Periodic Reporting for period 2 - NEWFRAC (New strategies for multifield fracture problems across scales in heterogeneous systems for Energy, Health and Transport)
Berichtszeitraum: 2022-05-01 bis 2024-10-31
A fast design-virtual testing and manufacturing cycle, automation, and data exchange in manufacturing technology requires highly efficient and reliable failure-predictive computational tools for an accurate prediction of fracture and damage phenomena associated with the initiation and propagation of cracks interacting with interfaces. These are critical for the structural integrity, reliability, and efficiency of different highly technological systems and components that are produced and used in a wide range of sectors, e.g. those related to the NEWFRAC project: i) Structural ceramics, and fiber-reinforced composites in the aeronautical, space and automotive industries; ii) Systems for renewable energy production such as photovoltaic modules, iii) Biomechanical systems for surgery.
The optimal exploitation of the capacities of such systems requires a deep knowledge of different fracture mechanisms affecting their integrity. The total losses due to fracture in the modern society can achieve a few percent of the gross economic product. These losses are at least partially evitable by a proper investment in research and application of new computational strategies for fracture prediction. However, the current modeling tools are insufficient for failure prediction in heterogeneous systems with high level of complexity, where cracks are interacting with bimaterial interfaces (initiating at/approaching/crossing/deflecting at/propagating along interfaces and kinking towards adjacent bulk) and in which multiple physical phenomena are coupled and occur at different length scales simultaneously.
NEWFRAC is the first coordinated initiative in the EU to systematically advance failure prediction in heterogeneous systems through a novel computational framework by integrating two modern modeling strategies: the Coupled Criterion of Finite Fracture Mechanics and the Phase Field Models of Fracture, which have undergone great development in the last two decades.
The overarching objective of the NEWFRAC network is a high-level training of a new generation of creative, entrepreneurial, and innovative early-stage researchers (ESRs) through the development and engineering applications of these modelling strategies focusing on the prediction and analysis of multi-field fracture phenomena in specific heterogeneous engineering systems at different scales.
The main research objective of the NEWFRAC network is the development of a new modeling and simulation framework for the fracture mechanics optimization of high-level technological products involving heterogeneous systems (materials and structures), employed in engineering fields of strategic societal and scientific impact, ranging from renewable energy production systems to biological hard tissues.
The optimal exploitation of the capacities of such systems requires a deep knowledge of different fracture mechanisms affecting their integrity. The total losses due to fracture in the modern society can achieve a few percent of the gross economic product. These losses are at least partially evitable by a proper investment in research and application of new computational strategies for fracture prediction. However, the current modeling tools are insufficient for failure prediction in heterogeneous systems with high level of complexity, where cracks are interacting with bimaterial interfaces (initiating at/approaching/crossing/deflecting at/propagating along interfaces and kinking towards adjacent bulk) and in which multiple physical phenomena are coupled and occur at different length scales simultaneously.
NEWFRAC is the first coordinated initiative in the EU to systematically advance failure prediction in heterogeneous systems through a novel computational framework by integrating two modern modeling strategies: the Coupled Criterion of Finite Fracture Mechanics and the Phase Field Models of Fracture, which have undergone great development in the last two decades.
The overarching objective of the NEWFRAC network is a high-level training of a new generation of creative, entrepreneurial, and innovative early-stage researchers (ESRs) through the development and engineering applications of these modelling strategies focusing on the prediction and analysis of multi-field fracture phenomena in specific heterogeneous engineering systems at different scales.
The main research objective of the NEWFRAC network is the development of a new modeling and simulation framework for the fracture mechanics optimization of high-level technological products involving heterogeneous systems (materials and structures), employed in engineering fields of strategic societal and scientific impact, ranging from renewable energy production systems to biological hard tissues.
The goals of the network, the development of innovative modeling strategies for fracture prediction and the training of the 13 Early Stage Researchers (ESRs), who become expert researchers ready to be incorporated as group-leaders in industrial and academic institutions, has been achieved by a unique combination of “hands-on” research training, webinars, non-academic placements and secondments, schools, scientific workshops and conferences, and courses on scientific and complementary transferable skills facilitated by the academic/non-academic composition of the network. During the project development, the main network wide training events for our ESRs but also for external young researchers have been, in addition to local training courses offered by academic beneficiaries.
The main scientific results of the NEWFRAC project are the following:
Application of the coupled criterion of Finite Fracture Mechanics at the micro-scale to bending tests of micro cantilever beams
A humidity dose-cohesive zone model formulation to simulate new end-of-life recycling methods for photovoltaic laminates
New computational methods to assist in the design of end-of-life recycling of photovoltaic laminates
Analytical modeling of debonding mechanism for long and short bond lengths in direct shear tests accounting for residual strength
Development of a new dynamic formulation of the coupled criterion of Finite Fracture Mechanics
Development of a new phase field model for cracks under compression
Development of a new phase field model for cracks in heterogeneous materials
Study of a size-effect on the apparent tensile strength of brittle materials with spherical cavities
Prediction of the interaction between cracks and curved interfaces by applying the coupled criterion of Finite Fracture Mechanics
A new anisotropic phase field implementation for composite laminates based on an equivalent single layer representation
New insights into the effects of the level of anisotropy on the notched response of thin-ply laminates
New insights into the use of phase field in computational micromechanics of fiber-reinforced polymers
Development of the phase field approach for 3d-printed composite parts, allowing the prediction of crack path and strength of these novel materials
Experimental evaluation of the fracture toughness in 3D composite materials and it dependence on the design parameters
Experimental and analytical determination of the critical energy release rate for the cortical part of the human bone as a function of the density recorded by CT scans
Improvements in the detection of human femurs prone to fracture by using CT scans and PFMs
Application of the coupled criterion of Finite Fracture Mechanics at the micro-scale to bending tests of micro cantilever beams
Development of a numerical tool to estimate fracture toughness of brittle matrices with short reinforcements, combining the matched asymptotic approach together with the coupled criterion
Study of the answer brought by both the coupled criterion and the phase field model when descending the scales from the macroscales to the microscale and even nanoscale
Proposal and analysis of a novel phase-field model for modelling crack nucleation under multi-axial stress
Theoretical and numerical understanding of the crack nucleation condition as an instability in softening damage models
Critical analysis of the existing phase-field models for crack nucleation and propagation under multi-axial stresses, and proposal of a new model
The main scientific results of the NEWFRAC project are the following:
Application of the coupled criterion of Finite Fracture Mechanics at the micro-scale to bending tests of micro cantilever beams
A humidity dose-cohesive zone model formulation to simulate new end-of-life recycling methods for photovoltaic laminates
New computational methods to assist in the design of end-of-life recycling of photovoltaic laminates
Analytical modeling of debonding mechanism for long and short bond lengths in direct shear tests accounting for residual strength
Development of a new dynamic formulation of the coupled criterion of Finite Fracture Mechanics
Development of a new phase field model for cracks under compression
Development of a new phase field model for cracks in heterogeneous materials
Study of a size-effect on the apparent tensile strength of brittle materials with spherical cavities
Prediction of the interaction between cracks and curved interfaces by applying the coupled criterion of Finite Fracture Mechanics
A new anisotropic phase field implementation for composite laminates based on an equivalent single layer representation
New insights into the effects of the level of anisotropy on the notched response of thin-ply laminates
New insights into the use of phase field in computational micromechanics of fiber-reinforced polymers
Development of the phase field approach for 3d-printed composite parts, allowing the prediction of crack path and strength of these novel materials
Experimental evaluation of the fracture toughness in 3D composite materials and it dependence on the design parameters
Experimental and analytical determination of the critical energy release rate for the cortical part of the human bone as a function of the density recorded by CT scans
Improvements in the detection of human femurs prone to fracture by using CT scans and PFMs
Application of the coupled criterion of Finite Fracture Mechanics at the micro-scale to bending tests of micro cantilever beams
Development of a numerical tool to estimate fracture toughness of brittle matrices with short reinforcements, combining the matched asymptotic approach together with the coupled criterion
Study of the answer brought by both the coupled criterion and the phase field model when descending the scales from the macroscales to the microscale and even nanoscale
Proposal and analysis of a novel phase-field model for modelling crack nucleation under multi-axial stress
Theoretical and numerical understanding of the crack nucleation condition as an instability in softening damage models
Critical analysis of the existing phase-field models for crack nucleation and propagation under multi-axial stresses, and proposal of a new model
The high-level training offered by NewFrac to 13 Early Stage Researchers (ESRs), all of them PhD students, is focused on new strategies for prediction and analysis of multi field fracture phenomena in heterogeneous engineering systems at different scales. These ESRs are developing new failure predictive computational tools and apply them to relevant problems in strategic industrial sectors like Energy, Health and Transport. Their doctoral theses address most relevant questions of current interest in failure prediction in heterogeneous systems, that are generating high impact research outputs which go beyond the current state of the art in fracture modelling. To this aim, NewFrac integrates two new strategies for computational fracture modelling: Finite Fracture Mechanics and a variational approach to fracture referred to as Phase Field, and solves wide ranging interconnected fundamental issues of fracture modelling. It is expected that these ESRs will become experts in fracture prediction in heterogeneous systems and will contribute to reduce the innovation gap by enhancing two ways academia industry transfer of knowledge.