Sinusoidal displacement loading protocol

[giovannimilan]

Hi all,

is there an easy-way to prescribe a displacement history at specific nodes of a structure, referring to a .tcl file containing the protocol?

I'd like use a sinusoidal loading protocol used during the lab test.

Cheers,

[Jhno]

sp
http://opensees.berkeley.edu/wiki/index.php/Sp_Command

[giovannimilan]

Jhno wrote:
> sp
> http://opensees.berkeley.edu/wiki/index.php/Sp_Command

Thanks for the reply.

Does it require a non-Plain constrain handler?

I ve got a model with zero length element and EqualDOF and i get a warning that I Cannot run the analysis.

the thing is that i switched to lagrange handler but the deform shape does not make sense. it is messing with the others constrains I have in the model ( i reckon EqualDOF in aprticular).

see code below:
if {$analysis == "protocol"} {
puts "Running the sinusoidal loading protocol...\n"

timeSeries Path 1 -fileTime "protocol_time.tcl" -filePath "protocol_value.tcl";

set controlnode 5; # top node belonging to a rotational zero length spring

pattern Plain 1 1 {
sp $controlnode 1 1.0
}

set numberOfsteps 1343; # corresponding to 300 sec

set incrOutput 0.01

# Cyclic loading to the model by Disp. control
constraints Lagrange
numberer Plain
system BandGeneral
set TolStatic 1.e-7; # Convergence Test: tolerance
set maxNumIterStatic 500; # Convergence Test: maximum number of iterations
set printFlagStatic 0; # Convergence Test: flag used to print information on convergence (optional) # 1: print information on each step;
test EnergyIncr $TolStatic $maxNumIterStatic $printFlagStatic;
algorithm KrylovNewton;
integrator LoadControl $incrOutput
analysis Static
analyze $numberOfsteps; #steps

set currentTime [getTime];

puts "current time is $currentTime in sec\n"

puts "the loading protocol has reached the end...\n"
}

[Jhno]

I am sorry I wouldn't know exactly the solution to your problems.

If you have alot of constraint in the model, I don't think the plain handler will work, especially adding more SP_Constraint with the SP command.
Maybe you can try using the penalty method (large values, say 1.e18) and see what the deform. shapes look likes? Gl.

[giovannimilan]

Jhno wrote:
> I am sorry I wouldn't know exactly the solution to your problems.
>
> If you have alot of constraint in the model, I don't think the plain
> handler will work, especially adding more SP_Constraint with the SP
> command.
> Maybe you can try using the penalty method (large values, say 1.e18) and
> see what the deform. shapes look likes? Gl.

I made it run with constraints Transformation

Cheers,