Testing Welded vs. Bonded Joints
As I refined my fabrication techniques, I sought ways to iterate designs more efficiently while maintaining precision. One approach was integrating key structural features into machined components, which simplified alignment and assembly. However, traditional welding weakened these components without post-weld heat treatment, which introduced potential misalignment. To explore an alternative, I investigated adhesive bonding—a method that had been widely used in past applications but had fallen out of favor in modern fabrication. Before committing to a bonded frame prototype, I conducted a comparative strength test between welded and bonded joints.
Project Definition
My objective was to evaluate whether adhesive bonding could provide sufficient strength for structural components while maintaining alignment. To benchmark its performance, I designed a prototype test setup comparing bonded and welded joints. The test needed to be representative of real-world loading conditions while allowing for controlled and repeatable comparisons.
Project Design
The test design was inspired by bonded A-arm assemblies used in motorsports, featuring a tapered lap joint to improve load distribution and self-alignment. I fabricated test samples using both bonded and welded joints, ensuring consistency in materials and dimensions. The bonded samples used a structural adhesive, while the welded samples featured a fish-mouth joint to maximize weld surface area. To compare their performance, I conducted a 3-point bend test to failure, measuring both maximum load capacity and failure modes.
Project Delivery
Testing revealed that while neither method matched the strength of an unaltered tube, the bonded joints outperformed the welded joints in both load capacity and failure mode. The welded samples exhibited catastrophic cracking and buckling, while the bonded joints failed in a more controlled manner, maintaining structural integrity under stress. The results validated the potential of adhesive bonding as a viable alternative to welding in certain applications, warranting further refinement and testing for future frame designs.
