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Machine Design Group

Description of the research Group

The research group activity deals with various issues concerning the behavior and structural integrity of components, machines and mechanical structures; it involves different research fields, ranging from Structural Design to Solid Mechanics, Mechanical Behavior of Materials, Experimental Mechanics and Diagnostics, Biomechanics.

In particular, the group is particularly active in the study of fatigue behavior of traditional and innovative materials, in the rolling contact fatigue, in the design and analysis of components for handling and transportation industry and in the study and modeling of biomedical devices, surgical procedures and biological systems.

Research activities are carried out following different approaches, mostly used in a complementary way:

  • experimental investigations, through the use of material testing machines, test benches for mechanical components and systems, instrumentation (strain gauges, magnetic and optical) for the analysis of stress and strain fields, residual stresses and material damage;
  • numerical models for the simulation of the operating behavior of components and structures, through the use of advanced finite element software, including multi-physics codes (Abaqus, Comsol);
  • theoretical-analytical methods for the schematization and resolution of problems related to the structural analysis of machines and components and to the simulation of the materials behavior under different operating conditions.

The group has many contacts with important companies of the territory, managing several joint research projects with them; it is also active in various research collaborations at national and international level.

Research activities
  • End points prediction of polymeric seals subjected to radioactive fields: the project deals with the study of the mechanical behavior of elastomeric O-ring seals used in innovative nuclear research equipment, where they are subjected to irradiation with intense neutron fields. In particular, the project aims to develop a procedure able to predict the safe operating life of these components by defining their end points.
  • Innovative methodologies for fatigue life prediction of metallic ropes: this projects proposes a new method for estimating fatigue life of metallic ropes basing on thermal measurements. The approach considers the rope temperature increase in its initial operating phase under the effect of a cyclic load and relates this parameter with the rope duration. Experimental rotational  bending tests were carried out on rope specimens to assess the validity of the method,  by analyzing the effect of some parameters: rotation speed, bending level, diameter of the rope, rope composition and lubrication condition. Finite elements models of the rope specimens under test were also developed, allowing to relate surface temperature measurements to energy dissipation per cycle due to friction in the contact between the most stressed rope wires.  
  • Theoretical-experimental investigations on damage of materials for rails and railway wheels: the research activity includes the experimentation on a bi-disc test bench of specimens in materials for rails and wheels, aimed at identifying and quantifying the main damage mechanisms under various working conditions, including the effect of external environment and operation factors, such as the atmospheric agents, solid contaminants (sand), brakes. 
  • Structural investigations of ancient vehicles: the activity consists in the application of the modern engineering techniques, both for the calculation and for the direct analysis, to the study of archaeological evidences, with particular focus on the war chariots, which in the antiquity were the most technologically advanced vehicles. Such activity is aimed at providing quantitative responses on the vehicle performance, in terms of both mechanical strength and stability and dynamics. Furthermore, this activity is aimed at investigating the possible used construction techniques, both for component fabrication and for assembly. Archaeological experts follow the research for the historical background.
  • Application of unconventional materials in the automotive sector, earth-moving machines and lifting equipment: the research concerns the use of unconventional materials instead steel (such as composite and eco-sustainable and environmentally materials) for structural applications in different industrial sectors such as automotive, earth-moving machines and lifting equipment. 
  • Study of corrosive phenomena and their implication on structural aspects: the research involves studying the corrosive phenomena, in particular biocorrosive, acting on steels or light alloys in order to estimate corrosion rates in relation to both the exposure times and the corrosive agent. This information, also supported by experimental tests, will be used for the design and structural verification of components dedicated to this specific use.
  • Fatigue behavior of additively manufactured materials for structural applications: the research aims at investigating fundamental fatigue properties of different materials produced via Additive Manufacturing, providing data necessary to extend its potential field of application to industrial components and fully take advantage of its disrupting potential. Fatigue damage mechanisms of different materials (i.e. metal alloys or fiber reinforced composites) components is investigated, considering the influence of a selection of processing parameters, post-processing treatments or loading mode and looking for correlations between microstructure and fatigue strength.
  • Fatigue behavior and cyclic damage of PEEK short fiber reinforced composites: PEEK short fiber reinforced composites are increasingly used for lightweight structural application as an alternative to metal alloys, but many aspects of their complex response to cyclic loads are not completely understood yet. Basing on experimental research activities, the fatigue response of this class of materials is considered from different points of view, including fatigue damage mechanisms and modeling under uniaxial loading, cyclic creep, influence of micro-notches and Rolling Contact Fatigue.
  • Structural analysis for the design of biomedical devices and simulation of surgical procedures: the goal of the research is the development of FEM models for the structural analysis in the biomedical field, with a focus on cardiovascular applications. Main research lines include the simulation of innovative devices for percutaneous treatments of heart valves or occlusions of blood vessel (balloon angioplasty), and structural analysis of biological heart valves. The research field includes the simulation of surgical procedures to provide useful additional information to surgeons and clinicians, with possibility of experimental characterization of mechanical properties of tissues and biomaterials via biaxial testing.
Keywords

Fatigue, Rolling Contact Fatigue, Structural Design, Material Strength and Mechanical Behavior, Biomechanics

Group members