MISCEA thesis offer ESR02 - Eco-innovative shape memory architected dampers for the seismic protection of infrastructures

Context

There is strong evidence that global climate change is likely to increase seismic activity, both in quantity (number of earthquakes per year) and intensity [1-3]. Factoring in the increasing densification of population, earthquakes are a crucial issue for resilient cities: there is a growing need of efficient strategies for mitigating the impact of earthquakes on infrastructures.

A possible strategy is to use Shape Memory Alloys (SMAs), a class of 'smart materials' which finds applications in various fields, such as aeronautics or biomedical. Those materials can dissipate energy through a solid-solid phase transformation. The relevance of SMA-based dampers in seismic protection has already been demonstrated in several works [4]. Compared to more conventional elastic-plastic or friction-based systems, SMA dampers have the advantage of displaying a recentering capacity, thus limiting residual displacements and preserving structural integrity after the earthquake. Because the dissipative function is a built-in property of the material, SMA dampers are very robust, which is essential for seismic protection devices. Moreover, needs of maintenance are minimal.

However, one drawback of SMA dampers is that the material behavior is strongly nonlinear and difficult to model in detail. Moreover, SMAs are expensive materials with a relatively high carbon footprint.

With those concerns in mind, the overall goal of the PhD project is to improve the performance of SMA dampers and to optimize the use of material, starting from recent computational and manufacturing tools and material knowledge.

In recent years, a lot of effort has indeed been devoted to improve material models for SMAs, including complex effects such as permanent inelasticity, two-way shape memory, cyclic behavior, and thermomechanical coupling [5,6]. The first objective of the PhD is to develop a new numerical strategy for implementing such models, allowing for the advanced simulation of SMA-based systems in the dynamic regime. Finite strain and self-heating need to be taken into account as they are likely to play an important role in seismic applications of SMAs (in contrast with other applications of those materials). Efficiency, consistency and robustness are critical features of the numerical strategy to be developed. Recent works making use of incremental energy minimization [7,8] could possibly be helpful in that regard.

Besides advanced simulation tools, the design of SMA dampers can also benefit from recent advances in metamaterials and additive manufacturing. On the one hand, thanks to the rational design of their unit cells, mechanical metamaterials possess extraordinary potential for improving the mechanical properties and energy absorption capabilities [9,10] of SMA dampers. On the other hand, additive manufacturing allows to produce objects in an additive, layer-by-layer fashion, potentially overcoming geometrical issues typical of other manufacturing approaches. This is fundamental for producing complex geometries, as in case of metamaterials, and to tune the design based on the type of building where the damper is used. Moreover, additive manufacturing allows to reduce production costs and times, in conjuction with a potential decrease of emissions and consequently of the carbon footprint of the part production, that is fundamental for the application and commercialization of SMA dampers. Accordingly, the second objective of the PhD is to propose a new topology optimization approach for SMAs. Thanks to this approach, the geometry of the damper could be designed to maximize its efficiency for a given quantity of material, before printing it. The validation of the approach will be possibly assessed by manufacturing and testing the optimized structures made of NiTi SMAs via laser powder bed fusion process, exploiting external collaborators’ facilities [11,12].

The outcomes of the PhD are tools and concepts for the design of efficient SMA dampers with optimized use of resources and reduced ecological footprint. 

References:

[1] Man-Jae Kim et al, Long-term patterns of earthquakes influenced by climate change: Insights from earthquake recurrence and stress field changes across the Korean Peninsula during interglacial periods, Quaternary Science Reviews (2023). DOI: 10.1016/j.quascirev.2023.108369

[2] Adven Masih 2018 An Enhanced Seismic Activity Observed Due To Climate Change: Preliminary Results from Alaska, IOP Conf. Ser.: Earth Environ. Sci. 167 012018

[3]https://www.theguardian.com/world/2016/oct/16/climate-change-triggers-e…

[4] Shape Memory Alloy Engineering (Second Edition), Chapter 22 : Civil Infrastructures, Lorenzo Casagrande, Costantino Menna, Domenico Asprone, Ferdinando Auricchio,, Butterworth-Heinemann, 2021,Pages 731-755

[5] G. Scalet, A. Karakalas, L. Xu, D. Lagoudas, Finite Strain Constitutive Modelling of Shape Memory Alloys Considering Partial Phase Transformation with Transformation-Induced Plasticity. Shape Memory & Superelasticity, 7, 206-221, 2021.

[6] G. Scalet, F. Niccoli, C. Garion, P. Chiggiato, C. Maletta, F. Auricchio. A three-dimensional phenomenological model for shape memory alloys including two-way shape memory effect and plasticity, Mechanics of Materials, 136, 103085, 2019.

[7] G. Scalet, M. Peigney. A robust and efficient radial return algorithm based on incremental energy minimization for the 3D Souza-Auricchio model for shape memory alloys, European Journal of Mechanics - A/Solids, 61, 364-382, 2017.

[8] M. Peigney, G. Scalet, F. Auricchio. A time integration algorithm for a 3D constitutive model for SMAs including permanent inelasticity and degradation effects, International Journal for Numerical Methods in Engineering, 115(9), 1053-1082, 2018

[9] G. Scalet, C.A. Biffi, J. Fiocchi, A. Tuissi, F. Auricchio, Additively manufactured Ti6Al4V lattice structures: mechanical characterization and numerical investigation, IOP Conference Series: Materials Science and Engineering, 1038, 012057, 2021.

[10] Hongye Ma, Ke Wang, Haifeng Zhao, Yilun Hong, Yanlin Zhou, Jing Xue, Qiushi Li, Gong Wang, Bo Yan, Energy dissipation in multistable auxetic mechanical metamaterials,Composite Structures, Volume 304, Part 1, 2023,116410,ISSN 0263-8223,https://doi.org/10.1016/j.compstruct.2022.116410.

[11] Carlo Alberto Biffi, Celal Soyarslan, Jacopo Fiocchi, Chiara Bregoli, Ausonio Tuissi, Mehrshad Mehrpouya, Functional performance of NiTi shape memory architected structures produced by laser powder bed fusion (LPBF), Transactions on Additive Manufacturing Meets Medicine Vol. 5 No. S1 (2023): Trans. AMMM Supplement https://doi.org/10.18416/AMMM.2023.2309821

[12] Carlo Alberto Biffi, Jacopo Fiocchi, Francesca Sisto, Chiara Bregoli, Ausonio Tuissi, Enhanced antibacterial response in Zn-modified additively manufactured NiTi alloy, Materials Letters,Volume 335,2023,133749,ISSN 0167-577X,https://doi.org/10.1016/j.matlet.2022.133749

Thesis supervisor(s)

The PhD is joint between Ecole des Ponts and University of Pavia. The supervisors in each institution are :

• Michael Peigney, Laboratoire Navier, Ecole des Ponts, michael.peigney@enpc.fr
• Giulia Scalet, Associate Professor at the Department of Civil Engineering and Architecture, University of Pavia (Italy), giulia.scalet@unipv.it

Working environment

Laboratoire Navier, Ecole des Ponts

At Ecole des Ponts, the candidate will be hosted by Laboratoire Navier (https://navier-lab.fr/en/research/), whoseresearch focuses on materials and structures for construction, energy and the environment. In the context of the energy transition and natural risks linked to climate change, the laboratory works in the field of innovative materials and implementation processes, the durability and resilience of structures under complex loads, the geomechanics of energy and the environment. Some of the research facilities enables the characterization of a wide spectrum of materials (construction materials, organic matrix composites, etc.) and structural components with different types of loads: static, fatigue, multi-axial loads:

• Electromechanical tension-compression: Inströn 3365, 6022 – MTS DY31, DY 35, 20 / M – 3R SYNTECH II -Shimadzu AGS-300kNX. Range of load cells between 10N and 300kN. Thermal chambers and strain measurement by strain gauges and optics.

• 3R 3000kN capacity hydraulic compression

• Bending apparatus with hydraulic cylinder with a capacity of 450kN (alternating fatigue with frequency up to 3Hz)

• MTS hydraulic tension-compression / torsion machine with a capacity of 100kN / 1600Nm

• Hydraulic cylinders with a capacity of 20kN to 200kN adapted on test frames designed for tensile, compression and bending tests

• The lab also has licences for Abaqus, Matlab and access to scientific databases (Scopus,…)

University of Pavia

The candidate will be hosted by the Department of Civil Engineering and Architecture (DICAr https://dicar.dip.unipv.it/it), that has a strong experience in research topics connected to the PhD project, i.e., structural and material mechanics, numerical methods, 3D/4D printing procedures and mechanical characterization for different types of materials, from biological and bio-artificial materials to ABS/PLA/elastomers and shape memory alloys.

Moreover, DICAr is connected with Eucentre (https://www.eucentre.it/?lang=en), a private non-profit foundation that pursues a mission of research, training and service provision in the field of earthquake engineering and, more generally, of risk engineering.

Within DICAr, the Laboratory of Programmable Materials and Structures (ProMaSt Lab – https ://www.promastlab.com), lead by Prof. Giulia Scalet, aims to achieve a fundamental understanding of the complex interactions between material behavior and geometry and has attracted national and international funding (including the ERC Starting Grant 2021 ‘CoDe4Bio’) to actively work on four core arguments: constitutive modelling of smart materials, 4D printing and biofabrication, experimental mechanics, and high-performance computational methods.

The lab and the department is equipped as follows:

- Computational equipment: Computational equipment: 1 HPC cluster with 4 nodes (4x CPU 2.1GHz) with 256 cores-1TB RAM; 1 access node (4x CPU 2.20 GHz) with 32 cores-252GB RAM; 1 server with 24 cores-66GB RAM; various workstations.

- Equipment for material synthesis/preparation: Fume hood, Heating magnetic stirrer; Ultrasonic bath; Vacuum oven; Analytical Balance.

- Equipment for material characterization: MTS Insight Testing Systems 10 kN (including video extensometer; thermostatic chamber and cooling system liquid Nitrogen; TestWorks4 software); Heating immersion circulator; Trinocular stereomicroscope; 3D scanner; Dynamic Mechanical Analyzer (DMA 850, TA); Differential Scanning Calorimetry (DSC 250, TA); Hybrid rotational rheometer (HR10 Discovery, TA).

- 3D printers/bioprinters: 1 Bioprinter (Cellink BioX6); 1 Digital Light Processing (Asiga MAXX35).

- Equipment for biological characterization: Biosafety cabinet; Centrifuge; Incubator;

Optical/fluorescence microscope; Thermo Shaker; Refrigerator; Freezers (-20, -80 °C).

- Others for literature search, computational/dissemination purpose: Well-equipped library; Access to numerous journals; Licensed software (Matlab, Mathematica); Covered open access fees (e.g., Springer, Elsevier, Wiley, ACS American Chem Soc, Cambridge Univ Press).

• 50 % at Ecole des Ponts (France), 50% at the University of Pavia (Italy)