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3 point bend test

3 point bend test

3 point bend test

(OP)
Does anyone know how to estimate the vertical deflection of a polymer test specimen (based on 2% strain) in a 3 point bend setup?
Thanks in advance.

RE: 3 point bend test

What is your definition of strain?

You can calculate the elastic deflection using the equation:

δ = [F l3]/[48 E I]

where

δ = beam deflection
F = applied force
l = beam length
E = elastic modulus
I = second area moment

You can calculate the onset of plastic strain in the outer fiber with the equation:

σ = [F l t]/[8 I]

where

σ = yield stress
F = applied force
l = beam length
t = beam thickness
I = second area moment

You can estimate the deflection at 2% strain by increasing the values a little over those for plastic strain onset.

Regards,

Cory

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