"Richard Smith" wrote in message news:lypm4hjemg.fsf@void.com...
Hi. Been at it again.
Having learned some PHP - the web-scripting langugage.
My beam calculations written in Lisp - done as webpage version. http://weldsmith.co.uk/cgi_my/ebbeam_rhs/230724_ebbeam_rhs.html
"Rectangular Hollow Section beam calculations"
Best wishes,
Rich S
----------------------
I try to do the math and then check it with on-line calculators. A
useful result is the deflection at maximum load or yield point, which
can be used as a gauge by placing something that high on the beam
center and observing its alignment with the two ends when the test or straightening setup is too unstable and risky to approach or put an
expensive load cell on. The 3" and 4" channel I found to build my
gantry hoist and sawmill tends to twist when near full load.
Hi. Been at it again.
Having learned some PHP - the web-scripting langugage.
My beam calculations written in Lisp - done as webpage version. >http://weldsmith.co.uk/cgi_my/ebbeam_rhs/230724_ebbeam_rhs.html
"Rectangular Hollow Section beam calculations"
Best wishes,
Rich S
"Richard Smith" wrote in message news:lypm4f826p.fsf@void.com...
Both the 2020 mathematical work and the online calculator are based on right-angled-corner sections (slight deviation from actual sections
with rounded corners).
---------------
If the corner is truly a quarter circle the area reduction is pi/4
times the wall thickness.
You must have experience of such "navigation" as a skilled
knowlegeable project driver...
On Wed, 26 Jul 2023 16:53:40 +0100
Richard Smith <null@void.com> wrote:
<snip>
You must have experience of such "navigation" as a skilled
knowlegeable project driver...
You ever read?
https://en.wikipedia.org/wiki/Zen_and_the_Art_of_Motorcycle_Maintenance
Quite the slog but I don't regret suffering it...
Your kinda discussions always bring it to mind..
--
Leon Fisk
Grand Rapids MI
So - I can assure you I am fine myself with your conjecture.
You must have experience of such "navigation" as a skilled
knowlegeable project driver...
"Richard Smith" wrote in message news:lypm4f826p.fsf@void.com...
Both the 2020 mathematical work and the online calculator are based on right-angled-corner sections (slight deviation from actual sections
with rounded corners).
---------------
If the corner is truly a quarter circle the area reduction is pi/4
times the wall thickness.
Hello all
Wrote following as example of a beam calculation in a project.
Following on from creating the "beam calculator" http://weldsmith.co.uk/cgi_my/ebbeam_rhs/230724_ebbeam_rhs.html
"Rectangular Hollow Section beam calculations"
webpage.
I have a feeling beam calculations are often like this.
Finding your way along.
Same as for the other case I made a webpage for http://www.weldsmith.co.uk/tech/struct/210314_ebbeam_drillplat/19_drillplat_calcs.html
"Cantilever drilling platform - analysis using beam calculations"
------------------------------------------------
I didn't give any idea why you might want a beam calculator when
interested in mines...
Take for example Wheal Round
(a hypothetical case).
It's accessed from high ground and water flows from adits draining
mines in the area. So there's a good chance a lot of the workings
remain dry.
Problem - the main shaft is blocked by a boulder 30m down which is
estimated to be 3 Tonnes.
The promise of many levels and interesting finds in Wheal Round has a
project to open the main shaft. Resin-anchor in an eye-bolt and hoist
the boulder out.
The beam would span 5m across the top bank around the shaft.
Wheal Round is in that high place with a small path as only access, so
that beam needs to be very portable.
It's lifting a boulder, there's no-one underneath anything and the
hoist can be worked from a safe distance, so the consequence is just
about zero of the beam totally collapsing by local plastic buckling.
So we can look to even a "Class 4" section (it could locally buckle
and instantly collapse on overload).
Considering all, we'd like a factor of 3 safety on the beam load bear
- mainly for it if boulder jams and the load on the beam with hoisting increases.
So that's 9 Tonnes point capacity at the middle.
Box-section - take as being S355 steel - 355MPa = 355e6Pa yield.
We'll get an estimate were to start looking for candidate sections in
"The Blue Book"
Pardon that I use "Lisp" in-line to calculate things. Using the
"emacs" text-processor, I can "fire-up" its interpreter on Lisp
expressions and it will insert its answer into the file.
M=FL/4 for a "simple beam" (end supported; central load)
M = ...
(/
(*
(* 9 1e3 9.81) ;; 88290.0 ;; N ;; (gravity - 9.81N/kg)
5 ;; m length
)
4e0 ;; ) ;; 110362.5 ;; N.m
1e3) ;; 110.3625 ;; kNm
Going straight to "The Blue Book" for hot-finished Rectangular Hollow
Section
https://www.steelforlifebluebook.co.uk/hfrhs/ec3-ukna/bending-s355/
and looking down the "Mc,y,Rd" column
plausible sections start at around 250x150x5mm - with a weight of
30.4kg/m
For squares - Square Hollow Sections https://www.steelforlifebluebook.co.uk/hfshs/ec3-ukna/bending-s355/
plausible sections start at around 200x200x6.3mm - with a weight of
38kg/m
Going with 250x150x5mm in my beam calculator http://weldsmith.co.uk/cgi_my/ebbeam_rhs/230724_ebbeam_rhs.html
"
Input values you provided
Variable Value (in familiar units)
Height 250e-3 (250mm)
Width / breadth 150e-3 (150mm)
Wall thickness 5e-3 (5mm)
Beam length 5 (m)
Maximum stress 355e6 (N mm^2)
Young's Modulus (E) 210e9 (N mm^2)
Beam intrinsic sectional properties
...
Derived variable Derived value (in familiar units)
Second moment of area: 3.403250e-5 (3403.25cm^4)
Section modulus: 2.722600e-4 (272.26cm^3)
Moment: 96652.3 (N.m)
Beam extrinsic properties
...
"simple beam"
The central load causing the selected stress is
77321.84Newtons
At that maximum stress, the deflection at the middle of the beam is 0.0281746031746metres (28.1746031746mm)
"
My calculation and "The Blue Book" agree - For "I" the Second Moment
of Area is 3.403250e-5m^4 = 3403.25cm^4 (my) to 3360cm^4 (Blue Book).
For what it's worth general geometric page https://www.steelforlifebluebook.co.uk/hfrhs/ec3-ukna/section-properties-dimensions-properties/
has "Z" as 269cm^4 (Blue Book) for "my" 272.26cm^3 - same.
We expect "my" "I" and "Z" to be a bit higher because "my" section is
a rectangular-cornered hypothetical sections, whereas the real section
has rounded corners, putting a bit less metal for from the neutral
plane where it would have counted the most.
But "my" calculation is quick to use to step through the logic
processes of selecting "candidate" beams.
The force at yield the beam calculator gives:
(/ 77321.84 9.81 1e3) ;; 7.881940876656472 ;; Tonnes-force
We might seek a bit higher; were it not for seeing the weight of
plausible sections - see later.
Continuing...
So the excess load carrying capacity is still okay - in the region of
what we wanted.
Using my beam calculator alone now for other sections seen in "The
Blue Book"
If that section fell over on its side, presenting 150x250, it would
still support the boulder, with 5.95 Tonnes capacity. Not as it would
be recommended to allow that to happen, but there wouldn't be the
buckled beam, chain-block and boulder dropping back down the
mineshaft.
300x100x5mm looks plausible too.
300x100x5 if it fell over - and it is tall and narrow - would give
41932.6N -> (/ 41932.6 9.81 1e3) ;; 4.274475025484199 Tonnes
so it would likely be "game over" or best keep well clear and lower
the boulder back from whence it came.
So if contemplated 300x100x5 - which is 30.4kg/m - would have to bring
some strong "keep upright" support with "feet" - likely a steel
fabrication weighing a few kg each end.
These two - 250x150x5mm and 300x100x5mm - are looking-in at about
30.5kg/m, and the beam to span 5m is 6m long.
(* 30.5 6) ;; 183.0 ;; kg
Thinking of the narrow path - if roped the steel beam so it just lofts
off the ground when a transverse pole at each end is lifted by two
people each side - so eight people lifting total, that's
(/ (* 30.5 6) 8) ;; 22.875 ;; kg
per person - doable.
But for a pole long enough to get 4 people on the pole, it would be
too long (wide) to fit between the trees and bushes and through gates
on the narrow path. Mind's-eye sees that as not a great option.
Path is quite straight, so look to a "tail wheel" at the back - some compliant pneumatic tyre from eg. a trailer rolling along supporting
the back of the beam - and have a forward-sticking-out pole with four
people on it lifting and pulling.
Other lifting strategies examined:
* Longitudinal pole with four people at each end? Well to be roped
with the beam just lofting above the ground, the pole has to be 6m +
about 2 x 2.5m = 11m, which is some pole - has its own weight.
* Pole attached to each end and carry at shoulder-height - NO! Never
where if say someone tripped and everyone fell over there is a
significant risk of someone getting hurt.
"Tail wheel" - could have additional people pulling on ropes for the
steep bits (not pushing from behind - not exposed to being "run-over"
if all goes horribly wrong.
So - is doable.
Go with whichever of those sections
250x150x5mm
300x100x5mm
or even
200x200x6.3mm (38kg/m - more grunting and perspiration)
is found to be available on a blagging / cadging mission...
The reason for the beam calculator is exploring options and scenarios
easily, at negligible effort to the person.
A person can with care get through one beam calculation with its
several steps.
For several beam scenarios a person tends to get overwhelmed and lose
their way.
There has been "freestyle" use of parts of the beam calculations.
There has been use of "The Blue Book".
However, the "beam calculator" made for a good portfolio of
calculations presenting the case for the option suggested.
"Richard Smith" wrote in message news:lyjzuewgpb.fsf@void.com...
...
Thinking of the narrow path - if roped the steel beam so it just lofts
off the ground when a transverse pole at each end is lifted by two
people each side - so eight people lifting total, that's
(/ (* 30.5 6) 8) ;; 22.875 ;; kg
per person - doable.
But for a pole long enough to get 4 people on the pole, it would be
too long (wide) to fit between the trees and bushes and through gates
on the narrow path. Mind's-eye sees that as not a great option.
Path is quite straight, so look to a "tail wheel" at the back - some compliant pneumatic tyre from eg. a trailer rolling along supporting
the back of the beam - and have a forward-sticking-out pole with four
people on it lifting and pulling.
-----------------
Trailer tongue jacks are heavy-duty swivel casters with load lifting capability. https://www.kendonusa.com/products/crank-down-trailer-swivel-jack-stand
That one has a short URL, they are much cheaper elsewhere.
A single-wheel one can be upgraded for soft ground with replacement
wheels on either side, on a longer axle. It won't track well and needs
a steering + towing handle, one of mine is the handle from a broken
snow shovel with a fork of steel flat stock that connects to the
extended axle, another is a pipe tee with slots milled in the ends for
the flat stock. The long pipe handle screws on to move by hand,
unscrews for storage or to tow the shop crane it's on behind the
tractor. The rather high mounting plate isn't a problem if attached to
the base of a gantry hoist or mast of a crane but it makes them
inconvenient for a low riding lift platform unless you can weld.
I have the shop crane, a trailer and a log splitter that all weigh
around 500 Lbs and can be moved by hand on level ground without
excessive effort. As a test I've pulled them uphill without the garden tractor by using a block and tackle (faster) or a lever chain hoist
(safer). A chain fall is very slow and doesn't work well
horizontally. First I tried cheap cable pullers but was disappointed
with how quickly they wore out and failed despite being greased. The
steel is very soft. A vehicle-mounted winch was best, assuming you can
drive to the hilltop, but then you could tow with it instead. https://www.amazon.com/2-Ton-Along-Puller-Heavy-Duty-Automotive/dp/B09SPT85DR Upgrading the axles and bearings helps somewhat, if you have a
lathe. On mine the ratchets deformed when manufacturing slop allowed
them to misalign.
...
Raising the boulder isn't enough; you need to move it off the hole. A modified gantry trolley might work on your rectangular tubing but in
my experience doesn't add much resistance to the beam bowing sideways
and twisting.
...
Sounds like a large tyre piano moving dolly would be suitable for the
task. I was impressed by how easily the piano movers removed my
mother's piano with one and how well it coped with multiple 6" - 7"
steps.
They appear to use hand truck wheels on 5/8" axles. I bought a batch of used >solid tire wheels with needle bearings for 3/4" axles that have served well >for loads as large as an 1100 Lb boulder but I haven't found anything
similar for sale new.
On Wed, 2 Aug 2023 10:04:04 -0400
"Jim Wilkins" <muratlanne@gmail.com> wrote:
<snip>
They appear to use hand truck wheels on 5/8" axles. I bought a batch of used >>solid tire wheels with needle bearings for 3/4" axles that have served well >>for loads as large as an 1100 Lb boulder but I haven't found anything >>similar for sale new.
You can buy "wheel bearings" now for autos and such that include the
hub. As you probably already know... they are throw away pieces
nowadays. Anyway... if I was building a small trailer or similar I'd be tempted to buy a couple for a small vehicle. Maybe pick something you
already have tires/rims for. Something like this:
https://www.amazon.com/WJB-WA513044-Assembly-Reference-BR930083K/dp/B00B7ROENY/
I've a couple that came off a RAM 3500 front, one was making noises.
For something to be used around your property and not on the road
they'd still work okay...
--
Leon Fisk
Grand Rapids MI
They appear to use hand truck wheels on 5/8" axles. I bought a batch of
used
solid tire wheels with needle bearings for 3/4" axles that have served well >for loads as large as an 1100 Lb boulder but I haven't found anything
similar for sale new.
I wish my Honda was made that way, replacing the wheel bearings requires >completely disassembling the front suspension to press the hub and then the >bearings out of the knuckle.
I wish my Honda was made that way, replacing the wheel bearings requires >completely disassembling the front suspension to press the hub and then the >bearings out of the knuckle.
I wonder if they have a machine that rough and finish turns it, mills or >broaches the sensor ring and grinds the bearing races in one chucking.
I wonder if they have a machine that rough and finish turns it, mills or >broaches the sensor ring and grinds the bearing races in one chucking.
"Leon Fisk" wrote in message news:uag753$orpn$1...@dont-email.me...
On Wed, 2 Aug 2023 18:12:15 -0400
"Jim Wilkins" <murat...@gmail.com> wrote:
<snip>
I wonder if they have a machine that rough and finish turns it, mills or >broaches the sensor ring and grinds the bearing races in one chucking.
That sounds like something Ed Huntress would've known or who to ask.
Really miss some of the old sources of info😑
--------------------
The only auto factory machine I've seen in operation made AC spark plugs, and the actual pressing operations weren't visible, only the rows of incomplete plugs running around the walls of the little stand-alone booth in Flint.
I quoted a test station to measure alternator rotor outputs and found out how they are made; everything pressed sequentially onto the shaft, but I never saw it done. AFAIK spark plugs are assembled the same way.
I hope everyone is well.
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