Hi at all,
I am using plane strain and plane stress elements very often in my calculations. But frequently I don't know, how I have to define the acting forces on such elements. There are two possibities:
- force per unit width
So I made some investigations in FEMAP 11.2, concerning plane stress and plane strain elements and found out, that there are some inconsistencies in calculation results and in model definition procedure (see attachments).
Depending on which solver you are using, the definition of acting forces are different (marked yellow)
In some cases the Mises stress or the translation will be calculated wrong.
What does the plane stress option in Femap structual options inside the formulation dialog box do?
Regarding 2-D PLANE STRESS Solid elements in NX NASTRAN please note the following:
Click in FORMULATION and under NASTRAN select 2.. CPLSTS3,CPLSTS4, etc.. that are the NX NASTRAN 2-D Solid Plane stress elements, OK?.
I will prepare a simply model using FEMAP V11.2 to check that everything runs correctly, and results are reasonable, OK?.
thx for your fast reply. Using solver 101 and 106:
The plain strain element in xy-plane calculates a Mises stress like plane stress element, but elongations like plane strain. Look at the Analysis_summary.pdf. That's very mysterious.
Also the fact, that xy-plain strain elements have to be loaded via a force and xz-plain strain element have to be loaded via a force per unit width to get the same result.
In the new release of FEMAP V11.2.1 the error of writting a 2-D solid plane stress CPLSTS4 element as CQUAD4 element is solved, now if you click in PREVIEW ANALYSIS you will see that the nx nastran input deck is correct:
Also, the output vector computed by NX NASTRAN are plane normal stress results in the X & Y plane, as well as vonMises stress.
thx, I have just installed the latest FEMAP Version. Next time I will repeat my investigations using version 11.2.1 and give feedback again.