Euler (FCT) solver, and SPH solver in ANSYS Autodyn use a structured mesh, while solid elements, shell elements, and beam elements in the Explicit Dynamics (Autodyn) system are based on unstructured meshes.

However, in the Autodyn GUI, solid, shell, and beam elements can also be defined on a structured mesh, depending on the chosen solver formulation when creating new parts.