high pressure envelope

At 50 bar will not your envelope become your constraint?

The proper envelope and you could use water in it.

I guess I need more data like temp, shear forces, thickness requirements, Envelope specs, use etc.

To many variables for me to fathom

Brad

Brad,

It is a new product to be developed, so many variables are still decided. But imagine two parallel metal plates sizes 500x1500mm (strong enough to hold 50 bars) at 50 mm distance.
The required envelope or bag is inserted between them and put under pressure of 50 bars. The metal plates will not move apart.
I've been looking into hoisting cushions which would be very interesting (max press ca 50 bar) although the metal plates will be curved iow as soon as they are radius-ed the inner sheet needs to be shorter. Our supplier is unable to tackle this.

Not concentrating on just one 'horse' I would like to know if there are (reinforced) materials available that can be sealed or vulcanized, strong enough to hold this pressure (air or oil).

Sorry for taking so long. Remodeling the office er living room. I answered late last night and checked the definition of a word, then closed the resource and I closed my answer. OOPS! so here here I go again.

This seems either for a bearing, vibration isolation, or a physical tensor.

As a bearing the angle of movement is small, as a tensor the vector is short and powerful, and as a vibration isolator the load is extreme.

All the products I know of that are able to handle that pressure as a envelope are non elastic. eg. Kevlar, spectra, carbon fiber, and some polycarbonates.

Liquids at that pressure (for the most part) are non compressible. This combined with a non elastic envelope is a concern. vibration or movement will cause large spikes in pressure because the envelope can flex but not stretch.

This leaves gas as the medium of choice. In a closed non dynamic system large inert molecules are best because they are easier to contain over time.

In a dynamic active system nitrogen or dry air is best because of cost. I prefer nitrogen due to less thermal expansion and contraction.

I've made several assumptions: they are not to be used as a single unit, they need a durable life span (years not days), they are functual not just aesthetic, and they will be assembled non pressurized.

The weight they will be able to bear is considerable.

when you get further along send me an e-mail www.elricc11@charter.net

I'm curious to the function and form.

Hope this helps some.

Brad

Dear Brad,

The problem (in this stage) is that I cannot disclose the purpose of this 'envelope'.
(The word 'envelope' is the closest to describe the shape).
It's neither one of your assumptions although some of the comments are applicable.
(Gas -N- or oil filled)
I'm more or less familiar with the Kevlar and carbonfibers, but see them as reinforcements in a matrix material s.a. Rubber, PU etc..
The thing is that this matrixmaterial should be strong enough to be sealed; iow the reinforced sheeth material should be strong enough on the seals to take this pressure.
Plus, the manufacturing method (vulcanizing?) should be able to be applied in various radii.
Right now I'm thinking to approach one of the car tire companies and see what they are willing and capable of doing.
Actually I hope to get a hint in a new direction.
Pls don't give up thinking!
Tom

Pls don't give up thinking!
Never my head would implode!

If you vulcanize you may be able to attach the edges of the envelope to the flat of the plates and do away with the faces of the envelope. Tap your steel plates for your couplers to fill and monitor. They would be thick sides at approximately 750psi.

Since I don't know what the cyclic variables are, I am at a loss for what you need. Tires max out at 140 to 150 psi that I know of, so you could make concentric rings of increasing pressure to get your envelope but size may be an issue.

If you want, contact me at elricc11@charter.net

Brad

Some of the high-tech materials developed over the last several years may do the job, the most common of which is Kevlar, and others using carbon fibers. Check out material properties at MatWeb Kevlar has a tensile strength of over 400,000 psi.

Not sure how these fibres would be deployed (Kevlar, carbon) to contain gas/liquid - as a reinforcement in rubber?

What pressures are the air springs using on buses and trucks?

Correct, the strength of the fiber is not the real problem, it's the type of seal that will be the vital link in the system. (manufacturing it in one cycle is no option).

Have looked into hoisting cushions but the manufacturer is not able to vulcanize curved models (with differenses in length of the sheets).

Will try to find out the construction of the springcushions and see what I can learn there.

You could well face a problem with the very different moduli and the concentration of stress/strain close to the fibres rbeaking the bond between fibres and matrix. I don't know off hand of any similar materials, but it's a bit like a big automotive brake hose!

Sorry, that was me (again)