Which test configuration is typically used to assess interlaminar shear strength?

Which test configuration is typically used to assess interlaminar shear strength?

• A. Four-point bending test
• B. Tension test on a flat plate
• C. Three-point bending used in short-beam shear testing
• D. Charpy impact test

Answer: (D)

Interlaminar shear strength is the resistance to sliding between adjacent laminas in a composite, so the test setup is chosen to promote failure between plies rather than through the fibers or along the full laminate. The standard way to measure this is a short-beam shear test, which uses a three-point bending configuration with a relatively short span-to-thickness ratio. This arrangement concentrates shear stresses at the midspan and encourages interlaminar failure, giving a direct measure of the bond between layers. Charpy impact testing, by contrast, is about energy absorbed during a high-velocity impact and reflects toughness and notch sensitivity rather than the interlayer shear properties. Four-point bending can characterize flexural behavior and stiffness but does not isolate interlaminar shear as clearly as the short-beam, three-point bending setup.

Interlaminar shear strength is the resistance to sliding between adjacent laminas in a composite, so the test setup is chosen to promote failure between plies rather than through the fibers or along the full laminate. The standard way to measure this is a short-beam shear test, which uses a three-point bending configuration with a relatively short span-to-thickness ratio. This arrangement concentrates shear stresses at the midspan and encourages interlaminar failure, giving a direct measure of the bond between layers. Charpy impact testing, by contrast, is about energy absorbed during a high-velocity impact and reflects toughness and notch sensitivity rather than the interlayer shear properties. Four-point bending can characterize flexural behavior and stiffness but does not isolate interlaminar shear as clearly as the short-beam, three-point bending setup.