During Centrifugal Pump Simulation by using ANSYS, I obtained more elements than nodes. Is this possible or the number of nodes should always be greater than number of elements?
Typically, no. of nodes are always higher than the no. of elements. It's highly unlikely that your element numbers are higher compare to node numbers! Please check the element type once again.
Generally speaking, yes, if such elements as spring, gap, mass, etс. are used.
Always, the elements are more than nodes;
Regards
Dr. Saad M.
Biomedical Engineering Department
University of Technology - Iraq
Hi Dr. Saad Mahmood Ali ,
Is it really 'Always' element numbers are more than the nodes? I agree with Victor J. Аdlucky that, for mass and spring cases, it might be more, however, in most cases if an element comprises of 2 nodes (which is the minimum) and if you have 10000 elements which means you have 20000 nodes, isn't it?
NO! MOST OF THE TIME THE NUMBER OF NODES ARE HIGHER THAN THE NUMBER OF ELEMENTS . THERE ARE EXCEPTIONAL CASES LIKE IN CASE OF MODELING DUMPING OR ENERGY ABSORB-ER (SUCH AS, SPRING, MASS...AND SO ON YOUR QUESTION HAVE THE ANSWER,YES!)
Best regards!
Alemayehu Dawit
Why not. If you have tet mesh... One node at the apex is shared by multiple elements... So it can happen in case of tet mesh
Number of nodes are usually higher than number of elements, but in shell, wire and spring elements sometimes it can be possible that number of elements are higher than number of nodes.
Its possible if during meshing you drop midside node option. You can check it under mesh section of analysis. so to do this be sure you got to ANSYS mechanical(check the figure attached). is you change the element order to linear the midside node is dropped.
and
Click on the Mesh title in the outline in Mechanical.
In the Defaults portion is Element Order which can be set to Linear to drop mid-side nodes or to Quadratic for what used to be called mid-side nodes kept.
that is all!
Best regards!
30 years of FEM's - typically the number of nodes is greater than the number of elements. If FEM processor spits out elements first and then nodes such as Patran, there could be a error where the pre-processor stops and doesn't spit out the entire collection of nodes. In that case, the solver would not be able to run an you would find a FATAL error as in the case of MSC Nastran.
A simple example: Consider a square plate meshed with 4x4 squares, and each of these squares divided into 2 triangles. The total number of elements (triangles) is 32. The total number of nodes (corners) is 25.
Any model in any software, with many linear triangles/tetrahedra, is prone to have more elements than nodes.
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