Fig. 2: Mechanical protection performance test.

a Experimental setup for mechanical protection performance test. b Applied forces required to achieve the same level of deformation in BIS and PFS, with deformation ranging from 0.5 mm to 4.5 mm. c Deformation response of BIS and PFS under the same applied force ranging from 0.2 N to 0.9 N. All experimental data were collected in multiple sets, and the average value of these data was taken as the final experimental result. To assess the data reliability, error analysis was conducted using the standard deviation, and the error bars in the figures represent the standard deviation values, providing a visual indication of the data variability. This approach of data processing was consistently applied to all subsequent experiments.