i am just doing modal analysis of an electronic box. in that i have connect the diskdrives by using CBUSH element. after connecting CBUSH element i am getting error message 316,350 and 9002.
please help me how to use CBUSH element and how to connect it betweeen two solids.
i have attached the model.please go through...
Solved! Go to Solution.
Simply read the NX Nastran output file *.f06 and search for word FATAL, you will have there the reason of the error: you have defined CBUSH element no. 450 where the same node is used twice to orient the element.
*** USER FATAL MESSAGE 350 (IFS350) THE FOLLOWING GRID OR SCALAR POINTS ARE SPECIFIED MORE THAN ONCE ON THE BULK DATA ENTRY SHOWN BELOW: 408 *** USER FATAL MESSAGE 316 (IFPDRV) ILLEGAL DATA ON BULK DATA ENTRY CBUSH User information: See Bulk Data entry description in Section 5 of the NX NASTRAN Quick Reference Guide. If you are using the large field format make sure the number of entries is even. CBUSH 450 8 366 408 408
Editing the element 450 we see the reason of the error:
Simply instead the third-node use the option CSYS = Basic Rectangular, and you are done!.
Well, you have a problem, CTETRA is a 3-D solid model then not possible to "repeat" a node, the solid element will be planar, then NX NASTRAN will complaint giving error. The solution?, simply remesh your part and make sure the mesh quality is good, use TOOLS > CHECK > ELEMENT QUALITY to check that all elements pass the NX NASTRAN quality control.
Thanks for your answer, Blas
That's right, elements like that become 'flat'. Untortunately, I've tried remeshing with smaller element size and I kept getting the same error.
In one case I got a different errors like:
USER FATAL MESSAGE 350 (IFS350)
USER FATAL MESSAGE 316 (IFPDRV)
which says almost the same - that one node is used twice in one CTETRA element.
My last idea is simplifying the geometry. Do you think it might help ?
All the best,
Actualy mesher produce bad mesh at default mesh setting.
Element Quality Quality Check Number Failed Worst Value Aspect Ratio 848 36652.77 Taper 0 0. Alternate Taper 0 0. Internal Angles 4461 119.2943 Skew 4270 0.000423228 Warping 0 0. Nastran Warping 0 0. Tet Collapse 1987 1631644. Jacobian 2445 1.000006 Combined Quality 4482 1. 4482 Elements Failed out of 4535 Checked.
Some elements have aspect ratio more than 35000 - it is unacceptable for solver. You can carefuly manualy set mesh size on each curve to get good mesh or use tool Mesh->Revolve->Element (before this step you must slice you ring and create plate mesh on cross section of ring) and revolve plates into hexa elements.