Yeah, FEM is like statistics, you can make anything look good..
Designing to Rp 0.2 works until you come unstuck.
Suddenly all the forces are not transmitted through the wheels and you are in big trouble.
Designing to Rp 0.2 works until you come unstuck.
Suddenly all the forces are not transmitted through the wheels and you are in big trouble.
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
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- Platinum
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- Joined: Tue Feb 21, 2006 10:05 pm
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Not quite following how the loads wind up not being transmitted through the wheels?Mats wrote:Yeah, FEM is like statistics, you can make anything look good..
Designing to Rp 0.2 works until you come unstuck.
Suddenly all the forces are not transmitted through the wheels and you are in big trouble.
Or are you talking about when you punch an alfetta shaped hole in the scenery?
Never heard about TIG rules, maybe related to CrMo-cages that are popular in the fraction mile crowd?
Here in Sweden we don't have a mandrel bend demand but the pipes must be cold drawn seamless pipes and the difference in diameter in the bent (compared to an undeformed pipe) part must be lower then a certain percentage.
Not sure if that helps though.
Here in Sweden we don't have a mandrel bend demand but the pipes must be cold drawn seamless pipes and the difference in diameter in the bent (compared to an undeformed pipe) part must be lower then a certain percentage.
Not sure if that helps though.
Mats Strandberg
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
-Scuderia Rosso- Now burned to the ground...
-onemanracing.com-
-Strandberg.photography-
GTV 2000 -77 - Died in the fire.
155 V6 Sport -96 - Sold!
Thanks for the reply Mats
I finally got the scca rules pdf to work.
6. Material:
A. Seamless, or DOM (Drawn Over Mandrel) mild steel tubing
(SAE 1010, 1020, 1025) or equivalent, or alloy steel tubing
(SAE, 4130) shall be used for all roll cage structures. Proof
of use of alloy steel is the responsibility of the entrant.
I think this is where the bs about mandrel bends came from.
All welds shall be visually inspected and shall be acceptable
if the following conditions are satisfied:
1. The weld shall have no cracks.
2. Thorough fusion shall exist between weld metal and
base metal.
3. All craters shall be filled to the cross section of the
weld.
4. Undercut shall be no more than 0.01 inch deep.
C. Aluminum bronze or silicon bronze welding technique is
permitted, but extreme care shall be used in preparation of
parts before bronze welding and in the design of the attaching
joints.
Seems that they only require the welds to look good, nothing more. I dont understand the parts that are in bold, however. Craters? Undercut?
Can anyone explain?
Thanks
James
I finally got the scca rules pdf to work.
6. Material:
A. Seamless, or DOM (Drawn Over Mandrel) mild steel tubing
(SAE 1010, 1020, 1025) or equivalent, or alloy steel tubing
(SAE, 4130) shall be used for all roll cage structures. Proof
of use of alloy steel is the responsibility of the entrant.
I think this is where the bs about mandrel bends came from.
All welds shall be visually inspected and shall be acceptable
if the following conditions are satisfied:
1. The weld shall have no cracks.
2. Thorough fusion shall exist between weld metal and
base metal.
3. All craters shall be filled to the cross section of the
weld.
4. Undercut shall be no more than 0.01 inch deep.
C. Aluminum bronze or silicon bronze welding technique is
permitted, but extreme care shall be used in preparation of
parts before bronze welding and in the design of the attaching
joints.
Seems that they only require the welds to look good, nothing more. I dont understand the parts that are in bold, however. Craters? Undercut?
Can anyone explain?
Thanks
James
A little while back we were debating the merrits of bracing techniques in the engine bay. Here's some photos of a strong set up for an old banger Ford Fairlane 500.
Note the triangulation from suspension turrets back to the firewall. If you had the room, (and clearly on the 4 cylinder Alfas I am sure you do) you could also add a bar across the top of the engine to fully triangulate.
What a tough set up? !! Sometimes it pays to look back. A lot of the time its has all been done before...
Note the triangulation from suspension turrets back to the firewall. If you had the room, (and clearly on the 4 cylinder Alfas I am sure you do) you could also add a bar across the top of the engine to fully triangulate.
What a tough set up? !! Sometimes it pays to look back. A lot of the time its has all been done before...
- Attachments
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- Firewall Connection Detail.jpg (220.41 KiB) Viewed 8656 times
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- Turret Connection Detail.jpg (217.04 KiB) Viewed 8657 times
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- Suspension Turret bracing.jpg (227.88 KiB) Viewed 8657 times
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- Failane 500.jpg (209.05 KiB) Viewed 8658 times
Transaxle Alfas Haul More Arse
You can't ignore the merits of triangulation, but your triangle can't act like a hinge, either, in response to a force applied perpendicular to the plane of the triangle. In the Fairlane, the majority of strut force is perpendicular to the brace triangle. In this case, the triangle acts more as a front fender brace(to the limits of flexion at the flat metal around the strut mount bolts).
I am not saying that the brace does not do anything(I noticed the crack in my windshield got MUCH bigger after a simple strut cross brace), just that the majority of the strut force is shared by the inner wheel well sheetmetal. The Fairlane brace does make the front box much stronger in case of impact.
Tying strut mounts with a cross brace does have some benefits based on the angle of the strut. But the flex in the brace limits the effectivness. Tying a cross brace to the body with additional attachment points (bracing) in any plane but perpendicular to the strut will have more pronounced benefits (Which is what the wheel well sheet metal is trying to do, but with forces in many directions).
I am not saying that the brace does not do anything(I noticed the crack in my windshield got MUCH bigger after a simple strut cross brace), just that the majority of the strut force is shared by the inner wheel well sheetmetal. The Fairlane brace does make the front box much stronger in case of impact.
Tying strut mounts with a cross brace does have some benefits based on the angle of the strut. But the flex in the brace limits the effectivness. Tying a cross brace to the body with additional attachment points (bracing) in any plane but perpendicular to the strut will have more pronounced benefits (Which is what the wheel well sheet metal is trying to do, but with forces in many directions).
- Attachments
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- Here is a pic borrowed form someone elsehttp://my105.com/classified.asp?id=6531
- 1611200685740710_m.jpg (39.91 KiB) Viewed 8647 times
- Maurizio
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@MD Since when is any American designed car able to go around corners!What a tough set up? !! Sometimes it pays to look back. A lot of the time its has all been done before...
I'm not convinced. The firewall is not the place to place forces into. In designing for stiffness you need to work only with pull/push tubes.
Firewall gets bending forces like you use it!
I would set it up like the red in the picture.
(see it as an example, this will not clear the pedal box)
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- engine_bay_strutts_789.jpg (227.78 KiB) Viewed 8633 times
Banned.. ? Daily donky.. ==> BMW 325d
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
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- Platinum
- Posts: 494
- Joined: Tue Feb 21, 2006 10:05 pm
- Location: Sunny Euro-Brisney
- Maurizio
- Verde
- Posts: 680
- Joined: Wed Dec 01, 2004 4:49 am
- Location: the Netherlands, 153.1km from the N'ring :-)
Came across some pics of a imsa replica.
Engine bay and the front nicely stiffened. I like what I see
Engine bay and the front nicely stiffened. I like what I see
- Attachments
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- imsa12.jpg (209.22 KiB) Viewed 7318 times
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- imsa5.jpg (207.69 KiB) Viewed 7318 times
Banned.. ? Daily donky.. ==> BMW 325d
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
- Maurizio
- Verde
- Posts: 680
- Joined: Wed Dec 01, 2004 4:49 am
- Location: the Netherlands, 153.1km from the N'ring :-)
and the rest, this car was probably done with a nice budget....Mats wrote:Yeah, it's amazing what you can get away with when you have a dry sump...
I like the way they did hide the space frame front in the original inner fenders.
Banned.. ? Daily donky.. ==> BMW 325d
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79
E36M3 (3.0) Ringtool ==> definitely BANNED!
AR 75 TS Ringtool '90, AR Spider 2000 veloce '79