Forming of Adhesive-Bonded Sandwich Sheets with a Rubber Pad

Abstract

The effect of a rubber pad, its quality, and diameter, on the forming limit of adhesive-bonded sandwich steel sheets is studied using hemispherical dome tests. The forming limit curve (FLC) is predicted with finite element simulations and the strain mapping method. The FLCs of sandwich sheets are compared with that of base, i.e., 0.4- and 1.2-mm-thick sheets. The forming limit of sandwich sheets when formed using rubber pads improve significantly, and is equivalent to that of the base sheet of equivalent thickness formed without a rubber pad. The rubber pad leads to a uniform strain distribution due to a cushioning effect provided by the rubber pad which also delays the onset of interface delamination. The polyurethane rubber performs better compared with the silicone rubber in improving the FLC. The effect of the rubber pad diameter is insignificant. The FLCs and forming height predicted by numerical simulations are reasonably accurate, when compared with the experimental results.