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The objective of these experiments was to determine a more accurate estimate of the ply properties of our carbon fiber with the Systems 3000 laminating epoxy. We created test coupons comprised of N (0/90) plies, and three strain gauges (x, y, xy) were attached to each coupon. Tensile tests were conducted using the IN-STRON machine in 1-307. From the stress-strain data, we were able to acquire E11, E22, G, and Poisson's ratio.
Laminate 1
We had a mishap when making the first coupons, when the carbon fiber layers had tape with labels put dead center on each sheet, rendering the centers unusable. We tried to salvage the fibers, but the coupons came out too small. It was still very useful in learning that the size of coupons would need to be heavily revised for the next round of testing, and that the surface finish was far from optimal. We used the mistakes from the first round to ensure that the second round would be perfect for testing.
Laminate 2
These samples were longer and thinner (10in x 1in) and as shown above (ft. Dylan Hall), are successfully hooked up to the instron. We use 3 strain gauges, and can use the combined data to determine the poisson's ratio, Young's modulus and shear modulus.
Shown above are a close up of a sample coupon, the full sheet prior to water jetting, and the sample being released from its metal sandwiching, in that order. The surface quality on one side is still far from perfect, but with sanding, is more than acceptable. The full sheet is a major upgrade, as we were able to generate a healthy 8 samples with the desired dimensions to be tested on the machine. We used metal plates to compress and improve the surface finish for the instron to grip our samples.
We observed a small amount of internal stress within our main sample, but have ruled out thermal and ply orientation as reasons for this occurring. (I NEED TO PROVIDE MORE DETAIL HERE)