I find this confusing.. Maybe it's because my background is in pressure vessels..
But let's consider a plate in tension only. If the design tension (nominal tension load × load factor) is just slightly greater than the design stress (yield divided by partial factor), then the design is...
Hi,@desertfox, you are correct. I'm also no expert as you can gather. I'm struggling a bit since from reading the standards here there are no 'rigid' guidelines.
Annex D as you point is based on testing (see image below) from EN 1990. The basic premise is that the partial factors and load...
Hi all,
I have begun to look into performing FEAs in accordance with EN 1993-1-5, and was a bit puzzled by Annex C of this standard which provides the rules. It allows the engineer to use any material model from linear elastic up to full elastic plastic, but does not mention any load factors...
Hi guys,
I recently came across a material which I have never seen before in an old boiler.
Name: EH 26 TI
Standard: VD/TUEV 478/1.
Does anyone know where I can find mechanical data on this material in a modern standard? What grade material does this correspond to?
Thanks
Hi guys!
I recently got asked by a client at what bending moment joint separation will occur (with and without internal pressure).
API 7G gives clear rules for calculation of separation tension (Eq. A.19), but as stated in A.10.7:
"A.10.7 CAUTION: The loads considered in this simpliÞed...
Hi all!
I'm attempting perform linear interpolation with 3 independent variables, like so:
The goal is to extract the rows corresponding to d0..d3 based on the inputs a, b and c.
Here is a simple test data set that I have put together:
Excel sheet here
I have done interpolation with 2...
Note that these are not bolts. These are more like pup-joints and X-overs, i.e. joints which connect large sections of piping in the main path of load transfer. Hence, the joints are subject to both tension and bending.
The joints are held in place by shear pins, not pretension.
Will this work for non-pretensioned joints in bending? My concern is that the peak stresses will become very large quickly in bending since the tension side is basically a point in a cross-section, rather than a uniform distribition across the entire cross-section as with tension.
Is there any...
Hi all,
I'm about to embark on 3D, pretty large scale, finite element calculations of a large assembly for subsea operations. In this assembly, there are a couple of large threaded contacts (think pup joints and X-overs). For strength calculations, I can either do this by hand or in a finite...
Hi ladies and gentlement,
I recently stumbled upon a drawing from 1997 with units of nozzle loads stated as "T" for force and "M.T" for moments. The vessel is delivered by Babcock. Are these given as tonnef and.. tonnef × meters? Any one familiar with this notation?
I haven't seen this...
Guys, thanks for pitching in. Since API 579 does not allow NOT taking residual stresses into account, I think that ends the debate (for my part). Assume, for the sake of argument, that some idiot machined in a crack in the vessel during manufacture.
The intention of this post was to ask how to...
Hi guys & girls,
I'm trying to enter the world of fracture mechanics of pressure vessels using FEAs. The first challenge I've encountered now is how to include residual stresses at weld beads?
An example of what a residual stress may look like (from API 579, Annex 9D):
I've also...
Thank you for replying guys,
I think I got it right. In my mind this was just a simple material mechanics problem concerned with converting the curvature/radius to bending moment. This can be done like so:
Should have posted this to the piping forums, my apologies.
Jules
@SnTMan, I'm actually not quite sure, but I think it's defined as the onset of yielding in the outermost fibre.
Simply put, I have been given data where the bending capacity (in pure bending) is given as 50°/100 ft. How to convert this to MKS units?
Jules
@TGS4, I was planning on doing a limit-load analysis for plastic collapse and Type 1 for buckling. Why do you propose Elastic plastic and type 3 instead?
Thanks.
Good day gents,
I about to embark on something I have never done before, which is design of a semielliptic head (2:1) via FEAs (I have only used DBF before). The head is to be designed for internal pressure and external pressure. There are a number of failure modes to investigate in both the...
Thank you for commenting!
I agree @TGS4. And using API 579 may lead us back to von Mises, correct?
However, what if 1) the client would like to know if the component is still in accordance with the original design code? Or 2)FEA calculations are required as part of a clients design...
