Flexural Strength

We designed our own apparatus to test the flexural strength of the samples.

We wished to determine how the samples responded to repeated stress from bending. We bent the samples as shown in the diagram and recorded the number of bends required to a) create an observable crack in the sample and b) completely break the sample, as well as the change in thickness.

To determine the maximum bending stress of our samples, we hung weights in 50.0g increments on the middle of the sample. We recorded the initial thickness and the mass added at which the sample breaks.

We found that the composites have very similar initial fracture properties: all of the composites, except one 5% sample, broke at the first bend. The control can generally withstand up to four bends. This is expected since the higher amount of fibre reinforcements, the lower amount of matrix, causing the stress to be more localized.