Numerical study on snakeskin-inspired pile subjected to repetitive lateral loads

Offshore monopile foundations are subjected to combined loading from waves, wind, and operational forces, which progressively degrade the surrounding soil and threaten long-term stability. Conventional approaches, such as increasing pile size or incorporating steel fins, offer enhanced stiffness but remain limited in improving resistance to cumulative lateral deformation. To address these challenges, a bio-inspired design mimicking the frictional anisotropy of snake ventral skin is proposed to enhance shaft resistance through directionally textured pile surfaces. This study investigates the long-term behavior of offshore monopile foundation equipped with snakeskin-inspired surface geometries under repetitive lateral loading. A semi-empirical numerical scheme is employed to extract stress and strains at the first cycle using the Modified Cam Clay model, and to track the progressive plastic deformation during repetitive loading using the polynomial-type accumulation function that includes volumetric strain, shear strain, and stress obliquity. Parametric analyses are performed to evaluate the influence of scale geometry (height and length) and installation orientation (cranial vs. caudal) on performance of snakeskin-inspired pile. The results show that greater scale height and shorter scale length (particularly under cranial installation) improve lateral resistance and limit displacement accumulation by enhancing load transfer efficiency. Deviatoric stress contours reveal a coupled mechanism where early-stage strain hardening transitions into localized softening, accompanied by progressive stress redistribution and displacement accumulation.