Computational Mechanics for industrial applications

Research focus

The Peer review has evaluated this group as Average

This research topic is concerned with the development of computational methods and tools devoted to the solution of industrial problems. The activities in this topic range from application driven basic research in computational methods (such as finite element methods, boundary element methods, particle methods) to non-standard applications of commercial codes to specific industrial problems. The research topic is currently articulated into four main research tasks. 1) Computational methods for the simulation of carton packaging problems This research was initiated in the 2002 with the financial support of Tetra Pak Packaging Solutions S.p.A. (formerly Tetra Pak Carton Ambient), a company of the Tetra Laval Group, a leading group in the market of food packaging solutions, operating in 165 markets with over 20,000 employees. The support of Tetra Pak has continued without interruption through the present date. Among the different type of problems which have been considered there are: a) experimental mechanical characterisation of the laminate material used for the packages; b) numerical simulation of package opening processes with different types of opening systems; c) numerical simulation of the package forming process; d) numerical simulation of the fluid-structure interaction between the forming carton laminate and the filling liquid. 2) Simulation of industrial magneto-mechanical switches This research topic was initiated in 2004 as a collaboration with the Italian numerical simulation group of ABB (Asea-Brown-Boveri). Several industrial relays working at low frequency display non-linear material behaviour of fixed and movable ferromagnetic parts embedded in the linear air domain. These features naturally call for the application of coupled BEM-FEM approaches and take advantage of the versatility of FEM to model material non-linearities and of the ability of integral approaches to account for infinite domains and movable structures. As often occurs in magnetostatics, the total scalar potential approach is privileged, since it is generally more robust than alternative edge element formulations and avoids cancellation errors which are intrinsic in the perturbation scalar potential approach. The main goal of numerical analyses is the evaluation of forces and moments which govern the mechanical response of the relay. 3) Modelling elastomeric microfluidic low-pressure valves The research started in 2003 in collaboration with professor Michael Ortiz (California Institute of Technology, Pasadena CA, USA), in support of the experimental physics group headed by Stephen R. Quake (previously at Caltech, presently in Stanford, Palo Alto CA, USA). Microdevices made in soft silicone rubber (polydimethylsiloxane) and fabricated with a technique called multilayer soft lithography (MSL) present several advantages with respect to the silicon-based micromachining and conventional photolithography. By adopting a two-channel crossing architecture, MSL allows for the fabrication of off-on fluidic microvalves, employed in biology, and for the fabrication of peristaltic micropumps or of microscopic fluidic circuits and chips with thousands more channels than silicon chips. The performance of elastomeric microvalves is strictly related to the geometry of the crossing channels and of the separation membrane. The costly and time-consuming experiments suggested the development of a finite element code able to analyze the performance of new geometries, which accounts for inelastic deformations induced by chemical reactions. 33 4) High performance adhesives for civil tiling applications Tiling is perhaps the most common type of cladding for the floors and external walls of residential and industrial buildings. Floor tiling usually consists of three layers: the tiles themselves in the upper layer, the adhesive intermediate layer and the lower cementitious substrate. Contiguous tiles are usually separated by a grouting interface, which helps to relax compressive stresses in the tile layer. Modern adhesives can guarantee a reliable adhesion in the most severe conditions, though at increasing costs. It is evident the industrial interest in being able to predict the required strength of the joint for the operating conditions of the tiling. Under particular conditions, such as shrinkage of the substrate due to early placement (before complete maturation of the substrate) of the tiles or thermal gradients in the floor thickness, combined with defective placement, tile detachment may occur, requiring a partial or complete replacement of the tiles. The activity in this area has been promoted and financially supported by Mapei S.p.A., a leading chemical company in the market of additives for civil engineering applications. The research activity has been focused on the following objectives: a) mechanical characterisation of the short term behaviour of the matured adhesive; b) determination of the stress state in the adhesive for different typologies of placement; c) derivation of simplified closed-form formulas for the engineering prediction of the tiling limit strength against detachment.

Dipartimento di afferenza

Dipartimento di Ingegneria Strutturale (DIS)

Docenti afferenti

Full Professors
Umberto Perego
Claudia Comi
Alberto Corigliano
Associate Professors
Valter Carvelli
Giuseppe Cocchetti
Attilio Frangi
Anna Pandolfi