Data Category 15 is used in all programs in the Aqwa suite, except Aqwa-Line, to input the 'starting conditions' for the analysis. Although data categories for each type of analysis are similar, they are documented separately as each requires information appropriate to the type of analysis. This description of Data Category 15 is appropriate to Aqwa-Fer and Aqwa-Librium only.

The programs Aqwa-Fer and Aqwa-Librium solve equations of motion that are in the frequency domain or quasi-static respectively. The programs therefore require the initial position of the body/bodies globally. These initial conditions or initial positions are referred to as starting conditions.

Starting Conditions - Defaults

Aqwa-Librium

The equations to be solved require only the specification of initial positions. These positions are given for each body and for each of the 6 body degrees of freedom. Default starting conditions will be assumed by Aqwa-Librium if the user omits any, or all (the latter by entering NONE for the Data Category Keyword) of the data records in this data category.

The default starting position is the position of the structure(s) as originally defined by the user in Data Categories 1 to 4. (See Motion Constraints on Structures - CONS (Data Category 12) if constraints are present.)

Aqwa-Fer

The equations to be solved require the specification of initial positions and articulation reactions (if there are any articulations in the model). The positions are given for each body and for each of the 6 body degrees of freedom. Default starting conditions will be assumed by Aqwa-Fer if the user omits any, or all (the latter by entering NONE for the Data Category Keyword) of the data records in this data category.

The default initial position is the position of the structure(s) as originally defined by the user in Data Categories 1 to 4.

The default initial articulation reactions are zero. Incorrect articulation reactions can affect the stiffness matrix and lead to inaccurate results. Therefore it is strongly recommended that the reactions are specified on the REA* data record, or read in from an EQP file created by Aqwa-Librium.

Starting Conditions with the RDEP Option

If the RDEP option (Administration and Calculation Options for the Aqwa Suite) is used with a filename given on the RESTART data record (e.g., FILE01), then the positions and reactions in the file FILE01.EQP will override the default positions and reactions. However, if starting positions or reactions are defined in Data Category 15 these will in turn override the data in the .EQP file.

Starting Conditions specified in Data Category 15

If the POS*, VEL* or REA* data records are used in Data Category 15 the values on these data records will override the defaults or the values in the .EQP file. Note that blank fields on these data records are treated as zero values.

Slow velocity and position are not used in Aqwa-Librium or Fer. If the SLP* or SLV* data records are used they will be ignored.