• Performed with Professor Rho in Golisano 1190

• Used MTS 45G Tensile Tester
• Performed test according to ASTM D5868
• Graphs generated in Excel

• All samples follow a similar modulus of elasticity. This suggests that the behavior of each bond is similar
• Sample 1 experienced significant slippage and therefore experienced significant displacement
• It was difficult to effectively use the shims 
  • Some shims were slightly too big
  • Even at best the samples were not perfectly vertical
  • The shims sometimes slipped in the fixture
• All tests were performed using a strain rate, however in an actual application each load would be instantaneous
• The surface finishes of each CF sample were significantly different
  • The IREC 2022 wind had a more uniform and smoother surface finish on the inside face
  • The 9/17 wind had divots and blemishes, resulting in stress concentrations in certain parts of the sample
• Stress could not be calculated due to complex part geometry

Conclusion:

• Surface finish/wind quality matters
• The epoxy matrices failed first, followed by the CF fibers
• Preparation of an adhesion joints is important

• Used 3 in grip separation

• Created and used shims to align samples vertically
• Tested Aluminum-Aluminum, Aluminum-CF, and CF-CF bonds
• Used strain rate of 13mm (0.5in) per min
• Labelled parts 1 through 7
• Tightened bottom jaw first

• Sample 1 broke in fixture. Need to reapply epoxy
• Sample 2 broke at bond
• Sample 3 broke at CF part, failed due to poor surface finish
• Sample 4 broke at CF part, failed due to poor surface finish
• Sample 5 failed at CF part, however no significant deformation. CF part buckled
• Sample 6 failed at bond, epoxy bonded better with exterior surface finish
• Sample 7 failed at bond, epoxy bonded better to interior surface finish
• Samples 2 through 5 were the strongest of the lap shear samples
  • Samples 3, 4, and 5 failed at the CF
  • Sample 2 failed at the bond
• Samples 6 and 7 were the weakest
  • They failed the same way
  • the bonds were not as strong?

• >1in in each jaw
• Used strain rate of 13mm (0.5in) per min
• Labelled parts 8 through 13
• CF samples
• Tightened top jaw first

• All parts failed near jaws
  • Jaws are flat, part is slightly curved. This caused stress concentrations
• Epoxy matrix failed first, then the CF fibers
  • Buckling =/= total failure?
  • After failure (the maximum load) each sample deformed prior to complete failure
• Samples 8 and 9 were the strongest
  • This could be attributed to a better surface finish
  • Better surface finish = stronger part?