Leonardo da Vinci on Wear

Abstract

Leonardo da Vinci (1452–1519) was a visionary engineer, scientist, and polymath of the Renaissance era who performed numerous experiments in tribology, including experiments on wear. As discussed by Prof. Dowson, due to the delayed discovery of several caches of his notebook pages (particularly the Codex Madrid I) recognition of Leonardo's immense contributions to the field of tribology was delayed and continues to unfold. Leonardo's illustrations and investigations clearly describe studies and patterns of wear, particularly for loaded shafts and bushings. In this work, we present an attempt to faithfully recreate Leonardo's observations of wear using bushing and shaft systems made from olive wood. Our experiments, performed roughly 500 years after Leonardo's, reproduced his findings and demonstrated shape evolutions during operation as a result of wear. Leonardo's elegant demonstration of a 2-dimensional bushing-and-shaft system in which the shaft is turning inside of the bushing, showed wear to both components and resulted in a tear-dropped shape as the shaft was consumed. Our experiment, which took over 260 days to complete generated a similar tear-drop shape with an acute angle within 5° of the angle in Leonardo's original drawing. This undertaking also revealed the extensive duration of time over which experiments, and mechanisms operated in Leonardo's laboratory and adds to our understanding of the laboratory environment: a dynamic, active, and busy laboratory in motion, with numerous ongoing experiments and moving mechanical assemblies at work. As Prof. Dowson recognized, Leonardo da Vinci was clearly curious and passionate about tribology, as the Codex Madrid I contains thousands of illustrations of tribological components and experiments in friction, wear, and lubrication.