Effect of Normal Load and Bulk Strain on Real Area of Contact in Aluminum Sheet Forming

Friction is one of the key parameters in sheet metal forming. During forming process, the surface of aluminum sheet undergoes flattening and roughening, leading to changes in real area of contact and therefore friction between tool and workpiece. Predicting real area of contact based on the loading condition is fundamental to model friction in a forming process. For this purpose, we designed a setup to conduct the combined normal load – bulk strain experiments on two different aluminum grades. The real area of contact for each sample was measured and characterized using the surface height probability density distribution. The results show that strain can significantly affect the real area of contact in both A6016 and A5182 grades.