Snakeskin-inspired patterns for frictional anisotropic behaviour of split set rock bolts

Abstract

The study explores the effect of directionally dependent frictional resistances (frictional anisotropy) inspired by snakeskin patterns, on the behaviour of split set rock bolts. The patterns of the ventral scales of a snake are selected, and different models of patterns are developed by varying the scale angle. Split set rock bolts with these patterns are designed, and three-dimensional (3D)-printed using polylactic acid material. The 3D-printed split sets are tested for insertion and pull-out loads in cylindrical blocks made of plaster of Paris, using a modified universal testing machine. The results of the tests show that insertion and pull-out loads exhibit bilinear relationships with various scale angles (10°, 13°, 16° and 19°). The different scale angles induce different levels of wearing in the surrounding rock simulant during the insertion and pull-out, with a minimum at 16° and maximum at 10°. All the snakeskin-inspired patterns show significant frictional anisotropy. The study opens up possibilities for further research of snakeskin-inspired frictional anisotropy enhancement of split sets.