Hi,
This is a relatively simple - but pivotal - query. How do we (or don't we) take into account the presence of longitudinal welds in continuous ERW members, like rectangular hollow section, circular hollow section, etc?
What about in fatigue applications (as my specific case is)?
I don't...
If we imagine a prismatic coloumn under cyclic compression with no buckling effects or similar, and we imagine that somehow a crack appears in it, then assuming the crack is closed (negligible gap - because how can it open up without a tension cycle to pull it apart?) then the thing is, the...
I think your proposed use of St Venants principle is miss-applying it quite badly...
Sounds like you're wanting to use it to say "Stress at a distance is a good substitute for stress at this point that's badly modelled" when what it really says is "Stress at a distance is correct, regardless of...
To add to drawoh's point, I suspect in most countries (at least in mine - Australia) the key is that the weld is going to need to be qualified, as defined by some standard. One way or another there should be a standard(s) that you can call that will end up making sure the weld is manufactured...
LittleInch - yes you're right, although 0.2% proof strain could be useful as a standard measure of "yield", and used in combination with UTS (defined as the highest point on the curve). That way if 0.2% proof is very low compared to UTS, at least you know that the thing is acting very...
My experience as a mixed metals/plastics engineer, is that for tensile results, the plastics industry runs a constant displacement/second test (as does metals industry), and then critically, much of it defines yield as "the highest load it was able to react" (what we would call ultimate strength...
Short and to-the-point answer, they need as much detail as is required to make sure the part functions. If you have a good relationship and understanding with a supplier and want to bet on that, that might be less than is explicitly required to define the part (e.g. if you know they will use a...
One more question,
I've established a datum reference frame using my 6 datum points, shown the axes X,Y,Z in two views to make it explicit, and now I need to decouple some of my tolerances of profile from one of the axes. For example, I have one complex surface that needs to be free to move on...
We are designing the component that goes into someone elses system. We as a business have a long term relationship with both our clients and our suppliers, and it's in our interests to make both parties happy, rather than hands-off "do as you will". Neither of those two parties has good context...
3DDave,
Ahhhhh I see what you mean. I have seen that about the irregular surfaces but didn't realise I could use datum targets to basically define multiple 'regular' surfaces into an irregular one.
In the interest of my continued professional development - I'd like to re-read the relevant...
I have a part which is intended to sit in a jig that restraints it on all 6 degrees of freedom, with only the necessary and sufficient points. This is required for part function, as it is manufactured on a jig, tweaked on the same jig, QC'd on an identical jig, then installed with another...
OK so that's interesting. A star for you for now teasing me with hopefully imminent good discussion ;)
1) I can 100% believe that phase transformation can take a while - mainly because I don't understand the mechanisms so I have no reason to believe it wouldn't take a while, except that I...
@R13
You're right ofcourse, but the chance that it changes the results enough to change the conclusion, is minimal, given how many (quadratic) elements are already there. Purely based off my judgement (not really worth a convergance analysis)
@Saplanti
Realistically the 20mm pin in 30mm hole...
R13:
They are identical models already. I mirrored them across the centre plane then deleted out the strip under the hole. The plates are also restrained between lugs so that stresses cannot transfer between lugs.
dik:
ANSYS
HTURKAK:
Pins 20mm, pulled horizontally. Tightened up mesh at...
Hi all,
The implication that this somehow solves some stress issues, and my inability to intuit my way through that (the explanation is very unclear to me), led to some comparative FEAs I wanted to share with you (which mostly confirm that this does not really help anything). Let me walk you...
Hi all,
I understand residual strains and uneven hardening at a non-metallurgists level (i.e. what I'm missing may be key to the answer of this question), but that understanding indicates that when you remove some of the steel, the residual strains it was imposing would redistribute basically...
Hi,
It's a fairly common occurance in my work that 4140 quenched and tempered shaft, when machined to reasonably precise tolerances (e.g. 0.1mm TIR over 500mm, for a Ø120mm shaft), needs to be 'rested' for 24 hours or more between the last few passes on the lathe, to let it distort, so that...
Yeah I would buy the "Carryover" design explanation - Suspect no one remembers why these exist thus no one has the confidence to eliminate them.
We can't ask "the" fabricators because these are across multiple fabricators, industries, and countries. Not one fabricator.
I have seen these...
Thanks for your responses so far guys. The most realistic sounding guess in our office so far, is that it gives a way for the padeye to shrink to relieve welding stresses along its length. For me though, while this would reduce welding stresses... why? If eliminating the stress was to reduce...
