unisa ITA  unisa ENG


PRIN 2017: Multiscale Innovative Materials and Structures - MIMS19

Prin 2017 Project "Multiscale Innoovative Materials and Structures" (MIMS)

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MIMS in short

Multiscale Innovative Materials and Structures (MIMS) is a PRIN 2017 granted project focused on the design, modeling, control and testing of unconventional materials at different scales, which will be able to fill holes in the to-date material property charts, by controlling the architecture of the material, so as to optimally combine material and space.

A fundamental goal of the project is the development of mechanical metamaterials to form next-generation cellular solids; devices; novel composites; and also building-scale structures. Taking inspiration from peculiar behaviors at multiple scales exhibited by lattice materials and nano/micro-structures (e.g., tensegrity-type response, instability, fracture, plasticity and damage), the project will investigate the creation of complex global systems (the metamaterials) with unprecedented mechanical properties. This Design and Modeling (D&M) Work Package (WP) of MIMS is directly inspired by nature, where tensegrity concepts and hierarchical structures are ubiquitous and appear, e.g., in every cell, in the microstructure of the spider silk, and in the arrangement of bones and tendons for control of locomotion. MIMS also employs multiscale lattices, fullerenes, nanotubes, and carbon nanostructures to optimally design fabrics, fibers and coatings of groundbreaking reinforcements for novel composite materials. The D&M WP makes use of advanced theoretical and computational approaches to predict the intrinsically complex mechanical behavior of the studied systems, which include: nonlinear homogenization techniques, multiscale methods for interacting failure modes, and/or mixed discrete-continuum methods.

The engineering implementation of the metamaterials developed by the project is addressed by the ENG WP, which takes inspiration and profit from the tunability of the mechanical response of tensegrity lattices through local and global prestress. The ability of such metamaterials to display tunable band gaps, where the propagation of mechanical waves is forbidden, is combined with internal resonance phenomena, in order to develop next-generation waveguides, sound-proof layers, and vibration-isolation devices. The ENG WP also includes the development of advanced composites with enhanced interlaminar shear strength, and improved overall strength and fracture toughness, which are enriched with functionalized carbon nanotubes, as well as particles and fibers with structural hierarchy originating from their geometric design. The latter are fabricated through additive manufacturing techniques based on polymeric and/or metallic materials, at different scales. A thin layer of the matrix covers the multiscale surface of such reinforcements, causing dramatic improvements in interfacial bonding. In addition, the pull-outs of fine-scale features of the reinforcements bridge the matrix, significantly contributing to the enhancement of composite strength and toughness.

The project is completed by the CTR WP, which deals with the formulation and implementation of quasi-real-time structural health monitoring and control systems dedicated to the materials and structures developed by the ENG WP. Novel approaches to operational modal analysis are developed, with the aim of formulating fast and accurate non-destructive identification methods of mechanical properties and damage detection. A first implementation of the control strategies developed by the project regards the tuning of local/global prestress variables and multiple resonances effects in vibration-isolation devices, and the experimental validation of such strategies on a scale model of floating-spar support for offshore wind turbines installed in sea water.  The CTR WP also includes the diffuse structural health monitoring of civil structures and historical building heritage, through functionalized carbon nanotubes embedded in cement-matrix composites. The present research task exploits the strain-sensing ability of carbon nanotubes induced by the variation of their electrical properties under mechanical loading.

Nano-, micro- and macro-scale materials and devices are studied through a closed-loop approach including the design and modeling of physical models; the fabrication of such models by combining multiscale additive manufacturing techniques with the enrichment of polymeric- and cement-matrix composites through functionalized carbon nanostructures; and the optimal control of the key design variables of the analyzed materials and structures. An experimental characterization phase implements and verifies the theoretical predictions.

 

Group Photo from the 2019 MIMS Review Meeting, Dec. 16 2019, Fisciano

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