Periodic Reporting for period 1 - CoMetaS (COncurrent METAmaterial-Structure design using functionally graded metamaterials)
Reporting period: 2021-08-01 to 2023-07-31
Taking advantage of the unique technological opportunity that the design freedom revolution of 3D-printing at microscales is bringing to industry and engineering, a main purpose of COMETAS is to help the European industry and future academic system by generating the needed interdisciplinary and intersectoral network of researchers and engineers capable of developing high-tech, value-added products to increase its technological leadership, critical for high living standards in a global market.
COMETAS project´s research is centered in solving a new scientific and technological challenge, consisting in developing an integrated, reliable and efficient multiscale methodology for Concurrent Metamaterial-Structure Design employing functionally graded mechanical metamaterials, being the subject of research of high interest of scientific community as well as of practical interest for industry. The international exchange of researchers will facilitate the groups involved in COMETAS to advance towards fulfilling the overall scientific goal, and the particular objectives of each one centered in the different technologies needed for that goal: manufacturing, material modeling, machine learning, topology optimization, software development and industry prototyping.
COMETAS project is forging international scientific cooperation at transnational and transcontinental level focusing on the scientific and industrial challenges posed by 3D printed mechanical metamaterial technologies.
COMETAS project´s research is centered in solving a new scientific and technological challenge, consisting in developing an integrated, reliable and efficient multiscale methodology for Concurrent Metamaterial-Structure Design employing functionally graded mechanical metamaterials, being the subject of research of high interest of scientific community as well as of practical interest for industry. The international exchange of researchers will facilitate the groups involved in COMETAS to advance towards fulfilling the overall scientific goal, and the particular objectives of each one centered in the different technologies needed for that goal: manufacturing, material modeling, machine learning, topology optimization, software development and industry prototyping.
COMETAS project is forging international scientific cooperation at transnational and transcontinental level focusing on the scientific and industrial challenges posed by 3D printed mechanical metamaterial technologies.
In the first year of the project, progress in several needed technologies is being obtained.
The first one is the preparation and characterization of the 3D printing process using Selective Laser Melting machines to print titanium-based metamaterials, including testing the 3D printed material under different conditions, the microstructural and defects characterization. UPM, Georgia-Tech and Alloyed are working on these topics.
The second one is the development of constitutive models for the 3D printed base material. In particular, the implementation of constitutive models considering porosity have been carried out. To this aim, a cellular automaton model has been developed to predict the resulting microstructure after additive manufacturing. The main challenge encountered has been that there are no accurate models that can predict reliably porosity. These models must be developed concurrently with the constitutive models. For this purpose, numerous simulations with different input parameters will be carried out to compare the different approaches for porosity. Machine learning approaches will be utilized to determine the model(s) that deliver the best results. These activities have been carried out in close collaboration with the host organization of the secondments of staff, but for the moment, these collaboration activities have been taking place mainly remotely owing to the pandemic.
The third one is the development of technologies to cross scales in constitutive modeling, in particular in nonlinear cases. We have developed a methodology to obtain constitutive behavior at the microscale from non-homogeneous tests at the continuum scale. For the moment, we have applied it successfully to obtain the macromolecule behavior in polymers, see figure. The next challenge is to extend it to general elastoplastic materials.
We have also advanced in data-driven characterization of a mechanical system from partial observations. We have proven that although data-driven approaches do not allow to build a complete model of the systems (all the inputs mapped to all the outputs, including those not being observed or measured), it is at least possible to build this model between observed input variables and output variables.
Another progress in the project is the development of topology optimization approaches not based on density. We have developed a novel approach based on energy derivatives suitable for anisotropic targets and materials (e.g. metamaterials).
As per industrial applications a first benchmark of space application is being developed for micro-vibrations absorption/damping, with auxetic (negative Poissons’ ratio) meta-structures.
The first one is the preparation and characterization of the 3D printing process using Selective Laser Melting machines to print titanium-based metamaterials, including testing the 3D printed material under different conditions, the microstructural and defects characterization. UPM, Georgia-Tech and Alloyed are working on these topics.
The second one is the development of constitutive models for the 3D printed base material. In particular, the implementation of constitutive models considering porosity have been carried out. To this aim, a cellular automaton model has been developed to predict the resulting microstructure after additive manufacturing. The main challenge encountered has been that there are no accurate models that can predict reliably porosity. These models must be developed concurrently with the constitutive models. For this purpose, numerous simulations with different input parameters will be carried out to compare the different approaches for porosity. Machine learning approaches will be utilized to determine the model(s) that deliver the best results. These activities have been carried out in close collaboration with the host organization of the secondments of staff, but for the moment, these collaboration activities have been taking place mainly remotely owing to the pandemic.
The third one is the development of technologies to cross scales in constitutive modeling, in particular in nonlinear cases. We have developed a methodology to obtain constitutive behavior at the microscale from non-homogeneous tests at the continuum scale. For the moment, we have applied it successfully to obtain the macromolecule behavior in polymers, see figure. The next challenge is to extend it to general elastoplastic materials.
We have also advanced in data-driven characterization of a mechanical system from partial observations. We have proven that although data-driven approaches do not allow to build a complete model of the systems (all the inputs mapped to all the outputs, including those not being observed or measured), it is at least possible to build this model between observed input variables and output variables.
Another progress in the project is the development of topology optimization approaches not based on density. We have developed a novel approach based on energy derivatives suitable for anisotropic targets and materials (e.g. metamaterials).
As per industrial applications a first benchmark of space application is being developed for micro-vibrations absorption/damping, with auxetic (negative Poissons’ ratio) meta-structures.
To achieve our goals, we have identified this challenges, for which we expect to contribute beyond the state-of-the-art:
a) The behavior and structure of 3DP materials differ substantially from those of cast or classically manufactured materials including porosity, anisotropy, geometric and material defects of diverse types. We aim to generate models and efficient algorithms that accurately predict the experimental behavior of the base printed material at large strains, including the continuum and microstructural scale (crystal plasticity level).
b) Concurrent material-structure design using mechanical metamaterials is at its incipient stages. The problem cannot be solved using a monolithic approach. We aim to develop a methodology that performs that double optimization problem (component and metamaterial at each component location) in a partitioned way, using topology-parametrized surrogate models that facilitate the inverse analysis for design from the continuum level.
c) The treatment of metamaterial connectivity (e.g. different metamaterial families or progressive changes in the family) is at an incipient stage, with very few works starting to address this very important issue in functionally graded metamaterials. We expect to address this problem through different techniques like machine learning and phase-field modeling.
d) Finally, two important challenges are the development of practical software and the application to prototypes of value for industry which demonstrates the practical interest of the technology.
COMETAS will bring tools and knowledge for the development of future technologies in key economic sectors of great economic interest as aerospace, automotive, defence and biomedical industries. These technologies constitute a change of paradigm in the way we perform the design-to-manufacturing circle, including the materials selection.
COMETAS facilitates an excellent interdisciplinary, international, intercontinental and intersectoral collaboration, allowing for the development of new technologies, interchanging of ideas and visions, and improving the training of staff, yielding more innovative, communicative and transversal researchers to shape the future of R&D in Europe.
a) The behavior and structure of 3DP materials differ substantially from those of cast or classically manufactured materials including porosity, anisotropy, geometric and material defects of diverse types. We aim to generate models and efficient algorithms that accurately predict the experimental behavior of the base printed material at large strains, including the continuum and microstructural scale (crystal plasticity level).
b) Concurrent material-structure design using mechanical metamaterials is at its incipient stages. The problem cannot be solved using a monolithic approach. We aim to develop a methodology that performs that double optimization problem (component and metamaterial at each component location) in a partitioned way, using topology-parametrized surrogate models that facilitate the inverse analysis for design from the continuum level.
c) The treatment of metamaterial connectivity (e.g. different metamaterial families or progressive changes in the family) is at an incipient stage, with very few works starting to address this very important issue in functionally graded metamaterials. We expect to address this problem through different techniques like machine learning and phase-field modeling.
d) Finally, two important challenges are the development of practical software and the application to prototypes of value for industry which demonstrates the practical interest of the technology.
COMETAS will bring tools and knowledge for the development of future technologies in key economic sectors of great economic interest as aerospace, automotive, defence and biomedical industries. These technologies constitute a change of paradigm in the way we perform the design-to-manufacturing circle, including the materials selection.
COMETAS facilitates an excellent interdisciplinary, international, intercontinental and intersectoral collaboration, allowing for the development of new technologies, interchanging of ideas and visions, and improving the training of staff, yielding more innovative, communicative and transversal researchers to shape the future of R&D in Europe.