開缶時の指掛かり性を考慮した飲料用アルミ缶蓋の設計

摘要

球頭ピンによる指先への押込み実験を実施し，荷重-変位曲線より痛感の発生，進展を考察した．また，タブによる指先の押込み実験と数値シミュレーションを行って，タブ指掛かり性解析用の有限要素モデルの有効性を確認した．さらに，指でアルミ飲料缶のタブを引上げる挙動の数値シミュレーションを実施し，指の不快感や痛感を力学指標と関連させ，指掛かり性を数値的に評価㌧，具体的な二つのタブ形状の指掛かり性について検討した．その結果より，指と接触面積が大きい形状をもつタブの指掛かり性がより良いことがわかった．%This paper introduced the finite element analyses into ergonomics designs of aluminum beverage can ends to evaluate perception of pressure applied to the human fingertip numerically and objectively. At first, experiments of indenting vertically the fingertip pulp by a probe and the tab of the can ends have been done to observe force responses and to experience feelings in the fingertip. It is found that a typical force-displacement curve can be divided into three parts according the curve gradient. We feel a touch at the first part of the force-displacement curve, and then feel pressure and our pulse at the second part, finally feel discomfort followed by pain at the last part. The finite element analyses have been performed to simulate the tab indenting the fin-gertip vertically for developing the finite element model of the fingertip. It is confirmed that the simulation results agree well with the experimental observations. Moreover, a simulation of finger lifting the tab of the can end has also been performed, and discomfort in the fingertip has been evaluated numerically to present the finger accessibility of the tab. Finally, the finger accessibility comparison of two kinds of tab ring shape designs showed that the finger accessibility of the tab that may have a larger contact area with the finger is better.