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The excitation of structural modes of vehicle roofs due to structure-borne excitations from the road and powertrain can generate boom and noise issues inside the passenger cabin. The use of elastomeric foams between the roof bows and roof panel can provide significant damping to the roof and reduce the vibration. If computer-aided engineering (CAE) can be used to predict the effect of elastomeric foams accurately on vibration and noise, then it would be possible to optimize the properties and placement of foam materials on the roof to attenuate vibration. The properties of the different foam materials were characterized in laboratory tests and then applied to a flat test panel and a vehicle body-in-white. This paper presents the results of an investigation into the testing and CAE analysis of the vibration and radiated sound power of flat steel panels and the roof from the BIW of an SUV with anti-flutter foam and Terophon® high damping foam (HDF) materials.

Modifications to the Limiting Dome Height test method and instrument enable in-lab production of controlled metal panels that can be used for cleaning and coating testing after stamping lubricant performance testing is complete. The differences in results between stamped and unstamped (flat) panels on a variety of common stamping lubricant acceptance tests will be explored using existing approved stamping lubricants. The value of using a standard stamped part for lubricant, cleaner, and coating development will be described. The importance of real-world process simulation will be reviewed in the context of coating failures.

Surface pretreatments based on dilute hexafluorozirconic acid (FZ) solution were evaluated as replacements for the phosphating process before paint application. The behavior of a FZ coating was compared to those of a modified FZ (MFZ) coating and phosphating treatments. Results of electrochemical tests on painted cold rolled steel (CRS) samples with different conversion coatings show that the MFZ surface treatment in combination with various paints provides corrosion protection performance comparable to phosphate conversion coatings. AFM studies of MFZ coatings on CRS reveal that the coating surface exhibits small features tens of nm in size and clusters of these features that are on the scale of microns. Clusters have lower surface potentials (higher activity). Z-contrast TEM images of MFZ coatings show that the coating is about 20 nm thick, continuous and adherent to the substrate. Major components are Zr, Fe and O; the Fe amount decreases toward the coating surface.

In recent years, automotive component manufacturer's use of autodeposited coatings has dramatically increased due to the performance, cost-effectiveness, versatility and environmental advantages that this technology offers. Although historically used to coat only steel substrates, the increased use of zinc and zinc alloy coatings presents further market opportunity for autodeposition of coatings. Due to differences in chemical reactivity between steel and zinc, obtaining high quality coatings by acidic chemical deposition (autodeposition) has required some process development innovations. In this paper, the procedure of coating deposition on galvanized surfaces is described and compared to the deposition on steel. Corrosion performance of autodeposited coatings on galvanized steel is evaluated by a cyclic corrosion test and compared to the performance of another widely used coating for galvanized substrates.