1 Scope
This standard specifies the test specimen, equipment, conditions, procedures and results calculation etc. for flexural property test.
This standard is applicable to measure the flexural strength, flexural modulus; to determine the flexural stress and flexural load-deflection curve at deflection of fibre-reinforced plastic composites.
2 Normative References
The following standard contains provisions which, through reference in the following text, constitute provisions of this standard. For dated reference, subsequent amendments (excluding correction) to, or revisions of, any of these publications do not apply. However, parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. For undated references, the latest edition of the normative document referred to applies.
GB/T 1446—2005 Fiber-reinforced plastics composites-The generals
3 Principles
The test specimen, supported freely, is deflected at a constant rate until the specimen fractures or until the deflection reaches some pre-determined value through three-point flexure. During the whole process, the force applied to the specimen and the deflection is measured to determine flexural strength, flexural modulus and other aspects of the flexural stress/strain relationship.
4 Terms and Definitions
For the purposes of this standard, the following terms and definitions apply.
4.1
Flexural stress
The nominal stress in the outer surface of the test specimen at mid-span
4.2
Flexural strength
The flexural stress sustained by the test specimen at the maximum load or acceptable failure loads.
4.3
Deflection
The distance through which the top or bottom surface of the test specimen at mid-span has deflected during flexure from its original position
4.4
Deflection at break
The deflection at break of the test specimen
4.5
Flexural strain
The nominal fractional change in length of an element in the outer surface of the test specimen at mid-span
4.6
Flexural modulus
The ratio of flexural stress to corresponding flexural strain within the elastic range of the material
