A new methodology for thermostructural topology optimization: Analytical definition and validation

In the last few years, the rapid diffusion of components produced through additive manufacturing processes has boosted the research on design methodologies based on topology optimization algorithms. Structural topology optimization is largely employed since it permits to minimize the component weight and maximize its stiffness and, accordingly, optimize its resistance under structural loads. On the other hand, thermal topology optimization has been less investigated, even if in many applications, such as turbine blades, engines, heat exchangers, thermal loads have a crucial impact. Currently, structural and thermal optimizations are mainly considered separately, despite the fact that they are both present and coupled in components in service condition. In the present paper, a novel methodology capable of defining the optimized structure under simultaneous thermomechanical constraints is proposed. The mathematical formulation behind the optimization algorithm is reported. The proposed methodology is finally validated on literature benchmarks and on a real component, confirming that it permits to define the topology, which presents the maximized thermal and mechanical performance

Guidelines for the study of subsidence triggered by hydrocarbon production

This study was carried out by the SEADOG Research Center at Politecnico di Torino (Italy). The purpose of this work was to evaluate which complexity degree would be required to reliably approach a subsidence study for different scenarios. The study was based on sensitivity analyses which were performed using a series of 3D synthetic numerical models of which the structural characteristics and geological and mechanical properties were based on available public data of onshore and offshore hydrocarbon fields in Italy. An array of simulations, both one-way and two-way coupled, were carried out to assess the magnitude and extension of subsidence potentially induced by hydrocarbon production. The results allowed the calculation of subsidence indices defined as the rate of compaction propagation (i.e., the ratio between the maximum surface displacement and the maximum reservoir compaction) and as the rate of volume loss (i.e. the ratio between the volume of the subsidence bowl or cone and the volume variation of the reservoir). These indices together with the degree of the underground systems’ heterogeneity led to the definition of the Intact Rock Qualitative Subsidence Index (IRQSI), upon which the needed complexity degree of a subsidence study can be discerned

Comparison of multi-objective optimization methodologies for engineering applications

Computational models describing the behavior of complex physical systems are often used in the engineering design field to identify better or optimal solutions with respect to previously defined performance criteria. Multi-objective optimization problems arise and the set of optimal compromise solutions (Pareto front) has to be identified by an effective and complete search procedure in order to let the decision maker, the designer, to carry out the best choice. Four multi-objective optimization techniques are analyzed by describing their formulation, advantages and disadvantages. The effectiveness of the selected techniques for engineering design purposes is verified by comparing the results obtained by solving a few benchmarks and a real structural engineering problem concerning an engine bracket of a ca

Tectonic evolution of the Ligurian accretionary wedge in Monferrato (NW Italy): new data from the analysis of tectonic, sedimentary and diapiric m\ue9langes

L\u2019evoluzione tettonica del Monferrato \ue8 ben conosciuta a partire dagli episodi deformativi oligocenici. Al contrario, la sua evoluzione pre-oligocenica legata alle fasi di accrezione del Cretacico superiore-Eocene medio del cuneo di accrezione Ligure \ue8 ancora poco conosciuta. Le Unit\ue0 Liguri Esterne che costituiscono il substrato della successione del Bacino Terziario Piemontese in Monferrato sono conosciute come un complesso caotico indifferenziato di et\ue0 Cretacico superiore-Eocene medio. Lo studio dettagliato di queste Unit\ue0 ha permesso di distinguere al loro interno tre unit\ue0 litostratigrafiche: le Argille varicolori (Santoniano-Campaniano), il Flysch di Monte Cassio (Campaniano superiore(?)-Maastrichtiano), e le Brecce argillose poligeniche (Oligocene superiore). Le Argille varicolori e le Brecce argillose poligeniche rappresentano il prodotto dell\u2019interazione e sovrapposizione di processi tettonici, sedimentari e diapirici che hanno operato in momenti diversi dell\u2019evoluzione del cuneo di accrezione Ligure formando m\ue9lange poligenici. L\u2019analisi della deformazione e la comprensione dei rapporti di sovrapposizione tra i diversi tipi di m\ue9langes poligenici individuati hanno permesso di: (i) distinguere pi\uf9 fasi deformative (Cretacico superiore, Rupeliano e Oligocene superiore); (ii) comprendere i rapporti di interazione e sovrapposizione tra processi tettonici, sedimentari e diapirici che hanno portato alla formazione di diversi tipi di m\ue9langes poligenici; (iii) ridefinire pi\uf9 in dettaglio, rispetto ai dati di letteratura, i tempi della deformazione dell\u2019intervallo di tempo Chattiano\u2013pre Burdigaliano

Polygenetic m\ue9langes: the interplay of tectonic, sedimentary and diapiric processes in exhumed accretionary wedges.

L'interazione e sovrapposizione di processi tettonici, sedimentari e diapirici a diversi livelli strutturali di cunei di accrezione, pu\uf2 portare alla formazione di m\ue9lange poligenici. Il riconoscimento del ruolo avuto da ognuno di questi processi \ue8 spesso problematico a causa della forte convergenza del fabric dei loro prodotti, della sucessiva deformazione e metamorfismo che obliterano le tracce del prevalente processo di formazione, e per il fatto che questi processi possono interagire e sovrapporsi in modi complessi. In questo lavoro mostriamo come diversi m\ue9lange formati in differenti posizioni strutturali di cunei di accrezione esumati e associati bacini di wedge-top, non rappresentano il prodotto di un unico processo, come invece sono stati comunementi interpretati in letteratura. Al contrario, essi rappresentano dei m\ue9lange poligenici formati dall'interazione e sovrapposizione di processi tettonici, sedimentari e diapirici. Gli esempi discussi riguardano il Taconic M\ue9lange della Hudson River Valey (Appalachi settentrionali), di et\ue0 tardo ordoviciana, le Unit\ue0 Liguri esterne di et\ue0 del Cretacico superiore affioranti in Monferrato e la successione caotica messiniana del Bacino Terziaro Piemontese