Periodic Reporting for period 1 - FRAMED (Fracture Across Scales and Materials, Processes and Disciplines)
Periodo di rendicontazione: 2017-09-01 al 2019-08-31
Asst. Prof. Avraam Kosntantindis worked at Composite Braiding Ltd in Derby, England (CBL) in the period from 26 July to 26 August. We discussed issues that we as a micro SME required assistance with and devised a work plan.
In particular the work focussed on WP3 – Multiscale Modelling Framework (Research), and specifically on deformation and fracture of thermoplastic braided composites. A draft regarding Gradient Stochastic Models for Multiscale Composite & Braided Materials was produced as part of the exercise and discussed in detail. A number of applications were then discussed and the need for further work discussed and agreed.
By completing this work CBL will be better able to predict and understand mechanical performance issues with the braided composite components it produces, which in turn will be of great benefit to the end customers and users. The current state of the art does not adequately predict performance. The models are too generic.
Prof Harm Askes and Dr Inna Gitman worked with colleagues from Perm National Research Polytechnic University during several visits in 2018 and 2019. We worked on the new multi-scale methodology, based on Fuzzy sets theory.
We would like to offer a new approach that could offer us an inexpensive and efficient method to obtain material's characteristics without lengthy numerical computations and with some limited experimental data.
In particular the work focussed on WP3 – Multiscale Modelling Framework (Research), and specifically on deformation and fracture of thermoplastic braided composites. A draft regarding Gradient Stochastic Models for Multiscale Composite & Braided Materials was produced as part of the exercise and discussed in detail. A number of applications were then discussed and the need for further work discussed and agreed.
By completing this work CBL will be better able to predict and understand mechanical performance issues with the braided composite components it produces, which in turn will be of great benefit to the end customers and users. The current state of the art does not adequately predict performance. The models are too generic.
Prof Harm Askes and Dr Inna Gitman worked with colleagues from Perm National Research Polytechnic University during several visits in 2018 and 2019. We worked on the new multi-scale methodology, based on Fuzzy sets theory.
We would like to offer a new approach that could offer us an inexpensive and efficient method to obtain material's characteristics without lengthy numerical computations and with some limited experimental data.
"The work focussed on WP3 – Multiscale Modelling Framework (Research), and specifically on deformation and fracture of thermoplastic braided composites.
A number of potential areas for investigation were discussed (both technical and market-based) and then scored dependant upon the resources and time available as well as the net benefit to CBL.
A paper regarding Gradient Stochastic Models for Multiscale Composite & Braided Materials was produced as part of the exercise and discussed in detail. The benefits of this type of approach on a nano, micro and macro scale were discussed and an approach agreed.
A number of potential applications were then identified and the need for further work agreed. CBL will be providing some materials and data to help with the understanding of the issues raised and to help identify potential best routes to solving the issues.
Our work focused on WP2 (Stochasticity and Disorder) and WP3 (Multiscale Modelling Framework). We tested our methodology on data, provided by our colleagues from the Nosov Magnitogorsk State Technical University.
We have published 2 papers and 1 more is on its way.
We have also organised a workshop ""Gradient Elasticity: Concept, Micro-Mechanics and Finite Element Implementations"" in Perm National Research Polytechnic University.
Together with colleagues from Perm National Research Polytechnic University we co-organised a conference ""Functional Materials: Predicting Properties and Manufacturing Technologies (ICFM-2019)"" http://fm.pstu.ru/icfm2019/
At FAU, brittle fracture and failure in beam and fuse networks was modelled with hierarchical structures. The choice is motivated by the observation of hierarchical microstructures in biological materials, characterized by fibrous crosslinked bundles with connectivity patterns repeated across several length scales, believed to enhance the flaw tolerance of such systems. To make the modelling problem approachable, model materials were envisaged with a clear distinction between load parallel fibers and load perpendicular cross links. The size scaling analysis suggests that a common and desirable feature of hierarchical materials is the presence of fiber gaps, broadly distributed in size along in the load parallel direction. While such structural scars exhibit an exponential size distribution in non-hierarchical systems, they display broad power-law size distributions in the hierarchical case.
The numerical study reveals that this structural feature is responsible for the emergence of a novel fracture mode, dominated by crack nucleation and crack arrest. While fracture in non-hierarchical crosslinked systems follows the well-known nucleation-plus-propagation behavior encountered in strongly disordered materials, in hierarchical systems crack growth is hindered by the presence of gaps, which results in systematic fracture containment. While the system softens as damage progresses, failure is reached only as the accumulated damages coalesces into a macro-crack traversing the system."
A number of potential areas for investigation were discussed (both technical and market-based) and then scored dependant upon the resources and time available as well as the net benefit to CBL.
A paper regarding Gradient Stochastic Models for Multiscale Composite & Braided Materials was produced as part of the exercise and discussed in detail. The benefits of this type of approach on a nano, micro and macro scale were discussed and an approach agreed.
A number of potential applications were then identified and the need for further work agreed. CBL will be providing some materials and data to help with the understanding of the issues raised and to help identify potential best routes to solving the issues.
Our work focused on WP2 (Stochasticity and Disorder) and WP3 (Multiscale Modelling Framework). We tested our methodology on data, provided by our colleagues from the Nosov Magnitogorsk State Technical University.
We have published 2 papers and 1 more is on its way.
We have also organised a workshop ""Gradient Elasticity: Concept, Micro-Mechanics and Finite Element Implementations"" in Perm National Research Polytechnic University.
Together with colleagues from Perm National Research Polytechnic University we co-organised a conference ""Functional Materials: Predicting Properties and Manufacturing Technologies (ICFM-2019)"" http://fm.pstu.ru/icfm2019/
At FAU, brittle fracture and failure in beam and fuse networks was modelled with hierarchical structures. The choice is motivated by the observation of hierarchical microstructures in biological materials, characterized by fibrous crosslinked bundles with connectivity patterns repeated across several length scales, believed to enhance the flaw tolerance of such systems. To make the modelling problem approachable, model materials were envisaged with a clear distinction between load parallel fibers and load perpendicular cross links. The size scaling analysis suggests that a common and desirable feature of hierarchical materials is the presence of fiber gaps, broadly distributed in size along in the load parallel direction. While such structural scars exhibit an exponential size distribution in non-hierarchical systems, they display broad power-law size distributions in the hierarchical case.
The numerical study reveals that this structural feature is responsible for the emergence of a novel fracture mode, dominated by crack nucleation and crack arrest. While fracture in non-hierarchical crosslinked systems follows the well-known nucleation-plus-propagation behavior encountered in strongly disordered materials, in hierarchical systems crack growth is hindered by the presence of gaps, which results in systematic fracture containment. While the system softens as damage progresses, failure is reached only as the accumulated damages coalesces into a macro-crack traversing the system."
Current design tools and models are too generic and do not predict the behaviour of braided structures sufficiently well. The current state of the art does not adequately predict performance and so we have over-engineered products that have too much material, waste and weight incorporated, with the inherent costs (financial and social) that are associated with that inefficiency.
By completing this work CBL will be better able to predict and understand mechanical performance issues with the braided composite components it produces, which in turn will be of great benefit to end customers and users. Products will be better designed allowing for more optimised structures that will reduce weight, emissions and waste.
Existing methodologies, could potentially be quite expensive (considering computational time and possible costs of experiments) our Fuzzy Sets based multi-scale methodology shows promising and fast results for the class of metal materials.
We would like to test it further on other applications. We are also targeting now questions of stochastic stability of our results.
By completing this work CBL will be better able to predict and understand mechanical performance issues with the braided composite components it produces, which in turn will be of great benefit to end customers and users. Products will be better designed allowing for more optimised structures that will reduce weight, emissions and waste.
Existing methodologies, could potentially be quite expensive (considering computational time and possible costs of experiments) our Fuzzy Sets based multi-scale methodology shows promising and fast results for the class of metal materials.
We would like to test it further on other applications. We are also targeting now questions of stochastic stability of our results.