Nonlinear adaptivity refers to the capability of the solution process to adapt to changing conditions during a nonlinear analysis. The solution process uses a feedback mechanism to discretely or continuously adjust some internal parameters automatically so that an accurate and convergent solution is obtained.
Adaptive meshing is an example of an adaptive process. In highly nonlinear problems, excessive deformation can cause parts to distort and/or fail. Examples include industrial applications involving:
Extrusion – The billet undergoes excessive deformation due to the flow of material into the die.
Gasket sealing – The gasket material is forced into narrow cavities to create a seal (a process known as gap filling).
Fracture mechanics – Localized high-stress and high-deformation fields around the crack-tip area can lead to part failure.
Nonlinear mesh adaptivity (also available in ANSYS Mechanical) modifies the mesh automatically based on specified criteria. Mesh modifications occur by splitting and/or morphing or by general remeshing. Loads, boundary conditions, contact conditions, solutions variables, etc., are seamlessly transferred to the new mesh as the solution progresses. The capability supports both local and global remeshing.
Some of the settings used to control nonlinear adaptivity in ANSYS Mechanical will be discussed and several example models will be shown.