Test purpose
This test can be used in determination of in-plane shear and interlaminar shear properties.In theory all six possible shear plane can separately.However, in order to measure the interlaminar shear strength properties of manufacturing the laminate is very time consuming, so don't usually used.
Test method is suitable for the unidirectional laminate, orthogonal laminate and weave structure.45 ° direction laminate can't use this method to test, because the 45 ° normal stress is very high, lead to wrong results.
Tests, the specimen deformation will cause in a v-shaped slit shear stress concentration, and eventually cause the specimen failure.In order to measure the shear extension, need to sample the shear plane strain gauge plus or minus 45 ° direction.There are two kinds of the test method, have been standardized:
- ASTM D5379And losipescu test method
- ASTM D7078V-shaped incision orbital shear test method
There are other methods can also be used for determination of in-plane shear properties of materials.
ASTM D5379 losipescu test method
- Due to the relatively small sample, the method is especially suitable for the measurement with a precision woven structure of one-way and orthogonal laminated board.
- Test using the test tool includes a fixed clamp, and an axial guide jig, testing machine by moving clamp loading specimen deformation.When applying compression load tester, minimal sample gap between cross section will form a reverse of pure shear stress area.
- Test results including shear behavior, 0.2% shear stress, the maximum shear stress and shear modulus.
Using Iosipescu method for v-shaped incision beam shear test
The shear stress and shear strain curve
V-shaped incision - ASTM D7078 rail shear test method
- V-shaped incision orbital shear test sample sample more than Iosipescu methods, means that the method is suitable for fiber layer bigger and more loose laminate.
- The shear stress of the method is derived from the test equipment of the two parts in the test axis movement.In the standard requirements of test equipment is not like Iosipescu test method requires the guide,
- Must be used before the test apparatus for precision of the test equipment.
- Test results including shear behavior, 0.2% shear stress, the maximum shear stress and shear modulus.
