I think the best measure is to check the ratio of bending or membrane energy to total internal energy in the model, but I don't believe most FE codes give such output.
One qualitative estimate would be to plot the stresses at the shell midsurface and the stresses at the top (or bottom) surface...
Hi Jsboy,
Are you talking about a shell or plate problem? In that case, there are two types of loading: bending-dominated and membrane-dominated. Is that what you mean?
Nagi
I agree with Drej that it all depends on the specifics of the model which we don't have that much information about.
For such a slow speed process implicit analysis (with the right contact settings) will usually work. In many cases, such as this one where mass scaling is significantly...
Also check out this website:
http://ppi2pass.com/catalog/servlet/MyPpi
They have a lot of useful references for the FE and the PE exams, as well as links to state boards. I just ordered a 30 day access to their Internet based Exam Cafe (for the FE exam).
Nagi
I believe that if you don't need any of the advanced features of high end FEA software, and you customer does not dictate the choice of FEA software then you might be better off with a cheaper FE software.
But I would be careful before concluding that I don't need the advanced features. Let's...
Hi dollbulldog,
In large deformation axisymmetric analysis the equation relating the hoop strain to the radial displacement changes, so that must be taken into account in the FE code.
Nagi
I would use the averaged stress since it is usually closer to the exact stress value. The difference between the non-averaged values at a node is a measure of the error. If it is too large I would use a finer mesh.
Nagi
I'm not familiar with ABAQUS, but this type of problem is common to FE analyses involving friction. You should try making the frictional constraint "softer". This means that the stick slip distinction is smoothed out.
I believe in ABAQUS the parameter to do is the called the...
You're right cb4 the principal stress can't be that much higher than the von Mises stress for a curved beam since it is unlikely that the 3 principal stresses in that case be all comparable in magnitude (and same sign).
Meher, what was the value of the maximum principal stress, the v.Mises...
Hi Meher,
That is perfectly acceptable. If the 3 principal stresses are S1, S2 and S3, the von Mises stress
Sv = sqrt( (S1-S2)^2 + (S1-S3)^3 + (S2-S3)^2 )/sqrt(2).
So, the principal stresses can be greater than the von Mises stress. Consider, for example, S1=S2=S3=1000. The von Mises...
Feadude,
I don't recall the values for the quadratic tet, but is should be relatively straightfoward (to go from nodal values to integration point values). You find the r,s,t coordinates of the integration point and substitute them in the shape function for each node. You then multiply the...
One more thing feadude,
If you have the unaveraged nodal values you can obtain the integration point values. For a 4-noded 2D element the stress (or any other quantity) at an integration point is 0.6220*value at closest node + 0.0446*value at farthest node + 0.16667*value at each of the 2...
I know that ADINA has a 900-node version that costs $140 and it comes together with a finite element book. That may be ideal if your 500-element model doesn't exceed the node limit above. See www.adina.com for details.
Hey FEMdude,
For the price you want, I suggest that you look into ADINA (www.adina.com). They have a 900-node version for about $100, and they sometimes give a full version for free for a couple of months. The full price of their structural module (with nonlinearities) is close to your price...
