V-Notch Rail Shear Fixture to ASTM D7078-05
CP105207 | Notch Rail Shear Fixture
Meets ASTM D7078-05
Consists of upper and lower specimen holders with serrated faces.
Complete with a set of spacers that cover specimen thickness from 1 to 13 mm (0.04 to 0.5 in)
Body fabricated from high strength stainless steel. Clamping plates fabricated from tool steel.
Includes specimen alignment fixture.
Maximum Static Load: 100 kN (10,000 kgf, 22,000 lbf)
Upper and lower interface: Type Dm (1.25 in connection with ½ in clevis pin)
Temperature Range: -70 to +250 °C (-94 to +482 °F)
Includes storage case.
| Accessory Height | 258 mm (10.2 in ) |
|---|---|
| Accessory Weight | 8 kg (17.6 lb ) |
| Accessory Width | 95.4 mm (3.8 in ) |
| Capacity | 100 kN (22,000 lbf ) |
| Lower Fitting | 1/2 in clevis pin (Type Dm) |
| Temperature Rating | -70 to +250 °C (-94 to +482 °F ) |
| Testing Standards | ASTM D7078 - 05 |
| Upper Fitting | 1/2 in clevis pin (Type Dm) |
V-Notch Shear Fixtures ASTM D 5379 & D 7078
Instron® Shear Test Fixtures are designed for in-plane or interlaminar shear testing of composite materials. The V-Notched Beam Method, or more commonly known as the Iosipescu Shear Method, was standardized into ASTM D5379 in 1993, while the V-Notched Rail Shear Method was more recently introduced in 2005 under ASTM D7078. Both test methods share many common characteristics and have the distinctive V-notches in the specimen design, which serve to create a localized and approximate uniform shear stress zone between the notches. Also, a ±45° two-element strain gauge is often used to directly verify the shear strains applied. It’s important to note that the two fi xtures in ASTM D7078 and D5379 are quite different in the way in which load is applied to the specimen, its specimen design, and consequently, the type of results obtained. For the V-Notched Beam Method, the shear stress is introduced via edge-wise clamping of the specimen. By contrast, the V-Notched Rail Shear Method is derived from the rail shear method with the specimen face clamped on both sides, which gives it a strong rigid hold. The consequence of this is that ASTM D7078 has a longer shear length, or larger gage section, compared to ASTM D5379. This is important particularly for laminates with ±45° plies. These laminates have higher shear strengths and an increased risk of premature failure on the specimen edges instead of the area of interest between the V-notches. Bonded tabs are often added to ASTM D5379 specimens as an attempt to overcome this weakness. But it remains a challenge as, with the smaller size of the specimen, the angle plies may not be fully supported and result in incorrect failure modes. Despite this, ASTM D5379 method has had extensive history of use and proven ability to produce good test results, particularly for unidirectional and 0/90 cross-ply laminates.
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- 8/27/2014
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