Search found 5866 matches

by fmk
Mon Mar 19, 2018 9:54 am
Forum: Framework
Topic: How to add a new time integration algorithm?
Replies: 1
Views: 836

Re: How to add a new time integration algorithm?

it is siilar to element .. example in OpenSees/DEVELOPER/integrator
by fmk
Mon Mar 19, 2018 9:19 am
Forum: OpenSees.exe Users
Topic: Earthquake Analysis by Uniform Exciattion Pattern
Replies: 3
Views: 917

Re: Earthquake Analysis by Uniform Exciattion Pattern

in actuality the motion is oming into the structure in a physical manner that the multi-support motion provides .. other than uniform or multi-support no (unless you want to define some set of your own nodal loads)
by fmk
Mon Mar 19, 2018 9:17 am
Forum: OpenSees.exe Users
Topic: EigenValue of Shell
Replies: 3
Views: 443

Re: EigenValue of Shell

no .. and feature is not really suppoerted for beam elemens (someday it may stop working)
by fmk
Mon Mar 19, 2018 9:15 am
Forum: OpenSees.exe Users
Topic: Hysteretic material model
Replies: 5
Views: 721

Re: Hysteretic material model

if you are askng can you set the properties of hystereic to give same as epp, then yes just set the the 2p and 2n points off at infinity (i.e. some large number) .. (assuming of course roundoff does not come into play in the material definitions)
by fmk
Mon Mar 19, 2018 9:12 am
Forum: OpenSees.exe Users
Topic: initial imperfection in 3D trusses
Replies: 3
Views: 425

Re: initial imperfection in 3D trusses

some initial stress or initial strain in the material! .. turss elements are by definition straight .. if you want to model lac kof straightness you need to model with beams with small bending stiffness.
by fmk
Mon Mar 19, 2018 9:10 am
Forum: OpenSees.exe Users
Topic: Stiffness proportional damping to zeroLength element
Replies: 4
Views: 1015

Re: Stiffness proportional damping to zeroLength element

use a region command .. create the region with just the zero length elements and the specified rayleigh factors .. and do not use mass proportional damping term.
by fmk
Sat Mar 17, 2018 8:45 pm
Forum: OpenSees.exe Users
Topic: How to release bending moment at the end of a beamColumn ele
Replies: 1
Views: 531

Re: How to release bending moment at the end of a beamColumn

ine option would be to rotate the frame itself .. another might be to use zeroLength hinges and specify the orientation, and gave stiff materials for all but the dof you wanted to be constrained you possibly could do it .. i would check with a small model first.
by fmk
Sat Mar 17, 2018 8:42 pm
Forum: OpenSees.exe Users
Topic: Earthquake Analysis by Uniform Exciattion Pattern
Replies: 3
Views: 917

Re: Earthquake Analysis by Uniform Exciattion Pattern

if you using uniform excitation, the code just adds the force -mAg to the applied forces at all nodes that are not fixed.
by fmk
Sat Mar 17, 2018 8:40 pm
Forum: OpenSees.exe Users
Topic: Stiffness proportional damping to zeroLength element
Replies: 4
Views: 1015

Re: Stiffness proportional damping to zeroLength element

why don't you read the command manual .. instructions on how to add rayleigh damping is spelled out there ..
http://opensees.berkeley.edu/wiki/index ... th_Element
by fmk
Sat Mar 17, 2018 8:37 pm
Forum: OpenSees.exe Users
Topic: Issue with ForceBeamColumn element and convergence
Replies: 1
Views: 901

Re: Issue with ForceBeamColumn element and convergence

of course it runs smoothly with an elastic element! .. the issue is happening because the force beam column needs to iterate to find equilibrium after the nodal displacements have been set .. i suggest you look at the theory of the element to see what it does before you actually use it ( http://open...
by fmk
Sat Mar 17, 2018 8:32 pm
Forum: OpenSees.exe Users
Topic: Issue with the force-based element
Replies: 2
Views: 928

Re: Issue with the force-based element

the numbering of the dof does not effect the answer (at least if numerical roundoff is not an issue) .. the error you see from the force beam column is coming from the formulation, it is force based and not displacement based .. as a consequence at each trail set of displacements the element does so...
by fmk
Sat Mar 17, 2018 8:16 pm
Forum: OpenSees.exe Users
Topic: EigenValue of Shell
Replies: 3
Views: 443

Re: EigenValue of Shell

do you have mass defined? if so, does a static analysis actually work for the model?
by fmk
Sat Mar 17, 2018 8:14 pm
Forum: OpenSees.exe Users
Topic: OpenSees and Mac
Replies: 2
Views: 648

Re: OpenSees and Mac

issue the command: pwd
when you start the application to see just exactly what dir you are in
by fmk
Tue Mar 06, 2018 3:05 pm
Forum: OpenSees.exe Users
Topic: Can we apply dynamic load using Opensees?
Replies: 8
Views: 2298

Re: Can we apply dynamic load using Opensees?

the examples on that page if you were to care to look at them do multiple different dynamic analysis for an imposed earthquake/ if you want to apply lateral nodes at the loads create a path time series that describes how the load changes with time .. you apply the loads by associating that time seri...
by fmk
Fri Mar 02, 2018 9:44 am
Forum: OpenSees.exe Users
Topic: modalDamping command problems
Replies: 2
Views: 449

Re: modalDamping command problems

not till the code is changed and released. if you want to build your own version you could modify said integators to return the vel they are computing .. POST ONCE IN FUTURE