User Area > Advice
Typical warning message in the Text Ouput window in Modeller:
Midside Node
L of Quadratic edge M does not define BMI21 Element P defined by the edge end
nodes
And the
typical warning message from LUSAS Solver text output file (*.OUT):
**WARNING*** ELEMENT P IS ONLY
ATTACHED TO ITS NEIGHBOURS AT THE CORNERS (MPLOTM PROCESSOR)
Most common causes & links to solutions
This warning occurs due to a combination of linear interpolation order elements (a node at each
end/corner) and quadratic interpolation order elements (that have a mid-side node).
For example, whilst the end nodes of
linear order beam elements can be shared with corner nodes of
quadratic order shell elements, the midside node of the shell has no counterpart on the beam. By default, these ‘free’ midside nodes will be automatically ‘connected’ by using constraint equations. The
message may occur for example, if using a linear order 3D thick beam
element (Eg. BMI21) with a quadratic order thick shell element for
example (QTS8). However, since the release of V15 note that
there is a quadratic 3D Thick beam element (BMI31) which is compatible
for use with QTS8.
It best (where possible) to use the same interpolation order for elements that share an edge in LUSAS and avoid the automatic creation of constraints which can slow the solution and make the edges they are applied to behave as if over-stiff. Elements that only share end or corner nodes intentionally can be of different interpolation order in the same analysis without any problem or warning message.
Please refer to the Element Reference Manual and the
Theory Manual Volume 2 for more detailed information regarding the elements available in LUSAS. These
manuals are available via the Help menu in Modeller:
Help > Help Topics > Contents
Please also see the user area page Rules for connecting elements.
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