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An exploratory study was performed to determine the feasibility of using oriented polypropylene rods as a replacement for metal in side impact beam applications. The study was divided into four phases: (i) laboratory testing of the impact and tensile properties of oriented polypropylene coupons, (ii) design of an oriented polypropylene side impact beam of comparable rigidity to that of a metal beam but with significant weight savings, (iii) development of a means of attaching the polymeric bar to the vehicle and (iv) flexural testing of a scaled down prototype. The oriented polymeric and metal beams exhibited comparable stress-strain behavior during scaled down testing. Although more research is required to validate the design of an oriented polymer side impact beam, the encouraging results suggest that oriented polymers should be considered for use in automotive components that can make use of their high specific strength and stiffness.

The purpose of this study was to determine the adequacy of butt and T-shape welds in predicting the burst strength of realistic nylon 66 parts. This study assessed the effects and interactions of vibration welding process parameters using a central composite design of experiment on selected part geometries. The results confirm that butt-welded plaques exhibit higher weld strengths under tensile load than T-welded plaques and simple cup-plaque parts. These latter two welds were typically 50% weaker than butt welds. A comparison of weld strengths suggests that the lab-scale T-joint geometry more closely models more complex vibration welded parts.

The objective of this study was to compare mechanical properties of lab-scale vibration welded test specimens with those of a complex automotive component using several different materials. Different laboratory specimens (butt, Tee, cup-plate with/without flash trap) were made under different vibration welding conditions (weld pressure, meltdown) and then tested in tension. The tensile properties of the specimens were then compared with the burst pressure results from a prototype air intake manifold. 30% glass reinforced nylon 66 and polypropylene compounds were used. The lab scale specimens and manifolds showed similar trends: (i) all parts failed at the weld; (ii) increased weld pressure generally caused decreased weld strength (iii) meltdown was observed to have little effect on part strength (iv) the ratio of lab specimen strength to burst strength was comparable but not equal for the materials tested. Flash traps significantly affect weld strength when over filled.

Resistive Implant Welding (RIW) is a technology that has the potential to join large thermoplastic automotive components. It involves placing an electrically conductive implant between two parts that are mated under pressure. Heat, dissipated at the interface by direct current, causes melting, flow and ultimately welding to occur. This research examines the RIW of long-glass-fiber reinforced polypropylene (LGF-PP) to continuous-glass-fiber reinforced polypropylene (CGF-PP) using a stainless steel mesh-implant. The effects of welding time, applied current, and weld pressure on the temperature near the mesh, meltdown and the compression-shear strength of the welds were assessed. The results show that it is possible to attain shear strengths of the order of 20 MPa under optimized welding conditions. The meltdown and strength correlate well with a semi-empirical lumped parameter dependent on weld-time, current squared and pressure.