[quote]Defiance wrote:
[quote]Razorslim wrote:
Can someone please run the Finite Element Analysis on this?[/quote]
ANSYS can.[/quote]
Got it all setup. If someone wants to give me some hard numbers on the geometry and material, I’ll run it.
[quote]BONEZ217 wrote:
[quote]rores28 wrote:
When I say bend, I’m referring to a difference you could note in the bar with the naked eye standing about 10ft away.
I’m looking at bars and package deals online, and I’m up in the air between the 1000lb 30mm and the 1500lb 32mm bar. So I unfortunately can’t just stack weight on and test. I’ll prolly never load more than 600 possibly 700 lbs on the bar. What I want to know is if I’m going to start having to be “afraid” as other posters have said about putting 315lb etc… on the bar. The question prolly would have been better phrased "If I have a 1000lb capacity bar, at what weight should I start getting worried about the weight that’s on it / will it significantly affect the mechanics of the lift. The primary lifts that I’d be doing would be dls, squats, pressing, pulling.
Another way of asking this might be, "Assuming I will prolly never put more than 600-700lbs on the bar, is there an advantage in having a 1500lb capacity bar over a 1000lb capacity bar, assuming same basic make and brand.[/quote]
Are you trying to say ‘probably’? [/quote]
No. I am saying “prolly.” You can consider it the functional equivalent of probably, though more economical.
[quote]DoubleDuce wrote:
[quote]Defiance wrote:
[quote]Razorslim wrote:
Can someone please run the Finite Element Analysis on this?[/quote]
ANSYS can.[/quote]
Got it all setup. If someone wants to give me some hard numbers on the geometry and material, I’ll run it.[/quote]
Olympic
Steel E=30x10^6 psi, FTU = 150ksi, FTY = 95ksi, bar dia = 1 1/8"
Standard
Steel E=30x10^6 psi, FTU = 95ksi, FTY = 60ksi, bar dia = 1"
Bar length = 7’. Weight = 45lbs. The ends are 2" in dia and are 16" long. The rings are 18" from the midpoint of the bar. Suggest analyzing @ 45lb increments until yielding
How much does using reverse strong bands when benching with the bands inside the collars versus on the sleeve outside of 4 plates affect how much a texas power bar bends with a full competition grip width and a thumbless grip? I really, really need to know the answer?
All kidding aside to the OP. Get the Texas Powerbar or other similar quality bar and you’ll be fine. If you start to squat more than say 700 pounds then consider a Texas Squat Bar (It really feels better on your back even if you don’t squat that much though). You’ll be fine with the Texas Powerbar for deadlifting too.
So I ran through some weights with the olympic barbells. I actually got some yielding at 855 pounds of bar weight (with the bar supported in the middle). Just a tinny patch on the surface of the bar. Which totaled 78mm of displacement from the tip of the bar to the middle.
And to the person earlier, 2.5 pound plates (with the bar weight) was getting 2.8 mm of displacement.
Yeilding
What’s your boundary condition in the middle? If the cross-section is fixed at the line of symmetry I’m not surprised there is yielding… kind of like supporting the bar at a point. Not real up on my stress analysis but there must be a way to apply a set of symmetry BCs and then an equal and opposite distributed load out to shoulder width.
With a piecewise constant x-sectional area this would probably be fairly easy to solve analytically in 1D.
[quote]DoubleDuce wrote:
Every bar starts bending when any amount of weight is put on it.[/quote]
OK, well then how about when does a bar start to bend to a degree perceptible by humans and not a Vulcan such as yourself?
[quote]Nards wrote:
[quote]DoubleDuce wrote:
Every bar starts bending when any amount of weight is put on it.[/quote]
OK, well then how about when does a bar start to bend to a degree perceptible by humans and not a Vulcan such as yourself?[/quote]
Take your pick from the excel chart!
[quote]grettiron wrote:
What’s your boundary condition in the middle? If the cross-section is fixed at the line of symmetry I’m not surprised there is yielding… kind of like supporting the bar at a point. Not real up on my stress analysis but there must be a way to apply a set of symmetry BCs and then an equal and opposite distributed load out to shoulder width.
With a piecewise constant x-sectional area this would probably be fairly easy to solve analytically in 1D.[/quote]
Yeah, supporting at the center will exaggerate the deflections. A more realistic estimate will be to support it on each of the grooves/rings, that’s where most people hold the bars I assume. I’m too lazy to do the math, can you run it through the model? 
I set it up as worst case. The other thing to consider is that some plastic deformation on the surface level is probably ok. I can run a more normally supported bar later.
Lean back, lean back
[quote]DoubleDuce wrote:
So I ran through some weights with the olympic barbells. I actually got some yielding at 855 pounds of bar weight (with the bar supported in the middle). Just a tinny patch on the surface of the bar. Which totaled 78mm of displacement from the tip of the bar to the middle.
And to the person earlier, 2.5 pound plates (with the bar weight) was getting 2.8 mm of displacement.[/quote]
That’s the problem with analysis and theory in general. It is a start point and a great place to start honing in on things, however it rarely meets real life expectations. If it did there would be no need for test labs. Test objects almost never fail where the analysis tells us it should.
I guess if there was enough acceleration/deceleration you could see this, but can you honestly tell me that if you loaded a 2.5 lb plate on a bar and picked it up from the center you would expect it to move nearly 1/8 of an inch. I don’t believe it would.
Who gives a shit?
[quote]Testy1 wrote:
[quote]DoubleDuce wrote:
So I ran through some weights with the olympic barbells. I actually got some yielding at 855 pounds of bar weight (with the bar supported in the middle). Just a tinny patch on the surface of the bar. Which totaled 78mm of displacement from the tip of the bar to the middle.
And to the person earlier, 2.5 pound plates (with the bar weight) was getting 2.8 mm of displacement.[/quote]
That’s the problem with analysis and theory in general. It is a start point and a great place to start honing in on things, however it rarely meets real life expectations. If it did there would be no need for test labs. Test objects almost never fail where the analysis tells us it should.
I guess if there was enough acceleration/deceleration you could see this, but can you honestly tell me that if you loaded a 2.5 lb plate on a bar and picked it up from the center you would expect it to move nearly 1/8 of an inch. I don’t believe it would.[/quote]
From the tip of the collar to the middle of the bar, I could believe it. That radius of curvature is going to be really really small to do that. It wouldn’t be noticeable. And for the record, most of that deflection is going to be due to bar weight.
[quote]FightinIrish26 wrote:
Who gives a shit?[/quote]
Physics nerds.
[quote]FightinIrish26 wrote:
Who gives a shit?[/quote]
Sorry, you obviously have more important things to do than read this in GAL.
Depends on how much I’ve had to drink.
1 Like
[quote]Iron Dwarf wrote:
Depends on how much I’ve had to drink.[/quote]
bahahahhaha