Hi,
I'm working on a project involving polyurethane shore A 80 , using fiberglass to reinforce it , I'd like to ask about a relation between the flexibility of the polyurethane and the percentage of fiberglass mixed with it? knowing that I need a high damping ratio for the composite but not to the extent of eliminating its flexibility


I'll really appreciate any help

 

Once you get up to 80A your "hardness" indicates quite a resistance to flexability. Mighty "tough" stuff. Adding glass to an elastomer will increase the stiffness dramatically. During flexure, the glasss fibers will start to break eventually, and the stiffness will decrease.
Urethane is generally chosen expressly because it has very little internal damping, known as high resiliancy. If you need a high damping ratio, I would suggest talking with EAR Corp. They named the company after Energy Absorbing Rubber.