I might have invented something good

[Nefarious]

Jordan, not James- it’s not the worst I’ve been called Would it not concern you if they decide what you’ve done gets outlawed you’ve then got a chassis full of foam to try and clean out?

Already have a plan for that. As you say, if this works, it'd only be a matter of time before then ban it. Then I'd be left with a useless, unsaleable racecar.

So when we get to that stage, we put out a whole bunch of PR in relation to recent accidents, calling for some sort of additional impact protection to be made mandatory. Then we reveal the idea to the world. If the scrutes object, we claim it as a safety device, and go public again with a hand-wringing, won't-somebody-think-of-the-children PR offensive.

Dave - like it! I could make a properly unpleasant version of that!

[RobYob]

Lots to do now - not least fitting a more accurate gauge to my hydraulic press for testing purposes. I have no idea what's already out there, but I may have accidentally stumbled on something actually quite good.

Was thinking about this. So you're checking force/displacement for elastic deformation. It'd be very interesting to do a force-hammer impact to measure the change in dynamic stiffness and damping from the composite parts. I imagine it could be quite a dramatic change.

[Nefarious]

Lots to do now - not least fitting a more accurate gauge to my hydraulic press for testing purposes. I have no idea what's already out there, but I may have accidentally stumbled on something actually quite good.

Was thinking about this. So you're checking force/displacement for elastic deformation. It'd be very interesting to do a force-hammer impact to measure the change in dynamic stiffness and damping from the composite parts. I imagine it could be quite a dramatic change.

Funnily enough, I was thinking exactly the same - there's a real danger that excess load or possibly vibration could cause the foam core to become compromised. There is no possibility of repair or re-application.

Just trying to work out how to do accurate, replicable impact tests with my current kit...

[RobYob]

Lots to do now - not least fitting a more accurate gauge to my hydraulic press for testing purposes. I have no idea what's already out there, but I may have accidentally stumbled on something actually quite good.

Was thinking about this. So you're checking force/displacement for elastic deformation. It'd be very interesting to do a force-hammer impact to measure the change in dynamic stiffness and damping from the composite parts. I imagine it could be quite a dramatic change.

Funnily enough, I was thinking exactly the same - there's a real danger that excess load or possibly vibration could cause the foam core to become compromised. There is no possibility of repair or re-application.

Just trying to work out how to do accurate, replicable impact tests with my current kit...

Cool, well I'm by no means a structures expert but I've done a fair bit of modal/resonance/dynamics stiffness testing over the years. Send me a PM if you want to have a chat about data acquisition and processing.

Long term, maybe think about a logging accelerometer or strain gauge on any chassis or extended durability test component you make. That'll be one way to get advanced warning of a change internally of the foam-metal.

[Nefarious]

Just in case anyone's interested, yesterday was the first proper mechanical test of the foam-based composities. Nothing too fancy yet in terms of the recipe, just testing the base foam product and the primer solution.


3 point test over a 30cm span. 2 materials - some really shitty <1mm wall ERW steel tube and some 15mm ABS.

The headline result was empty steel failed at 550psi, foam filled failed at 1100psi.
Filled ABS held out til just over 1000psi. No accurate reading for unfilled ABS, as it bent beyond the travel of the press.

Bit disappointed TBH. Fag packet sums said the foam-filled steel one should've held out til over 2k. I suspect the steel tube was just too shitty and failed in tension.

Also, testing methodology needs a lot of work. The hydraulic press just isn't accurate enough at small loads.

I've now arranged to use a friend of a friend's spring tester, which is not only more accurate, but will also allow longditudinal load tests. Will also re-test using a decent quality CDS tube for a better match between the compressive strength of the doam and the tensile strength of the metal.

[Nefarious]

More positively, I did also make this for my friend:



In case the images aren't showing, it's a walking cane made from a piece of structural carbon fibre tube and the gearknob from a TVR Cerbera. Filled with the PU foam, and stuck together with helicopter glue (the friend is an ex-Airbus pilot, and the glue is what the Airbuses are stuck together with)

[mik]

No images showing for me on iPhone or iPad Neil

[Nefarious]

Tits.

What does everyone else use for image hosting these days? I normally post of FB and just link to here, but in this instance, I don't want these on FB at the moment.

[jamcg]

Tits.

What does everyone else use for image hosting these days? I normally post of FB and just link to here, but in this instance, I don't want these on FB at the moment.

The forum has its own hosting http://gallery.ov9.co.uk/

[mik]

I use imgur

[RobYob]

I use imgur

2nded for Imgur, although the interface that used to work on mobile no longer does for me which is annoying.

[RobYob]

Just in case anyone's interested, yesterday was the first proper mechanical test of the foam-based composities. Nothing too fancy yet in terms of the recipe, just testing the base foam product and the primer solution.

...

I've now arranged to use a friend of a friend's spring tester, which is not only more accurate, but will also allow longditudinal load tests. Will also re-test using a decent quality CDS tube for a better match between the compressive strength of the doam and the tensile strength of the metal.

Strain gauges run through a Fluke multitester an option? Just to correlate you mate's spring tester.

[Nefarious]

Should be kinda fixed now

Rob - I think you overestimate the kit I have at my disposal!

[jamcg]

@Nefarious Pics now working on iPhone at least. Are you going to open up the filled tubes to check for air pockets, even density, adhesion to tube etc? Would show if you need to modify application technique, could be a reason why it didn’t match with calculation?

[mik]

Pics now work and even though you didn’t get the result you were hoping for.... double the force of an unfilled tube isn’t exactly shit

Walking cane is superb

[McSwede]

Walking cane is superb

Isn't it just!! Well done.

[Jobbo]

More positively, I did also make this for my friend:



In case the images aren't showing, it's a walking cane made from a piece of structural carbon fibre tube and the gearknob from a TVR Cerbera. Filled with the PU foam, and stuck together with helicopter glue (the friend is an ex-Airbus pilot, and the glue is what the Airbuses are stuck together with)

Do you think he’ll mind that it’s a Ford Puma gear knob?

[Nefarious]

I thought I knew where all the TVR bits ultimately came from, but that's a new one on me. I doff my cap to your encyclopedic knowledge of such matter, as always!

[duncs500]

I use imgur

2nded for Imgur, although the interface that used to work on mobile no longer does for me which is annoying.

There was a problem with my Imgur phone app, they said to uninstall and reinstall and it has been fine ever since.

[Beany]

I thought I knew where all the TVR bits ultimately came from, but that's a new one on me. I doff my cap to your encyclopedic knowledge of such matter, as always!

I thought it looked familiar, but given some of the bonkers custom interior stuff they did, I assumed I was mistaken