Is there any data on the compressiv 1

[gida2]

Is there any data on the compressive stiffness of neoprene rubber? This is for Mil-R-6855 Type 2 Gr40 (40 Durometer) extruded sheet rubber 2" x 20" x 1/8" thick. Can you quantify the compressive stiffness from the durometer? This is for small deflections used in a finite element model. I know it is non-linear but I would like to model it as linear since the loading is under 100#'s.

Thanks,

 

[ramakant]

hi gida2
i am working on a project i have to use rubber as gasket. i have to calculate bolt loads required .in my case actually i want to use nitrile rubbber(shore A hardness 5,40,70) and i want to know if you could get some data about rubbers i am basically interested in %compression and stress developped ......if you can help me....

thanks and regards
Ramakant

 

[ParaDoc]

...there is a dump rule which relates shore-hardness to modulus of elasticity (irrespective of the rubber grade you are using). This rule tells us for example:

70 Shore A gives Youngs-Modulus roughly about 6MPa
55 Shore A gives Youngs-Modulus roughly about 3MPa
40 Shore A gives Youngs-Modulus roughly about 1.5MPa

... and so forth. The modulus of elasticity can, in case of small strains, be identified with the compression modulus. If you need the Youngs Modulus for other than above given rubber hardness values, please feel free to ask!
best regards
ParaDoc

 

[ramakant]

thanks ParaDoc!
can i have some information regarding % compression and required stress on rubbers of different kind(Shore A 40,55,70 or more).


regards
Ramakant

 

[ParaDoc]

... well, this may depend on which component (body) you are thinking about. For this to clarify I would suggest to read the
following paper:

"Load-compression Relationship of Rubber Unit" by P.B.LINDLEY; Journal of Strain Analysis Vol I No 3 1966

By the way I have in my lab an appropriate EXCEL-Sheet, which is capable to give the right answer; unfortunately it is not available to the public.
regards
M.A.

 

[dravid]

Hi ParaDoc and others.

i am doing the joint analysis for the filament wound pressure vessel and its laminated skirt. Between the joint i am using some shear ply, for this purpose i have to use some shear ply, does any of you recomend me some elastomer. I have read about the use of EPDM, but dont know which grade, can some one provide me the follwoing properties for the epdm or some other shear ply.

Shear Modulus, Shear Strength & coefficient of thermal expansion.

 

[ParaDoc]

Shear Modulus roughly depends on the Shore-Hardness of the EPDM-grade. Let us assume you would take "ShA50" then the Shear Modulus is about 1MPa. The coefficient of thermal expansion is in the range of 120 to 180*10**(-6) 1/Kelvin
depending on the compound (content of filler etc).
best regards
M.A.

 

[KenO]

How can I get a copy of this "Load-compression Relationship of Rubber Unit" by P.B.LINDLEY; Journal of Strain Analysis Vol I No 3 1966?" It sounds very interesting.

KenO

 

[corrosionman]

gida2 and ramakant We did real life compression tests last month to check out stresses in gaskets of different thickness, size and hardness (gaskets of several sizes up to 6" dia pipe sizes) We found that not only was the stress/strain was non linear; it was very influenced by material thickness, and also non linear to the area being compressed. In fact we concluded that it is impossible to predict anything regarding compressibility of rubber . Workshop testing is the surest way of analysing what you have got. YOU would probably do this anyway so why not do it first > bEST OF LUCK. David Whitlock.

 

[ElastomerXpert]

Unfortunately, a 40 duro Neoprene to meet that spec can be made about 1000 different ways, and the compressive moduli of those compounds will vary at least +/- 30%, so there is not easy answer to your question. Actually running experiments is the best approach. Good luck.

 

[APH]

Here is what you do.

Get the rubber from McMaster carr. Machine a dummy flange from whatever material you use and assemble it like the way you want it. Pre-load the joint to a arbitratry point and start testing your joing assembly for leaks, etc.

Corrosionman is right on the money.

my 2 cents
APH