$ $ THIS ALTER IS CONFIDENTIAL AND A TRADE SECRET OF THE $ MSC.SOFTWARE CORP. THE RECEIPT OR POSSESSION OF $ THIS ALTER DOES NOT CONVEY ANY RIGHTS TO REPRODUCE OR $ DISCLOSE ITS CONTENTS, OR TO MANUFACTURE, USE, OR SELL $ ANYTHING HEREIN, IN WHOLE OR IN PART, WITHOUT THE $ SPECIFIC WRITTEN CONSENT OF THE MSC.SOFTWARE CORPORATION. $ Alter to perform Coupled Dynamic Analysis using PART superelements Name: alter1ha.v707 alter2ha.v707 alter9ga.v707 Purpose: These alters demonstrate an approach using MSC/NASTRAN, which can be used to create assembly models using a series of components. This series of alters uses the new PART superelements (introduced in V69) to create reduced models representing component models. These "reduced models" may then be combined into an "assembly model". Once this is done, the model may be used as any conventional superelement model in MSC/NASTRAN, including data recovery and assembly plots. alter1ha.vxx - creates reduced model (often referred to as Craig-Bampton models) of components. These reduced models contain the "boundary matrices" and transformation matrices (often known as OTM, ATM, DTM, or LTM). alter2ha.vxx - reads in the reduced matrices from alter1ha and stores them in the MSC/NASTRAN database in such a way that they appear to belong to a normal PART superelement (that is, support all standard restarts even although the component came from another run). alter9ga.vxx - same purpose as when used with the alter1g-series. Will calculate interface loads and also use OTM to calculate output for the component and will write the results using standard MSC/NASTRAN data recovery formats. Data created using this alter is available for XY-plots if desired. (This alter is not needed if you wish standard data recovery items, the information necessary to calculate standard results information - displacements, velocities, stresses, etc - is stored by the second run). Input: alter1ha uses the following input to control it's operations: PARAM,NOOTM - integer - -1 = default = Create OTM as requested in Case Control Section +1 = Do not create OTM USET,U2 - if used, the "U2" set of dof are the only ones which will be stored in the boundary transformation matrix (GOA). If not used, all interior dof are used in the transformation matrix. When using the reduced matrices in any runs, loads may only be applied on dof are stored in the transformation matrix. If deformed plots are requested in subsequent runs, the only dof which will have non-zero deformations in the plots are the ones contained in the transformation matrix (once again, if the U2 set is not defined, all dof are retained for this purpose) PARAM, MATFILE - integer - mandatory - this parameter indicates the FORTRAN unit number for the OUTPUT2 file, which the alter will be writing information to. Default value = -1, which indicates that the reduced matrices should be 'punched' as DMIG entries in the "PUNCH" file. If this is used, the automatic attachment will not work. PARAM,FIXEDB,-1 - must be set to this value if OTM are desired. PARAM,NEUTRAL - integer - controls the writing of the tables which describe what is in the OTM (only necessary when creating OTM) -1 => unformatted (DRMH1 tables are written to OUTPUT file) 1 => formatted (DRMH1 tables are written to the punch file using DTI format and should be included in the partitioned bulk data in the run reading the data for this superelement) SDAMP - if modal damping is desired on the superelement component modes, this should be used in the Case Control with a TABDMP1 in the partitioned bulk data section. Step 2 - Reading the reduced Matrices into a new model using Automatic Attachment This is the second step (often referred to as the "system integrator" run) in the solution process. In this run, you have the structure, to which you wish to attach the reduced matrices, modeled as the residual structure and/or other superelements. The reduced matrices are read in by creating a section in the input file for a PART (by using a BEGIN SUPER = I , where I is the superelement id to be read in as reduced matrices). In the section of the input file following the BEGIN SUPER, you have: PARAM,INFILE, integer, 0, (default) implies that the data is in the section using DMIG entries. i, (A positive value) is the unit number of the file containing the reduced matrices from the first step. This file needs to be available and (if possible) attached using an ASSIGN statement in the FMS. PARAM,NEUTRAL integer, -1 ,(default)- binary file implies that the tables describing the OTM are on the OUTPUT2 file created in the previous run. Used only if OTM were created during step 1. >0 (formatted - beutral) then the tables are defined using DTI entries in the partitioned input data (should have the same value as was used in the run which created the reduced matrices) As many sets of matrices as are desired may be read in during one run. The limit is the number of files that may be opened on your computer at one time. Once steps 1 and 2 are complete, the alters are no longer needed, and the resulting databases should support the standard restart logic of MSC/NASTRAN. If you are using the OTM or if you want boundary forces on the superelements, then the third alter (alter9ga.v707) will be needed in any transient or frequency response restarts. OUTPUT: Standard MSC/NASTRAN output, plus any information calculated by the OTM. This information will also be in the standard output formats, unless the tables which describe the OTM are not used. LIMITATIONS: The alters use the automatic attachment logic of MSC/NASTRAN, but there is no checking in the alters to verify that the second run is using the same attachment locations as the first. If you incorrectly attach points, the results will be incorrect. SAMPLE FILES: The following files demonstrate the usage of these alters: alter1h1.dat - the standard sample problem from the superelement seminar notes. This run will create reduced files for 7 superelements. alter2h1.dat - reads in the reduced components from the first run and adds the residual structure model (a single element with its attachment points). This run solves for the assembly modes and creates deformed plots. Although the files are not included, the second run creates a database which could be used for restarts into a modal transient or modal frequency response solution. ADDITIONAL REFERENCE: Creation and Automatic Attachment of Reduced Component Models for Dynamic Analysis, by Ted Rose, Manager, MSC/NASTRAN Training and Support, The MSC.SOFTWARE Corporation Presented at the 1997 MSC Aerospace Users' Conference