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9
The results are obtained in the form of flexural stress and strain.
Flexural strength is the ability of the material to withstand bending
forces applied perpendicular to its longitudinal axis. The stresses
induced by the flexural load are a combination of compressive and
tensile stresses. The calculations for flexural strength, strain, and
modulus are given by Eqs. 9.6, 9.7, and 9.8, respectively.
Flexural strength = 3
2
2
PL bd
/
(9.6)
Flexural strain = 6
2
Dd L
/
(9.7)
Flexural modulus Flexural strength Flexural strain
=
/
(9.8)
where:
5 P = Flexural load
5 L = Span length
5 b = Width
5 d = Thickness
5 D = Deflection
. Fig. 9.8 Tensile testing of a composite on a UTM (Instron) [11]
Chapter 9 · Characterization and Testing of Polymeric Composites