Periodic Reporting for period 2 - MetaVEH (Metamaterial Enabled Vibration Energy Harvesting)
Período documentado: 2022-01-01 hasta 2023-06-30
The primary aim of this project is to develop and realise innovative Lead-free electromechanical energy harvesting systems; these will be easily transported, and installed, to power, in a clean and low-cost manner, autonomous wireless sensing devices thereby eliminating batteries and human intervention: Achieving this aim would revolutionise sensor applications in emerging technologies such as wearable technology and IoT devices, whilst simultaneously reducing chemical waste.
The mechanical core of the harvester will be based on advanced multiresonator designs integrating Lead-free piezoelectric patches enhanced by the unique wave control capacities of resonant elastic metamaterials. This will dramatically increase the energy available for harvesting, and the operational bandwidth, as compared with the current state of the art. For electronic applications the integration of rectifiers in the circuitry will allow for the full exploitation of the multiresonant design.
We will reduce chemical toxicity as energy harvesting devices at the MEMS scale usually exploit PZT as the piezoelectric element, with the serious drawback of introducing Lead and its associated environmental issues. PZT is widely used because of its outstanding performance for both actuation and sensing purposes, as well as for its full compatibility with MEMS fabrication. Nonetheless, our project aims for the implementation of Lead-free energy harvesting systems, leveraging recent research on piezoelectric materials such as aluminum nitride and potassium sodium niobate.
The mechanical core of the harvester will be based on advanced multiresonator designs integrating Lead-free piezoelectric patches enhanced by the unique wave control capacities of resonant elastic metamaterials. This will dramatically increase the energy available for harvesting, and the operational bandwidth, as compared with the current state of the art. For electronic applications the integration of rectifiers in the circuitry will allow for the full exploitation of the multiresonant design.
We will reduce chemical toxicity as energy harvesting devices at the MEMS scale usually exploit PZT as the piezoelectric element, with the serious drawback of introducing Lead and its associated environmental issues. PZT is widely used because of its outstanding performance for both actuation and sensing purposes, as well as for its full compatibility with MEMS fabrication. Nonetheless, our project aims for the implementation of Lead-free energy harvesting systems, leveraging recent research on piezoelectric materials such as aluminum nitride and potassium sodium niobate.
DDuring these 30 months of the project, work has proceeded as planned despite the Covid-19 pandemic, which has unfortunately reduced interaction and exchange possibilities between partners, and, during lockdown periods, even among colleagues of the same group.
The work has continued in WP1 to 6. WP3, 4, 5 and 6 have produced a large amount of results that are currently been used to develop a novel metamaterial design for vibration energy harvesting at the macroscale (1 Hz to 1 kHz). A similar design has been studied at the microscale for MEMS harvesters. The usable frequency range and the solution for up-conversion are under study and a few have been published.
WP2 (Management and dissemination): the administrative platform of the project has been regularly used, communication and data sharing are working smoothly also with the help of the website and communication application like Slack and Zoom and shared editing platform such as Overleaf and MS word. Management of exceptional situations such as third-party amendment and coordination transfer between ETH and ZHAW have required an higher than planned effort.
WP3 (Mathematical and numerical tools) has continued with the development of several innovative approaches for the modelling of distinct types of waveguide modes, including topologically protected modes, have focused on several promising structures, including frame structures, and geometrically non-linear geometries, looking at optimization of dynamic properties, tunability, and adaptation to different goals. We also worked on optimising numerical tools and bespoke software library.
In WP4 (Macrofabrication) we have extensively adopted 3D printing techniques for obtaining prototypes of the metastructures. We have used a special process, i.e. binder jetting, to obtain the prototype of a planar metasurface with graded array of resonators. The binder jetting 3D priting has been chosen since it is specially suited for the realization of ceramic and piezoelectric materials. Indeed, we started working on novel lead-free piezoelectric materials that could replace PZT and studied fully self-powered and low consumption circuits that can condition (rectify) multiple, out of phase resonators without external switches.
In WP5 (MEMS meta-harvester fabrication), After the succesful patenting of the micro metaharvester, the fabrication and laboratory experiments continued to new prototype. We have realized two kinds of MEMS device, one with the silicon layer only (to investigate the mechanical features of the metasurface), the other with the combination of AIN piezoelectric material deposited on the microharvesters. The MEMS devices with AlN are currently under experimental investigation. At the end of the experimental campaign, we’ll achieve the Objective 3 of our project.
In WP6 (Laboratory testing and benchmark), a novel laboratory setup capable to dynamically test a 1D waveguide as if it was infinite has been developed using immersive boundary conditions. An experimental protocol has been designed to test harvesters in a variety of real conditions (acceleration and input forces) and provide benchmark against current harvesting technology. Testing platform for non-linear magnetic, bistable, and contact harvester has been assembled and used.
In terms of project outputs, there have been already some 20 publications in international journals and some dissemination and outreach activities. Several articles are currently submitted or in preparation. Two workshops are planned and are in preparation for the next 12 months. One will be co-hosted by the prestigious Euromech Colloquia series.
Preliminary results in the project have led to the successful submission of patent application. Further exploitable results are foreseen in this second half of the project.
The work has continued in WP1 to 6. WP3, 4, 5 and 6 have produced a large amount of results that are currently been used to develop a novel metamaterial design for vibration energy harvesting at the macroscale (1 Hz to 1 kHz). A similar design has been studied at the microscale for MEMS harvesters. The usable frequency range and the solution for up-conversion are under study and a few have been published.
WP2 (Management and dissemination): the administrative platform of the project has been regularly used, communication and data sharing are working smoothly also with the help of the website and communication application like Slack and Zoom and shared editing platform such as Overleaf and MS word. Management of exceptional situations such as third-party amendment and coordination transfer between ETH and ZHAW have required an higher than planned effort.
WP3 (Mathematical and numerical tools) has continued with the development of several innovative approaches for the modelling of distinct types of waveguide modes, including topologically protected modes, have focused on several promising structures, including frame structures, and geometrically non-linear geometries, looking at optimization of dynamic properties, tunability, and adaptation to different goals. We also worked on optimising numerical tools and bespoke software library.
In WP4 (Macrofabrication) we have extensively adopted 3D printing techniques for obtaining prototypes of the metastructures. We have used a special process, i.e. binder jetting, to obtain the prototype of a planar metasurface with graded array of resonators. The binder jetting 3D priting has been chosen since it is specially suited for the realization of ceramic and piezoelectric materials. Indeed, we started working on novel lead-free piezoelectric materials that could replace PZT and studied fully self-powered and low consumption circuits that can condition (rectify) multiple, out of phase resonators without external switches.
In WP5 (MEMS meta-harvester fabrication), After the succesful patenting of the micro metaharvester, the fabrication and laboratory experiments continued to new prototype. We have realized two kinds of MEMS device, one with the silicon layer only (to investigate the mechanical features of the metasurface), the other with the combination of AIN piezoelectric material deposited on the microharvesters. The MEMS devices with AlN are currently under experimental investigation. At the end of the experimental campaign, we’ll achieve the Objective 3 of our project.
In WP6 (Laboratory testing and benchmark), a novel laboratory setup capable to dynamically test a 1D waveguide as if it was infinite has been developed using immersive boundary conditions. An experimental protocol has been designed to test harvesters in a variety of real conditions (acceleration and input forces) and provide benchmark against current harvesting technology. Testing platform for non-linear magnetic, bistable, and contact harvester has been assembled and used.
In terms of project outputs, there have been already some 20 publications in international journals and some dissemination and outreach activities. Several articles are currently submitted or in preparation. Two workshops are planned and are in preparation for the next 12 months. One will be co-hosted by the prestigious Euromech Colloquia series.
Preliminary results in the project have led to the successful submission of patent application. Further exploitable results are foreseen in this second half of the project.
This research project is motivated by the exponential growth of the wireless sensors market, hence the active involvement of Assimilate, an emerging technologies SME, ST Microelectronics, world leader in MEMS fabrication, in this project, and the need to probe key physical parameters (motion and acceleration, temperature, chemical markers amongst others) for sensors that must be powered without human intervention; furthermore in sensors there is a drive for green sustainable chemistry and thereby to avoid solar panels containing rare metals and toxic materials (e.g. Lead, Cadmium), and ultimately, to remove the need for batteries. The achievement of such a result is enabled by the continuous reduction of the energy demand of sensors. Today, it is possible to purchase MEMS for sensing inertial quantities (acceleration and/or angular velocity) that need less than 10 μW to stay in the idle condition; measurements can be done in ultra-low power mode, asking for an average of 20-40 μW and peaks around 200 μW. Moreover, the technology roadmaps of microelectronics foresee that power consumption will decrease to tens of nanowatts and below in the next future. The applications include, for instance, structural health monitoring (SHM) devices used in civil engineering, sensors used in the aerospace and automotive industries, geophysical networks located around faults, volcanoes and coastal areas and for space exploration. Many of these sensors are integrated in early warning systems, and their deployment and operational stability are critical for the safety and the resilience of modern society, transport systems and scientific missions.