Dun dun dun...iiiiit's homework help time!
Discussion
I'm just asking for ideas, not for anybody to do my assignment for me...although feel free to if you're bored...
One of the tasks is to select an automotive component or system which could be made from an advanced composite material, but at present is made from a more traditional material. It has to be something where use of a composite material can be justified, i.e. not parts like a dashboard or gear knob because it'd be neither cheaper nor stronger or lighter than using a plastic.
Any ideas for components that you think might fit the bill? My brain burnt out after trying to work out how CF springs would work
One of the tasks is to select an automotive component or system which could be made from an advanced composite material, but at present is made from a more traditional material. It has to be something where use of a composite material can be justified, i.e. not parts like a dashboard or gear knob because it'd be neither cheaper nor stronger or lighter than using a plastic.
Any ideas for components that you think might fit the bill? My brain burnt out after trying to work out how CF springs would work
tyres. saw an interesting thing in the paper tuther day about an idea for tyres that are not made from rubber or solid in the sense that they are now. they were sort of constructed from a series of geodesic shapes and were able to be seen through as their structure was mostly hollow. think it was in the times. clever stuff.
Well the most obvious is the body or at least the body skin. I had the privledge of opening and shutting the door on a MacLaren Racer (the one in FINA livery) at a BMW technical seminar, the door felt quite rigid but seemed to have a mass of about 2 kg.
How about the propshat on a RWD setup? You can get an aluminum one here in the states, custom built, seems to me this is an expensive way to get rid of a little rotating inertia, but, whatever.
Or at least parts of the road wheels. You would probably still need an aluminum rim and maybe the mounting hole(s) but most of the middle could be carbon fibre.
How about the propshat on a RWD setup? You can get an aluminum one here in the states, custom built, seems to me this is an expensive way to get rid of a little rotating inertia, but, whatever.
Or at least parts of the road wheels. You would probably still need an aluminum rim and maybe the mounting hole(s) but most of the middle could be carbon fibre.
Pigeon said:
My brain burnt out after trying to work out how CF springs would work
Think of the GF ones on a Sherpa van, but lighter
You might be on to something there! The Unofficial Austin Rover Web Resource said:Although leaf springs aren't really the most modern car technology, by a long shot, I guess they're still used alot on vans etc.? I could do something with that...
This was in the early 80s, GKN were in talks with Freight Rover about the supply of composite leaf springs as F-R wanted to launch a revised Sherpa for the 1986 model year. They wanted to add a feature that would give the Sherpa a more high-tech image...
Also thinking of carbon-fibre disc brakes...already being done, but rarely on road cars. I should be able to find a fair bit on the net about them.
ATG said:
wishbones, trailing arms and other exciting suspension stuff?
This is the area where saving weight has the most benefit. As well as improving overall efficiency through lightness, it improves ride and handling. It's an area where F1 technology could be, but hasn't yet transferred to road cars.Brake discs are not carbon fibre, they are carbon-carbon matrix. Not appropriate for road cars due to excessive differences in performance between hot and cold.
Composite leaf springs (also used on the Corvette) save significant weight, especially if the alternative is/was multi-leaf springs. One concern expressed with the Freight Rover springs was whether they maintained stiffness in all three planes. As a straight swap on the vans, the springs also provided lateral axles control. There were suspicions that they were not delivering n this front, and that spring wind-up characteristics were different. Both could be dealt with, but as a straight change new variables were introduced. The Corvette leaf has been designed in from the start, and provides only the springing medium.
Other areas where you might consider advanced materials would include areas of:
- high loads,
- excessive weight (e.g where a casting is used)
- Great complexity (e.g. where you use complex, multi-layer sheet pressings with difficult welding)
So you might wish to consider:
- Frame structure around apertures (doors, engine bay): You need stiffness & strength with high loadings. Pressings get very complicated, suffer fatigue, and compromise styling. Casting or sintering components would add a lot of weight.
- Impact protection: Composite side impact beams in the doors would add a very strong safety cell. Given the parts would be destroyed in a crash, whether composite or steel, they are single-use parts.
- Extreme load elements: Crossmembers & subframes for suspension and engine. These have to take huge loads, and distribute them sensitively and evenly into the main frame. They are amongst the first components to be FEA'd. Pressed steel assemblies struggle. Castings are often too heavy and expensive. Composites would offer the theoretical benefits of casting, with light weight (and less concerns of corrcosion?). Fatigue should not be an issue with good design.
- Gearbox casing: The F1 boys are fairly well experienced with these now. Although few roadcars use the gearbox as a stressed member, the box (especially auto boxes for large RWD cars, such as Jaguar & Mercedes) is huge. Composites could significantly reduce weight, handle the laods, and handle the heat stress.
Composite leaf springs (also used on the Corvette) save significant weight, especially if the alternative is/was multi-leaf springs. One concern expressed with the Freight Rover springs was whether they maintained stiffness in all three planes. As a straight swap on the vans, the springs also provided lateral axles control. There were suspicions that they were not delivering n this front, and that spring wind-up characteristics were different. Both could be dealt with, but as a straight change new variables were introduced. The Corvette leaf has been designed in from the start, and provides only the springing medium.
Other areas where you might consider advanced materials would include areas of:
- high loads,
- excessive weight (e.g where a casting is used)
- Great complexity (e.g. where you use complex, multi-layer sheet pressings with difficult welding)
So you might wish to consider:
- Frame structure around apertures (doors, engine bay): You need stiffness & strength with high loadings. Pressings get very complicated, suffer fatigue, and compromise styling. Casting or sintering components would add a lot of weight.
- Impact protection: Composite side impact beams in the doors would add a very strong safety cell. Given the parts would be destroyed in a crash, whether composite or steel, they are single-use parts.
- Extreme load elements: Crossmembers & subframes for suspension and engine. These have to take huge loads, and distribute them sensitively and evenly into the main frame. They are amongst the first components to be FEA'd. Pressed steel assemblies struggle. Castings are often too heavy and expensive. Composites would offer the theoretical benefits of casting, with light weight (and less concerns of corrcosion?). Fatigue should not be an issue with good design.
- Gearbox casing: The F1 boys are fairly well experienced with these now. Although few roadcars use the gearbox as a stressed member, the box (especially auto boxes for large RWD cars, such as Jaguar & Mercedes) is huge. Composites could significantly reduce weight, handle the laods, and handle the heat stress.
Yup, anything around the wheel area would be good, reducing unsprung weight etc. I think cost effectiveness does need to be included, although it's not mentioned specifically. Just found a very good website about composite driveshafts...
I'll see if I can find some good info for all of your suggestions. Thanks for your help chaps!
I'll see if I can find some good info for all of your suggestions. Thanks for your help chaps!
HiRich said:Fair enough, only said it because of...
Brake discs are not carbon fibre, they are carbon-carbon matrix...
Jarno Trulli said:Probably just a language thing
The use of carbon-fibre brakes requires a little time to get used to...In fact, during the first milliseconds after pressing the brake-pedal; it feels like nothing is happening.
Thanks though, some very good stuff there.Gassing Station | The Pie & Piston Archive | Top of Page | What's New | My Stuff