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creating spring support for beam element.

Pioneer
Pioneer
Hi, i am new on femap, i wish to know how to model spring support to the tip of beam element by assigning stiffnesses in all 3 translations. kindly assist.
4 REPLIES

Re: creating spring support for beam element.

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Rajith,

Here you are a tutorial to learn how to define in FEMAP a CELAS2 spring element with FEMAP & NX NASTRAN:

http://www.iberisa.com/soporte/femap/nolineal/celas2_nolineal.htm

 

spring

 

In order to enter the three stiffness in the three directions, simply create three elements sharing the same nodes, one per stiffness direction.

 

But, let me give you a recomendation: forget the spring element, better use the CBUSH element. The generalized spring-damper element CBUSH is a structural scalar element connecting two noncoincident grid points, or two coincident grid points, or one grid point with an associated PBUSH entry.

The advantages of using the CBUSH element over CELASi elements are impressing. For example, if you use CELASi elements and the geometry isn’t aligned properly, internal constraints may be induced. The CBUSH element contains all the features of the CELASi elements plus it avoids the internal constraint problem.

 

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: creating spring support for beam element.

Pioneer
Pioneer
thank for that... i chose to model as a DOF spring which you have suggested as first option .. as i am novice in the modelling, i am still having issues...i have 3 parallel columns(circular), each one arranged at corner of an equilateral triangle. the total length of column is over 100m but i am modelling the 3 columns only for 5m, then i wish to model an equivalent single beam element with the equivalent property of 3 parallel columns. so at the junction, i wanted to mate the 3 circular edges with one single beam element tip with all translations getting effectively transfered. i chose rigid element and i get the follwoing errors. kindly assist

5289 *** USER FATAL MESSAGE 5289, COMPONENT WITH EXTERNAL ID = ***, DOF = **, APPEARS MORE THAN ONCE ON THE SAME MPC CARD OR RIGID ELEMENT CARD.

An MPC entry or rigid element entry lists the same independent grid point more than once.

List each grid point once per entry.

Re: creating spring support for beam element.

Solution Partner Phenom Solution Partner Phenom
Solution Partner Phenom

Dear Rajith,

Make sure your RBE2 element don't have repeated nodes under the dependent nodes. What is telling you the error message is that a dependent node is used in more than one rigid element, or it appears more than once in the same rigid element, check your model.

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: creating spring support for beam element.

Pioneer
Pioneer
HI,

is it possible for me to attach screen shot of my model? thanks for your quick reply,

thanks once again.