Modelling the failure mechanisms of Michelangelo’s David trough small-scale centrifuge experiments.

It has been noted since the mid 1800s that the Michelangelo¡¯s David, the standing marble male nude rep-resenting a masterpiece of the Italian Renaissance, is affected by small cracks on both legs that threatenits stability. Understanding the characteristics and the conditions under which these lesions developedis thus critical for the preservation of this universal masterpiece. In this study, we use an analogue mod-elling approach to test the conditions that led to the development of fractures in the David¡¯s legs andto get insights into its stability. Small-scale (10 cm-high) gypsum replicas of the statue were deformedin a centrifuge, where the models were affected by a body force stronger than gravity but otherwiseplaying the same role. Analysis of the model results suggests that both the stability and the resultingdeformation of the statue are highly sensitive to its attitude. A forward inclination promotes destabiliza-tion: the higher the angle of inclination (¢­), the more unstable the statue becomes under its own weight,confirming existing FEM modelling. In a vertical position, rupture of the statue typically occurs in thelower portions of the legs, but ruptures tend to develop progressively higher along the legs as ¢­ increases.Comparison of these results with the lesions detected on the actual David suggests that a long-lasting,small forward inclination (likely close to ¡­ 5.) of the statue may have represented a critical driving factorfor the development of the observed damages.