Excessive Pivot Ratios Using RBE3 to surface 2

[MegaStructures]

Why do RBE3's connected to "nodes on surface" produce excessive pivot ratios error, yet RBE2 does not?

See attached model for example

 

[BlasMolero]

Hello!,
You have activated rotational DOF in the independent nodes of RBE3 elements, and this is forbidden, then the error. Please visit my blog in the following address:

https://iberisa.wordpress.com/2015/10/13/rbe2-vs-rbe3-on-femap-with-nx-nastran/

The most common end user error in RBE3 element specification results from placing 4, 5, or 6 in the Ci (independent DOF) field in addition to the translation components. The rotations of the dependent point are fully defined by the translational motion of the independent points. The ability to input 4, 5, or 6 in the Ci field is only for special applications, such as when all of the connected points are collinear.

Edit your RBE3 elements and select all the independent nodes in the list with Ctrl+Shift, click in UPDATE and remove the RX, RY & RZ rotational DOF, click OK and you are done!.

Best regards,
Blas.

~~~~~~~~~~~~~~~~~~~~~~
Blas Molero Hidalgo
Ingeniero Industrial
Director

IBERISA
48004 BILBAO (SPAIN)
WEB:

http://www.iberisa.com

Blog de FEMAP & NX Nastran:

http://iberisa.wordpress.com/