Available Solution Methods

The Lagrange solver utilizes a mesh that moves and distorts with the material it models as a result of forces from neighboring elements. This is the most efficient solution methodology with accurate pressure history definition. If however, there is too much deformation of any element, it results in a very slowly advancing solution and is usually terminated because the smallest dimension of an element results in a time step that is below the threshold level. For problems with too much deformation involving gases and liquids, the Euler solver is better suited.

The Euler (multi-material) solver utilizes a fixed mesh, allowing materials to flow (advect) from one element to the next. The Euler solver is very well suited for problems involving extreme material movement, such as those involving fluids and gases. Euler is generally more computationally intensive than Lagrange and requires higher resolution (smaller elements) to accurately capture sharp pressure peaks that often occur with shocks.

The ALE (Arbitrary Lagrange, Euler) solver utilizes the advantages of both the Lagrange and Euler solvers. It works as a Lagrangian solver but periodically repairs the mesh as it becomes distorted. This solver is well suited for problems that lie between the Lagrange and Euler sweet spots.

The Euler–FCT solver, used for ideal gases, is a special-purpose Euler solver that is very fast and highly accurate. It is best suited for use in problems simulating blast loadings.

SPH (smooth particle hydrodynamic) mesh-free method is ideally suited for certain types of problems with extensive material damage and separation such as cracking. This type of response often occurs with brittle materials and with hypervelocity impacts.

The Shell solver is assigned to two-dimensional parts such as membranes. It enables efficient computation in spite of the very small dimension of the membrane.

The Beam solver is used for one-dimensional parts such as reinforcements. When used in conjunction with solid elements, beams can be located inside a solid element and need not be aligned with the nodes of the Lagrangian elements, making their use unlimited, while requiring very little effort to set-up.

Lagrange (structures)
Euler (fluids)
ALE (auto remesh)
SPH (brittle)
Shell/Surface (thin 2-D)
Beam - Reinforcement (long 1-D)

The numerical methods accessible for the three explicit dynamics products cover almost all possible areas of application appropriate to explicit simulation.