Coupon tests for stress based failure

Question 1

What is the test for tension failure?

Answer 1

Simple coupon test, with tabs bonded onto each end, force is applied parallel to specimen

• may have a waisted section
• The alignment is important
• Strain gauges or laser extensometers may be used to monitor the test

Question 2

What is the test for compression failure?

Answer 2

Simple coupon test, loaded in compression

• need to prevent macro-buckling of the specimen (could use support)
• Use squat specimens or have anti-buckling guides

Question 3

What are 3 methods for doing shear tests?

Answer 3

• Tube tests- can apply a moment/torsion to it, hard to prepare specimens)
• Off axis tests - interpretation of results required
• Iosipescu shear test (uses specialised rig and specimen)

Question 4

How are interlaminar shear tests performed?

Answer 4

Using a short beam shear test - utilised 3 beams, 2 on the bottom on each end and 1 in the middle on the top pushing down (like a 3 point bend test)
A short specimen is used to enhance the interlaminar shear mode over the flexure mode.

Question 5

How are flexure tests performed?

Answer 5

3 point bend test with a long span specimen

Question 6

What is the test for Mode I toughness?

Answer 6

Double cantilever beam (DCB), with loads pulling the two beams apart perpendicular to the axes of the beams (there will be a starter crack in the specimen)

Question 7

What is the test for Mode II and mixed mode toughness?

Answer 7

End-notched flexure test- specimen with a notch/starter crack at one end is loaded in a 3 point bend test to test the in-plane shear performance.

Question 8

What are the last test types that test impacts?

Answer 8

Impact tests and Compression after impact tests