This research was performed to explore the possibility of using epoxy joint connections in place of welded connections in a tube frame structural design. Welded connections work very well when the frame is made of steel, aluminum or titanium. Carbon fiber tubes are available and have a higher strength-to-ratio than the metal tubes, but the connection<; cannot be welded. The long-term goal of this research is to be able to use carbon fiber tubing to construct the solar car chassis. A junction made using high strength epoxy to bond an insert into the adjoining tubes can be almost as strong as a tube that has not been cut. Using a 6061-T6 aluminum tube, an insert of the same material, and Araldite 2015 two-part epoxy the junction was almost as strong as a welded connection in two different types of tests. In a 3-point bending test a sample with the glued joint yielded at bending stresses of 10 to 20 ksi. In a torsion test the glue yielded at shear stresses of 4.5 to 10 ksi. A welded connection will typically yield at 16 ksi in bending and 8 ksi in shear. Since the results are so close to the strength of welded connections, this method may be examined as an alternative to welding in some instances.
Pieper, Eric, "High Strength Epoxy as an Alternative to Welding" (2004). Opportunities for Undergraduate Research Experience Program (OURE). 163.