the kikuchi bearing element.. A VERY STRANGE ELEMENT!!!!

[aflo]

Hi,
I'm working with the kikuchi bearing element but I have a serious problem with it....
It works very well if used alone (I mean in a very simple configuration, like for example a single element with a mass on the top) while it has many problems when used into a more complex structure (for example a grid of high stiff beams on 4 isolators)

In particular I noted that in the second case (grid of high stiff beams, just like to simulate a big slab) it works in a time history analysis only if the Plain constraint handler is used????? Is there a specific reason for that?


thanks

[aflo]

Can you please HELP ME!!!

[fmk]

its a new element and has not been tested that much.

if 2d, you might try modeling with another element using the materials you are using now. if 3d you might need to use another element.

you might also send the script to see if the authors can spend some time figuring out why it is not working for your particular model.

[aflo]

Hi fmk,
I understand what you are saying, I know that this element is very new but at the same time It is very interesting... that's the reason why I studied all the papers by Kikuchi related to this element and the source code in cpp!!!! As I told you before, the KikichiElement works very good if used alone (I tested it with different loading path, carrying out static and dynamic analysis) but gives many problems when used into a 3D structure.

Anyway after many trial analysis I discovered the problem...I guess that all the problems are related to the axial springs (the MNS element) that represent the axial behaviour of the device. Neglecting this behaviour the element works, even in a TH analysis of a 3D base isolated structure. However, I would like to take into account the aforesaid axial behaviour!...In this case what you suggest? If you want I can send you the model by email (it is composed by three different files).

Thanks in advance!!!

[fmk]

you can send me the example you have. i was having problems with the one provided if i take out the stiff spring and change the forces to those that were coming out of the element in the original example. the more examples i can provide that demonstrate the problems the easier it might be to track them down.