Periodic Reporting for period 2 - INSPIRE (INNOVATIVE GROUND INTERFACE CONCEPTS FOR STRUCTURE PROTECTION)
Berichtszeitraum: 2021-03-01 bis 2023-08-31
Aiming to foster a new generation of highly skilled researchers and engineers, INSPIRE has successfully carried out a comprehensive set of research, training, and dissemination activities. Throughout a total duration of four and a half years, from 1st March 2019 to 31st August 2023, the project has delivered excellent research outcomes (as evidenced by the approximately 100 publications in top-notch scientific journals and international conference proceedings) and a wide array of educational activities. The project’s focus has centred on the scientific field of engineering metamaterials, with a specific emphasis on the development and implementation of an innovative, holistic approach to safeguard structures against various ground-induced hazards. This protection encompasses threats such as earthquakes, as well as other sources of low-frequency noise and vibration excitations.
The INSPIRE training programme has equipped researchers with innovative and creative skills, implementing a joint multidisciplinary research training programme focused on the growth of scientific and technological knowledge and professional skills through research on individual, personalized projects. The project has crucially enhanced the European innovation through high-impact technological applications, leading to directly exploitable solutions for a market the global size of which is expected to reach USD 11.72 trillion by 2025. INSPIRE has created a legacy for the future generations of researchers, with training material and relationships with companies offering secondment opportunities for further cohorts of students outside of the project.
The INSPIRE training programme has equipped researchers with innovative and creative skills, implementing a joint multidisciplinary research training programme focused on the growth of scientific and technological knowledge and professional skills through research on individual, personalized projects. The project has crucially enhanced the European innovation through high-impact technological applications, leading to directly exploitable solutions for a market the global size of which is expected to reach USD 11.72 trillion by 2025. INSPIRE has created a legacy for the future generations of researchers, with training material and relationships with companies offering secondment opportunities for further cohorts of students outside of the project.
RESEARCH
Several infrasound wave conditioning concepts have been examined demonstrating the wave screening properties of meta-materials:
A) Pile arrays and foundation blocks: Work is being undertaken in developing systems able to trap low frequency waves and have wide band-gaps (0.5Hz-5.0Hz) required to mitigate the effects of seismic waves Such performance cannot be met by the currently proposed designs of seismic meta-material unit cell concepts.
B) Trapped rainbows: Work has been focused on developing efficient near- and on-surface meta-material concepts against Rayleigh surface waves.
C) Meta-material on a city scale: Work has focused on developing city-scale inelastic time-domain analysis tools and models to evaluate the effectiveness of the proposed meta-soils , as part of the design of a conceptual “Meta-City”.
A common characteristic of the concepts examined - and a major objective of the project indeed - is to prove simple, reliable and resilient meta-soil designs, leading to easy and low-cost implementation and maintenance to make use of meta-soils possible in both developed and developing countries with high seismic risks
Furthermore, a class of novel absorption and isolation concepts have been investigated:
A) Negative Stiffness Dampers (NSD): Work produced already has confirmed that the concept features not only enhanced wave damping, but also extended band-gaps, especially for seismic and low-frequency acoustic applications.
B) Micro-structured materials under frictional forces and self-oscillatory behaviour: Bifurcation phenomena - such as buckling and in flutter instability - guide the development of new technological concepts and tools for novel isolators in classical foundations. Inspired by elastic meta-materials with inertial locally resonant structures, nonlinear structures are designed with non-propagation frequencies in the infrasound range.
C) Meta-Columns: Vertically supported slender bodies. The concepts have already been implemented in designing systems that can protect structures from seismic shaking by promoting rocking behavior.
D) Meta-Panels: Mitigation measures at the receiver (building): Research on this topic has been focused on developing sound absorption panels incorporating negative stiffness inclusions and disordered phononic approaches.
The following meta-structures are currently under examination:
A) Meta Pipes: A class of meta-material-based solutions are currently under investigation, to protect underground pipes from seismic events.
B) Meta-Gravel: Research is focused on metamaterial concepts that can lead to superior behavior in blast/shock impacts.
C) Meta-Bridges”, traffic-ways and transportation: Research emphasis has been on bridge pier foundations, focused on the concepts of rocking and negative-stiffness dampers..
D) Meta-Rail/A novel paradigm for rail tracks: Meta-materials and novel absorbers are currently being considered in order to control dynamic excitations from high loaded trains.
TRAINING
At an individual level, each ESR has established a Personal Career Development Plan in coordination with their supervisor, tailored to their career goals. At the network level, each ESR has completed the following actions:
• All ESRs have completed at least one secondment in another academic INSPIRE team and one in a non-academic partner.
• 2 ESRs have spent 6 months at leading academic institutions in the United States, namely the California Institute of Technology and the University of California, Davis.
• Several Network meetings have been organized for ESRs to present their results, exchange ideas and experiences and discuss secondments between members. Most notable among them has been the organization of a Special Session titled “Innovative ground interventions and metamaterial concepts for structure protection” during the International Conference on Natural Hazards and Infrastructure (ICONHIC 2022).
• Three Training schools and three multi-disciplinary development and innovation workshops have been delivered, with more than 150 participants from 12 countries and featuring a diverse selection of lectures and seminars from worl renowned academics and industry leaders.
Several infrasound wave conditioning concepts have been examined demonstrating the wave screening properties of meta-materials:
A) Pile arrays and foundation blocks: Work is being undertaken in developing systems able to trap low frequency waves and have wide band-gaps (0.5Hz-5.0Hz) required to mitigate the effects of seismic waves Such performance cannot be met by the currently proposed designs of seismic meta-material unit cell concepts.
B) Trapped rainbows: Work has been focused on developing efficient near- and on-surface meta-material concepts against Rayleigh surface waves.
C) Meta-material on a city scale: Work has focused on developing city-scale inelastic time-domain analysis tools and models to evaluate the effectiveness of the proposed meta-soils , as part of the design of a conceptual “Meta-City”.
A common characteristic of the concepts examined - and a major objective of the project indeed - is to prove simple, reliable and resilient meta-soil designs, leading to easy and low-cost implementation and maintenance to make use of meta-soils possible in both developed and developing countries with high seismic risks
Furthermore, a class of novel absorption and isolation concepts have been investigated:
A) Negative Stiffness Dampers (NSD): Work produced already has confirmed that the concept features not only enhanced wave damping, but also extended band-gaps, especially for seismic and low-frequency acoustic applications.
B) Micro-structured materials under frictional forces and self-oscillatory behaviour: Bifurcation phenomena - such as buckling and in flutter instability - guide the development of new technological concepts and tools for novel isolators in classical foundations. Inspired by elastic meta-materials with inertial locally resonant structures, nonlinear structures are designed with non-propagation frequencies in the infrasound range.
C) Meta-Columns: Vertically supported slender bodies. The concepts have already been implemented in designing systems that can protect structures from seismic shaking by promoting rocking behavior.
D) Meta-Panels: Mitigation measures at the receiver (building): Research on this topic has been focused on developing sound absorption panels incorporating negative stiffness inclusions and disordered phononic approaches.
The following meta-structures are currently under examination:
A) Meta Pipes: A class of meta-material-based solutions are currently under investigation, to protect underground pipes from seismic events.
B) Meta-Gravel: Research is focused on metamaterial concepts that can lead to superior behavior in blast/shock impacts.
C) Meta-Bridges”, traffic-ways and transportation: Research emphasis has been on bridge pier foundations, focused on the concepts of rocking and negative-stiffness dampers..
D) Meta-Rail/A novel paradigm for rail tracks: Meta-materials and novel absorbers are currently being considered in order to control dynamic excitations from high loaded trains.
TRAINING
At an individual level, each ESR has established a Personal Career Development Plan in coordination with their supervisor, tailored to their career goals. At the network level, each ESR has completed the following actions:
• All ESRs have completed at least one secondment in another academic INSPIRE team and one in a non-academic partner.
• 2 ESRs have spent 6 months at leading academic institutions in the United States, namely the California Institute of Technology and the University of California, Davis.
• Several Network meetings have been organized for ESRs to present their results, exchange ideas and experiences and discuss secondments between members. Most notable among them has been the organization of a Special Session titled “Innovative ground interventions and metamaterial concepts for structure protection” during the International Conference on Natural Hazards and Infrastructure (ICONHIC 2022).
• Three Training schools and three multi-disciplinary development and innovation workshops have been delivered, with more than 150 participants from 12 countries and featuring a diverse selection of lectures and seminars from worl renowned academics and industry leaders.
INSPIRE will incorporate scientific and technological breakthroughs, mainly developed within the broad concept of meta-materials, to propose and implement holistic and novel soil-foundation-structure concepts for the efficient protection of structures from ground induced hazards. Key results include:
• Interventions to the foundation soil intended to divert seismic waves or substantially attenuate the earthquake motion before exciting the structure.
• Broad-band isolation concepts incorporating negative stiffness inclusions and engineered microstructures of hyper-damping behavior aiming at high impact – infrastructure components.
• Urban scale soil-foundation-structure schemes integrating combinations of meta-concepts to provide seismic protection at a community level.
• Interventions to the foundation soil intended to divert seismic waves or substantially attenuate the earthquake motion before exciting the structure.
• Broad-band isolation concepts incorporating negative stiffness inclusions and engineered microstructures of hyper-damping behavior aiming at high impact – infrastructure components.
• Urban scale soil-foundation-structure schemes integrating combinations of meta-concepts to provide seismic protection at a community level.