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ASTM D3518_Standard Test Method for In-Plane Shear Response of Polymer Matrix Composite Materials by Tensile Test

ASTM D3518_Standard Test Method for In-Plane Shear Response of Polymer Matrix Composite Materials by Tensile Test

Owned by Maciek Pajak (Deactivated)
Last updated: Feb 08, 2021 by Tommy Tran
3 min read

The following summary is from the ASTM document D3518/D3518M.

 

The following symbols should be known along with these two diagrams:

 

 

 

The meaning of the test:

  • The purpose is to produce in-plane shear property data

  • The following factors will influence the shear response and should therefore be reported:

    • material

    • methods of material prep and lay-up

    • specimen

    • stacking sequence

    • overall thickness

    • specimen prep

    • specimen conditioning

    • environment of testing

    • specimen alignment and gripping

    • speed of testing

    • time at temperature

    • void content

    • volume percent reinforcement

  • The following properties will be derived during this test:

    • In-lane shear stress versus shear strain response

    • In-plane shear chord modulus of elasticity

    • Offset shear properties

    • Max in-plane shear stress for +/- 45o laminate

    • Max in-plane engineering shear strain for a +/- 45o laminate

 

Equipment required:

Refer to: https://uwmidsun.atlassian.net/wiki/spaces/MECH/pages/2076409857

 

The only difference is that this method requires that the force-normal strain data will be measured in both the longitudinal and transverse directions of the coupon.

Geometry:

Refer to: https://uwmidsun.atlassian.net/wiki/spaces/MECH/pages/2076409857

 

Along with these geometries, you must also:

  • modify the stacking sequence so it will be [45/-45]ns, where 4 </- 5 for unidirectional tape (16, 20, or 24 plies) and 2</- n </- 4 for woven fabric (8, 12, or 16 plies).

  • The coupon has a recommended width of 25mm [1.0 in.], and the recommended coupon length range is 200 to 300mm [8 to 12 in.]

  • Tabs are not required for this test

 

Specimen Preparation:

Refer to: https://uwmidsun.atlassian.net/wiki/spaces/MECH/pages/2076409857

 

 

Procedure:

Refer to: https://uwmidsun.atlassian.net/wiki/spaces/MECH/pages/2076409857

 

Along with the above procedure, this test will have normal strain instrumentation in both the longitudinal and transverse directions. It will also have continuous or nearly continuous force-normal strain data recording. Also, note that if ultimate failure doesn’t occur within 5% engineering shear strain, the data will be truncated to the 5% engineering shear strain mark. Once truncated, the 5% engineering shear strain will become the maximum shear stress. Any truncation must be noted in the report. The following are some typical shear stress-engineering shear strain plots:

The following are some calculations that shall be done during the test