Roll Cage

[OutCell]

I am designing a Roll Cage (Using CAD+FE) and trying out new materials for testing/analysis. Commonly used materials i found are:

CDS Carbon Steel[/*:m:1vxtgusj]
ERW Mild Steel[/*:m:1vxtgusj]
DOM Mild Steel[/*:m:1vxtgusj]
Cr (Chrome Molybdenum) Steel[/*:m:1vxtgusj]
T-45[/*:m:1vxtgusj]
1020 Grade Mild Steel CDW[/*:m:1vxtgusj]
Anybody knows any other suitable material i could use? It would be highly appreciated :)

OutCell

[Zico]

See article 253 section 8.3 of the FIA regulations http://www.fia.com/sport/Regulations/Rally/Middle_east_championship/Sporting_code/appendixj.html relating to material specification. and also see what Safety devices have to say about suitable materials here..http://www.safetydevices.com/index.php?option=com_content&task=view&id=29&Itemid=49

"Only by using the correct material of a reputable source to produce roll cages it is possible to guarantee that the product will do what it was designed to do should you be so unfortunate to have a serious crash. This is why we do not use anything else but the best. Your life and our reputation depend on it.

T-45 (light weight)
Initially used only for aerospace applications, T45 has for a while now been used in the manufacture of roll cages by Safety Devices. The advantage of T45 is that it has a tensile strength of approximately twice that of the standard Cold Drawn Seamless tube (CDS). Due to its high tensile strength we can manufacture the roll cage using tubing of the same diameter but of a thinner gauge (wall thickness). As a guide this equates to a weight saving of approximately 0.5 kg per metre of tubing or 10 - 15% of the total roll cage weight when compared to CDS. However this does come at a cost, as a roll cage manufactured in T45 is substantially more expensive to purchase than the same in CDS and therefore only really required by competitors competing at the higher end of the motor sport spectrum.

CDS Carbon Steel
Otherwise known as Cold Drawn Seamless Carbon Steel, this is the material is used to manufacture all of our standard motor sport and 4 x 4 roll cages as it conforms to FIA material specification requirements and offers good elongation and weld-ability, which are key. Compared to T-45 it is a very cost effective material.

ERW mild Steel
The full description is Electrically Resistance Welded mild steel. Because this material does not have a high enough tensile strength value to comply with article 253 section 8.3 of the FIA regulations relating to material specification, it is only used for non structural applications such as roof racks whre a durable product is required.

Cr (Chrome Molybdenum) Steel
Although popular with some roll cage manufacturers, we do not use Cr in any of our tubular products. This is because the properties of Cr Steel are not considered a particularly suitable as achieving a constant quality is problematic and its ductility is far less effective in deformation than T45."





As explained above.. Personally I'd use T-45 if I could, expensive but its higher tensile strength allows a thinner tube wall thickness to be used for a 15% reduction in weight over a cheaper, but thicker tubed cage. Failing that I'd resort to CDS..

[rallymaster]

there is also 15CDV6 Steel tube, it may come under one of the materials listed but its a tube thats used in the wrc and fia GT cages and chassis

[OutCell]

See article 253 section 8.3 of the FIA regulations http://www.fia.com/sport/Regulations/Rally/Middle_east_championship/Sporting_code/appendixj.html relating to material specification. and also see what Safety devices have to say about suitable materials here..http://www.safetydevices.com/index.php?option=com_content&task=view&id=29&Itemid=49

"Only by using the correct material of a reputable source to produce roll cages it is possible to guarantee that the product will do what it was designed to do should you be so unfortunate to have a serious crash. This is why we do not use anything else but the best. Your life and our reputation depend on it.

T-45 (light weight)
Initially used only for aerospace applications, T45 has for a while now been used in the manufacture of roll cages by Safety Devices. The advantage of T45 is that it has a tensile strength of approximately twice that of the standard Cold Drawn Seamless tube (CDS). Due to its high tensile strength we can manufacture the roll cage using tubing of the same diameter but of a thinner gauge (wall thickness). As a guide this equates to a weight saving of approximately 0.5 kg per metre of tubing or 10 - 15% of the total roll cage weight when compared to CDS. However this does come at a cost, as a roll cage manufactured in T45 is substantially more expensive to purchase than the same in CDS and therefore only really required by competitors competing at the higher end of the motor sport spectrum.

CDS Carbon Steel
Otherwise known as Cold Drawn Seamless Carbon Steel, this is the material is used to manufacture all of our standard motor sport and 4 x 4 roll cages as it conforms to FIA material specification requirements and offers good elongation and weld-ability, which are key. Compared to T-45 it is a very cost effective material.

ERW mild Steel
The full description is Electrically Resistance Welded mild steel. Because this material does not have a high enough tensile strength value to comply with article 253 section 8.3 of the FIA regulations relating to material specification, it is only used for non structural applications such as roof racks whre a durable product is required.

Cr (Chrome Molybdenum) Steel
Although popular with some roll cage manufacturers, we do not use Cr in any of our tubular products. This is because the properties of Cr Steel are not considered a particularly suitable as achieving a constant quality is problematic and its ductility is far less effective in deformation than T45."





As explained above.. Personally I'd use T-45 if I could, expensive but its higher tensile strength allows a thinner tube wall thickness to be used for a 15% reduction in weight over a cheaper, but thicker tubed cage. Failing that I'd resort to CDS..

Thanks mate. I saw the safey devices website and i have all their materials listed. But ERW & DOM were the most i found information about.

I agree the T-45 looks like a very solid solution for me

[OutCell]

there is also 15CDV6 Steel tube, it may come under one of the materials listed but its a tube thats used in the wrc and fia GT cages and chassis

Thanks mate
It looks like it is more expensive than T-45 but the strength is impressive. Found this :
http://fsae.com/eve/forums/a/tpc/f/125607348/m/86510213831

[Zico]

If you were feeling flush I dare say you could use Titanium :D highest strength to weight ratio of any metal and 45% lighter than steel.. be a B1tch to weld unless you could do it in a sealed tank with an inert atmosphere of argon or helium to shield it from the contamination of oxygen, nitrogen and hydrogen... and to prevent fires, molten titanium being highly reactive to oxygen. Contamination will also cause a variety of conditions, such as embrittlement, which will reduce the integrity of the assembly welds and lead to joint failure.

It would be the ultimate tho.. ;)


My old man sells Machine tools for a living.. if you need any info on tube benders/notchers etc let me know..

[OutCell]

If you were feeling flush I dare say you could use Titanium :D highest strength to weight ratio of any metal and 45% lighter than steel.. be a B1tch to weld unless you could do it in a sealed tank with an inert atmosphere of argon or helium to shield it from the contamination of oxygen, nitrogen and hydrogen... and to prevent fires, molten titanium being highly reactive to oxygen. Contamination will also cause a variety of conditions, such as embrittlement, which will reduce the integrity of the assembly welds and lead to joint failure.

It would be the ultimate tho.. ;)


My old man sells Machine tools for a living.. if you need any info on tube benders/notchers etc let me know..

I am actually looking into Titanium alloys/Aluminum alloys and carbon composites just to see if any would be useful. But i haven't yet pinpointed any specific specs..

I really appreciate it Zico :D Lucky for you experience+knowledge is living close to you :D

I will be searching the processes more after i find the suffecient materials i am looking for.. So i might take you for your word soon :p

Thanks mate

[Steve Boyd]

I'm not sure that looking at the highest tensile strength to weight ratio for the material is necessarily the best answer. It would be if the failure mode of the cage was always tensile or shear but in an accident the load is frequently compression or bending and the failure mode is crushing or buckling. In this case it is the material stiffness (Young's modulus) and section dimensions that determine the strength and in such a case a thick section CDS cage may well be better than a thinner section T-45 as both materials have similar Young's modulus.

Is this why we have seen WRC retirements due to cage damage recently?

If you do go for the heavier section it does mean you have to look somewhere else to save the weight though!

[OutCell]

I'm not sure that looking at the highest tensile strength to weight ratio for the material is necessarily the best answer. It would be if the failure mode of the cage was always tensile or shear but in an accident the load is frequently compression or bending and the failure mode is crushing or buckling. In this case it is the material stiffness (Young's modulus) and section dimensions that determine the strength and in such a case a thick section CDS cage may well be better than a thinner section T-45 as both materials have similar Young's modulus.

Is this why we have seen WRC retirements due to cage damage recently?

If you do go for the heavier section it does mean you have to look somewhere else to save the weight though!

True but i am looking for a material that is strong and light in weight, i am concentraiting on the roll cage part, so the light weight and strength is what i am looking for.. It is a project i am doing on roll cages :)

I really appreciate your reply mate, it was interesting and helpful :D