Subject: Re: Craig-Bampton reduction From: Ted Rose Date: Tue, 23 Apr 2002 08:09:27 -0700 Reply-To: "MSC.NASTRAN Discussion Group" MIME-Version: 1.0 Hi - if you just want to create a reduced model to send to someone else, there are many ways to do this. There are 3 sets of DMAP alters in the sssalter directory (alterxga.vxx, alterxha.vxx, or alteria.vxx - x =1,2,9 and xx = version of Nastran) which will do it. There is also a standard feature in the program using a parameter called EXTOUT To use this, do the following: 1) Set up your model to run (probably for SOL 103), including the METHOD command and the EIGRL for the modal reduction. 2) add the following entries to your bulk data: PARAM,EXTOUT,yyyyyyy yyyyyyy = DMIGPCH = matrices written as DMIG in punch file DMIGOP2 = matrices written as "DMIG" in OUTPUT2 file MATRIXDB = matrices stored in database DMIGDB = matrices stored as DMIG in database SPOINT,i, thru,j i = starting id j = ending id create one SPOINT for each mode you are going to calculate - (these are the "placeholders" for the modes) ASET1,dof,GRID for each interface GRID point, add one ASET or ASET1 entry which lists the dof you want to have in the reduced matrices (if in doubt, use all 6 dof) that's it..... There is a conference paper I wrote on this (I think for the 1999 Aero conference), which goes into more detail. Good luck - Ted At 03:57 PM 4/22/2002 +0200, Roman Chomicz wrote: >MSC.NASTRAN Discussion >Hi everybody, > > > >I have to perform a Craig Bampton reduction but I have no idea about how I >can implement it. Anybody knows something about it? > >Thanks, > > > >Roman > > > > >--- >You are currently subscribed to msc.nastran as: ted.rose@mscsoftware.com >To unsubscribe send a blank email to >%%email.unsub%% *************************************************************************** Ted Rose - ted.rose@mscsoftware.com Manager of MSC.Nastran Training and Support MSC.Software Corporation 815 Colorado Blvd., Los Angeles, Calif., 90041 Tel: 323-259-3825 Fax: 323-259-4999 *************************************************************************** DISCLAIMER: The views expressed in this e-mail are those of the author and do not reflect corporate views or policies of The MSC.Software Corp. (and for that matter they probably don't even reflect reality) ###################################################################### Men stumble over the truth from time to time, but most pick themselves up and hurry off as if nothing happened. --Sir Winston Churchill ######################################################################