Periodic Reporting for period 2 - QUANTIFY (Unraveling the role of anisotropy in material failure)
Okres sprawozdawczy: 2020-01-01 do 2023-06-30
QUANTIFY is an international network of 8 organisations, working on a joint research programme in the field of Solid Mechanics. The 8 organisations (4 EU beneficiaries and 4 US partner organisations) have exchanged and share skills and knowledge with the view to understand and model the effect of anisotropy in the dynamic mechanical failure of lightweight metallic materials used in the transportation and civilian-security industries. Breakthroughs in this field will allow lightweight metals fabricated with microstructure optimization techniques and additive manufacturing to replace steel and heavy alloys in manufacturing high structural responsibility components for automobiles, ships, aircrafts and civil infrastructures, all sectors of crucial importance for the European economy and society. During the last decade, large efforts have been directed in the transportation and civilian-security industries toward the development of aluminium, magnesium and titanium alloys for high-performance applications in which structural elements are usually subjected to large deformations and high strain rates. Enhanced by the increasing restrictions in fuel consumption and the encouragement for emissions reduction, there is an emerging trend to replace the conventional Fe-based materials by these non-ferrous alloys in the construction of passive safety structures for automobiles, ships and aircrafts. Lightweight alloys are now being used in the design of protective structures because of their improved strength-to-weight ratio, which make them attractive for the construction of portable shields and fortifications. Protection structures that can be transported, deployed/mountable and retracted/detachable in short periods of time are required for an effective protection of critical infrastructures (like bridges, government buildings and ports) against events such as explosions, attacks and natural disasters. Unfortunately, the strong anisotropy of aluminium, magnesium and titanium alloys is usually considered as a weakness for their application in the aforementioned industrial sectors. The anisotropy of these alloys, which usually comes from their microstructure and/or manufacturing process, is known to have great influence on their failure strength and strain, and therefore on their energy absorption capacity under extreme loading. The specific mechanisms which determine such influence are largely unknown and poorly understood, which impedes to model and predict accurately the limits of the energy absorption capacity of this type of materials. QUANTIFY was the first attempt ever to develop an international, integral, multiscale and multidisciplinary approach to bring to light, understand and model the effect of anisotropy in the dynamic mechanical failure of lightweight metallic materials used in the transportation and civilian-security industries.
The European researchers have spent 30 months in the US institutions, and the US researchers have been seconded for almost 8 months in the EU beneficiaries. All these mutual visits to enabled to carry out significant scientific progresses, which are divided into the two scientific work packages of the project.
Work Package 1: The effect of microstructure optimization induced anisotropy on the dynamic mechanical failure of lightweight alloys. The goal is to uncover, understand and model the role of material anisotropy on the dynamic mechanical failure of lightweight metallic structures fabricated with microstructure optimization techniques. The goal of this WP was to uncover, understand and model the role of material anisotropy on the dynamic mechanical failure of lightweight metallic structures fabricated with microstructure optimization techniques. We have used an innovative multiscale and multiphysical approach, which specifically considers micromechanical constitutive models, to address necking and shear band failure of oligocrystalline and polycrystalline lightweight metals subjected to dynamic loading. For that purpose, we have developed analytical and numerical models to describe the role of anisotropy in the problems at hand. As a methodological standpoint, we have performed experiments to validate and assess the predictive capacity of such models.
Work Package 2: The effect of additive manufacturing induced anisotropy on the dynamic mechanical failure of lightweight alloys. The goal of this WP was to uncover, understand and model the role of porous microstructure on the dynamic failure of anisotropic lightweight alloys fabricated with 3D printing. We have used homogenization techniques to account for the characteristic porosity of 3D printed materials, and we have described using both macromechanical and microstructurally-informed constitutive models, the dynamic failure of lightweight porous metals under shear dominated and pressure dominated loading conditions. Pores resulting from the 3D-printing process act as defects and preferential sites for crack nucleation and propagation, so that it is essential to understand the effect of voids size, voids shape and void volume fraction on dynamic localization and fracture of parts and components used in the transportation and security industrial sectors. For that purpose, we have developed analytical and numerical models to describe the role of anisotropy in the problems at hand. As a methodological standpoint, we have performed experiments to validate and assess the predictive capacity of such models.
In addition to the secondments, we have developed a series of networking activities which include the organization of three international conferences sponsored by international scientific societies EUROMECH, IUTAM and SEMTA-MECAMAT, several thematic sessions in international congresses and one technical training course at the International Center of Mechanical Sciences. We have also participated in an Industrial Workshop to identify practical problems faced by aerospace and civilian-security industries which can be tackled with the scientific developments of QUANTIFY.
Work Package 1: The effect of microstructure optimization induced anisotropy on the dynamic mechanical failure of lightweight alloys. The goal is to uncover, understand and model the role of material anisotropy on the dynamic mechanical failure of lightweight metallic structures fabricated with microstructure optimization techniques. The goal of this WP was to uncover, understand and model the role of material anisotropy on the dynamic mechanical failure of lightweight metallic structures fabricated with microstructure optimization techniques. We have used an innovative multiscale and multiphysical approach, which specifically considers micromechanical constitutive models, to address necking and shear band failure of oligocrystalline and polycrystalline lightweight metals subjected to dynamic loading. For that purpose, we have developed analytical and numerical models to describe the role of anisotropy in the problems at hand. As a methodological standpoint, we have performed experiments to validate and assess the predictive capacity of such models.
Work Package 2: The effect of additive manufacturing induced anisotropy on the dynamic mechanical failure of lightweight alloys. The goal of this WP was to uncover, understand and model the role of porous microstructure on the dynamic failure of anisotropic lightweight alloys fabricated with 3D printing. We have used homogenization techniques to account for the characteristic porosity of 3D printed materials, and we have described using both macromechanical and microstructurally-informed constitutive models, the dynamic failure of lightweight porous metals under shear dominated and pressure dominated loading conditions. Pores resulting from the 3D-printing process act as defects and preferential sites for crack nucleation and propagation, so that it is essential to understand the effect of voids size, voids shape and void volume fraction on dynamic localization and fracture of parts and components used in the transportation and security industrial sectors. For that purpose, we have developed analytical and numerical models to describe the role of anisotropy in the problems at hand. As a methodological standpoint, we have performed experiments to validate and assess the predictive capacity of such models.
In addition to the secondments, we have developed a series of networking activities which include the organization of three international conferences sponsored by international scientific societies EUROMECH, IUTAM and SEMTA-MECAMAT, several thematic sessions in international congresses and one technical training course at the International Center of Mechanical Sciences. We have also participated in an Industrial Workshop to identify practical problems faced by aerospace and civilian-security industries which can be tackled with the scientific developments of QUANTIFY.
The main scientific contribution of QUANTIFY has been to develop an integral approach, including experiments, finite element simulations and analytical models, to unravel the role of anisotropy on the fracture behavior of anisotropy materials. The key point is that the problem has been addressed jointly by different groups, with different backgrounds and fields of expertise, which created a unique synergetic network of researchers sharing knowledge and know-how. We have developed the first multiscale experimental-numerical-analytical verification of the role of microstructure of shear-dominated, tensile-dominated and pressure-dominated fracture of anisotropic materials. This outcome has scientific relevance and has lead to the publication of 13 papers in renowned international journals (JMPS, IJP, MOM, EFM, CPBE, etc)), and presentation in different international conferences, seminars in Universities and Research Centers, etc. On the other hand, we have found applications in real scenarios, and started a series of collaborations with the non-academic sector to develop technology transfer activities that will lead to improvements in the design of structures made of lightweight alloys which are used in the aerospace, automotive and civilian-security industries.