Periodic Reporting for period 1 - THREAD (Joint Training on Numerical Modelling of Highly Flexible Structures for Industrial Applications)
Berichtszeitraum: 2019-10-01 bis 2021-09-30
Virtual prototyping is a cornerstone in modern industrial product development cycles, as it is used to accelerate the design process, reduce the cost associated with real prototypes and improve the final product’s performances. The European Training Network THREAD addresses the numerical modelling of slender and highly flexible structures like yarns, cables, hoses or ropes that are essential parts of high-performance engineering systems. The complex response of such structures in real operational conditions is far beyond the capabilities of current modelling tools that are at the core of modern product development.
The mechanical response of highly flexible structures in application areas such as mechanical and aerospace engineering, biomedical engineering, offshore engineering, civil engineering and textile engineering is dominated by very complex phenomena that occur at different spatial and temporal scales. Full-scale 3D models of multimaterial rods based on a detailed representation of their internal structure would be incompatible with the requirements of a system-level analysis because of their high complexity and computational cost. Current 1D rod models lead to lower-dimensional problems but can hardly reproduce experimental results because of their inability to account for local nonlinear phenomena in the cross-section and of their extreme sensitivity to numerical disturbances.
THREAD is a unique network of universities, research organisations and industry from Austria, Belgium, Croatia, France, Germany, Norway, Slovenia and Spain that brings together mechanical engineers and mathematicians around major challenges in industrial applications and simulation software development. It establishes an innovative modelling chain starting from detailed 3D models and experimental measurements to build validated 1D rod models which are then brought to a system-level simulation thanks to the development of next-generation algorithms with outstanding numerical properties.
The 14 Early Stage Researchers (ESRs) benefit from cooperation with 12 industrial partner organisations implementing a comprehensive programme of research secondments and contributing their experience. The training programme in THREAD aims at scientific skills in Cosserat rod models, their numerical treatment and practical application, transferable skills including high level experience in dissemination and communication as well as interdisciplinary and inter-sectoral experience. The local training in supervised individual research projects and local PhD programmes is accompanied by a comprehensive network-wide training programme with 14 network-wide training events, six industrial workshops and secondments to academic and non-academic partners.
The mechanical response of highly flexible structures in application areas such as mechanical and aerospace engineering, biomedical engineering, offshore engineering, civil engineering and textile engineering is dominated by very complex phenomena that occur at different spatial and temporal scales. Full-scale 3D models of multimaterial rods based on a detailed representation of their internal structure would be incompatible with the requirements of a system-level analysis because of their high complexity and computational cost. Current 1D rod models lead to lower-dimensional problems but can hardly reproduce experimental results because of their inability to account for local nonlinear phenomena in the cross-section and of their extreme sensitivity to numerical disturbances.
THREAD is a unique network of universities, research organisations and industry from Austria, Belgium, Croatia, France, Germany, Norway, Slovenia and Spain that brings together mechanical engineers and mathematicians around major challenges in industrial applications and simulation software development. It establishes an innovative modelling chain starting from detailed 3D models and experimental measurements to build validated 1D rod models which are then brought to a system-level simulation thanks to the development of next-generation algorithms with outstanding numerical properties.
The 14 Early Stage Researchers (ESRs) benefit from cooperation with 12 industrial partner organisations implementing a comprehensive programme of research secondments and contributing their experience. The training programme in THREAD aims at scientific skills in Cosserat rod models, their numerical treatment and practical application, transferable skills including high level experience in dissemination and communication as well as interdisciplinary and inter-sectoral experience. The local training in supervised individual research projects and local PhD programmes is accompanied by a comprehensive network-wide training programme with 14 network-wide training events, six industrial workshops and secondments to academic and non-academic partners.
The team of highly qualified and motivated PhD students with five female and nine male ESRs from three continents represents well the interdisciplinary character of the ETN with backgrounds in the fields of mechanical engineering, computational sciences and mathematics. They started with core research training in one-week courses on fundamental modelling techniques and on virtual product development. Courses on ropes and cables, on applications in textile engineering and on the mathematical framework behind geometric integration contributed to the advanced research training at network level. They were accompanied by the first series of two-day industrial workshops at three non-academic partner organisations to highlight industrial challenges in modelling and simulation. The transferable skills training in local PhD programmes and at network level has been closely related to dissemination and communication activities that were, however, strongly affected by the COVID-19 confinement measures.
The ESRs started their individual research projects with literature reviews for the three research- related work packages on advanced constitutive laws, on interactions of 1D structures in a 3D world and on geometric numerical integration methods. Other important steps were the definition of test cases for validation of new computational models and the definition of industrial use cases in tight interaction with the non-academic partners. The inter-sectoral three-month secondments of six ESRs provided deep insights into how modelling and simulation are utilised in virtual product development processes to address industrial challenges.
The physical phenomena in the deformation of electric cables, spiral strands, wire ropes and hollow endoscopes have been studied by test-rig experiments and by numerical simulations with newly developed methods and software components in specially tailored simulation tools. This experimental work has provided the basis for designing novel constitutive laws which can deal with, e.g. variable axial forces, composite cross sections, hysteretic operators or data driven models. The analysis of contact and friction phenomena inside spiral strands and cable harnesses, in braiding processes and in ropeway systems has been addressed by improved modelling and simulation techniques that are implemented in the open-source software packages Odin and Exudyn and in the proprietary software Multifil for exploitation in industrial projects. Research on geometric integration methods has shown their feasibility in this industrial context with challenging open problems concerning adaptivity, efficiency and parameter identification. Structure preserving model reduction and reduced order models with nonlinear normal modes have been investigated as key technologies for further gains in efficiency.
ESRs have presented these research results in a series of THREAD mini-symposia and special sessions at leading international conferences in this field such as WCCM 2020, ECMI 2021, ASME/MSNDC 2021 and NUMDIFF-16. They are co-authors of four papers that have been submitted for open-access publication in highly reputable journals from mathematics and engineering.
The ESRs started their individual research projects with literature reviews for the three research- related work packages on advanced constitutive laws, on interactions of 1D structures in a 3D world and on geometric numerical integration methods. Other important steps were the definition of test cases for validation of new computational models and the definition of industrial use cases in tight interaction with the non-academic partners. The inter-sectoral three-month secondments of six ESRs provided deep insights into how modelling and simulation are utilised in virtual product development processes to address industrial challenges.
The physical phenomena in the deformation of electric cables, spiral strands, wire ropes and hollow endoscopes have been studied by test-rig experiments and by numerical simulations with newly developed methods and software components in specially tailored simulation tools. This experimental work has provided the basis for designing novel constitutive laws which can deal with, e.g. variable axial forces, composite cross sections, hysteretic operators or data driven models. The analysis of contact and friction phenomena inside spiral strands and cable harnesses, in braiding processes and in ropeway systems has been addressed by improved modelling and simulation techniques that are implemented in the open-source software packages Odin and Exudyn and in the proprietary software Multifil for exploitation in industrial projects. Research on geometric integration methods has shown their feasibility in this industrial context with challenging open problems concerning adaptivity, efficiency and parameter identification. Structure preserving model reduction and reduced order models with nonlinear normal modes have been investigated as key technologies for further gains in efficiency.
ESRs have presented these research results in a series of THREAD mini-symposia and special sessions at leading international conferences in this field such as WCCM 2020, ECMI 2021, ASME/MSNDC 2021 and NUMDIFF-16. They are co-authors of four papers that have been submitted for open-access publication in highly reputable journals from mathematics and engineering.
The interdisciplinary and inter-sectoral cooperation in THREAD has put the challenges from industrial applications in virtual product development into the focus of cutting-edge research on modelling and simulation of highly flexible structures.
A unique network-wide training programme has been implemented combining in a holistic approach advanced concepts in experimental and theoretical structural mechanics, non-smooth dynamics, computational geometry, discretisation methods and geometric numerical integration to enable the next generation of virtual prototyping and to boost the career development of the ESRs. Despite all limitations caused by the COVID-19 pandemic, the mobility of ESRs is strongly supported by THREAD’s comprehensive secondment programme including mandatory three-month secondments to industrial partner organisations. The international cooperation in THREAD actively contributes to the European Research Area and puts strong emphasis on scientific excellence in terms of open-access publications in peer-reviewed high impact journals.
The results of 14 individual ESR projects have shown significant progress beyond the state of the art in application-specific constitutive models for highly flexible structures and contributed to significant gains of robustness and efficiency in computational methods and software tools for industrial use. In that way, the project advances the innovation capacity and the competitiveness of European industries related to the topics of THREAD.
A unique network-wide training programme has been implemented combining in a holistic approach advanced concepts in experimental and theoretical structural mechanics, non-smooth dynamics, computational geometry, discretisation methods and geometric numerical integration to enable the next generation of virtual prototyping and to boost the career development of the ESRs. Despite all limitations caused by the COVID-19 pandemic, the mobility of ESRs is strongly supported by THREAD’s comprehensive secondment programme including mandatory three-month secondments to industrial partner organisations. The international cooperation in THREAD actively contributes to the European Research Area and puts strong emphasis on scientific excellence in terms of open-access publications in peer-reviewed high impact journals.
The results of 14 individual ESR projects have shown significant progress beyond the state of the art in application-specific constitutive models for highly flexible structures and contributed to significant gains of robustness and efficiency in computational methods and software tools for industrial use. In that way, the project advances the innovation capacity and the competitiveness of European industries related to the topics of THREAD.