4.2.5.4. Output Files

SubDyn produces three types of output files: an echo file, a summary file, and a time-series results file. The following sections detail the purpose and contents of these files.

4.2.5.4.1. Echo File

If the user sets the Echo flag to TRUE in the SubDyn driver file or the primary SubDyn input file, the contents of those files will be echoed to a file with the naming conventions, OutRootName.dvr.ech for the driver input file and OutRootName.SD.ech for the primary SubDyn input file. OutRootName is either specified in the SUBDYN section of the driver input file, or in the FAST input file. The echo files are helpful for debugging the input files. The contents of an echo file will be truncated if SubDyn encounters an error while parsing an input file. The error usually corresponds to the line after the last successfully echoed line.

4.2.5.4.2. Summary File

SubDyn generates a summary file with the naming convention, OutRootName.SD.sum if the SumPrint parameter is set to TRUE. This file summarizes key information about the substructure model, including:

  • Undisplaced node geometry: a list of all of the (NNodes) nodes and the X,Y,Z coordinates in the global SS coordinate system. Note that NNodes may be greater or equal to NJoints, depending on NDiv (primary input file parameters).

  • Element connectivity and properties at end nodes: a list of all (NElems) elements, the start and end nodes (Node_I, Node_J) and the ID of the property set (Prop_I, Prop_J) at the start and end nodes. NElems may be greater or equal to NMembers, depending on NDiv (primary input file parameters).

  • Property sets. If tapered members are used, additional property sets may be included beyond those specified in the main input file, based on interpolated diameter and thickness values. Headers and their meanings are identical to those described in Section .

  • Reaction DOFs and interface DOFs and their associated fixity; the actual indices of the DOFs (DOF_ID) associated with reaction and interface nodes are listed together with the (1/0) flag to distinguish the fixity level.

  • Concentrated mass schedule. This is an echo of the equivalent section in the primary input file. Refer to Section .

  • Member schedule including connectivity to joints, nodes, and their masses. A table lists all of the members by identifier (MemberID), with their start and end nodes (Joint1_ID, Joint2_ID), associated mass (Mass), and list of node identifiers along the length of the members.

  • Direction cosine matrices for the members. Each row (columns 2-10) corresponds to the direction cosine matrix entries (DC(1,1) through DC(3,3)) for the member whose identifier is listed in the first column. The direction cosine matrices specify the transformation from the global reference to the local coordinate system for each member.

  • Sorted eigenfrequencies [in Hertz (Hz)] for the full substructural system (neglecting a possible coupling to ElastoDyn through FAST), assuming the TP reference point is a free end. There are a total of NDOFs eigenfrequencies and eigenvectors.

  • Sorted eigenfrequencies (in Hz) for the C-B reduced system, assuming the TP reference point is a fixed end. There are a total of Nmodes C-B reduced eigenfrequencies and eigenvectors.

  • Full substructural system eigenvectors. Each column represents an eigenvector associated with the corresponding eigenfrequency identified previously in the file.

  • C-B reduced system eigenvectors (PhiM matrix). Each column represents an eigenvector associated with the corresponding eigenfrequency identified previously in the file.

  • PhiR matrix or displacements of the internal nodes caused by unit rigid body motions of the interface DOFs (see Section ). Each column of the matrix represents the internal DOF displacements for a given unit rigid-body motion along an interface DOF for each base and interface joint.

  • Substructure equivalent stiffness and mass matrices referred to the TP reference point (KBBt and MBBt), based on a Guyan reduction. These are useful to calculate effects of substructure flexibility while calculating tower eigenmodes for ElastoDyn.

  • Rigid-body-equivalent mass matrix relative to global origin (MRB); a 6x6 mass matrix.

  • Substructure total (dry) mass.

  • Substructure center of mass coordinates in the global coordinate system.

The various sections of the summary file and variables are self-explanatory and easily identifiable in the file.

4.2.5.4.3. Results File

The SubDyn time-series results are written to a text-based file with the naming convention OutRootName.SD.out when OutSwtch is set to either one or three. If SubDyn is coupled to FAST and OutSwtch is set to two or three, then FAST will generate a master results file that includes the SubDyn results. The results in OutRootName.SD.out are in table format, where each column is a data channel (the first column always being the simulation time), and each row corresponds to a simulation time step. The data channels are specified in the SDOutList section of the input file. The column format of the SubDyn-generated file is specified using the OutFmt and OutSFmt parameters of the input file.