New Functionality for Version 4

  • A flexible definition of elastic material data enables the solid mechanics interfaces to support bulk modulus and shear modulus, Lamé constants, and pressure-wave and shear-wave speed in addition to Young’s modulus and Poisson’s ratio.
  • Custom hyperelastic material models can be created by specifying a strain energy function in terms of deformation tensor components and invariants.
  • A flexible 2D solid mechanics interface allows you to switch between plane stress and plane strain approximations at any point during modeling. For example, it is now easy to compare the results with plane strain and plane stress assumptions.
  • Prescribed velocity and acceleration boundary conditions are now available also in transient analysis. Previously, these conditions were available only in the frequency domain.
  • A new rigid connector boundary condition (only in 3D in version 4.0) makes it possible to apply kinematic constraints, forces, and moments on boundaries assumed to displace as a rigid body.
  • A new 3D shell and 2D plate element formulations based on first-order or second-order Lagrange shape functions on both triangles and quadrilaterals gives improved accuracy. Curved surfaces and mixed solid-shell models, in particular, are improved. In addition, the new shell elements are fully multiphysics-enabled and support large deformations and anisotropic materials.
  • Frequency-domain and time-domain modal solvers let you run fast frequency sweeps and transient response analyses on reduced models.
  • The Elastoplastic Material Model now allows the use of a non associated flow rule.

Backward Compatibility

Cross-Section Library

The cross-section library for beams is not available in version 4.0a. This is planned for version 4.1.

Plane Stress

Version 4 represents the out-of-plane strain as a separate degree of freedom. Plane stress models made with version 3.5a need to be re-solved to correctly compute strains and stresses. Displacements are correctly computed.


Symbols in the graphics window representing constraints and loads are not yet available in version 4.0a. Symbols will be available in version 4.1.

Iterative solver used in 3D by default

GMRES/GMG with LU preconditioner is the default solver in version 4.0a for 3D static and time dependent studies.

For stretched elements, this solver may run into convergence problems. If you run into convergence problems, try to improve the quality of the tetrahedral mesh by reducing the variations in mesh size. For smaller and medium-size problems, switch to a direct solver.