The OpenSees Community

I am using pressure dependent material I am getting convergence error after 25 iterations do i need to modify my analsis commands as i am posting here constraints Transformation test NormDispIncr 1.e-12 25 0 algorithm Newton numberer RCM system ProfileSPD integrator Newmark 0.5 0.25 analysis Transient

Can we get stress as output for quad elements?
are force are stiffness only recorded using quad element and is there any way we can get stresses from quad element?
Can any body suggest me the format of recording stress usind element recorder if it is possible?
Thank you

I am doing a 2d analysis and can we use quad element and beamcolumn element in the same model?
since ndf of 3 is not allowed in case of quad elem
Please suggest me

while using zerolength elements between two surfaces to simulate seperation, what can be the stiffness at the interface?
Is it zero?

can we give mass density as argument while defining ndmaterial elastic isotropic
It is not showing any error but will it actually take it as an argument as mass density?

while simulating transmitting boundary i have used zerolength elements fixed at one node and the other node connected to soil domain I am getting some results if i use uniform excitation command but if i use multisupport excitation by converting the acceleration time history to displacement time his...

so i need to specify density as well as body force of -rho*g for the element
I dont want to calculate stresses for gravity loading but i just need to define initial condition before transient analysis
So can i proceed with element density or provide both

If we want to specify mass density for a material, can we input it through body force in quad element? there is also element density in quad element. So which one i have to use for density?
I am in confusion some one please help me out

you can use Gid as pre-processor as well as post processor with some coding,
and run opensees from Gid itself

If i am using SI units (m, s, KN, ton) and using a quad element, how can i define mass density i mean its units ?
is ton/cubic meter ok

we will specify mass density of material for this pressure dependent material, do we need to define density in element command also, Is there any difference between material density and element density?

it is for 2d analysis and you can always use brick elements for 3-d elements,
check the manual for different element types

I am using rayleing damping for my model, so it has alpha and beta. But there there are other 2 parameters in rayleigh command and if i need constant damping ratio of 5% to all modes how can i define by this command.
rayleigh 0 0.05 0 0
is it ok?

I am working in windows xp environment
you can download some tcl scripts from boris jeremic home page,
you need to use consistent units i.e you have to follow the same system of units through out your problem

How can we define a constant damping ratio with rayleigh damping?
Is it possible to define constant damping ratio for all modes?
can any body suggest me to define 4 constants in rayleigh command