velocity or displacement time history in nonlinear analysis

[horizon]

Hi all,
Is it possible to apply velocity or displacement record as uniform excitatioin to the structure in nonlinear analysis?
Bests

[silvia]

not velocity, but displacement yes, but with the multiple-excitation command (you just apply the same excitation to all the nodes).
remember, to make this match the acceleration input you have to put in the proper initial conditions for velocity.
here is a script that I have, i haven't used it in a while, but it should work, or, at least, it gives you a good place to start:

Code: Select all

      set inFile $GMdirectory$GMFileNameA
      set modtxt Mod
      set outFile $GMdirectory$modtxt$GMFileNameA;   # set variable holding new filename 
      procReadSMDFile $inFile $outFile dt;      # call procedure to convert the ground-motion file
      set dispSeries "Series -dt $dt -filePath $outFile -factor  $GMfattA ";   # time series information
      pattern MultipleSupport $IDloadTagGMA  {
         groundMotion $IDgmSeries Plain -disp  $dispSeries
         foreach SupNode $iSupNode {imposedSupportMotion $SupNode  $IDdofA  $IDgmSeries }
      };   # end pattern

another one:

Code: Select all

--------------------------------------------lateral-load analysis
# ------------------------------------------------------------------
# GroundMotion.tcl: dynamic ground-motion analysis
# Silvia Mazzoni, Febr 2005
#
# create load pattern
set IDloadTagA 4;

# set analysis parameters
set DtAnalysis	[expr 0.01*$sec];	# time-step Dt for lateral analysis
set DtGround 	[expr 0.02*$sec];	# time-step Dt for input grond motion
set TmaxGround	[expr 5. *$sec];	# maximum duration of ground-motion analysis -- should be 50*$sec

# setTime -$DtGround

set GMampl [expr 2*$in];			# sine ground-motion acceleration amplitude
set omegaSine [expr 0.5*$omega];
set TperiodSine [expr 2*$Tperiod];
set vel0 [expr -$omegaSine*$GMampl];
	set dirn 1;		# ground-motion direction
	set basenode 1;
	set GroundFile "H-e12140"  ;	# ground-motion filenames 
	set GMfact 1.0;	# ground-motion scaling factor
	# read a PEER strong motion database file, extracts dt from the header and converts the file 
	# to the format G3 expects for Unifform ground motions 
	source ReadSMDFile.tcl;	# read in procedure Multinition
	set dir "GMfiles/"
	set outFile $dir$GroundFile.g3;	# set variable holding new filename (PEER files have .at2 extension)

	if {$ModelType == "CantiMSsine"} {
		set GMscale [expr $GMampl]
		set dispSeries "Sine 0. $TmaxGround $TperiodSine -factor $GMscale "
		pattern MultipleSupport  $IDloadTagA    {
	    		  set IDgm 1
	    		  groundMotion $IDgm Series -disp $dispSeries
			  imposedMotion $basenode $dirn $IDgm 
		}
	} elseif {$ModelType == "CantiUSsine"} {
		set GMscale [expr $GMampl*(-1.)*$omegaSine*$omegaSine ];	# acceleration corresponding to displacement hist.
		set accelSeries "Sine 0. $TmaxGround $TperiodSine -factor $GMscale"
		pattern UniformExcitation  $IDloadTagA  1 -accel $accelSeries -vel0 $vel0
	} elseif {$ModelType == "CantiUS"} {;		# UnifFORM EXCITATION
		set inFile $dir$GroundFile.at2
		ReadSMDFile $inFile $outFile dt;		# call procedure to convert the ground-motion file
		set GMfatt [expr $g*$GMfact];		# data in input file is in g Unifts -- ACCELERATION TH
		set GMseries "Series -dt $dt -filePath $outFile -factor  $GMfatt";	# time series information
		pattern UniformExcitation  $IDloadTagA  $dirn -accel  $GMseries ;		# create Unifform excitation
	} elseif {$ModelType == "CantiMS"} {;	# MultPLE-SUPPORT EXCITATION each node has a Multferent input ground motion
		   set inFile $dir$GroundFile.dt2
		   ReadSMDFile $inFile $outFile dt;		# call procedure to convert the ground-motion file
		   set GMfatt [expr $cm*$GMfact];	# data in input file is in cm Unifts -- DISPLACEMENT TH
		   set GMseries "Series -dt $dt -filePath $outFile -factor  $GMfatt";	# time series information
		   pattern MultipleSupport $IDloadTagA  {
			groundMotion 1 Plain -disp  $GMseries 
		     	imposedSupportMotion 1 $dirn 1
		   };	# end pattern
	}