I am planning to mesh an axisymmetric "Casing", which approximately looks like a cylinder with some changing diameters as a shell model. I have already been trying to read myself into the different element types, but I was not able to extract the correct element for my case.
After the meshing, I am going to do a dynamic reduction.
The Quad elements are to prefer because of quality and precision reasons according to some references. But there are three main Quad elements in NX: CQUAD4, CQUAD8, CQUADR
CQUAD4 is according to the element guide the most common element, but is perhaps not perfectly fitting for my cylinder-like casing. CQUAD4 is better when meshing a doubly-curved shell (like a sphere) whereas the CQUAD8 performs better by singly-curved shells like cylinder. Is there anything I have to consider concerning the midnodes as there are 3 different possibilites to generate them?
Can somebody explain the advantages of the CQUADR to me please?
And which kind of element would be the best-suited for my case?
I already did a comparison with these three elements. The resulting eigenvalues are approximately up to 1% different. Where do these deviation come from?
Thank you a lot!
CQUAD4 has a linear strain variation and 5dof stiffness. There is no in-plane rotational (drilling) stiffness in the formulation. The in-plane rotations are typically constrained automatically by AUTOSPC
CQUADR has a linear strain variation and 6dof stiffness. An in-plane rotational stiffness is part of the formulation
CQUAD8 has a parabolic strain distribution. There is no in-plane rotational (drilling) stiffness in the formulation.