Fired Up the Sawzall - New Project Pics!
01-28-2006, 12:08 PM
#46
Nordschleife Master
A quick search of the torrent sites would probably yield you guys with solidworks...which comes with cosmosexpress which would let you find out which idea is truly better for a given load/constraint scenario. However this would require a solid model and it can be difficult to create a good solid model that can be analyzed.
An easier way to do it is with pro/mechanica...which I have access to through school. It simply uses points and axises and you assign the properties of your beam to each axis. This is referred to as beam element FEA (finite element analysis....the computers way of letting you view the stress at every point in the material). All I need is X,Y,Z coordinates (doesn't need to be exact...+/- 1/2" would be fine) for each node and the tube dimensions and it will be a 5-10 minute job to find out which solution is really the best.
Of course the problem with such a thing is the load and how it is applied to the structure. But you could say "this one is best for side impact, this one best for a rollover..." etc etc...
Maybe we can even have a little contest...winner gets a cookie? haha
An easier way to do it is with pro/mechanica...which I have access to through school. It simply uses points and axises and you assign the properties of your beam to each axis. This is referred to as beam element FEA (finite element analysis....the computers way of letting you view the stress at every point in the material). All I need is X,Y,Z coordinates (doesn't need to be exact...+/- 1/2" would be fine) for each node and the tube dimensions and it will be a 5-10 minute job to find out which solution is really the best.
Of course the problem with such a thing is the load and how it is applied to the structure. But you could say "this one is best for side impact, this one best for a rollover..." etc etc...
Maybe we can even have a little contest...winner gets a cookie? haha
01-28-2006, 02:45 PM
#47
Formula One Spin Doctor
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Redlineman ,
Nice Work and effort, THe finished work will look good , but it does appear it will be difficult to put roll bar padding where it will be needed .
Nice Work and effort, THe finished work will look good , but it does appear it will be difficult to put roll bar padding where it will be needed .
01-28-2006, 02:58 PM
#48
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Originally Posted by A.Wayne
Redlineman ,
Nice Work and effort, THe finished work will look good , but it does appear it will be difficult to put roll bar padding where it will be needed .
Nice Work and effort, THe finished work will look good , but it does appear it will be difficult to put roll bar padding where it will be needed .
Au Contraire;
I don't need it behind the seat. All the tubing from shoulder height upward and to the side or front of the seat is exposed and ready for padding. The main hoop and diagonal create a nice little halo above and slightly behind my head.
I'm mulling over a design for a seat back brace that is solid mounted for my position, but has a release mechanism for different size drivers (mostly my dolly
).
01-31-2006, 03:46 PM
#49
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My 2 cents
The design does not work as drawn.There is no cross support.with all the bars angled back the crush is still the same. Accually there is an 3 percent increace but that is just because of there being more bars to absorb the energy. Sad to say but you still need a bar to go from top to botton on opposite sides.
I really like the looks of it too.
Before I go to far... as far as support for your suspension the design works great.
This is what we came up with here by entering all the info into Solid Works. Takes a little longer than ten minutes but this stuff really interests me
The design does not work as drawn.There is no cross support.with all the bars angled back the crush is still the same. Accually there is an 3 percent increace but that is just because of there being more bars to absorb the energy. Sad to say but you still need a bar to go from top to botton on opposite sides.
I really like the looks of it too.
Before I go to far... as far as support for your suspension the design works great.
This is what we came up with here by entering all the info into Solid Works. Takes a little longer than ten minutes but this stuff really interests me
01-31-2006, 08:26 PM
#50
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Originally Posted by tinman944
My 2 cents
The design does not work as drawn.There is no cross support.with all the bars angled back the crush is still the same....
...Before I go to far... as far as support for your suspension the design works great.
The design does not work as drawn.There is no cross support.with all the bars angled back the crush is still the same....
...Before I go to far... as far as support for your suspension the design works great.
I think you missed some of the earlier photos or discussion. This "inverted vaulted ceiling truss" as Mike refered to it exists soley to counter rear suspension forces. Whatever stiffness it adds to the rest of the cage is a bonus. It is not intended to improve the crash worthiness of the cage, as that is already quite substantial... even to the point of overkill. Of course, it WILL improve that, but that is not the jist of its existance.
Stay tuned. I decided to do door bars today. There is much more coming... including computer analysis.
02-01-2006, 12:45 PM
#52
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I do see an angle brace in one photo but do not see it in the next where it should be attached.
By the looks you are just building a car to do DE. When you have no rules you can do as you wish.
By the looks you are just building a car to do DE. When you have no rules you can do as you wish.
02-01-2006, 01:48 PM
#53
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Originally Posted by tinman944
I do see an angle brace in one photo but do not see it in the next where it should be attached.
By the looks you are just building a car to do DE. When you have no rules you can do as you wish.
By the looks you are just building a car to do DE. When you have no rules you can do as you wish.
Well, it's all there. Those photos don't necessarily follow a time line, but the things you don't see are there, if not depicted directly. If this thing is deemed to be not worthy of any race organization, they can kiss my asteroid. It is not a narrow, simplistic interpretation of general race rules for sure, but it will easily be a million times stronger and safer than any gaggle of tubes coming out of a box.
Photos of the door bar coming tonite... as soon as I get back and finish it!
02-01-2006, 03:21 PM
#55
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If as you say it is overkill why not just use much smaller tubing and make a stronger shape like an X? Simple, clean, no complex shape issues and much less weight. The small tubing will have less visual impact than full size tube. You could get some eye shape tubing used for open wheel susp and make it simple, light(er) weight, to the point and still be cool looking.
02-01-2006, 03:39 PM
#56
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Kurt, that will not work as good as it sounds.
streamline tubing at a little under $17.00 a foot for the light stuff.or you can get the medium range with a major of 1.375 and a minor of .571 that is just $24.00 a foot. I have some of that is stock....It is light, under half a pound a foot.
It does not bend very good at all ..more like not at all.and you could never fish mouth it to another piece very well either.
Other than the cool factor of the way your drawings look there is really no advantage to what John is doing. with the main hoop crossed the way is is supose to be your vision is already blocked. the bars further back can be crossed the same way and will intersect lower so they should not be in the way at all.
With 147 hp and a heavy car you should just drive around with your arm out the window..and not worry about who is passing you , just let them by.
streamline tubing at a little under $17.00 a foot for the light stuff.or you can get the medium range with a major of 1.375 and a minor of .571 that is just $24.00 a foot. I have some of that is stock....It is light, under half a pound a foot.
It does not bend very good at all ..more like not at all.and you could never fish mouth it to another piece very well either.
Other than the cool factor of the way your drawings look there is really no advantage to what John is doing. with the main hoop crossed the way is is supose to be your vision is already blocked. the bars further back can be crossed the same way and will intersect lower so they should not be in the way at all.
With 147 hp and a heavy car you should just drive around with your arm out the window..and not worry about who is passing you , just let them by.
02-01-2006, 03:49 PM
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Originally Posted by M758
Wow... I get a bar named after me! 
Hmm... Well the good news with the bar is you took the load off of the support braces.
The BAD NEWS is that you cataleviered all the load from two based points to just one. Now all the belt load will go through the base plate in bending probably a worse situation.
Now... however you tie the front of the "joe bar" and either complete the hoop or tie it in to the main hoop and then to ground with a door bar system you are ok.
The only good thing is that my guess is that belts are the weak spot. With this or your old design the belts would fail before the bars would fail.
Worse case with this desing is a little flex may come in as bar acts like a spring.
Sorry... BTW... don't feel bad. I am a trained Mechanical Engineer and spent years designing and analyzing the structural components in Jet Engines.
Hmm... Well the good news with the bar is you took the load off of the support braces.
The BAD NEWS is that you cataleviered all the load from two based points to just one. Now all the belt load will go through the base plate in bending probably a worse situation.
Now... however you tie the front of the "joe bar" and either complete the hoop or tie it in to the main hoop and then to ground with a door bar system you are ok.
The only good thing is that my guess is that belts are the weak spot. With this or your old design the belts would fail before the bars would fail.
Worse case with this desing is a little flex may come in as bar acts like a spring.
Sorry... BTW... don't feel bad. I am a trained Mechanical Engineer and spent years designing and analyzing the structural components in Jet Engines.
I'm not a scrutineer but I suspect that if one looked at this setup they would not allow you to race with that setup. I would run two "A"s, one on each end of the harness bar to the main hoop. That would solve the problem.
Just trying to provide constructive input.
02-01-2006, 05:09 PM
#59
Mr. Excitement
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No bends would be needed and you CAN fishmouth it if you have nothing but time to grind and fit about 30 times. (I don't) I only put that out to keep the looks cool factor in play. Personaly am a fan of as small a dia tubing as you can use and simple shapes wherever needed and allowed.
This is all for fun for most of us and as long as the end result is not unsafe have at it!
This is all for fun for most of us and as long as the end result is not unsafe have at it!
02-01-2006, 06:21 PM
#60
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Hey John,
Forgive me for dabbling in this, but I figured it might be interesting to try out my photoshop prgram. Anyway, here is an idea which might help. Just drop a diagonal bar like the one I drew in grey, and weld the belt bar to it, rather than add those curved pieces. That seems to provide some strength to the uprights and puts the belt bar in a good solid position.
Forgive me for dabbling in this, but I figured it might be interesting to try out my photoshop prgram. Anyway, here is an idea which might help. Just drop a diagonal bar like the one I drew in grey, and weld the belt bar to it, rather than add those curved pieces. That seems to provide some strength to the uprights and puts the belt bar in a good solid position.