Lateral and Angular method

I am modelling individual bellow elements for a press. bal. exp.joint by three methods.
1)inserting axial and lateral stiffneses
2)inserting axial and angular with zero length of bellow
3)inserting axial and angular with with non-zero length of bellow
The results(loads on adjascent equipment nozzle) by three methods differ substantially in lateral direction.
What may be the cause of difference in results and which is the recommended method?
Caesar calculates transverse stiffness for non-zero bellow element, where this calculated value appears.
What is the equation to calculate overall lateral stiffness based on individual stffness.

Thanks,
Rocky

Review the article on the Expansion Joint Modeler in the May 1993 newsletter . This will give you the background on the relation between the lateral and angular stiffnesses.

From what you describe you should get three different results.

The recommended method is to use the built-in modeler.

Thanks for the reply,
We got the vendor data for overall stiffness and individual stiffness.
This formula
Klat = 3/2 Kax * Deff(square)/l(square) suits for individual stiffnesses.
Can it be used for overall Lateral stiffness and Overall axial stiffness?
In that case what would be the l (flexible length of joint)
For press bal bellow would it be from from centre of elbow flange to nozzle flange end? or two individual bellow length+ length of spool peice in between or else.


Regards,