ASTM D6415 Standard Test Method for Measuring the Curved Beam Strength of a Fiber-Reinforced Polymer Matrix Composite

Scope

ASTM D6415 covers the measurement of curved beam strength, used for composites made from woven layers or layers of unidirectional fibers. The test method can also measure interlaminar tensile strength by having a unidirectional specimen where fibers are arranged continuously along the legs and the curve. 

Test procedure

ASTM D6415 test method covers the determination of the curved beam strength; the procedure is as follows:

1. Take 5 test specimens and measure the width at two locations in the curved region. Record the thickness of each specimen at a curved region along each leg with variation not exceeding 5% of normal thickness.
2. Place the specimen in a bend fixture that should center between the bar when force is applied.
3. Force is applied at a constant crosshead displacement rate to produce failure within 1 –610 min. Record the force and displacement data continuously, i.e., the maximum force, the force at failure, and the displacement at a moment of delamination.
4. Stop the test after the force has decreased to less than half of the peak force. 

Results

The results of the ASTM D6415 test method are recorded to determine the failure load of the specimen where it is subject to delamination. This allows us to know the curved beam strength but also the interlaminar strength of the specimen. 

Read more: ASTM D7565/D7565M Standard Method for Measuring Tensile Properties of Fiber-Reinforced Polymer (FRP) Matrix Composites

Conclusion

ASTM D6415 covers the measurement of the curved beam strength used for composites made from woven layers or layers of unidirectional fibers.