/STOP
Engine Keyword The Engine is stopped, due to reached energy error ratio criteria, total mass ratio criteria or nodal mass ratio criteria.
Format
/STOP
Emax | NTH | NANIM | NERR_POSIT | ||
Definition
Field | Contents | SI Unit Example |
---|---|---|
Emax | Energy error ratio.
Defined as the ratio of the current simulation energy to the initial
energy plus the work added in the system. Unlike the energy error
listed in the Engine output file, this value can be greater than
0.999 (99.9%). By default, the run is stopped, if the absolute value
of the energy error is exceeded. To only stop for positive energy
error, use
NERR_POSIT =1.
Default = 1030 |
|
Total mass added ratio
criteria is defined as the ratio of total added mass of the model at
a given time divided by the initial total mass. Default = 1030 |
||
Nodal mass ratio criteria.
Defined for each node as the ratio of its mass divided by its
initial mass. The computation is stopped; if, at least, one node
meets the criteria. Default = 1030 |
||
NTH |
|
|
NANIM |
|
|
NERR_POSIT |
|
Comments
- Energy error ratio:
(1) Where,- Translational kinetic energy at current time.
- Rotational kinetic energy at current time.
- Internal energy.
- Work of external forces (energy brought to the system).
- Energy at beginning of the RUN (not at time t=0).
- To find the divergence of the Engine run, it is better to only check for the positive energy error and not the negative energy error. To find early divergence, it is recommended to use NERR_POSIT = 1, NTH = 1, NANIM = 1, and a relatively low value for Emax.
- The total mass criteria is defined as the ratio of total added mass at a given time divided by the initial total mass.
- The nodal mass ratio criteria is defined for each node as the ratio of its mass divided by its initial mass. The computation is stopped, if at least one node meets the criteria.
- A restart file is written, if the Engine is stopped, due to one of these events.