PARAM, SH4NRP

Bulk Data Entry This parameter controls the full projection of 4-node shell elements in NLGEOM implicit analysis.

Parameter	Values	Description
`SH4NRP`	0, 1, 2 Default = 0 in NLGEOM subcase Default = 1 in IMPDYN subcase	0 The full projection for warped QEPH shell elements will be deactivated. This option may improve the implicit nonlinear analysis with QEPH warped shell elements if the rigid rotation of warped elements is small enough. 1 The full projection for warped elements will be applied only for internal force calculation; the option gives accurate results if it converges successfully, but convergence issues could be encountered with very warped elements. 2 The full projection for warped QEPH shell elements will be activated for the stiffness matrix to stay consistent with the internal force calculation. This option can improve the convergence of implicit nonlinear analysis with QEPH warped shell elements at the cost of some additional calculations. In the case of finite rigid rotations with warped shell elements, PARAM, `SH4NRP`, 1 gives accurate results. If convergence difficulties are encountered, PARAM, `SH4NRP`, 2 should be used. If PARAM, `SMDISP`, 1 is present, `SH4NRP` is always set as 0 internally.

Parameter

Values

Description

SH4NRP

0, 1, 2

Default = 0 in NLGEOM subcase

Default = 1 in IMPDYN subcase

0: The full projection for warped QEPH shell elements will be deactivated. This option may improve the implicit nonlinear analysis with QEPH warped shell elements if the rigid rotation of warped elements is small enough.
1: The full projection for warped elements will be applied only for internal force calculation; the option gives accurate results if it converges successfully, but convergence issues could be encountered with very warped elements.
2: The full projection for warped QEPH shell elements will be activated for the stiffness matrix to stay consistent with the internal force calculation. This option can improve the convergence of implicit nonlinear analysis with QEPH warped shell elements at the cost of some additional calculations.

In the case of finite rigid rotations with warped shell elements, PARAM, SH4NRP, 1 gives accurate results. If convergence difficulties are encountered, PARAM, SH4NRP, 2 should be used.

If PARAM, SMDISP, 1 is present, SH4NRP is always set as 0 internally.