$ $ 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. $ File mm44r.rdm MULTIPLE MASS CONFIGURATION SOLUTIONS IN SOL 144, mm44r.v707 M. A. Gockel, Last revised March 6th, 1997. (see new limitations section at end) 1. SUMMARY This alter package allows solution of mulitiple mass configurations in SOL 144 on on one job submittal. The bulk data includes a table each of whose rows include the name of a mass configuration [mnamei], followed by a list of mid's for mass matrices to be retrieved from the external data base and a scaling factor for each mass configuration. The basic mass configuration is included in the main bulk section. Masses for new configurations are included after the main bulk data section, in sections starting with BEGIN AUXMODEL=[mid], where [mid] is an integer. Each mnamei value may be selected by the M2PP command in a subcase. Each mass change subcase causes a loop through the entire analysis. After all internal matrices are computed and all outputs are provided in the first loop, all matrices relating to solutions and loads are deleted from the database, and re-calculated on the next pass through the loop. A similar looping takes place for each mass change subcase. The stiffness matrix and its many intermediate forms and factors are computed only once per run. 2. FMS INPUT Although this alter has not yet been tested for restart, it is essential that items stored in the data base are not deleted by the automatic functions associated with "scratch" data bases. Use "scr=no" on your nastran command line when submitting this job, if this is not the default value in your installation. Do NOT use "scr=yes". Do NOT include "init master(s)" in your FMS section, as this is similar in effect to "scr=yes". Use of these scratch data base features may cause stiffness components to be erased after the first pass through the loop, resulting in abnormal exits from the program or incorrect answers. It may be that the data base is reusable on restarts, but this has not yet been confirmed by testing. Restart testing is underway now. If necessary, an update to the alter will be delivered if changes are necessary for restart. In any event, the dbstore/dbfetch macros are used to store the auxmodel matrices, and this feature is not supported in restart at present. The reduced stiffness matrix and its factor are re-usable on restart, but the auxmodel data must be re-submitted on every run. 3. EXECUTIVE DECK INPUT This is conventional for SOL 144. Add include 'mm44a.v707' $ before the CEND entry. 4. CASE CONTROL INPUT Insert a subcase for each trim condition, and for each mass configuration. A mass configuration requires the presence of a M2PP = [mnamei] command in the subcase. The M2PP command does not normally cause any action in SOL 144. It is used in this alter to select a mass configuration. [mnamei] is the char8 value from the bulk data table described below. Place subcases with the same mass configuration but differing TRIM commands together for efficiency. For example, SUBCASE 1 TRIM = 1 $ 1 G LEVEL FLIGHT (LOW SPEED) M2PP = BASIC SUBCASE 2 TRIM = 2 $ 1 G LEVEL FLIGHT (HIGH SUBSONIC SPEED) M2PP = BASIC $ SUBCASE 11 TRIM = 1 $ 1 G LEVEL FLIGHT (LOW SPEED) M2PP = CONFIG2 $ CHANGE IN M2PP CAUSES NEW LOOP $ SUBCASE 21 TRIM = 1 $ M2PP = CONFIG4 $ NOTE M2PP CHANGED AGAIN The first two subcases have the same M2PP command, and will therefore be done on the same pass. Each of the other subcases requires a separate pass. 5. BULK DATA INPUT Input here is conventional. Also insert a DTI entry of the following form: $DTI MASSCF IREC MNAME S1 M1 Si Mid ETC DTI, MASSCF, 1, BASIC $ no incremental masses DTI, MASSCF, 2, CONFIG2 1.0, 2 $ full tip store DTI, MASSCF, 4, CONFIG4 0.1, 2 $ one-tenth full store IREC may be any unique integer. Open sets are allowed. MNAME is a char8 variable. This form does not allow included blank spaces. Si is the real scale factor used when adding in mass matrix MJJ(mid). Mid is the integer mid number. It must be >0. The first null or blank Si field signals the end of that record. A DTI record starts with DTI, MASSCF, . . There may be any number of continuation cards used for one record. There is no limit on the number of Si, Mi pairs that may be used on any record. The basic mass M(0) from the main bulk data deck is always added in automatically, with a unit scale factor. The total mass used in mass configuration [mnamei] is then M(mnamei) = M(0) + Sum[ Sj*M(midj)], j = 1 to N In this example the first record (mass configuration) use only the "basic" (main bulk data deck) configuration, while the third and fourth subcases add in the same incremental mass matrix (mid=2) but with different scaling factors. Each incremental mass bulk data deck follows the main bulk data section, and starts with the command BEGIN AUXMODEL=[Mid] Mid is a unique integer number used to identify the mass matrix Mjj(Mid) made from the incremental bulk data deck. Open sets are allowed. The last incremental bulk data deck is followed by the ENDDATA entry, which marks the end of the input file. For example, BEGIN BULK $ main bulk data section [include all of the conventional sol 144 bulk data here] $DTI MASSCF IREC MNAME S1 M1 Si Mid ETC DTI, MASSCF, 1, BASIC $ no incremental masses DTI, MASSCF, 2, CONFIG2 1.0, 2 $ full tip store DTI, MASSCF, 4, CONFIG4 0.1, 2 $ one-tenth full store $ begin auxmodel=2 $ first incremental mass input file $conm2 eid gid c mi CONM2 122 122 0 100.0 $ begin auxmodel = 4 $ second incremental mass input file CONM2, 122 122 0 10.0 ENDDATA The main bulk data deck includes all data to be used in the solution run. AUXMODEL=2 describes one incremental mass item. Any number of mass items may be included in any of these sections. Note that AUXMODEL=4 uses the same EID, but inputs a different value of mass. All bulk data sections, including the main bulk data section, must have unique eid's within themselves, but EID’s need not be unique with regard to other sections. The only data read in the incremental sections are data items in the GEOM2 file, which includes CONM1 and -2, CXXX's such as CBAR's, but not the scalar mass elements CMASSi. When other data, such as GRID, MATi, or CMASSi is present it is ignored without warning messages. The relevant data is obtained instead from the main bulk section. It is recommended that only CONM1 and CONM2 input be used in this section. When a structural element connectivity entry such as a CBAR entry is added its mass effect, if any, is added. It does NOT add to the stiffness matrix, however. This action is closer to an unprotected user error than a design feature. It is therefore recommended that strucutural element connectivity entries appear in only the main bulk data section. User parameters related to mass, namely WTMASS and GRDPNT, may be input above the case control level and/or in the main bulk data section. The latter placement takes precedence when the data is present in both locations. If these parameters are placed in the auxmodel sections they are ignored without warning. The sample problem mm441.dat is derived from the HA144A test problem described in the Aeroelastic Analysis User's Guide, and will provide the same answers as that input file. The bulk data is identical except that the WTMASS parameter is moved from the bulk data deck to case control to demonstrate this capability. This alter package replaces the mmprep and mmsol alter packages which are now withdrawn. The new package removes many of the limitations of the two prior packages. The user interface is basically unchanged, however. KNOWN LIMITATIONS These limitations may be removed over time. Contact your MSC Technical Representative if you encouter any other errors, and they can be rapidly fixed too. 1. There is some dmap in the alter inteded for superlements, but this phase of the development is not complete. Any use of part or any other superelement types at present will cause a fatal error. Some error messages include strange seid numbers, such as -1. These messages may be safely ignored. 2. If there are bulk data errors they are identified but the program does not terminate. Inspect your output for error messages before accepgting the results. End of 6 Mar 97 Notes.