Fig. 7: Effect of the initial boundary curvature on the pulling-out force of kirigami grippers.
From: Boundary curvature guided programmable shape-morphing kirigami sheets
a–c Experimental illustration of shapes formed by 2D precursors with the different initial-boundary curvatures \({\bar{k}}_{{{{{{\mathrm{bo}}}}}}}\) at the maximum applied strain. The insets show the schematic figure of the 2D precursors. The white dashed line represents the angle between the tips of the gripper. d Schematic illustration of measuring the pulling-out force F via pulling out a red sphere from the grippers with various boundary curvatures \({\bar{k}}_{{{{{{\mathrm{bo}}}}}}}\). Red arrows are the direction of the pulling-out force. e The experimental results on the curve of F vs. \({\bar{k}}_{{{{{{\mathrm{bo}}}}}}}\). The error bars represent the standard errors of the mean.
