ASTM D7264
Flexural Test Fixture for Polymer Matrix Composites (3- and 4-Point)
ASTM D7264 Bend Fixture – Universal Grip Data Sheet (PDF)
ASTM D7264 measures the flexural strength and stiffness of polymer matrix composites. A rectangular bar is supported near its ends and loaded either at mid-span (Procedure A, three-point) or at two points (Procedure B, four-point). Universal Grip supplies an adjustable flexure fixture that converts between the two procedures and sets the spans the standard requires.
What ASTM D7264 Measures
The test reports flexural strength, flexural strain at failure and flexural chord modulus. The standard span-to-thickness ratio is 32:1, so the support span scales with specimen thickness; the common specimen is about 4 mm thick and 13 mm wide on a 128 mm span. Four-point loading puts a constant bending moment over the center section, which many labs prefer for comparing laminates.
How the ASTM D7264 Test Works
Measure specimen width and thickness at mid-section.
Set the support span to the required span-to-thickness ratio; for Procedure B set the load span to half the support span.
Center the specimen on the supports with the loading nose or noses square to it.
Load at a constant crosshead rate until failure or the specified deflection.
Record force and deflection, then calculate flexural stress, strain and modulus.
Specimens and Setup
Test at least five specimens per condition.
Measure the span accurately; the standard sets the measurement precision by span length.
Use a deflectometer under the specimen for modulus rather than crosshead travel alone.
Check that failure occurs on the tension or compression face, not by crushing under the nose.
Confirm span, nose and support diameters and test rate against your copy of the current standard.
Universal Grip ASTM D7264 Fixture
Converts between Procedure A (3-point) and Procedure B (4-point)
Adjustable spans set to the required span-to-thickness ratio
Hardened, ground cylindrical supports and loading noses
Scale markings for quick, symmetric span setup
Provision for a deflectometer under the specimen
10 kN standard capacity; higher capacities on request
Applications
Composite laminate flexural properties
Material screening and QC
Aerospace and automotive composites
Resin and fiber development
Related Standards and Products
Send us your specimen dimensions, required capacity and machine connection through our contact page and we will quote an ASTM D7264 flexure fixture. Request a quote
ASTM D7264 FAQ
What is the span-to-thickness ratio in D7264?
The standard ratio is 32:1. A 4 mm thick specimen is tested on a 128 mm support span. Other ratios can be used when agreed, but they must be reported.
Should I use Procedure A or B?
Procedure A (three-point) is simpler and common for screening. Procedure B (four-point) gives a constant moment between the load points, so failure is less influenced by the loading nose. Many specifications state which one to use.
How is D7264 different from D790?
ASTM D790 is written for unreinforced and reinforced plastics at a 16:1 ratio. D7264 is written for high-modulus polymer matrix composites and uses a 32:1 ratio, which reduces shear effects in stiff laminates.
Can one fixture do both procedures?
Yes. Our fixture converts between three- and four-point loading and has adjustable spans, so one fixture covers a range of specimen thicknesses and both procedures.