Zero length element using impact material.

[ftoledoj]

Hi: am modelling impact with a zero length element, but when i run the model i get force 0 in all directions but displacement different than zero in the zerolengthelement, the displacement of the structure is enough to activate the element but i cant find why the element doesn't seems to work. Is the dir am using ok? my model is 2d model. Here is what i have used in the code

#impact element
set K1 [expr 1311899*$tonf/$m];
set K2 [expr 473332*$tonf/$m];
set dy [expr -0.1*$cm];
set gap [expr -0.1*$m];
set itag 10;

uniaxialMaterial ImpactMaterial $itag $K1 $K2 $dy $gap

set dir1 1;

element zeroLength 9000 1 110 -mat $itag -dir $dir1 0 0 0 0 0
element zeroLength 9001 2 111 -mat $itag -dir $dir1 0 0 0 0 0
element zeroLength 9002 3 112 -mat $itag -dir $dir1 0 0 0 0 0

[vesna]

you should specify your elements like this:

element zeroLength 9000 1 110 -mat $itag -dir $dir1
element zeroLength 9001 2 111 -mat $itag -dir $dir1
element zeroLength 9002 3 112 -mat $itag -dir $dir1

in addition, you need to tie together nodes of zeroLenght elements in other two directions. you can do it either by using equalDOF command or by using fix command (if master nodes are fixed in directions 2 or 3).

[megiddo]

You can try this element:

http://opensees.berkeley.edu/wiki/index ... thImpact3D