Alessandro Godi: "Characterisation and Testing of Multifunctional Surfaces". Monday, August 12th, at 13:00. Principal supervisor: Professor Leonardo De Chiffre, Co-supervisor: Professor Hans Nørgaard Hansen,Co-supervisor: Professor Peder Klit.
Surface texturing is considered an effective way for reducing friction losses and wear occurrence in mechanical systems. Recently a new typology of textured surfaces has been developed, the so-called multifunctional (MUFU) surfaces. Produced by hard-turning followed by a highly controllable Robot Assisted Polishing process, MUFU surfaces feature reservoirs providing extra-lubrication between the contacting parts as well as uppermost flat regions ensuring the bearing capability.
The PhD project touches a number of disciplines encompassing metrology, tribology and modeling. The metrological investigation represents the core of the work. Robust filtering methods are adopted, extended, coded and implemented in the commercial software SPIPTM.
Moreover, algorithms are developed for permitting the separation of surface features which can be analysed independently depending on their function. These methods are applied throughout the whole experimental work in assessing the performances of MUFU surfaces in different applications. The tests show how the employment of MUFU surfaces can reduce friction up to 50% compared to conventionally machined surfaces in machine elements applications, while in deep drawing applications MUFU surfaces reduce the likelihood of galling occurrence compared to highly polished surfaces. Both analytical and numerical methods are utilized for the functional modeling of MUFU surfaces predicting friction stresses and fluid exchanges as a function of the texture geometry.