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Hybrid polymer composites are very promising for applications in a wide variety of sectors, such as automotive, aerospace, robotics, energy and construction. These materials consist of a polymer matrix and two or more fillers, which synergically interact resulting in enhanced specific properties and performance. Among hybrid polymer composites, those based on carbon fibers reinforced poly(ether ether ketone) (C-PEEK) are gaining a primary role for their excellent mechanical and chemical properties; zirconium oxide (ZrO2) nanoparticles can further enhance these properties, improving also the wear resistance. In this paper, a new hybrid C-PEEK+ZrO2 composite has been studied and its mechanical properties compared with its reference composite C-PEEK.

Despite the widespread use of electronic devices and consumer products integrating flexible electronics, in industrial practice, the assembly process of film-based coverlays is still performed manually, and this, in turn, affects process accuracy in first place. Additionally, the related manual tasks can be troublesome for workers, causing stress and fatigue. As a result, such a process can represent a bottleneck in the fabrication of Flexible Printed Circuit Boards (FPCBs). In the present paper, the architecture of a gripper is proposed as the core device of a completely automated film-coverlay assembly process. The architecture of the gripper is vacuum-based and exploits the action of several independent valves, enabling the grip configuration according to the geometry of the component. The gripper operation is shown by implementing specific solutions related to the removal of the coverlay protective film and partial coverlay thermal bonding, thus providing also a detailed description of the phases concerning a feasible automated assembly process. The results of the tests concerning the evaluation of both solutions are reported and discussed in the paper. Finally, a simplified gripper version is prototyped to perform some of the tests, and it is also used to preliminarily assess the performance of the gripping strategy, with good results.

At the present time, there is a growing interest in additive manufacturing (AM) technologies and their integration into current process chains. In particular, the implementation of AM for tool production in micro injection molding (µ-IM), a well-established process, could introduce many advantages. First of all, AM could avoid the need for the time-consuming and expensive fabrication of molds for small series of customized products. In this work, the feasibility, quality, and reliability of an AM/µ-IM process chain were evaluated by designing and fabricating mold inserts for µ-IM by stereolithography (SLA) technology, the mold inserts were characterized and tested experimentally. The selected geometry is composed of four thin cavities: This particular feature represents an actual challenge for both the SLA and µ-IM perspective due to the large surface-to-volume ratio of the cavity. Two different materials were used for the mold fabrication, showing sharply different performance in terms of endurance limit and cavity degradation. The obtained results confirm that the µ-IM process, exploiting an SLA fabricated mold insert, is feasible but requires great accuracy in material choice, mold design, fabrication, and assembly.

In modern electronics, flexible and rigid-flex PCBs are largely used due to their intrinsic versatility and performance, allowing to increase the available volume, or enabling connection between unconstrained components. Rigid-flex PCBs consists of rigid board portions with flexible interconnections and are commonly used in a wide variety of industrial applications. However, the assembly process of these devices still has some bottlenecks. Specifically, they require the application of cover layers (namely, coverlays), to provide insulation and protection of the flexible circuits. Due to the variability in planar shape and dimensions, the coverlay application is still performed manually, requiring troublesome manipulation steps and resulting in undetermined time-cycle and precision.This paper aims at the improvement of the industrial process currently performed, by proposing an approach for the automation of Kapton coverlay manipulation and application. Since these products are commercially provided as a film with a protective layer to be removed, the peeling issue is addressed, representing a challenging step of the automated process; the results of a systematic series of tests, performed in order to validate the peeling strategy, are reported in the paper. The overall assembly strategy relies on the development of a customized multi-hole vacuum gripper, whose concept is presented and contextualized in the proposed assembly process by outlining a suitable workcell architecture.

Additive Manufacturing (AM) has recently proved its feasibility for the fabrication of compact electronic and telecommunication components with high level of customization. Compared to conventional manufacturing technologies, AM exhibits the dramatic capability of rapid prototyping parts and devices fast and at reasonable costs. In order to have a clear view about the way AM is developing into recent and future telecommunication contexts, the present work will show the most recent antenna design for 5G communications, highlighting the use of AM solutions for the antenna fabrication. To this aim, 3D-shaped dielectric resonator antennas (DRAs) were designed and fabricated, pointing out the role played on the DRA performance by the chosen fabrication technique. Two AM technologies are investigated in terms of usable materials, surface quality and dimensional accuracy of the produced device. Relevant results concerning the effects induced by fused deposition modelling (FDM) and stereolithography (SLA) on the scattering parameter S 11 and gain of 3D-DRA designs are illustrated and discussed.

Advanced composite structural components in aeronautics are characterized by very high production costs because of their dimensions, complex shapes and expensive forming equipment. For these components, such as horizontal stabilizers and wings, a defect occurrence is often critical because large part of inner surfaces, made of long and tapered narrow tunnels, are not reachable for repair operations. In these cases, the part is rejected with a relevant economic loss and high production costs. For this reason, aircraft constructors plan huge investments for defects avoidance during the forming processes of CFRP and to develop effective, robust and reliable repair tools and methods. Mobile robotics can play an important role, with specific systems capable of moving into narrow channels of wings structures (i.e. multi spar boxes) and repair it in accordance to technical standards. This paper describes an innovative mobile robot architecture for bonded repair scarfing operations on CFRP components. Targeting and responding to the demanding machining requirements, the functional-oriented design approach clearly highlights the advantages of a modular robotic solution. The mobile robotic architecture can be also applied in other fields with similar challenging manufacturing operations for further inspection, detection and machining operations.

In fused deposition modeling (FDM) process, several uncertainty sources contribute to low accuracy and bad surface finishing. Besides intrinsic uncertainties, other factors, related to the machine structure and actuation, participate to increase complexity and reduce the controllability of the process. On-board vision systems can be successfully exploited to monitor the deposition process and to acquire quantitative information on geometry and transients. This information can be used to calibrate the process parameters where a compensation strategy is implemented. In this paper, a low-cost vision system capable of microscopic acquisitions is integrated into an FDM machine and image-processing techniques are exploited to define calibration procedures to improve the process accuracy, thus extending the use of this equipment to micromanufacturing applications. The effectiveness of the integration is evaluated through the fabrication of a microfluidic device.

The aim of the research activity reported in this paper is to investigate a promising approach for the rapid and customized manufacturing of miniature flexure hinges with predictable and reliable mechanical performances. With these premises, the proposed methodology combines stereolithography and micro injection moulding, with the aim of exploiting the advantages of both manufacturing techniques. As a preliminary case study, a corner filleted hinge made of polyoxymethylene (POM) has been realized in multiple identical specimens that are then characterized in terms of both dimensional accuracy and function.

The capability to manufacture high-precision components with microscale features is enhanced by the combination of different micromanufacturing processes in a single process chain. This study explores an effective process chain that combines micro-abrasive water jet (μ-AWJ) and microwire electrical discharge machining (μ-WEDM) technologies. An experimental spring component is chosen as a leading test case, since fine geometric features machining and low roughness on the cut walls are required. The advantages deriving from the two technologies combination are discussed in terms of machining time, surface roughness, and feature accuracy. First, the performances of both processes are assessed by experimentation and discussed. Successively, different process chains are conceived for fabricating two test cases with different sizes, displaying some useful indications that can be drawn from this experience.

Traditional shape memory polymers (SMPs) are mostly thermoresponsive and their applications in nanooptics are hindered by heat-demanding programming and recovery processes. By integrating a polyurethane-based shape memory copolymer with templating nanofabrication, reconfigurable/rewritable macroporous photonic crystals have been demonstrated. This SMP coupled with the unique macroporous structure enables unusual all-room-temperature shape memory cycles. "Cold" programming involving microscopic order-disorder transitions of the templated macropores is achieved by mechanically deforming the macroporous SMP membranes. The rapid recovery of the permanent, highly ordered photonic crystal structure from the temporary, disordered configuration can be triggered by multiple stimuli, including a large variety of vapors and solvents, heat, and microwave radiation. Importantly, the striking chromogenic effects associated with these athermal and thermal processes render a sensitive and noninvasive optical methodology for quantitatively characterizing the intriguing nanoscopic shape memory effects. Some critical parameters/mechanisms that could significantly affect the final performance of SMP-based reconfigurable photonic crystals, including strain recovery ratio, dynamics and reversibility of shape recovery, as well as capillary condensation of vapors in macropores, which plays a crucial role in vapor-triggered recovery, can be evaluated using this new optical technology.

In this work, a variety of polymers with relatively low dielectric permittivity were used to fabricate 3D-shaped DRAs with identical geometry by means of two different Additive Manufacturing (AM) technologies. Three DRA prototypes made of polylactic acid (PLA), its conductive counterpart (conductive PLA) and glass-fiber filled polyamide (PA+GF) were manufactured via Fused Deposition Modelling (FDM). Other two prototypes were fabricated using photopolymer epoxy resins via stereolithography (SLA). All the DRAs were designed to operate in the 3.5 GHz band for 5G applications. The fabricated prototypes were characterized by means of a Vector Network Analyzer and an anechoic chamber, using the feeding monopole as reference. It is worth stressing that, since the two AM technologies feature different dimensional accuracy and surface quality, the effect of the polymer characteristics and manufacturing technologies on DRAs performance were evaluated. The experimental results show that PLA, PA+GF and epoxy resin-made DRAs have good performance in terms of scattering parameter S 11 (−35 dB for PLA and PA+GF, and −40dB for epoxy resins) and gain up to +3dB over a bandwidth of 1 GHz centred at 3.5 GHz. Moreover, the lower dimensional accuracy and surface quality exhibited by the FDM-made samples show to have impact mainly on the intensity of scattering parameter S 11 . Furthermore, although conductive PLA displays higher e r value and lower tan δ than the other considered polymers, this particular prototype shows worse overall performance: indeed, losses induced by low electrical conductivity (σ == 10−6 S) lead to a negative gain of about −5 dB.

Additive Manufacturing (AM) technologies have recently emerged as key technologies to be integrated in current process chains. In particular, AM technologies could be successfully applied for molds and inserts fabrication for small batches production of components and microcomponents. In terms of economy and sustainability, the AM offers several advantages with respect to traditional manufacturing technologies for molds and inserts fabrication, such as waste reduction, minimized energy consumption, reduced cycle time and time to market. In this work, a thin cavities mold insert was manufactured via inverted (bottom-up) stereolitography (SLA) and tested via micro-injection molding in order to assess the feasibility of the SLA/?-IM (Injection Molding) process chain. The designed geometry is composed by four thin cavities: this particular feature represents the actual challenge, due to the large surface to volume ratio that characterizes the sample. Design rules for AM have been applied in order to fulfill injection molding issues and ensure a longer mold insert duration. The mold insert cavities have been characterized to evaluate the achieved dimensional and geometrical precision showing a quite good geometry accuracy in thickness; the mold insert geometrical deviation, which could prevent the correct assembly of the insert into the mold, have been measured too. Finally, a short-series of about 30 molding cycles has been carried out evaluating the capacity of filling the thin cavities and the capability of SLA mold insert.

Macroporous photonic crystals with optically bistable states have been fabricated by using thermoresponsive shape memory polymers. The reversible transition between an ordered permanent state and a disordered temporary state results in tremendous changes in the appearance and the optical properties of the membranes.

A partire dallo stato dell'arte e dalla definizione del contesto di riferimento sviluppati nell'attività AR.2.1, si sono svolte le attività di ricerca focalizzate sulle tecnologie Additive Manufacturing, sulle tecnologie metrologiche e di acquisizione della geometria e delle proprietà superficiali di particolari meccanici ottenuti da AM, e dei criteri e metodi di ottimizzazione di tali tecnologie. Il report descrive le fasi della ricerca (metodi, strumenti, materiali) e mostra i risultati delle attività (AR.2.2) relative allo studio e definizione di un metodo di ottimizzazione del processo produttivo del progetto VMAN Virtual Manufacturing, Cluster Tecnologici Regionali, Puglia. Il report tecnico è il deliverable dell'attività AR2.2.

The present study explores the design of an effective process chain that combines micro Abrasive Waterjet (micro-AWJ) and micro Wire Electro Discharge Machining (micro-WEDM) technologies. An experimental spring component is chosen as leading test case, since fine geometric features machining and low roughness on the cut walls are required. The advantages deriving from the two technologies combination are discussed in terms of machining time, surface roughness and feature accuracy. First, the performance of both processes are assessed by experimentation and discussed. Successively, different process chains are conceived for realizing two test cases with different size, displaying the advantages and drawbacks of the combinations.

The aim of the present study is the assessment of the integration of a low cost optical measurement device into a high-precision machine tool for micro manufacturing applications. The measurement system can be effectively integrated into the working volume of different types of machines allowing both tool and workpiece measurements and avoiding its disassembly from the machine stage for off-line measurements and, consequently, reference losses. The fast measurements of tool and workpiece during the machining contribute to increase the accuracy and reduce the overall machining-measurement iterations. The assessment is achieved by a test case where a low cost USB microscope is applied to a micro-EDM machine. The low cost device has been applied for tool electrode measurements and tool wear evaluation after an accuracy enhanced calibration procedure and high performance image processing algorithms, which effectively reduce the lack of the hardware performance. The measurement performance gives a feedback on the deviations of the machined features from nominal geometry and allows their compensations by an adequate machining strategy.

In this paper a parametric, modular and scalable algorithm allowing a fully automated assembly of a backplane fiber-optic interconnection circuit is presented. This approach guarantees the optimization of the optical fiber routing inside the backplane with respect to specific criteria (i.e. bending power losses), addressing both transmission performance and overall costs issues. Graph theory has been exploited to simplify the complexity of the NxN full-mesh backplane interconnection topology, firstly, into N independent sub-circuits and then, recursively, into a limited number of loops easier to be generated. Afterwards, the proposed algorithm selects a set of geometrical and architectural parameters whose optimization allows to identify the optimal fiber optic routing for each sub-circuit of the backplane. The topological and numerical information provided by the algorithm are then exploited to control a robot which performs the automated assembly of the backplane sub-circuits. The proposed routing algorithm can be extended to any array architecture and number of connections thanks to its modularity and scalability. Finally, the algorithm has been exploited for the automated assembly of an 8x8 optical backplane realized with standard multimode (MM) 12-fiber ribbons.

Ricostruzione dello stato dell'arte e del contesto di riferimento relative alle tecnologie additive amnufacturing di metalli per la realizzazione di giranti di turbine per applicazioni Oil and Gas. Definizione del test case tecnologico e delle tecnologie di manufacturing.

Stato dell'arte e contesto di riferimento per l'integrazione di tecnologie di computer aided manufacturing in ambienti di realtà virtuale, per la definizione delle specifiche di progetto delle applicazioni da sviluppare. Definizione del test case tecnologico relativo alle attività di ITIA CNR.

In recent years, fused deposition modelling technology (FDM) has become one of the most important additive manufacturing technology due to its capability to produce functional prototypes with complex shape in a cost effective way. Recently, the trend towards miniaturization invested also this technology, since the request of micro-component is rapidly growing due to the increasing number industrial sectors involved. Mechanical properties are fundamental in some sectors of high-quality micro-parts, so the knowledge of the influence of FDM process parameters on mechanical properties can be useful to extend its application and help the optimization of the parameter selection. In this context, the aim of this study is the analysis of the FDM capability and the room for improvement, through a comparison with a well-consolidated industrial process, such as the micro-injection moulding. Although FDM quality cannot compete with the technologies industrially used for final products, its low cost and short time are very attractive for some applications. Moreover, the comparison can be interesting since FDM is often used to manufacture prototypes eventually made with more performing industrial technologies, so that a measure of the quality and functionality of these prototypes can be extremely useful for product developers.

We present a cost-effective and highly-portable plastic prototype that can be interfaced with a cell phone to implement an optofluidic imaging cytometry platform. It is based on a PMMA microfluidic chip that fits inside an opto-mechanical platform fabricated by a 3D printer. The fluorescence excitation and imaging is performed using the LED and the CMOS from the cell phone increasing the compactness of the system. A custom developed application is used to analyze the images and provide a value of particle concentration.

The wide investigation of the last decades on a variety of electronic products in order to increase their performance while miniaturizing them, has raised new issues related to their manufacturing, remanufacturing and reuse at their end-of-life. This scenario introduces further challenges, related to demanding specifications, to be addressed with enhanced or new (re-) manufacturing processes, innovative systems, and advanced strategies. In this context, this paper discusses some challenging applications exploiting novel automatic solutions on different complexity levels of the process, from the component to the whole system, including devices, tools and robotized work-cells developed by the authors.

The mechanical behaviour of specimens fabricated using FDM machine has been thoroughly studied and several works have been presented. However, they are focused on few materials, in particular ABS, while very few papers analysed the mechanical properties of FDM samples made by PLA filament. Even though ABS is well known for its superior mechanical properties, some applications might require materials with other properties, such as PLA. Therefore, a deeper investigation of the effect of the process on its properties is needed. In this study, at first, the influence of the main FDM process parameters, such as raster angle, extrusion width, air gap and extrusion temperature, on mechanical performance of PLA samples has been evaluated. The mechanical tests have been carried out on miniaturized tensile specimens focusing on the tensile test main properties: ultimate tensile stress, Young modulus and elongation at break. Moreover, an experimental campaign has been carried out on the effect of a thermal post-processing, in order to evaluate the effects of the treatment and its relation with the process parameters on the mechanical properties of the specimens.

In the present paper, a numerical approach to model the layer-by-layer construction of cured material during the Additive Manufacturing (AM) process is proposed. The method is developed by a recursive mechanical finite element (FE) analysis and takes into account forces and pressures acting on the cured material during the process, in order to simulate the behavior and investigate the failure condition sources, which lead to defects in the final part geometry. The study is focused on the evaluation of the process capability Stereolithography (SLA), to build parts with challenging features in meso-micro scale without supports. Two test cases, a cantilever part and a bridge shape component, have been considered in order to evaluate the potentiality of the approach. Numerical models have been tuned by experimental test. The simulations are validated considering two test cases and briefly compared to the printed samples. Results show the potential of the approach adopted but also the difficulties on simulation settings.

A new optical backplane solution is proposed for high-capacity ICT apparatus. A modular, scalable and full-mesh bandwidth-upgradable optical interconnection between optoelectronic boards is guaranteed thanks to an optimized layout of standard MM 12-fiber ribbons which divides the overall backplane into several independent optical sub-circuits. The novel automated assembly procedure of fiber ribbons inside sub-circuits with a robotic work-cell is described. System validation of the optical backplane performed with commercially available MM 12-fiber transceivers @10Gb/s proved the feasibility of the proposed solution for future optical interconnections with terabit overall capacity.

A comparison of the machining performance of micro-electro-discharge machining (EDM) milling and sinking is proposed considering the fabrication of microchannels with controlled sloped walls realized in a hardened steel workpiece. Adopting the fine-finishing machining regime for both micro-EDM techniques, the experimental results show that micro-EDM sinking is about ten times faster than milling in the worst case, though a lack of accuracy in the final microfeatures in the former case is detected due to not compensated tool wear. On the contrary, micro-EDM milling provides a better control of the microchannel dimensions. Finally, a microfilter mold for medical applications is machined in order to show the potential of the combination of both technologies.

The demand for polymeric micro-components is increasing for applications in several industrial fields. Fused deposition modelling (FDM) is a consolidated rapid prototyping technology growing rapidly as industrial additive manufacturing technology due to its ability to build cheap and functional parts with complex geometry. In this study, several dog-bone miniaturized specimens in PLA were prepared by FDM and the relationships among the processing conditions and the mechanical properties were investigated. An ANOVA allowed to identify the influence of the FDM parameters on the part dimensional and geometrical accuracy. Since in micro FDM manufacturing the parameter setting is not sufficient to assure the final quality of the product, the part 3D solid model was modified to compensate both dimensional and geometrical errors. Finally, the miniaturized specimens were fabricated by micro-injection moulding (µIM) and their mechanical properties compared with those obtained using FDM.

This paper reports on design, fabrication, and characterization of a microfilter to be used in biomedical applications. The microfilter, with mesh of 80 μm, is fabricated by micro-injection molding process in polymeric material (polyoxymethylene (POM)) using a steel mold manufactured by micro-electrical discharge machining process. The characteristics of the filter are investigated by numerical simulation in order to define a suitable geometry for micro-injection molding. Then, different process configurations of parameters (melt temperature, injection velocity, mold temperature, holding pressure and time, cooling time, pressure limit) are tested in order to obtain the complete part filling via micro-injection molding process preventing any defects. Finally, the component is dimensionally characterized and the process parameters optimized to obtain the maximum filtration capacity.

Il documento ha lo scopo di illustrare le attività di ricerca svolte nell'ambito del progetto di ricerca IC Plus finalizzate allo sviluppo di un prototipo dimostratore della tecnologia di diagnostica basato su Lab-On-Chip, dispositivo multimediale portatile e dispositivo ottico customizzato. Il documento illustra brevemente schemi di principio, sviluppo e progettazione dei dispositivi e risultati ottenuti.

A modular, scalable and full-mesh bandwidth-upgradable optical interconnection between optoelectronic boards is guaranteed thanks to an optimized layout of standard MM fiber ribbons which divides the overall backplane into independent optical sub-circuits.

The paper presents the design and development of a new robotized assembly system of optical backplanes in high-capacity ICT (Information and Communication Technology) apparatus, mainly used for switching stations and distribution networks. The optical backplane solution consists of several optical fiber ribbons positioned on a planar backplane according to an innovative and optimized full-mesh layout where the overall optical interconnection is partialized into a plurality of different independent sub-circuits. Each optical interconnection sub-circuit consists of optical fiber ribbons with standardized optical and mechanical interfaces and customized components that have to be carefully and precisely assembled in order to achieve connections with low optical power losses. The paper describes the method and the main devices and tools conceived for the automatic assembly of optical interconnection sub-circuits, highlighting the critical aspects and the proposed solutions towards the automatized assembly of the whole optical backplane.Copyright © 2015 by ASME

A novel optical backplane relying on standard MM 12-fiber ribbons and MPO connectors is proposed for high-capacity ICT apparatus. A modular, scalable and full-mesh optical interconnection between optoelectronic boards is guaranteed thanks to an optimized fiber ribbon layout routing that divides the overall backplane into different and independent optical sub-circuits. The automated assembly of fiber ribbons into sub-circuits with a robotic work-cell is described. System validation of the optical backplane performed with commercial MM 12-fiber transceivers @10Gb/s proved the feasibility of the proposed solution for future optical interconnections with terabit overall capacity.

Here novel chromogenic photonic crystal sensors based on smart shape memory polymers (SMPs) comprising polyester/polyether-based urethane acrylates blended with tripropylene glycol diacrylate are reported, which exhibit nontraditional all-room-temperature shape memory (SM) effects. Stepwise recovery of the collapsed macropores with 350 nm diameter created by a "cold" programming process leads to easily perceived color changes that can be correlated with the concentrations of swelling analytes in complex, multicomponent nonswelling mixtures. High sensitivity (as low as 10 ppm) and unprecedented measurement range (from 10 ppm to 30 vol%) for analyzing ethanol in octane and gasoline have been demonstrated by leveraging colorimetric sensing in both liquid and gas phases. Proof-of-concept tests for specifically detecting ethanol in consumer medical and healthcare products have also been demonstrated. These sensors are inexpensive, reusable, durable, and readily deployable with mobile platforms for quantitative analysis. Additionally, theoretical modeling of solvent diffusion in macroporous SMPs provides fundamental insights into the mechanisms of nanoscopic SM recovery, which is a topic that has received little examination. These novel sensors are of great technological importance in a wide spectrum of applications ranging from environmental monitoring and workplace hazard identification to threat detection and process/product control in chemical, petroleum, and pharmaceutical industries.

Smart shape memory polymers (SMPs) can memorize and recover their permanent shape in response to an external stimulus, such as heat, light, and solvent. They have been extensively exploited for a wide spectrum of applications ranging from biomedical devices (e.g., surgical stents and sutures) and implants for minimally invasive surgery to aerospace morphing structures and self-healing materials. However, most of the existing SMPs are thermoresponsive and their performance is hindered by slow response speed, heat-demanding programming and recovery steps. In this manuscript, by integrating scientific principles drawn from two disparate fields that do not typically intersect - the photonic crystal and SMP technologies, we report a new type of SMP that enables unusual "cold" programming and instantaneous shape recovery triggered by exposing the samples to various organic vapors. These stimuli-responsive materials differ greatly from existing SMPs as they enable orders of magnitude faster response, striking chromogenic effects, and room-temperature operations for the entire shape memory cycle, promising for many applications ranging from reusable chromogenic vapor sensors to reconfigurable nanooptical devices. Moreover, this interdisciplinary integration provides a simple yet sensitive optical technique for investigating the intriguing shape memory effects at nanoscale.

Il documento rappresenta il contributo dell'Unità Operativa ITIA-CNR al Rapporto Tecnico sugli Stati d'Avanzamento Intermedi del Progetto (SAL) 7 del progetto BACKOP che riporta le attività relative allo Sviluppo dell'automazione dell'assemblaggio di circuiti di interconnessione ottica da integrare su backplane svolte dall'unità dal 01/10/2014 al 31/03/2015.

Macroporous photonic crystals with optically bistable states are fabricated by P. Jiang and co-workers using thermoresponsive shape memory polymers. On page 1509, the reversible transition between an ordered permanent state and a disordered temporary state during the shape memory "programming" and "recovery" processes results in tremendous changes in the appearance and optical properties of the photonic crystal membranes.

In previous research activities, the nanoporous structure SMP has been investigated showing the SMP behavior, the deformation induced by water extraction or mechanical pressure and other action, the recovery action, nanomechanical experimentation, and relate the mechanical deformation state with optical behavior. In studying these nanoporous materials, validated optical, mechanical FEM and Multiphysics models should be a very useful tool for understand the behavior of the SMP photonic crystal. The research activity proposal is focused on knowledge, methods and tools development for nanoporous structures SMP modeling, simulation of mechanical and optical phenomena and behavior. The aim is to formulate a consistent, accurate and reliable framework for numerical prediction of multi-physic (coupled mechanical and optical) behavior of nanoporous SMP structures. These results will be achieved studying and developing a very effective example of multi-physics device and material: a photonic crystal Nanoporous Shape Memory Polymer (SMP). This choice has been made in order to take into account the mechanical state transitions of the SMP and its consequences on optical performances and properties of the photonic crystal. There are two main research challenges: oThe first challenge is to consider the complexity of nanoporous structure SMP in geometry, mechanical behavior and material properties. As already stated, nonlinearities, elastic instability and nanoscale effects contribute to increase the complexity. oThe second challenge refers to the development of a multi-physics (mechanical and optical) model and simulation of nanoporous SMP because of the novelty of this material. The objective of the research project is the mathematical representation of the mechanical and optical properties of the nanoporous crystal photonic SMP. The objective can be acquired by: - Development of a parametric and accurate geometrical models of native nanoporous structure; - Mechanical modelling of nanoporous crystal photonic SMP via FEA in order to obtain stress/strain status for three different situations (undeformed-native, deformed and recovered) managing structural non linearity in dependence of external loads, constrains, pore size and spatial distribution, material properties and residual stress/strain; - Development of optical models of the nanoporous photonic crystal SMP at the different states and predict the optical behaviors via geometrical optics simulation. - Coupling the mechanical state (deformation, stress-strain, nanoporous collapse etc.) with the optical properties (mainly reflection index) via multi physics modeling/simulation and different approaches (FEA modeling and geometrical optics) and data fusion. - Validation by experiments of the simulations performed on each model (mechanical, optical and multi-physic)