question 1

Benutella:

Think for second. Glass is a supercooled liquid. Therefore it behaves similar to a viscous liquid in the very long term, yet in the short term it behaves more like a rigid elastic solid.

So, its behavior really depends on the timescale you wish to choose. If you choose the normal range, you would have to expect glass fiber to behave like a rigid, elastic solid exhibiting very low strain-to-failure; represented by a simple rigid spring.

If, on the other hand, you are contemplating the mechanical behavior of glass in the range of thousands of years, you may represent the material simply as a dashpot; i.e., a highly viscous material with no recovery.

The Kelvin model, with the spring and dashpot in parallel, represents a mechanical behavior that exhibits viscoelastic recovery --- which wouldn’t apply to glass fiber.

On the other hand, the Maxwell model, with spring and dashpot in series, represents elastic deformation and recovery together with viscoelastic stress relaxation behavior with no recovery. With a very rigid elastic component and an extremely viscous dashpot element, the Maxwell model would best represent the mechanical behavior of a glass fiber.

Rich Geoffroy
Polymer Services Group
POLYSERV@aol.com

An excellent explanation

Regards
pat pprimmer@acay.com.au
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