5.2. NLAD-GPAD Requirements and Limitations

Following are the supported analysis types, elements, materials, loads, boundary conditions, and other NLAD-GPAD requirements:

Support Category Support Details

Solid elements

Contact elements

  • Pair-based contact only.[c][d]

  • TARGE170

  • CONTA174 with any of the following KEYOPT settings:

    KEYOPT (1) = 0, 1
    KEYOPT (2) = 0, 1, 2, 3, 4
    KEYOPT (3) = 0
    KEYOPT (4) = 0, 1, 2, 3
    KEYOPT (5) = 0, 1, 2, 3, 4
    KEYOPT (6) = 0, 1, 2, 3
    KEYOPT (7) = 0, 1, 2, 3
    KEYOPT (8) = 0 , 2
    KEYOPT (9) = 0, 1, 2, 3, 4
    KEYOPT (10) = 0, 1, 2
    KEYOPT (11) = 0
    KEYOPT (12) = 0, 1, 2, 3, 4, 5, 6
    KEYOPT(14) = 0
    KEYOPT(18) = 0, 1, 2

Contact pair behavior

  • Rigid-flexible[c]

  • Flexible-flexible

Surface-effect elements

Materials

  • Linear elastic and elastoplastic models:

    ELASTIC
    PLASTIC (BISO, BKIN, MISO, KINH)
Analysis types

  • All static analysis types with small-deformation effects (NLGEOM,OFF).[f][g]

Loads and boundary conditions (BCs)[g]

  • Displacements, forces, pressures, and nodal temperatures (BF,TEMP).

  • Tabular displacements, forces, and pressures that are functions of time only.

  • Fluid-penetration loads applied to contact elements (SFE).[h]

Region to be remeshed[i]

  • The selected nodes inside the region must have the same nodal coordinate system.

  • Boundary nodes can have different nodal coordinate systems.[j]

  • Elements must be of the same element type, material, element coordinate system, and real constant.

[a] General remeshing only.

[b] NLADAPTIVE does not support elements with dropped mid-side nodes in element.

[c] General contact is not supported.

[d] For flexible-to-flexible contact pairs, any large initial penetration approaching or exceeding a single-element depth may cause remeshing to fail. In such cases, Ansys, Inc. recommends assigning different material and/or element types to the contacting bodies.

[e] Only normal and tangential pressures applied on SURF154 are supported.

[f] For linear analyses with linear elastic materials and small-deflection effects (NLGEOM,OFF), the iterative Newton-Raphson solution procedure is set automatically. The smallest possible number of substeps must also be set (either directly via NSUBST or indirectly via DELTIM) to a value that ensures remeshing. Guidance for setting the number of substeps can be taken from the NLADAPTIVE,,ON,VAL1 value specifying the remeshing frequency.

[g] Do not remove nodal constraints (DDELE, FDELE, BFDELE, SFDELE) during solution before remeshing.

[h] CONTA172, CONTA174.

[i] Initial state, element birth and death, and cyclic symmetry analysis are not supported.

[j] For initially coarse meshes on curved surfaces, the Euler rotation angles of the nodes may be improperly interpolated onto the newly meshed region of the same curved surfaces. If applied nodal boundary conditions (such as displacement) exist on those nodes, they are mapped incorrectly, as the boundary conditions are specified on the local nodal coordinate system (defined by the Euler angles). Curved surfaces should therefore have a reasonably fine mesh. Adjacent nodes on a boundary cannot have different nodal coordinate systems, if this boundary is selected for remeshing.