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hello i compare elastic, viscous and viscousdamper materials to model transmitting boundary. by alpha (power factor) equals 1, elastic and viscousdamper materials give further absorbed energy, but viscous material gives less absorbed energy. should they be the same by the same property? what power f...

thanks frank

I'll check it with 0 damping.

is not necessary to add the base displacement ( imposed motion) to frame displacement by 0 damping to get the same result with uniform excitaion.
what is damping role that must zero to give same results?

best regards

hello all i create velocity history by integrating of accel history and create disp history by integrating of vel history. is it correct to multisupport excitation? when i use multi support excitation with them by constraint transformation and add for example disp history excitation to frame respons...

thanks mhscott

hi

how can i get initial and current stiffness matrices.

thanks a lot dear frank i want to consider soil foundation structure interaction. and i don't have any pile under column. i know about them. thanks, i didn't attend that quad elements with have 2 DOFs in every nodes, don't result rotation. i modeled the base plate under columns as rigid, and got rea...

but it results zero rotation at bottom the column.
i want the rotation equals to rotation of quad node.

hi and thanks frank i know that. but i don't know how can i connect it in model -ndm 2 -ndf 2. rotation is not fixed and column is unstable. in other my model, i created smaller quad elements and define rigid link below the column then use new equal DOF between nodes of rigid link and nodes of quad ...

hi for viscous damper. try viscous materials uniaxialMaterial Viscous $matTag $C $alpha $matTag integer tag identifying material $C damping coeficient $alpha power factor (=1 means linear damping) link: http://opensees.berkeley.edu/wiki/index.php/Viscous_Material i guess you should assign it to a tr...

hello and thanks vesna

i used equalDOF command in 2 DOFs and it has error.
i guess i should add element between column and quad elements, for example (base plate), and then use equalDOF command in 2 DOFs that creates rigid connection between them.
is it right?
is there any better or easier way?

hello i cant connect beamcolumn element to quad element. i has error in calculating the first period that shows unstability. quad elements are built in model -ndm 2 -ndf 2 model and beamcolumn elements are built in -ndm 2 -ndf 3 and i cant connect them properly. in following cod if i wrote (equalDOF...

hello i cant connect beamcolumn element to quad element. first period is very big that may show unstability. results of column force are zero. quad elements are built in model -ndm 2 -ndf 2 model and beamcolumn elements are built in -ndm 2 -ndf 3 and i cant connect them properly. in following cod if...

thanks a lot Vesna

thanks Vesna

thanks a lot Vesna i have one question else. i use Hinton-Rock-Zienkiewicz (HRZ) method method to calculate nodal mass of non rectangular quad elements. for a big domain, i saw slithery differences to calculate period between mass density usage of quad elements and nodal mass by HRZ method. what met...