About element length devided????

[yuyanyanmegan]

I try to set up a bridge model .The pier is 30m. If set the element length as 30m,the period of the whole structure is 1.47s，but set the length of each element as 5m，the period is 0.83m； set the length of each element as 10m，the period is 0.87m； set the length of each element as 15m，the period is 1.09m；so Idon't know
which is the right one .Is there a reasonable range of element length? Thanks for your help!

[vesna]

This indicates that there is something wrong with your model. Make sure that mass formulation is consistent for different cases.

[yuyanyanmegan]

I want to make multiple nodes in a line move as a body ，how to do？'rigid link' is between double nodes , if it can use among nodes ,how to decide which one is the master node, which one is the slave nodes? By the way，cammad 'EqualDOF' how to use it?

[vesna]

Try to describe your problem in greater depth.

[yuyanyanmegan]

I'm building a bridge model, main girder is 6 T beams, don't consider bridge panel, so must make six T-beams movetogether, like a body, how to make ? what's more, piers is fixed to the upper structure, so want to make the pier , capping beam,and the girders move together, can we use 'rigidlink' ? The important question is, if use this command, how to decide , the master node and the slave node? It has a great effect on the dynamic characteristics . thank you so much !!

[vesna]

check this out: http://peer.berkeley.edu/publications/p ... M_etal.pdf