ASTM D5379  – Iosipescu Shear Test Fixture

ASTM D5379 – This test method determines the shear properties of composite materials reinforced by high-modulus fibers.

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

– Laminates composed only of unidirectional fibrous laminae, with the fiber direction oriented either parallel or perpendicular to the loading axis.

– Laminates composed only of woven fabric filamentary laminae with the warp direction oriented either parallel or perpendicular to the loading axis.

– Laminates composed only of unidirectional fibrous laminae, containing equal numbers of plies oriented at 0 and 90° in a balanced and symmetric stacking sequence,

with the 0° direction oriented either parallel or perpendicular to the loading axis.

– Short-fiber-reinforced composites with a majority of the fibers being randomly distributed.

ASTM D5379 – Significance and Use

*** This test method is designed to produce shear property data for material specifications, research and development quality assurance, and structural design

and analysis.

Either in-plane or interlaminar shear properties may be evaluated, depending upon the orientation of the material coordinate system relative to the loading axis.

Factors that influence the shear response and should therefore be reported include the following:

Material, methods of material preparation and layup, specimen stacking sequence, specimen preparation, specimen conditioning,

environment of testing, specimen alignment and gripping, speed of testing, time at temperature, void content, and volume percent reinforcement.

*** In anisotropic materials, properties may be obtained in any of the six possible shear planes by orienting the testing plane of the specimen with

the desired material plane (1-2 or 2-1, 1-3 or 3-1, 2-3 or 3-2). Only a single shear plane may be evaluated for any given specimen.

 *** Properties, in the test direction, which may be obtained from this test method, include the following:

* Shear stress/strain response,

*  Ultimate strength,

*  Ultimate strain,

*  Shear chord modulus of elasticity, and Transition strain.

ASTM D5379 – Geometry

The sample is about 3 inches long and has a V notch along the center on both the top and the bottom which is cut at a 45 degree angle.

This type of geometry isolates the area where the shear stress is focused.

ASTM D5379 – Solution

This test requires an Iosipescu shear fixture which is specifically designed for use with a Universal Testing Machine. UGC offers a complete line of shear

fixtures for ASTM testing.

ASTM D5379 – Analysis

Specific calculations can be made based on the exact size of the cross-sectional area that experiences the shear stress.

Shear strength is usually given by the peak load seen during the test divided by the area of the shearing zone.

Along with shear strength, there are a few additional calculations which are laid out in the official ASTM publication.

Strain guages can be mounted directly onto the sample to measure localized strain deformation.

  Similar Specifications

ASTM D5379 

ASTM D7078 – V-Notched Rail Shear Method