How to create spring and attach to it a zeroLength element?

[ismailqeshta]

Hi,

I need to create a spring with a trilinear material and attach to it a zeroLength element with Elastic-No Tension Material.

Can anyone please guide me on how to create that?

Thank you.

[Prafullamalla]

try multilinear material with load-displacement relation instead of stress-strain. Assign this to zero length material and it will act as spring.
for no tension, i dont know about it,

[gswarup]

Hi,

I have once developed a compression only multilinear material in OpenSees by just modifying the existing multilinear material. I can give you the source file (.cpp) and also the .dll file but don't know whether the .dll file will work on your system. I am using 64bit Windows 8.1. But once you have the .cpp file you can link it with OpenSees based on the guidelines provided in "add a new material in Opensees". To use the material just replace the term 'MultiLinear' with 'MultiLinearCO',

'uniaxialMaterial MultiLinear $matTag $u1 $f1 $u2 $f2 $u3 $f3 $u4 $f4 ...' should be replaced by 'uniaxialMaterial MultiLinearCO $matTag $u1 $f1 $u2 $f2 $u3 $f3 $u4 $f4 ...'

Just make sure that your system doesn't have any rigid motion during reversal of loading, i.e. when tension is acting...

Best wishes...