Red Bull RB18

[ringo]

Resonation may be unlikely. The natural frequency of metal is very high. And if it takes the form of a hard pipe being held between two fixed points and there is high pressure fluid in it moving through its hard to see such a low frequency bounce causing resonation.
The natural frequency is the square root of the stiffness over the mass. The resonant frequency would be factor of how the line is setup. I just cannot see the low frequency bounce resonating the fuel pipe. The tail pipe and exhaust pipes would probably resonate before this fuel line.
Likely a threaded coupling came loose from the vibration of the engine itself and the line lost sealing. And i suspect its a feul return line and not the fuel supply line.

[matteosc]

Resonation may be unlikely. The natural frequency of metal is very high. And if it takes the form of a hard pipe being held between two fixed points and there is high pressure fluid in it moving through its hard to see such a low frequency bounce causing resonation.
The natural frequency is the square root of the stiffness over the mass. The resonant frequency would be factor of how the line is setup. I just cannot see the low frequency bounce resonating the fuel pipe. The tail pipe and exhaust pipes would probably resonate before this fuel line.
Likely a threaded coupling came loose from the vibration of the engine itself and the line lost sealing. And i suspect its a feul return line and not the fuel supply line.

Frequency does not depend on the material alone and a very slender metallic structure can have extremely low natural frequencies. The bending stiffness is the one contributing the most to the first natural frequency, which is usually the first bending for pipe/beam-like structures. Large radius pipe have in general higher stiffness than small radius one; obviously what really matters is the length/diameter ratio, but a long and large pipe can have a first bending frequency close to a short small one.
Additionally, where the structure is located (different forces acting on it) and boundary conditions highly affect not only the natural frequencies, but also the response.

I am not claiming that this is what happened to RB, but I really do not think we can exclude it based on the fact that the pipe is metallic.

[Big Tea]

Resonation may be unlikely. The natural frequency of metal is very high. And if it takes the form of a hard pipe being held between two fixed points and there is high pressure fluid in it moving through its hard to see such a low frequency bounce causing resonation.
The natural frequency is the square root of the stiffness over the mass. The resonant frequency would be factor of how the line is setup. I just cannot see the low frequency bounce resonating the fuel pipe. The tail pipe and exhaust pipes would probably resonate before this fuel line.
Likely a threaded coupling came loose from the vibration of the engine itself and the line lost sealing. And i suspect its a feul return line and not the fuel supply line.

Frequency does not depend on the material alone and a very slender metallic structure can have extremely low natural frequencies. The bending stiffness is the one contributing the most to the first natural frequency, which is usually the first bending for pipe/beam-like structures. Large radius pipe have in general higher stiffness than small radius one; obviously what really matters is the length/diameter ratio, but a long and large pipe can have a first bending frequency close to a short small one.
Additionally, where the structure is located (different forces acting on it) and boundary conditions highly affect not only the natural frequencies, but also the response.

I am not claiming that this is what happened to RB, but I really do not think we can exclude it based on the fact that the pipe is metallic.

Would the resonant frequency not be the unsupported length between two fixing points? (and multiples of)

So several different frequencies in the run of the whole 'pipe'. Is the new fuel pore prone to frothing I wonder?

[matteosc]

Resonation may be unlikely. The natural frequency of metal is very high. And if it takes the form of a hard pipe being held between two fixed points and there is high pressure fluid in it moving through its hard to see such a low frequency bounce causing resonation.
The natural frequency is the square root of the stiffness over the mass. The resonant frequency would be factor of how the line is setup. I just cannot see the low frequency bounce resonating the fuel pipe. The tail pipe and exhaust pipes would probably resonate before this fuel line.
Likely a threaded coupling came loose from the vibration of the engine itself and the line lost sealing. And i suspect its a feul return line and not the fuel supply line.

Frequency does not depend on the material alone and a very slender metallic structure can have extremely low natural frequencies. The bending stiffness is the one contributing the most to the first natural frequency, which is usually the first bending for pipe/beam-like structures. Large radius pipe have in general higher stiffness than small radius one; obviously what really matters is the length/diameter ratio, but a long and large pipe can have a first bending frequency close to a short small one.
Additionally, where the structure is located (different forces acting on it) and boundary conditions highly affect not only the natural frequencies, but also the response.

I am not claiming that this is what happened to RB, but I really do not think we can exclude it based on the fact that the pipe is metallic.

Would the resonant frequency not be the unsupported length between two fixing points? (and multiples of)

So several different frequencies in the run of the whole 'pipe'. Is the new fuel pore prone to frothing I wonder?

Not sure I understand your question, but the natural frequency would depend on Young modulus (material), diameter, length and density (again: material). If we consider it as a beam (which is not, but just to make an example) the first natural frequency would be omega_1 = 1.875^2 * ( (E * I)/(rho * A * L^4) )^0.5. Second and third would be the same formula, just replacing 1.875 with 4.694 and 7.855 respectively.
No point in trying to come up with number for these frequencies, since we have no idea about the value of most of the parameters here.

[cooken]

While you're all at it, better not forget to throw in load effects (e.g. tension stiffening). I suggest not being in a hurry to oversimplify the problem of a pressurized bent tube. Is it rigid or flexible tubing? I reckon that's the first thing to agree on here...

[Big Tea]

Frequency does not depend on the material alone and a very slender metallic structure can have extremely low natural frequencies. The bending stiffness is the one contributing the most to the first natural frequency, which is usually the first bending for pipe/beam-like structures. Large radius pipe have in general higher stiffness than small radius one; obviously what really matters is the length/diameter ratio, but a long and large pipe can have a first bending frequency close to a short small one.
Additionally, where the structure is located (different forces acting on it) and boundary conditions highly affect not only the natural frequencies, but also the response.

I am not claiming that this is what happened to RB, but I really do not think we can exclude it based on the fact that the pipe is metallic.

Would the resonant frequency not be the unsupported length between two fixing points? (and multiples of)

So several different frequencies in the run of the whole 'pipe'. Is the new fuel pore prone to frothing I wonder?

Not sure I understand your question, but the natural frequency would depend on Young modulus (material), diameter, length and density (again: material). If we consider it as a beam (which is not, but just to make an example) the first natural frequency would be omega_1 = 1.875^2 * ( (E * I)/(rho * A * L^4) )^0.5. Second and third would be the same formula, just replacing 1.875 with 4.694 and 7.855 respectively.
No point in trying to come up with number for these frequencies, since we have no idea about the value of most of the parameters here.

Thats what I mean. There could be many different lengths which would vibrate at different frequencies and harmonics in the pipe run which could even pass along the run. it would have to be literally rigid to rule out completely.

[Big Tea]

Double post sorry

[matteosc]

Would the resonant frequency not be the unsupported length between two fixing points? (and multiples of)

So several different frequencies in the run of the whole 'pipe'. Is the new fuel pore prone to frothing I wonder?

Not sure I understand your question, but the natural frequency would depend on Young modulus (material), diameter, length and density (again: material). If we consider it as a beam (which is not, but just to make an example) the first natural frequency would be omega_1 = 1.875^2 * ( (E * I)/(rho * A * L^4) )^0.5. Second and third would be the same formula, just replacing 1.875 with 4.694 and 7.855 respectively.
No point in trying to come up with number for these frequencies, since we have no idea about the value of most of the parameters here.

Thats what I mean. There could be many different lengths which would vibrate at different frequencies and harmonics in the pipe run which could even pass along the run. it would have to be literally rigid to rule out completely.

Yes, there are several frequencies (in theory there is an infinite number of them), which corresponds to the various modes. Typically the higher the frequency, the lower the response amplitude and it is usually easier to excite lower modes. That is why normally the issues are only with the first few natural frequencies.

[ringo]

Would the resonant frequency not be the unsupported length between two fixing points? (and multiples of)

So several different frequencies in the run of the whole 'pipe'. Is the new fuel pore prone to frothing I wonder?

Not sure I understand your question, but the natural frequency would depend on Young modulus (material), diameter, length and density (again: material). If we consider it as a beam (which is not, but just to make an example) the first natural frequency would be omega_1 = 1.875^2 * ( (E * I)/(rho * A * L^4) )^0.5. Second and third would be the same formula, just replacing 1.875 with 4.694 and 7.855 respectively.
No point in trying to come up with number for these frequencies, since we have no idea about the value of most of the parameters here.

Thats what I mean. There could be many different lengths which would vibrate at different frequencies and harmonics in the pipe run which could even pass along the run. it would have to be literally rigid to rule out completely.

Yes, but for resonance the frequency has to match the natural frequency of the arrangement; correct me if I wrong.
The car is bouncing no more than 5 Hz.

check this link for some equations : https://www.engineeringtoolbox.com/stru ... _1989.html


Say I use the Structure with Fixed Ends and Distributed Mass model, with a 20kg/m load; which we know is not the case. f = 3.56 (E I / q L4)0.5

L may be as much as 0.5 metres. Say the pipe is 10mm OD and 9mm ID. I get a frequency of 74Hz for example.
The lesser the external load the higher the frequency will be.

It's more complex than I am making it out here but its just an idea of the scale of things and how far the porpoising frequency is from a possible resonance issues. Then you must ask, what is the damage mechanism from the resonance?
Will fatigue failure arrive so quickly?

[Andi76]

I am not an expert in relation to vibrations and frecquencies, but i remember 1996. Ferrari had huge problems with the vibrations of their first V10 engine. The vibrations of the 046 engine caused cracks in the titanium gearbox. The vibration problems were very complex and Ferrari was not able to get rid of it in 1996. In 1995, with the gearbox being very similar and a V12 engine with different and less vibrations, they did not have any problems at all. In the first races of 1997 Ferrari ran exactly the same gearbox and engine like they did late in 1996, but they also had no problems with cracks at all. So obviously the differences in the design of other parts in that area resulted in a different "distribution" of the vibrations, hence no cracks in the gearbox. So it seems to me that sometimes vibrations and its effects can be unpredictable and extremely complex and influenced by a lot of things. So i think that Red Bulls problem can indeed be down to vibrations, no matter what the frecquencies are. But like i said - i am not an expert on that and i can be totally wrong, but Ferraris 1996 "vibration-problem" and the lack of it in 1997, even if the source and frecquencies being the same, suggests that to me.

[saviour stivala]

1996/1997 FERRARI - F310/F310B. Schumacher/Irvine. The first FERRARI to run on Shell fuel since 1970's. The cars troublesome developments - had to use 1995 car partsearly in the season. Car was first to use the V10 engine - engineered by Osamu Goto. First F1 car futured dashboard 'gauges/controls all on steering wheel. The 'B' Byrne/Brawn/Totd - the first titanium gearbox (housing) - 1997 - was produced by, and was fabricated as opposed to cast. This gearbox housing fabrication was a true work of art. All fabricated (welded) parts were machined from one inch thick sheet to form and down to 3mm wall thickness to achieve a constant wall thickness all round, something that the cast process at the time could not achieve.

[Big Tea]

Not sure I understand your question, but the natural frequency would depend on Young modulus (material), diameter, length and density (again: material). If we consider it as a beam (which is not, but just to make an example) the first natural frequency would be omega_1 = 1.875^2 * ( (E * I)/(rho * A * L^4) )^0.5. Second and third would be the same formula, just replacing 1.875 with 4.694 and 7.855 respectively.
No point in trying to come up with number for these frequencies, since we have no idea about the value of most of the parameters here.

Thats what I mean. There could be many different lengths which would vibrate at different frequencies and harmonics in the pipe run which could even pass along the run. it would have to be literally rigid to rule out completely.

Yes, but for resonance the frequency has to match the natural frequency of the arrangement; correct me if I wrong.
The car is bouncing no more than 5 Hz.

check this link for some equations : https://www.engineeringtoolbox.com/stru ... _1989.html


Say I use the Structure with Fixed Ends and Distributed Mass model, with a 20kg/m load; which we know is not the case. f = 3.56 (E I / q L4)0.5

L may be as much as 0.5 metres. Say the pipe is 10mm OD and 9mm ID. I get a frequency of 74Hz for example.
The lesser the external load the higher the frequency will be.

It's more complex than I am making it out here but its just an idea of the scale of things and how far the porpoising frequency is from a possible resonance issues. Then you must ask, what is the damage mechanism from the resonance?
Will fatigue failure arrive so quickly?

TBH, I was thinking of engine or pump generated vibration rather than proposing, which would be very long wave.
As you say the whole thing is complex and inter related. As they seem to struggle for weight even adding a few more fixing points would have to be studied and balanced weight v possible problem. I think just sit back and see what they find.

[TNTHead]

Thats what I mean. There could be many different lengths which would vibrate at different frequencies and harmonics in the pipe run which could even pass along the run. it would have to be literally rigid to rule out completely.

Yes, but for resonance the frequency has to match the natural frequency of the arrangement; correct me if I wrong.
The car is bouncing no more than 5 Hz.

check this link for some equations : https://www.engineeringtoolbox.com/stru ... _1989.html


Say I use the Structure with Fixed Ends and Distributed Mass model, with a 20kg/m load; which we know is not the case. f = 3.56 (E I / q L4)0.5

L may be as much as 0.5 metres. Say the pipe is 10mm OD and 9mm ID. I get a frequency of 74Hz for example.
The lesser the external load the higher the frequency will be.

It's more complex than I am making it out here but its just an idea of the scale of things and how far the porpoising frequency is from a possible resonance issues. Then you must ask, what is the damage mechanism from the resonance?
Will fatigue failure arrive so quickly?

TBH, I was thinking of engine or pump generated vibration rather than proposing, which would be very long wave.
As you say the whole thing is complex and inter related. As they seem to struggle for weight even adding a few more fixing points would have to be studied and balanced weight v possible problem. I think just sit back and see what they find.

I would suggest it seems mainly engine related vibrations, may be leading to fatigue at the connection points. I wonder whether the combustion characteristics due to E10 has lead to increased vibration levels on the high pressure pump and/or block. If not one would assume it would be a consequence of the packaging layout.

[CaribouBread]

A decent view of the rear suspension/gearbox bits

[toraabe]

What I expected. Good news. https://www.planetf1.com/news/max-verst ... -new-cars/