Hi all
I would like to know if someone could tell me the formula to apply to calculate the stress at point A on the diagram.
The idea is to make a form to quickly calculate if it fits with a coefficient given at the start.
The variables are: Beam section (Tube, IPN etc...), Embedded length, Applied weight, distance of weight on beam (L1), offset of weight with respect to beam (L2).
Thank you
Hello @ronathan
View the attached PDF. It seems to me that there is in addition to the PDF formulas such a tool natively in SW (like for ball bearings but I never use it)
Look here you have the formulas if the load is not centered, works as a lever, etc...
Kind regards
Thank you for your answer, but unfortunately I don't have a MyCadservices account.
Otherwise the link gives us the formula for the displacement, I want to have the formula for the max stress at the recessed point.
From there I could deduce Rpe and therefore check the chosen section.
Hello ronathan
I would like to share with you (a little off-topic) a point of view on recessed beams.
From my point of view and experience, the solidity of the embedding is often undermined by a lack of precision on the nature of the embedding (rdm of the embedding itself and especially the depth of the recessed part of the said beam as well as the quality of the supports.
Even when you have, for example, a square tube with a large cross-section or a large IPN embedded during the pouring of concrete : if you look some time later you will notice that the embedding has taken on some play, especially because it cannot take into account thermal expansion or the decrease in length. The only advantage of strict embedding is to reduce in theory the nature of the bending.
Just out of curiosity between colleagues, what do you do as a type of embedding and why?
Kind regards
On my example it is a tube welded at the ends on steel plates of a chassis (20 to 30 mm thick).
Your remark about the case of an embedding in concrete holds up but in steel I don't really know.
In steel, if it is fixed for example with nuts, it is known as a weld.
In your it's a butt weld on a thick plate, so it can be considered as a perfect embedding modulo the simultaneous deformation of the plate and the chassis, which is unlikely.
Kind regards
PS: you could look at these free software I think
http://www.freelem.com
and the kings of taxonomy https://www.cticm.com/centre-de-ressources/?fwp_taxonomy_first_line=logiciel
Hello @ronathan
The theoretical study of stresses within a structure in hyperstatic assembly, whose beams are stressed in bending/torsion is far from simple, especially in the conditions you are considering: closed or open sections, with various and varied shapes.
Even in the case of a single beam like the one shown in your image, the evaluation of torsional stresses will be problematic, especially on profiles with open sections...
The attached pdf deals with the case of a thin-walled, square-section tube inspired by your illustration.
The "manual" result applied in Excel is compared to a static simulation with SolidWorks.
The result: a 6% gap on the constraint according to von Mises, which is quite reasonable...
Dealing with the different cases by formulas is possible if the structure is simple, and if the beams are only stressed in bending. In the case of stress combined with torsion, this method seems tricky given the variety of situations.
On the other hand, a simulation with SolidWorks on a simple structure limited to a few beams is relatively quick to implement, and will adapt to the different geometries you are considering. This is an avenue that I believe should be explored.