Test for Shear Properties of Composite Materials by ASTM D7078 V-Notched Rail Cutting Method

EUROLAB, with its state-of-the-art accredited laboratories and expert team, provides precise and fast testing services within the scope of ASTM D7078 testing. This standard covers the determination of the shear properties of high modulus fiber-reinforced composite materials by clamping the ends of the V-notched specimen between two pairs of load rails.

When tension-loaded, the rails apply shear forces to the specimen through the specimen faces. By comparison, the Test Method D5379/D5379M specimen is loaded from its top and bottom edges. Surface loading allows higher shear forces to be applied to the sample if necessary.

Additionally, the current test method uses a sample with a larger measuring cross section than the V-notch sample of Test Method D5379/D5379M. In both test methods, the use of a V-notched specimen increases the gauge section shear stresses in relation to the shear stresses around the jaws, thus causing the shear stress distribution to be more uniform than for an unnotched sample, while the error is localized in the gauge section.

By comparison, the Test Method D4255/D4255M uses an unnotched specimen sandwiched between two pairs of tension-loaded loading rails. Also, unlike the Test Method D4255/D4255M, the current test method allows sample retention without the need for holes in the sample.

Composite materials are limited to continuous fiber or discontinuous fiber reinforced composites in the following material forms:

• Laminates consisting of only unidirectional fibrous layers, with the fiber direction oriented parallel or perpendicular to the connecting rails.
• Laminates with a balanced and symmetrical structure, 0?? oriented direction parallel or perpendicular to the fixture rails.
• Laminates consisting of woven, braided or knitted fabric fiber layers.
• Short fiber reinforced composites with the majority of fibers randomly dispersed.

Values ​​stated in SI units or inch-pound units will be considered standard separately. Inch-pound units are shown in parentheses throughout the text. The values ​​specified in each system are not exactly equivalent; therefore, each system should be used independently of the other. Combining values ​​from the two systems may result in non-compliance with the standard.

EUROLAB assists manufacturers with ASTM D7078 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.