Evaluation of vibration welds in an automotive air intake manifold

Burst testing of vibration welded air intake manifolds is often used in industry to assess part and vibration welded joint integrity under load. Due to the complex three-dimensional part geometry, a complicated stress field is generated during burst testing. The complex geometry also causes variations in joining force during welding which can further weaken this low strength region. In spite of these complexities, the vibration weldability of reinforced thermoplastics is generally determined using simple one-dimensional pull tests on lab-scale butt and T-shape welded specimens under ideal welding conditions. In order to examine this difference between laboratory and industrial practice, this research compares the behavior during vibration welding and the mechanical properties of simple laboratory specimens and a complex air intake manifold. The laboratory samples include butt and Tee geometries tested in tension and flexion, as well as a simple cup-plaque assembly tested under pressure. Both the laboratory test specimens and the industrial manifolds were vibration welded at a range of weld pressures and meltdowns using 30% glass reinforced nylon 6, nylon 66 and polypropylene.; The tensile properties of the specimens were compared to the burst pressure results from the prototype air intake manifold. (Abstract shortened by UMI.)...