Yes, FEA is probably the only way. Another concern is linearity, meaning that to some extent it is like a Belville spring and, if one isn't careful - or lucky - one will start to tug along the length of the material. Ie run out of things to flex.
I see on Jacob's stirling engine that they use this design in order to *avoid* radial movement. I, of course, want it. I can see how it serves their purpose with the wide leaves. It seems it may have to get more complicated.
C
Hi all,
Israel has it right, and the leaves don't overlap. The idea is to create a cheap (ie. with water jet cutting or laser cut) and compact spring which is internally well damped. A spring in steel with a nominal resonance with the supported mass of about 10Hz would have self resonances...
It's not fantastically clear and one has to imagine an annulus at the centre and at the rim onto which each of the curved ribs attaches. It was very quickly drawn and I couldn't easily get the compound curve that I ideally wanted.
By way of explanation in this instance it is effectively 8...
Hi
Here's a pdf of the dxf I uploaded yesterday.http://files.engineering.com/getfile.aspx?folder=90bf14f8-bb63-4905-9886-3024a0482425&file=scan0002.pdf
Hi Erwin and others
Here is a very rough sketch of what it might look like. The spirals could go round further, or more than once, but this is the basic outline (and the easiest to draw).
As to just picking a thickness the structure would seem to be the dominant factor here. The deflection...
The discs are almost certainly going to be 1.6mm carbon plate with a diameter of 60mm and a static deflection of about 5mm for a force of 12.5N. It should be quite well damped so I wouldn't expect dynamic displacement of more than 3mm or so.
There are actually two of these springs with an...
Thanks Megabill. That looks a really useful site but probably for another time as I'm trying to do a spring out of a sheet (probably now carbon rather than s/s). It is a spiral, though I'm still no further ahead on it.
Best
Christian Thomas
"Conversion to rectangular section is non-trivial." Oh dear. I was going to go assume it was easier, though I did have some doubts about, say, an identical vertical and horizontal displacement adding up to root two, especially with it working across the hypotenuse of the section.
Is your...
"do you mean perpendicular to the plane of the sheet?" Yes, thanks, that is what I should have written. And therefore the same for the horizontal, too.
I don't quite have a mental image of the plan of the spring as viewed from above. It will probably have four fixing holes on the rim, each...
Hi, I want to make a flat circular spiral spring which will be laser cut from sheet stainless steel and I need the spring constant to be the same horizontally as vertically. It is supporting a mass of about 1.25kg for a deflection of around 3 to 5mm. I also need to know about linearity and...
