Measuring fracture toughness
The aim of this demonstration is to use measurements of the load required to propagate a crack (tear) in packaging tape to determine its fracture toughness.
We will also observe what happens when a load is applied to a material with a sub-critical sized crack.
Question 1:
Tape width was 36mm and the thickness was 0.05mm
2
Only 1 vertical slit test was done with an initial crack length of 8mm. The load required was 1950g to fail the sample.
3
You will need to do this at home - you can just load the strip of insulation tape with a small cut in it by hand and describe how it behaves. Use standard electrical insulation tape. Contrast it to the behaviour you see for either sticky tape or packaging tape (and explain why they are different in the terms we have been using in lectures)