Experimental Study of Mechanical Fastening Design for Underhood Components

As many underhood products have shifted from metal to plastic designs over the last decade, often parts break during assembly due rough handling conditions and less than ideal manufacturing practices. In particular assemblies often crack during screw torquing at the mounting tabs. The goal of this study is to determine how different mounting tab designs compare in strength. Designs with an external rib on the perimeter of the mounting tab behave differently than designs without a complete or lacking an external rib on the perimeter of the mounting tab. A positive correlation was found between knit line cross-sectional area and mounting tab strength for designs with an external rib on the perimeter of the mounting tab. A positive correlation was found between tab thickness and mounting tab strength for designs lacking an external rib. Material type was found to impact mounting tab strength.