Apply Displacement History

[bassking]

Hi, i wuold like to know how to apply a displacement time-history record to a model.
Thanks for any help

[vesna]

You can use Multiple Support Excitation load pattern: http://opensees.berkeley.edu/wiki/index ... on_Pattern

You can find examples of this on the example page: http://opensees.berkeley.edu/wiki/index ... les_Manual

[bassking]

Thank you for your help!
With this command is possible to impose a rotation just setting the right DoF at the imposedMotion?

[vesna]

Yes, it is.

[bassking]

Which command do i use to impose a displacement in 2 direction (for example 1 (for me X) and 5 (Rotation in Y) at the same time??

[vesna]

you need to use "ImposedMotion" command, but you need two of this commands within the load pattern.

e.g.

pattern MultipleSupport $patternTag {
groundMotion 1...
groundMotion 2 ...
imposedMotion 3 1 1
imposedMotion 3 5 2
}

[bassking]

Dear Vesna i have a question,
i must found the acceleration of a simple oscillator applying this 2 motion (X and RY).
Is the same if i firsly found the response only for the X motion, then the response for RY motion and then with a simple sum the response of both the eccitations?

[vesna]

your question is not clear. would you restate it?

[bassking]

I would like to know how Opensees work with 2 different ground motion in 2 different Dof, wich are connected to 2 different vibration mode.
Do Opensees finds the structural response for the first input, after for the second input, and then makes the sum of the two output?

[vesna]

If the two ground motions are acting on the system at the same time they need to be applied on the system at the same time, unless all of your elements are elastic in which case you can superimpose the responses from two ground motions.

So, the response to your question is YES if the system is elastic, and NO if the system is inelastic.

[bassking]

Im make this question because i notice some probleme with rayleigh damping in my structure. It seems that if i apply this 2 kind of motion opensees don't take in account the damping. Like i said before i model a linear oscillator, with a lumped parameter model (spring mass and dashpot) at the base tho model the soil, i use region command to impose damping at the elastic beam column that rapresent the oscillator. When i run the 2 motion at the same time results are not the same as the sum of the two

[vesna]

It is strange.

Would you post the script that includes all cases that you consider.

[bassking]

This is my model, Rayleigh damping is imposed only in the elastic beam column with region command


# --------------------------------------------------------------------------------------------------
# Force=Kn, Lenght=m Kpa=Kn/m^2 Mass=Tonn
# SET UP ----------------------------------------------------------------------------
wipe; # clear opensees model
model basic -ndm 3 -ndf 6; # 3 dimensions, 6 dof per node
file mkdir myloes; # create data directory

# define GEOMETRY -------------------------------------------------------------
set massDeck 350;
set Lpier 6;
# Lumped-Parameter Model (Excel-Lumped Parameter Model(Fondazioni cilindriche incassate Foglio3))
set M1rot 115.02;
set M0rot 0.;
set Kh 295177.14;
set Krot 248483.10;
set C0h 12032.19;
set C0rot 1490.90;
set C1rot 3441.5;
set ecc 1;
#___________________END INPUT__________________________________________________

# nodal coordinates:
node 11 0. 0. 0. -mass 0 0 0 0 $M0rot 0;
node 12 0. 0. 0.;
node 13 0. 0. 0. -mass 0 0 0 0 $M1rot 0;
node 14 0. 0. $ecc;
node 15 0. 0. $ecc;
node 2 0. 0. $Lpier -mass $massDeck $massDeck $massDeck 0 0 0;

# Single point constraints -- Boundary Conditions

fix 15 1 1 1 1 1 1;
fix 12 1 1 1 1 1 1; # node DX DY RZ
fix 11 0 1 1 1 0 1;
fix 13 1 1 1 1 0 1;

# Lumped-Parameter Model

set StiffX 4;
set DampX 6;
set ImpX 8; #Impedence in X
set StiffRY 5;
set DampRY 11;
set ImpRY 9; #Impedence in RY

set DampRY0 7;
set Zero 10;
set ImpRY0 12; #Impedence in RYO

uniaxialMaterial Elastic $StiffX $Kh ;
uniaxialMaterial Elastic $StiffRY $Krot;
uniaxialMaterial Elastic $Zero 0.00000001;
uniaxialMaterial Viscous $DampX $C0h 1;
uniaxialMaterial Viscous $DampRY0 $C1rot 1;
uniaxialMaterial Viscous $DampRY $C0rot 1;

uniaxialMaterial Parallel $ImpX $DampX $StiffX;
uniaxialMaterial Parallel $ImpRY0 $DampRY0 $Zero;
uniaxialMaterial Parallel $ImpRY $DampRY $StiffRY;

element zeroLength 1415 15 14 -mat $ImpX -dir 1;
element zeroLength 1112 12 11 -mat $ImpRY -dir 5;
element zeroLength 1113 11 13 -mat $ImpRY0 -dir 5;

# define ELEMENTS -------------------------------------------------------
# set up geometric transformations of element
# separate columns and beams
# in 3D model, assign vector vecxz

set IDColTransf 1; # all columns
set IDBeamTransf 2; # all beams

geomTransf Linear $IDColTransf 0 1 0;
geomTransf Linear $IDBeamTransf 0 0 1;

#PIER-------------------------------------------------------------- (from Pile.tcl)
element elasticBeamColumn 1 11 2 1.3273 25000000 12500000 100 0.1402 0.1402 $IDColTransf;
#Rigid Link
rigidLink beam 11 14
# Define RECORDERS -------------------------------------------------------------
recorder Node -file myloes/DFree2.out -time -node 2 -dof 1 2 3 4 5 6 accel; # accel of free nodes
recorder Node -file myloes/DFree11.out -time -node 11 -dof 1 2 3 4 5 6 accel; # accel of free nodes
recorder Element -file myloes/FCol.out -time -ele 1 force; # element forces -- column

region 1 -ele 1 -rayleigh 0.671999 0. 0. 0.002581; # RAYLEIGH damping

#define GRAVITY -------------------------------------------------------------
timeSeries Linear 1
pattern Plain 1 1 {
load 2 0 0 -3500 0 0 0;
}
constraints Transformation; # how it handles boundary conditions
numberer Plain; # renumber dof's to minimize band-width (optimization), if you want to
system BandGeneral; # how to store and solve the system of equations in the analysis
algorithm Linear; # use Linear algorithm for linear analysis
integrator LoadControl 0.1; # determine the next time step for an analysis, # apply gravity in 10 steps
analysis Static; # define type of analysis static or transient
analyze 1; # perform gravity analysis
loadConst -time 0.0; # hold gravity constant and restart time

# DYNAMIC ground-motion analysis -------------------------------------------------------------
# create load pattern
timeSeries Path 99 -dt 0.02 -filePath PacoimaMYLO_traslaz3m.tcl ;# Displacements Time-History Pacoima
timeSeries Path 98 -dt 0.02 -filePath PacoimaMYLO_rotaz3m.tcl ; # Displacements Time-History Pacoima

pattern MultipleSupport 99 {
groundMotion 70 Plain -disp 99; # groundMotion $gmTag Plain <-accel $tsTag> <-vel $tsTag> <-disp $tsTag> <-int (IntegratorType intArgs)>
groundMotion 71 Plain -disp 98;
imposedMotion 11 1 70
imposedMotion 11 5 71
};

# --------------------------------------------------------------------------------------------------

# display displacement shape of the column
#recorder display "Displaced shape" 10 10 500 500 -wipe
#prp 200. 50. 1;
#vup 0 0 1;
#vpn 2 1 0;
#display 1 5 40

# create the analysis
wipeAnalysis; # clear previously-define analysis parameters
constraints Transformation; # how it handles boundary conditions
numberer RCM; # renumber dof's to minimiz7e band-width (optimization), if you want to
system BandSPD; # how to store and solve the system of equations in the analysis
test NormDispIncr 1.0e-3 100 0; # ConvergenceTest object
algorithm ModifiedNewton -initial; # use e Newton-Raphson algorithm to solve the nonlinear residual equation
integrator Newmark 0.5 0.25 ; # determine the next time step for an analysis
analysis Transient; # define type of analysis: time-dependent
analyze 1232 0.02; # apply 1231 0.002-sec time steps in analysis


puts "Done!"
wipe

[vesna]

I want to let you know that you can not have in parallel viscous material with other materials. When in parallel with other materials viscous material is ignored.

What load pattern did you use for the cases where you applied the loads one at a time?

I need your ground motions to be able to test your code (vesna at berkeley dot edu).

[bassking]

In another discussion you say i can model my spring and dashpot sistem with Parallel material command, what is change?

http://opensees.berkeley.edu/community/ ... =2&t=53587

when i use only 1 load i simply delete one of the imposed motion command