EPDM AS SHEAR PLY

[dravid]

hi,

I want to use the some material as shear ply between the laminated skirt and composite pressure vessel joint, for this i have found out that epdm is quite suitable, can any body recomend me some edpm grade and its mechanical properties, especially shear modulus ( which is dependent on temperature). As i want to find out the minimum thickness of shear ply.

Thanks in advance.

 

[inthemiddle]

although I don't have an answer for you on the EPDM, we have used NBR for shear ply typically 1.0mm and 1.5mm thickness with a 70 Shore A hardness when bonding hardware to carbon fiber. My question concerns the use of shear ply. I know it is common in the aerospace industry to spread the stress distribution out through the bondline thickness but there seems to be a trade off between the maximum shear stress that a non-shear ply joint can accomodate and one that has a shear ply used. At what point, from a pure stress level standpoint, not considering differences in thermal coefficients of expansion and contraction between different material does one use a shear ply in a bonded joint and when is a shear ply not a good idea? Any direction would be appreciated. Thank you