/DT/SHNOD/Keyword3

Format

/DT/SHNOD/Keyword3

$Δ T_{s c a}$ $Δ T_{\min}$

Data	Description	SI Unit Example
`Keyword3`	Time step control type. `CST` Nodal mass of the shell elements is increased to maintain the constant time step, $Δ T_{\min}$ . Due to this mass increase, momentum is not conserved and the mass increase of the model should be carefully monitored during the computation. If `Keyword3` is not specified, i.e. /DT/SHNOD, then the shell elements will use the nodal time step method and is not used.
$Δ T_{s c a}$	Scale factor on nodal stability time step for shells. Default = 0.9
$Δ T_{\min}$	Minimum time step.

Data

Description

SI Unit Example

Keyword3

Time step control type.

CST: Nodal mass of the shell elements is increased to maintain the constant time step, $Δ T_{\min}$ . Due to this mass increase, momentum is not conserved and the mass increase of the model should be carefully monitored during the computation.

If Keyword3 is not specified, i.e. /DT/SHNOD, then the shell elements will use the nodal time step method and is not used.

Δ T_{s c a}

Scale factor on nodal stability time step for shells.

Default = 0.9

Δ T_{\min}

Minimum time step.

Shell sub-cycling is activated by using the Engine file option, /SHSUB.
/DT/SHNOD/CST can be set in the Radioss Engine file, to use an imposed nodal time step for SHELL and SH3N elements sub-cycling. Just like /DT/NODA/CST, mass will be added to maintain $Δ T_{\min}$ .
(1)
$Δ T_{sca} \cdot \sqrt{2 \frac{M}{Ksh}}$
is lower than $Δ T_{\min}$
/DT/SHNOD sets a different time step for all shells (SHELL and SH3N) and shells only. Time step parameters of the rest of the model are defined in /DT/NODA. /DT/NODA is required, if /DT/SHNOD is used.