Ergonomic design of beverage can lift tabs based on numerical evaluations of fingertip discomfort

This paper introduces finite element analyses to evaluate numerically and objectively the feelings in the fingertip when opening aluminum beverage cans, in order to design the shape of the tab. Experiments of indenting vertically the fingertip pulp by a probe and by tabs of aluminum beverage can ends have allowed us to observe force responses and feelings in the fingertip. It was found that a typical force-displacement curve may be simplified as a combination of three curves with different gradients. Participants feel a touch at Curve 1 of the force-displacement curve, then feel a pressure and their pulse at Curve 2, finally feel discomfort followed by a pain in the fingertip at Curve 3. Finite element analyses have been performed to simulate indenting the tab with the fingertip vertically to confirm that the simulation results agree well with the experimental observations. Finally, numerical simulations of the finger pulling up the tab of the can end has also been performed and discomfort in the fingertip has been related to the maximum value of the contact stress of the finger model. Comparisons of three designs of tab ring shape showed that the tab with a larger contact area with finger is better.