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resistance to bending angle or tube which is more resistance



 
 
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  #1  
Old February 10th 17, 11:13 PM posted to rec.crafts.metalworking
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Posts: 1
Default resistance to bending angle or tube which is more resistance

Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree incline and the gravel and rocks would slide down the slope rocks sliding off the top of the grizzly bars, and sand falling between the grizzly bars under the grizzly bars to be picked up and moved to usage area. the rocks moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be slowly dumped on the grizzly bars would be 1.75 x 2800 lbs in yard = 4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.
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  #2  
Old February 11th 17, 12:58 AM posted to rec.crafts.metalworking
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Posts: 231
Default resistance to bending angle or tube which is more resistance

On Friday, February 10, 2017 at 6:13:43 PM UTC-5, lakeside bob wrote:
Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree incline and the gravel and rocks would slide down the slope rocks sliding off the top of the grizzly bars, and sand falling between the grizzly bars under the grizzly bars to be picked up and moved to usage area. the rocks moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be slowly dumped on the grizzly bars would be 1.75 x 2800 lbs in yard = 4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.


The last one will bend the least, by far. The stiffness of the angles will depend on how they're oriented, but neither one is even close to the tubes, no matter how you arrange them.

--
Ed Huntress

  #3  
Old February 11th 17, 01:14 AM posted to rec.crafts.metalworking
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Posts: 3,704
Default resistance to bending angle or tube which is more resistance

On Friday, February 10, 2017 at 6:13:43 PM UTC-5, lakeside bob wrote:
Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree incline and the gravel and rocks would slide down the slope rocks sliding off the top of the grizzly bars, and sand falling between the grizzly bars under the grizzly bars to be picked up and moved to usage area. the rocks moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be slowly dumped on the grizzly bars would be 1.75 x 2800 lbs in yard = 4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.



You provided a lot of information, but not quite enough. How long are the bars? Are there any supports other than at the ends? When you dump a load on to the bars how many bars got the load. How are the bars supported at the ends. Welded or sitting on top of a r? Why 36,000 steel. Low alloy would probably be cheaper for equal strength.

Dan

  #4  
Old February 11th 17, 01:35 AM posted to rec.crafts.metalworking
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Posts: 231
Default resistance to bending angle or tube which is more resistance

On Friday, February 10, 2017 at 8:14:34 PM UTC-5, wrote:
On Friday, February 10, 2017 at 6:13:43 PM UTC-5, lakeside bob wrote:
Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree incline and the gravel and rocks would slide down the slope rocks sliding off the top of the grizzly bars, and sand falling between the grizzly bars under the grizzly bars to be picked up and moved to usage area. the rocks moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be slowly dumped on the grizzly bars would be 1.75 x 2800 lbs in yard = 4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.



You provided a lot of information, but not quite enough. How long are the bars? Are there any supports other than at the ends? When you dump a load on to the bars how many bars got the load. How are the bars supported at the ends. Welded or sitting on top of a r? Why 36,000 steel. Low alloy would probably be cheaper for equal strength.

Dan


If by "bending" he's referring to stiffness (resistance to springing, not resistance to permanent bending), then the alloy makes no difference at all. 36,000 psi tensile-strength steel us just as stiff as 200,000 psi hgh strength alloy.

If he's referring to permanent bending, then a little deeper section of low-strength steel is still 'way less expensive than a lesser depth of high-strength steel.

--
Ed Huntress
  #5  
Old February 11th 17, 04:43 PM posted to rec.crafts.metalworking
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Posts: 3
Default resistance to bending angle or tube which is more resistance

On Friday, February 10, 2017 at 5:13:43 PM UTC-6, lakeside bob wrote:
Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree incline and the gravel and rocks would slide down the slope rocks sliding off the top of the grizzly bars, and sand falling between the grizzly bars under the grizzly bars to be picked up and moved to usage area. the rocks moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be slowly dumped on the grizzly bars would be 1.75 x 2800 lbs in yard = 4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.


OK some more information.
Bars will be 8 feet long with a support under each one three feet down from the top of the sloping deck. The bars will be welded to cross tubes of 3 x 3 x 1/4 inch steel at the top of the frame and bottom along with one at 3 ft down from the top of frame.
the 36,000 pound steel is what the local shop sells.
the wheel loader bucket is 8 feet long or wide, so with the cap between bars at 3 inches and each bar being say 3 inches wide the gravel will be dumped on 16 or 17 bars.
  #6  
Old February 11th 17, 05:01 PM posted to rec.crafts.metalworking
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Posts: 17,107
Default resistance to bending angle or tube which is more resistance

On Sat, 11 Feb 2017 08:43:58 -0800 (PST), wrote:

On Friday, February 10, 2017 at 5:13:43 PM UTC-6, lakeside bob wrote:
Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree incline and the gravel and rocks would slide down the slope rocks sliding off the top of the grizzly bars, and sand falling between the grizzly bars under the grizzly bars to be picked up and moved to usage area. the rocks moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be slowly dumped on the grizzly bars would be 1.75 x 2800 lbs in yard = 4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.


OK some more information.
Bars will be 8 feet long with a support under each one three feet down from the top of the sloping deck. The bars will be welded to cross tubes of 3 x 3 x 1/4 inch steel at the top of the frame and bottom along with one at 3 ft down from the top of frame.
the 36,000 pound steel is what the local shop sells.


I'd say the 2.5 X 2.5 angle, particularly if you weld 1/4" plate
across the bottom.of the angle, but I'm not an ME.
  #7  
Old February 11th 17, 06:24 PM posted to rec.crafts.metalworking
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Posts: 231
Default resistance to bending angle or tube which is more resistance

On Saturday, February 11, 2017 at 12:01:33 PM UTC-5, Clare wrote:
On Sat, 11 Feb 2017 08:43:58 -0800 (PST), wrote:

On Friday, February 10, 2017 at 5:13:43 PM UTC-6, lakeside bob wrote:
Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree incline and the gravel and rocks would slide down the slope rocks sliding off the top of the grizzly bars, and sand falling between the grizzly bars under the grizzly bars to be picked up and moved to usage area. the rocks moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be slowly dumped on the grizzly bars would be 1.75 x 2800 lbs in yard = 4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.


OK some more information.
Bars will be 8 feet long with a support under each one three feet down from the top of the sloping deck. The bars will be welded to cross tubes of 3 x 3 x 1/4 inch steel at the top of the frame and bottom along with one at 3 ft down from the top of frame.
the 36,000 pound steel is what the local shop sells.


I'd say the 2.5 X 2.5 angle, particularly if you weld 1/4" plate
across the bottom.of the angle, but I'm not an ME.


This is a duck-soup-simple statics problem taught in elementary engineering and technology classes all over the world. Any decent book on statics and strength of materials will show the solutions in a minute, with very simple formulas for solving a particular question.

But my statics book is in a box in my attic, and I'm too warm and comfortable where I am. d8-)

--
Ed Huntress
  #8  
Old February 11th 17, 06:49 PM posted to rec.crafts.metalworking
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Posts: 41
Default resistance to bending angle or tube which is more resistance

Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree
incline and the gravel and rocks would slide down the slope rocks sliding
off the top of the grizzly bars, and sand falling between the grizzly bars
under the grizzly bars to be picked up and moved to usage area. the rocks
moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped
on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped
about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be
slowly dumped on the grizzly bars would be 1.75 x 2800 lbs. in yard =
4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.


Just to get you started, the spec that determines how stiff a beam will be
is the moment of inertia, and you can look it up in tables for standard
structural beams. Assuming the angle is oriented with one flange horizontal
and one vertical, and the load is in the vertical plane:

2x2x3/8 angle 0.473 in^4
2.5x2.5x1/2 angle 1.219
3x3x1/8 tube 1.851
3x3x1/4 tube 2.888

So, the 3x3x1/4 wall tube is 2.888/0.473=6.1 times stiffer than the 2x2x3/8
angle. In another post you say that each beam will be 8' long and supported
5' from one end,m and I'm going to guess the grate will be 3' wide so with
3" bars and 3" gaps that's 7 bars so 4900 lbs./7=700 lbs. per bar. I'm not
an ME but I like to use a program called engineering power tools for stuff
like this (http://www.pwr-tools.com/). According to it, a 5' beam of
3x3x.25 tube simply supported at each end (I'm assuming the end beam can
twist a bit) with a load of 700 lbs. uniformly distributed will flex 0.023"
and the maximum stress will be 2700 psi. That stress is about 1/13 of the
tensile strength which looks good, but in reality if you dump the load on
all at once the peak load will be at least 3 times the static load, and you
don't know if the load will really be exactly uniformly distributed, so your
real safety margin is more like 4x which still should be good. The
deflection and the peak stress are inversely proportional to the moment of
inertia, so if the beam is twice as stiff the deflection and peak stress
will be half. Going to 3x3x1/8" wall square tubing raises the deflection to
0.036", the peak stress to 4210 psi, and the safety margin drops to about
2.8. I wouldn't go less than that even if no people will be on or under the
grate without a much more careful analysis, and if I just wanted to be sure
I was only going to build it once I'd go with the 3x3x1/4 tube at the least.
Going to a stronger alloy won't change the deflection (which is so small it
shouldn't be an issue anyway) but will raise the tensile strength so you
could go with smaller tubes to support the weight, but you won't save money
so why bother. The real problem you will eventually have is wear as the
rock and sand grind away your tubes. If that's a real issue you could weld
on flat tops of armor plate as needed, but again, it might just be cheaper
to buy more mild steel tube. The more you buy the cheaper per pound, so
build it once and see how long it lasts, then buy enough tubing for 2-5 more
:-). Remember, I'm not an ME and this is just for fun and probably worth
what you are paying for it :-).

-----
Regards,
Carl Ijames


  #9  
Old February 11th 17, 07:17 PM posted to rec.crafts.metalworking
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Posts: 3
Default resistance to bending angle or tube which is more resistance

On Saturday, February 11, 2017 at 10:44:00 AM UTC-6, wrote:
On Friday, February 10, 2017 at 5:13:43 PM UTC-6, lakeside bob wrote:
Want to build a gravel screen to sort out over size rocks from sand.
The gravel and rocks would be dumped on grizzly bars on a 40 degree incline and the gravel and rocks would slide down the slope rocks sliding off the top of the grizzly bars, and sand falling between the grizzly bars under the grizzly bars to be picked up and moved to usage area. the rocks moved to waste area. Spacing between bars would be 3 inches.
Question which would bend the least when the gravel and rocks are dumped on the grizzly bars?
Rocks would be up to 18 inches round so about 150 pounds each. Dropped about 18 inches on to the bars.
Size of wheel loader bucket is 1.75 cubic yards so total weight to be slowly dumped on the grizzly bars would be 1.75 x 2800 lbs in yard = 4,900 pounds.
Data
grizzly bars angle 2 inch x 2 inch and 3/8 inch thick.
grizzly bars angle 2.5 inch x 2.5 inch and 1/2 inch thick
grizzly bars 3 inch x 3 inch x 1/8 inch thick square tube
grizzly bars 3 inch x 3 inch x 1/4 inch thick square tube
all 36,000 pound strength steel

thank you for replying it is much appreciated.


OK some more information.
Bars will be 8 feet long with a support under each one three feet down from the top of the sloping deck. The bars will be welded to cross tubes of 3 x 3 x 1/4 inch steel at the top of the frame and bottom along with one at 3 ft down from the top of frame.
the 36,000 pound steel is what the local shop sells.
the wheel loader bucket is 8 feet long or wide, so with the cap between bars at 3 inches and each bar being say 3 inches wide the gravel will be dumped on 16 or 17 bars.

OK some more information, the width of the grizzly box is 10 feet wide that the 8 foot wide wheel loader bucket will be dropping the gravel onto.
 




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