Leibniz Universität Hannover Faculty Faculty of Mechanical Engineering
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Peter Wriggers

Prof. em. Dr.-Ing. habil. Dr. h.c. mult. Dr.-Ing. E.h. Peter Wriggers

Prof. em. Dr.-Ing. habil. Dr. h.c. mult. Dr.-Ing. E.h. Peter Wriggers
Phone
+49 511 762 2220
Email
wriggersikm.uni-hannover.de
Address
An der Universität 1
30823 Garbsen
Building
8142
Room
317
Prof. em. Dr.-Ing. habil. Dr. h.c. mult. Dr.-Ing. E.h. Peter Wriggers
Phone
+49 511 762 2220
Email
wriggersikm.uni-hannover.de
Address
An der Universität 1
30823 Garbsen
Building
8142
Room
317
Position
Emeritus/Retired Professors
Leibniz Emeritus
Institute of Continuum Mechanics
http://www.ikm.uni-hannover.de
  • Academic degrees
    1988 Habilitation, Mechanics, Leibniz Universität Hannover, Prof. E. Stein
    1981 Doctorate, Civil Engineering, Leibniz Universität Hannover, Prof. E. Stein
    1976 Dipl.-Ing., Civil-Engineering, Leibniz Universität Hannover, Prof. S. Spierig
  • Academic positions
    since 2008 Full Professor of Mechanics at the Faculty of Mechanical Engineering, Leibniz Universität Hannover
    2005 - 2006 Conjoint Professor at University of Newcastle, Australia
    1998 - 2008 Full Professor of Mechanics at the Faculty of Civil Engineering, Leibniz Universität Hannover
    1990 - 1998 Full Professor of Mechanics at Technische Universität Darmstadt
    1988 - 1988 Visiting Professor at Department of Civil Engineering, University of California, Berkeley, USA
    1984 - 1990 Lecturer at Institute for Mechanics and Computational Mechacnics, University of Hannover
    1983 - 1984 Visiting Scholar at University of California, Berkeley, USA (with Prof. Robert L. Taylor)
    1976 - 1983 Staff Member at Institute of Construction Mechanics, Leibniz Universität Hannover
  • Activities
    since 2019 Member of the Scientific Advisory Board of Rocini (Rostock Centre for Interdisciplinary Implant Research) Link
    since 2020 President of the Advisory scientific council of CIMNE (International Centre for Numerical Methods in Engineering) Link
    since 2018 Corresponding Member of the Croatian Academy of Sciences and Arts
    2009 - 2022 Re-elected member of the Executive Committee of IACM

    2015 - 2016

    		 Chair of the Executive Committee of the Applied Mechanics Division of ASME
    2015 - 2021 Vice President for Research at Leibniz Universität Hannover
    since 2015 Member of "Board of Directors" and "Scientific Council" of CISM (International Center of Mechanical Sciences) Link
    since 2014 Editor in Chief of „Computational Particle Mechanics“
    since  2012 Member of the Scientific Advisory Board of CIMNE, UPC Barcelona
    2011 - 2018 Vice President of IACM (International Association for Computational Mechanics)
    2011 - 2013 Vice President of GAMM (Society for Applied Mathematics and Mechanics)
    2011 - 2016 Member of the Executive Committee of the Applied Mechanics Division of ASME
    2011 - 2017 Member of the DFG senate committee for Collaborate Research Centres (CRC)
    2010 - 2019 Charman of International Research Training Group: IRTG1627: Virtual Materials and Structures and their Validation
    2009 - 2022 Member of the steering committee of the maximum performance computer center Stuttgart (HLRS)
    2008 - 2012 President of GACM (German Association for Computational Mechanics)
    2008 - 2010 President of GAMM (Society for Applied Mathematics and Mechanics)
    2007 - 2011 Member of the ERC review panel for Starting and Consolidator Grants
    2006 - 2015 Member of selection committee of the Alexander von Humboldt Foundation for Humboldt Fellowships (since 2010 chairman)
    2004 - 2011 Member of DFG Experts Architecture/Civil Engineering and Medical Technology
    since 2004 Member of acatech (German Academy of Technology Science)
    since 2003 Associated editor of “Bauingenieur”
    since 2003 Member of Academy for Science and Literature Mainz
    2001 - 2004 Member of the Advisory Board of the "Transatlantic Science and Humanities Program" of the Alexander von Humboldt Foundation
    2001 - 2008 Vice President of GACM
    since 2001 Editor in Chief von “Computational Mechanics”
    1996 - 2001 Member of the DFG senate committee for graduate schools
  • Awards
    2015 Honorary Doctorate “Dr.-Ing. E.h.” of the TU Darmstadt, Germany
    2013 Honorary Doctorate “Dr. h. c. “ of the ENS Cachan, Paris, France
    2013 Honorary Doctorate “Dr. h. c. “ of the University of Technology Poznan  
    2013 “Zienkiewicz Medal” of the Polish Association for Computational Mechanics (PACM)
    2011 Grand Prize of the Japan Society for Computational Engineering and Science (JSCES)
    2011 “Russell Severance Springer Professor“, Visiting Chair at ME Department, UC Berkeley
    2010 “IACM Award” (IACM)
    2008 “Euler Medal” of ECCOMAS

    2006

    		 Computational Mechanics Award (IACM)

    2004

    		 “Highly Commended Award” for paper in Engineering Computations

     

    2003 - 2004

    		 ARC Linkage Professorship at University of Newcastle, NSW, Australia

    2002

    		 Fellow of the International Association for Computational Mechanics (IACM)

    2002

    		 “Literati Award for Excellence” to the best paper 2002 in Engineering Computations

    1981

    		 “Christian-Kuhlemann-Scholarship” for best PhD-thesis, University of Hannover
  • Academic memberships
    since 2018 Corresponding Member of the Croatian Academy of Sciences and Arts
    since 2004 Member of the National Academy of Engineering, “acatech”, Gemany
    since 2004 Member of the “Academy of Science and Literature”, Mainz, Germany
    since 1999 Member of Braunschweigische Wissenschaftliche Gesellschaft, Braunschweig, Germany
  • Books
    • Technische Mechanik, Band 4
      Hydromechanik, Elemente der Höheren Mechanik, Numerische Methoden
      Springer-Verlag Berlin/Heidelberg
      3. Aufl. 1999. XI, 434 S. 213 Abb. Brosch.
      ISBN 3-540-65205-1
  • Journals
    • Editor-in-Chief:
    • Associated Editor
      International Journal for Numerical methods in Engineering (1998-2001)
      Der Bauingenieur (since 2003)
    • Member of the Editorial Board:
      • Since 1990    Engineering Computations
      • Since 1990    International Journal for Numerical Methods in Engineering
      • Since 1994    International Journal for Engineering Analysis and Design
      • Since 1995    Archives of Computational Methods in Engineering
      • Since 1997    Computers & Structures
      • Since 1997    International Journal of Solids and Structures
      • Since 1997    International Journal of Forming Processes
      • Since 1998    Engineering with Computers
      • Since 2000    Computer Methods in Applied Mechanics and Engineering
      • Since 2000    International Journal for Computational Civil and Structural Engineering
      • Since 2000    Computational Engineering Science
      • Since 2002    Journal of Computational Biomechanics
      • Since 2003    International Journal of Computational Methods
      • Since 2003    Latin American Journal of Solids and Structures
      • Since 2003    International Journal for Multiscale Computational Engineering
  • Research projects

    FOR5250

    • In-silico design of implants based on a multi-scale approach
      Optimized permanent implants are to be developed in the research group. Additive manufacturing results in a great degree of freedom in terms of geometric design. As a result, the lattice structure in the implant can be adjusted in a targeted manner in order to optimally adapt the implant to the surrounding bone. Funding period 1 focuses on permanent implants. In particular, the functionality of the implant must be guaranteed over a long period of loading. In this SP-7, a cross-scale model is developed that takes into account the influence of damage effects on the microscale, of notch effects of the grid structures on the mesoscale, and stress shielding on the macroscale. To this end, a new type of homogenization approach is being introduced that allows the scales to be linked in a time-efficient manner using machine learning. In addition, the thermodynamic topology optimization is further developed in order to determine the optimal digital implant across all scales, taking into account process-related damage and stress-induced fatigue effects. In order to find the optimum between lattice structure and functionality, an efficient multi-scale algorithm is developed. The fatigue behavior under stress at high (HCF, High Cycle Fatigue) and very high number of load cycles (VHCF, Very High Cycle Fatigue) is modeled on the microscale. It is assumed that the failure occurs mainly at the grain boundaries. The investigation of the influence of the lattice structure on the stress-strain relationship takes place on the mesoscale. The optimization of the implant in terms of fatigue strength, load-bearing capacity, and morphology is ultimately carried out on the macro scale. The data transfer between the individual scales will be realized based on specially developed artificial neural networks.
      Led by: Philipp Junker, Peter Wriggers
      Team: Hüray Ilayda Kök
      Year: 2022

    Damage modeling

    • In-silico design of implants based on a multi-scale approach
      Optimized permanent implants are to be developed in the research group. Additive manufacturing results in a great degree of freedom in terms of geometric design. As a result, the lattice structure in the implant can be adjusted in a targeted manner in order to optimally adapt the implant to the surrounding bone. Funding period 1 focuses on permanent implants. In particular, the functionality of the implant must be guaranteed over a long period of loading. In this SP-7, a cross-scale model is developed that takes into account the influence of damage effects on the microscale, of notch effects of the grid structures on the mesoscale, and stress shielding on the macroscale. To this end, a new type of homogenization approach is being introduced that allows the scales to be linked in a time-efficient manner using machine learning. In addition, the thermodynamic topology optimization is further developed in order to determine the optimal digital implant across all scales, taking into account process-related damage and stress-induced fatigue effects. In order to find the optimum between lattice structure and functionality, an efficient multi-scale algorithm is developed. The fatigue behavior under stress at high (HCF, High Cycle Fatigue) and very high number of load cycles (VHCF, Very High Cycle Fatigue) is modeled on the microscale. It is assumed that the failure occurs mainly at the grain boundaries. The investigation of the influence of the lattice structure on the stress-strain relationship takes place on the mesoscale. The optimization of the implant in terms of fatigue strength, load-bearing capacity, and morphology is ultimately carried out on the macro scale. The data transfer between the individual scales will be realized based on specially developed artificial neural networks.
      Led by: Philipp Junker, Peter Wriggers
      Team: Hüray Ilayda Kök
      Year: 2022

    Improving Accuracy and Performance of Meshfree Methods

    • Process Simulation for Selective Laser Melting
      A phase change model for solution with the meshfree Galerkin OTM method is developed.
      Led by: Christian Weißenfels, Peter Wriggers
      Team: M.Sc. Henning Wessels
      Year: 2016
    • ISPH-based Simulation of the Selective Laser Melting Process
      Development of a thermo-mechanical model for the simulation of the SLM process.
      Led by: Christian Weißenfels, Peter Wriggers
      Team: M.Sc. Jan-Philipp Fürstenau
      Year: 2017
    • Using Machine Learning to Improve the Modelling of Machining and Cutting Processes
      Metal cutting is a fundamental process in industrial production. The fast and accurate on-line prediction of metal cutting processes is crucial for the Intelligent Manufacturing (IM). With the advent of high-speed computing, robust numerical algorithms and machine learning technology, computational modelling serves as a tool for not only accurate but also fast predicting the complex machining processes and understanding the complex physics. In this work, the machine learning based numerical model is developed for simulation of metal cutting processes.
      Led by: C. Weißenfels, P. Wriggers
      Team: M.Sc. Dengpeng Huang
      Year: 2018
      Funding: China Scholarship Council (CSC)
    • Peridynamic Galerkin Methods
      Simulation-driven product development is nowadays an essential part in the industrial digitalization. Notably, there is an increasing interest in realistic high-fidelity simulation methods in the fast-growing field of additive and ablative manufacturing processes. Thanks to their flexibility, meshfree solution methods are particularly suitable for simulating the stated processes, often accompanied by large deformations, variable discontinuities, or phase changes. Furthermore, in the industrial domain, the meshing of complex geometries represents a significant workload, which is usually minor for meshfree methods. Over the years, several meshfree schemes have been developed. Nevertheless, along with their flexibility in discretization, meshfree methods often endure a decrease in accuracy, efficiency and stability or suffer from a significantly increased computation time. Peridynamics is an alternative theory to local continuum mechanics for describing partial differential equations in a non-local integro-differential form. The combination of the so-called peridynamic correspondence formulation with a particle discretization yields a flexible meshfree simulation method, though does not lead to reliable results without further treatment. In order to develop a reliable, robust and still flexible meshfree simulation method, the classical correspondence formulation is generalized into the Peridynamic Galerkin (PG) methods in this project. On this basis, conditions on the meshfree shape functions of virtual and actual displacement are presented, which allow an accurate imposition of force and displacement boundary conditions and lead to stability and optimal convergence rates. Based on Taylor expansions moving with the evaluation point, special shape functions are introduced that satisfy all the previously mentioned requirements employing correction schemes. In addition to displacement-based formulations, a variety of stabilized, mixed and enriched variants are developed, which are tailored in their application to the nearly incompressible and elasto-plastic finite deformation of solids, highlighting the broad design scope within the PG methods. Compared to related Finite Element formulations, the PG methods exhibit similar convergence properties. Furthermore, an increased computation time due to non-locality is counterbalanced by a considerably improved robustness against poorly meshed discretizations.
      Led by: Christian Weißenfels, Peter Wriggers
      Team: M.Sc. Tobias Bode
      Year: 2019
    • Numerical simulation of pile installation in a hypoplastic framework using an SPH based Method
      In this project, a 3D computational tool using smoothed particle hydrodynamics (SPH) is developed which based on a hypoplastic constitutive approach for the mechanical behavior of the soil. The numerical code is firstly validated against a benchmark problem. Then several test cases are simulated including monotonic and vibratory penetration of piles into the soil. A good agreement with the experimental observation is found. Additionally, the impact of pile running in the presence of sheetpiles (retainers) are investigated to see how pile running can alter the applied forces on the sheet piles. The simulation of such complex geotechnical problems which involve large deformation, material nonlinearity and moving boundary conditions demonstrates the applicability and versatility of the proposed numerical tool in this field.
      Led by: Peter Wriggers
      Team: Meisam Soleimani, Christian Weißenfels
      Year: 2020

    In Silicio Analyses

    Virtual Elements For Engineering Appications

    • 2D VEM for crack-propagation
      Led by: F. Aldakheel, B. Hudobivnik, P. Wriggers
      Team: A. Hussein
      Year: 2018
      Funding: IRTG 1627
    • Virtual element method (VEM) for phase-field modeling of brittle and ductile fracture
      Led by: F. Aldakheel, B. Hudobivnik, P. Wriggers
      Year: 2018
      Funding: DFG SPP 1748
    • Virtual Element Method for Dynamic Applications
      The Virtual Element Method is a recent developed discretization method, which can be seen as an extension of the classical Galerkin finite element method. It has been applied to various engineering fields, such as elasto-plasticity, multiphysics, damage and fracture mechanics. This project focuses on the extension of VEM towards dynamic applications. In the first part the appropriate computation of the Massmatrix regarding the vitual element ansatzspace will be done. In future works, VEM will be applied to engineering problems, considering the dynamic behavior.
      Led by: F. Aldakheel, B. Hudobivnik, P. Wriggers
      Team: M. Cihan
      Year: 2019
    • Virtual Element Method for 3D Contact
      The computational modeling of contact has always been a challenging task, especially when the interface between two or more bodies, which will come into contact, has a non-conforming mesh. In this case, the virtual element method (VEM) can be used to modify the interface mesh, such that a conforming mesh arises. In this project, we employ the virtual element method in 3D to project the interface meshes between each other, such that new nodes can be inserted on both bodies, to obtain matching meshes at the interface. The insertion of new nodes does not change the Ansatz or total number of elements. These new nodes are either stemming from already existing vertices, or edge-to-edge intersections (a). The later can be easily inserted in to the existing mesh, since this nodes are located at element edges. Nodes, which are getting projected from vertices will most probably lie in element faces. The insertion of these nodes needs an additional treatment. However, the projection-based node insertion algorithm leads to matching meshes and allows to employ a simple node-to-node contact at the interface. The numerical results are showing that this way of modeling contact passes the patch test exactly (b)-(c).
      Led by: F. Aldakheel, B. Hudobivnik, P. Wriggers
      Team: M. Cihan
      Year: 2020
    • Virtual Kirchhoff-Love plate elements for isotropic and anisotropic materials
      The virtual element method allows to revisit the construction of Kirchhoff-Love elements because the C1-continuity condition is much easier to handle in the VEM framework than in the traditional finite element methodology. Here we study the two most simple VEM elements suitable for Kirchhoff-Love plates as stated in (Brezzi and Marini (2013)). The formulation contains new ideas and different approaches for the stabilization needed in a virtual element, including classic and stabilization. An efficient stabilization is crucial in the case of C1-continuous elements because the rank deficiency of the stiffness matrix associated to the projected part of the ansatz function is larger than for C0-continuous elements. This project aims at providing engineering inside in how to construct simple and efficient virtual plate elements for isotropic and anisotropic materials and at comparing different possibilities for the stabilization. Different examples and convergence studies discuss and demonstrate the accuracy of the resulting VEM elements. Finally, reduction of virtual plate elements to triangular and quadrilateral elements with 3 and 4 nodes, respectively, yields finite element like plate elements. These C1-continuous elements can be easily incorporated in legacy codes and demonstrate an efficiency and accuracy that is much higher than provided by traditional finite elements for thin plates.
      Led by: P. Wriggers, B. Hudobivnik
      Team: P. Wriggers, B. Hudobivnik, O. Allix
      Year: 2021
    • Virtual element formulation for trusses and beams
      The virtual element method (VEM) was developed not too long ago, starting with the paper Beirao da Veiga et al. (2013) related to elasticity in solid mechanics. The virtual element method allows to revisit the construction of different elements in solid mechanics, however, has so far not been applied to one dimensional structures like trusses and beams. In this project, several VEM elements suitable for trusses and beams are derived. It could be shown that the virtual element methodology produces elements that are equivalent to well know finite elements but also elements that are different, especially for higher order ansatz functions, like 2nd and 3rd order for the truss and 4th order for the beam. It will be shown that these elements can be easily incorporated in classical finite element codes since they have the same nodal degrees of freedom as finite beam elements. Furthermore, the formulation allows to compute nonlinear structural problems undergoing large deflections and rotations.
      Led by: P. Wriggers
      Year: 2021

    Phase Field Modeling of Fracture in Multi-Field Environments

    Multiscale and Multifield problems

    • Multiscale Method for Hydro-Chemo-Thermo-Mechanics Coupling due to Alkali Silica Reaction in Concrete
      Alkali Silica Reaction(ASR) is one of most determinant reasons leading to the deterioration of concrete structures, which can be ascribed to the expansion of gel produced by ASR in the microstructural level of concrete. The challenge in the modeling of ASR is due to the necessity to take into account the presence of heterogeneities and physical processes distributed over multiple length scales. With increasing computation power and the tomography scan technology, it can be implemented by numerical simulation . In this contribution, 3D multiscale hydro-chemo-thermal-mechanical coupling based on a staggered method is demonstrated, which explicitly describes the damage evolution originating from the chemical reaction in the microscale and the dependence on environmental factors.
      Led by: P. Wriggers
      Team: T. Wu
      Year: 2009
    • MULTIPHYSICS COMPUTATIONAL HOMOGENIZATION METHODOLOGIES
      Computational homogenization techniques that are amenable to a multiscale implementation are being developed for multiphysics problems at the finite deformation regime. Applications include the estimation of the contact conductance for rough interfaces and the modeling of the coupled thermomechanical response of heterogeneous materials.
      Led by: P. Wriggers, I. Temizer
      Year: 2009
    • Direct Numerical Simulation of Multiphase Flows
      Multiphase flows consisting of a continuous fluid phase and a dispersed phase of macroscopic particles are present in many engineering applications. In general, a main task in the study of the particle-laden fluid flow of an application is to make predictions about the system's nature for various boundary conditions, since, depending on the volume fraction and mass concentration of the dispersed phase a fluid-particle system shows quite different flow properties. Unfortunately, often it is impossible to investigate such a system experimentally in detail or even at all. An option to capture and to predict its properties is performing a direct numerical simulation of the particulate fluid. For this purpose, an efficient approach is developed in this project by coupling the discrete element method and finite element method.
      Led by: P. Wriggers
      Team: B. Avci
      Year: 2009
    • Numerical modeling of electrical contacts
      The focus of this work is the investigation of the behavior in electrical contacts, where electrical, thermal and mechanical fields are coupled. Specifically, theoretical constitutive models for the electrical conductance and electrical wear phenomena are developed and implemented in a three dimensional finite element setting. Also a new relation for wear is proposed, where the amount of wear is coupled to the dissipation arising at the contact interface. </a></p>
      Led by: P. Wriggers
      Team: C. Weißenfels
      Year: 2009
    • RAMWASS - Integrated Decision Support System for Risk Assessment and Management
      The objective of the EU-project RAMWASS is to develop and validate a new decision support system (DSS) for the risk assessment and management for the prevention and/or reduction of the negative impacts caused by human activities on the water/sediment/soil system at river basin scale in fluvial ecosystems.
      Led by: P. Wriggers
      Team: B. Avci
      Year: 2009
    • Homogenization procedures for coupled thermo-chemo-mechanical problems
      In order to understand processes of continuum damage mechanics it is necessary to investigate thermo-chemo-mechanical coupled processes at micro scale. However for engineering purposes it is still necessary to be able to model these processes at macro scale, especially when large structures have to be designed. Thus a homogenization procedure or a FE^2 framework is necessary to transform the relation, describing the coupled thermo-chemo-mechanical response at micro scale to the macro scale. The related equations and procedures have to be developed and implemented in a finite element software system.
      Led by: P. Wriggers, E. Baranger
      Team: Jin Man Mok
      Year: 2013
    • Multi-Fluid Simulations for High Density Ratios
      Although the contact between fluids or gases of different densities is a common event in nature, like the interaction of water and air, the simulation of multiple fluids often comes along with numerous problems. With the Lagrangian description of continuous fluids in terms of the Smoothed Particle Hydrodynamics (SPH) method multi-fluid interactions within the particle scale can simulated. Nevertheless with the standard SPH algorithms multi-fluid problems can not be solved because of the density jumps at the interfaces. Within the project the state of the art of current multi-fluid approaches are compared and evaluated to develop appropriate methods for the simulation of multi-fluid systems with high density ratios.
      Led by: P. Wriggers, B. Avci
      Team: J.-P. Fürstenau
      Year: 2014
    • Towards multiscale modeling of Abrasive wear
      The work is motivated towards understanding wear as a multiscale-multiphysics approach. A 3D framework is developed to simulate cracks propagation in a microstructure due to contact loading to eventually predict wear trends in filled elastomeric compounds.
      Led by: P. Wriggers
      Team: A. B. Harish
      Year: 2015
    • Entropic approach to modeling Mullins effect in non-crystallizing filled elastomers
      The work was done in collaboration with Mrs. Aarohi B. Shah and Dr. Julian J Rimoli of School of Aerospace Engineering, Georgia Tech, USA. In this work, we investigate non-crystallizing nanoparticle-reinforced polymers. The effects of the interface rubber between elastomeric matrix and filler particles and its alteration are investigated as a primary cause of Mullins and Payne effect.
      Led by: P. Wriggers, J. J. Rimoli
      Team: A. B. Harish, A. B. Shah
      Year: 2016

    Life time prediction and failure of modern complex materials and structures

    Material modeling

    • FAILURE ANALYSIS - ERROR ESTIMATION FOR MULTISCALE METHODS
      This project is concerned with the development of tools for error-estimation based adaptive multiscale failure analysis. In order to enable a more accurate mechanical analysis of composite aircraft substructures, existing discretisation error estimators will be improved to be used as indicators for mesh refinement. Additionally, physical error estimators will be developed to identify regions where higher-order material modelling is required.
      Led by: P. Wriggers
      Team: N. Hajibeik
      Year: 2009
    • ADAPTIVE MULTISCALE MODELING AND ANALYSIS OF HETEROGENEOUS MATERIALS
      Accurate computational analyses of a composite structure requires multiple levels of resolution: (i) a region where effective elastic properties are employed, (ii) a region where embedded micro-macro problems are solved, and (iii) a region where explicit microstructural evaluation is required. Development of such computational schemes for the adaptive multiscale analysis of heterogeneous materials is the main purpose of this project.
      Led by: P. Wriggers, I. Temizer
      Year: 2009
    • Multiscale modeling and extended finite element analysis of fracture processes in ceramics
      The extended finite element method (XFEM) enables the modelling and calculation of cracks independent of mesh topologies. Due to this advantage it has become the most widely used method for computations of fracture processes. In the vicinity of a macrocrack front the microstructure of the material can have a significant influence and needs to be considered in detail. Especially microcracks can affect crack propagation drastically. This leads to the necessity of multiscale methods like the multiscale projection method to capture microstructural details where necessary. Even though the XFEM is known to be a comparably accurate method to calculate cracks, discretisation errors occur. Therefore, the discretisation error on the finescale is estimated via a stress smoothing technique. The realtive error of stresses enables adaptive mesh refinement on the microscale leading to more accurate results also on the macroscale. The computational model is validated by comparison of the results to experimental data.
      Led by: P. Wriggers, S. Löhnert
      Team: C. Prange
      Year: 2009
    • Crack propagation and crack coalescence in a multiscale framework
      In this project a numerical framework for propagating and intersecting cracks on micro and macro scales is set up. Modeling cracks using the eXtended Finite Element Method (XFEM) provides an accurate and efficient numerical framework to model propagating and intersecting cracks. Since cracks of different length scales are assumed, a multiscale method is applied in order to be numerical efficient.
      Led by: S. Löhnert, P. Wriggers
      Team: M. Holl
      Year: 2010
    • Multiscale Methods for Fracturing Solids
      In this project multiscale methods and homogenization techniques for the numerical simulation of three dimensional fracture processes are developed. These methods are important in aerospace and automotive industries and many other fields of mechanical and civil engineering as well as in bio-mechanics and material science. They will improve the prediction of the failure of structures.
      Led by: P. Wriggers, S. Löhnert
      Team: D. Müller-Hoeppe
      Year: 2011
    • Computational homogenisation of elasto plastic material
      Particle-matrix materials are commonly used in different fields(aerospace components, bicycle frames and racing car bodies) for its mechanical and economical advantages,such as high strength, low weight and less expense.However,Because of the microstructural complexities,it is very time and labor consuming to determin the mechanical properties of composite materials. Hence,in order to reduce laboratory expense, numerical simulations via Homogenized techniques are performed on RVE to predict mechanical behavior of composite material.
      Led by: P.Wriggers
      Team: Chao Zhang
      Year: 2012
    • Computational multiscale modelling of localized ductile failure
      Many phenomenological material models capture ductile damage. However, to flexibly incorporate the underlying the governing microstructural properties and damage mechanisms, a multiscale framework is needed. The few recent numerical multiscale works on localized failure are limited to brittle microdamage. Therefore, the goal of this project is to provide a computational multiscale framework for the modelling of localized failure stemming from a microstructure undergoing ductile damage.
      Led by: P. Wriggers
      Team: H. Clasen
      Year: 2012
      Funding: DFG im Normalverfahren
    • Constitutive modeling of large deformation behavior of filled elastomers
      In this work, a finite thickness cohesive zone model is used to study the large deformation & fracture behavior of filled elastomeric materials at the mesoscale. The study includes and has implications on filler cluster breakage, Mullins softening etc.
      Led by: P.. Wriggers
      Team: A. B. Harish
      Year: 2015
    • Nanoindentation for material property characterization
      In this work, techniques are developed for nanoindentation of soft polymers and brittle powdery materials and measurement of properties like modulus, hardness and fracture toughness.
      Led by: P. Wriggers, S. Löhnert
      Team: A. B. Harish, V. Kruppernikova
      Year: 2016
    • Hypoplastic material models for soil-structure interaction problems
      In this work, a hypoplastic material model is implemented using AceGen with an eventual goal to model soil-structure interaction.
      Led by: P. Wriggers, C. Weissenfels
      Team: A. B. Harish
      Year: 2016
    • Entropic approach to modeling Mullins effect in non-crystallizing filled elastomers
      The work was done in collaboration with Mrs. Aarohi B. Shah and Dr. Julian J Rimoli of School of Aerospace Engineering, Georgia Tech, USA. In this work, we investigate non-crystallizing nanoparticle-reinforced polymers. The effects of the interface rubber between elastomeric matrix and filler particles and its alteration are investigated as a primary cause of Mullins and Payne effect.
      Led by: P. Wriggers, J. J. Rimoli
      Team: A. B. Harish, A. B. Shah
      Year: 2016
    • Process Simulation for Selective Laser Melting
      A phase change model for solution with the meshfree Galerkin OTM method is developed.
      Led by: Christian Weißenfels, Peter Wriggers
      Team: M.Sc. Henning Wessels
      Year: 2016
    • In silico morphogenesis of collagen tissues for targeted drugs and bio-printing
      This project targets to understand the mechanisms behind the morphogenesis and the development of living tissues. To this aim, mechanical and biological actions that contribute to confer tissue desired topology and functionality will be modelled and analysed in silico. A computational framework for the modeling of tissue morphogenesis in natural and bio-printed systems will be developed. In particular, the project will address: the multiscale hierarchical and organized arrangement of tissue constituents; the chemo-mechanical interaction among tissue constituents and among cells; the chemo-mechano-biological mechanisms driving growth and remodeling; the extrusion and the curing of multicellular aggregates blended with bio-inks. Obtained results will target to elucidate mechanisms behind tissue functional/dysfunctional structure; conceive targeted drug systems for stimulating optimal molecular pathways promoting tissue healing; develop novel or optimize existing 3D bio-printing technologies.
      Led by: M. Marino
      Year: 2017
      Funding: Masterplan SmartBiotecs, MWK (Lower Saxony, Germany)
    • Creep deformation of nickel based superalloys
      Modeling of nickel based superalloys on two scales using crystal plasticity and XFEM methods.
      Led by: P. Wriggers
      Team: Lukas Munk
      Year: 2018
    • Modelling and simulation of the joining zone during the tailored forming process
      [Translate to Englisch:] The topic of project C4 is the multiphysical modelling and simulation of the microstructural behaviour of the joining zone during the tailored forming process. The goal is the determination of the macroscopic, effective, thermomechanical properties of joining zones during and after forming.The model will be able to capture the contact and diffusion processes during joining, the thermal and mechanical properties during forming as well as the material behaviour during heat treatment which is responsible for calibrating material properties.
      Led by: F. Aldakheel, P. Wriggers
      Team: C. Böhm, F. Töller
      Year: 2019
      Funding: DFG im Rahmen des SFB 1153

    Biomedical technology

    • Numerical simulation and experimental validation of biofilm formation
      In this Reserch , a state-of-the-art 3D computational model has been developed to investigate biofilms in a multi-physics framework using smoothed particle hydrodynamics (SPH) based on a continuum approach. Biofilms are in fact aggregation of microorganisms such as bacteria. Biofilm formation is a complex process in the sense that several physical phenomena are coupled and consequently different time-scales are involved. On one hand, biofilm growth is driven by biological reaction and nutrient diffusion and on the other hand, it is influenced by the fluid flow causing biofilm deformation and interface erosion in the context of fluid and deformable solid interaction (FSI). The geometrical and numerical complexity arising from these phenomena poses serious complications and challenges in grid-based techniques such as finite element (FE). Such issues are generally referred to as mesh distortion. Here the solution is based on SPH as one of the powerful meshless methods. SPH based computational modeling is quite new in the biological community and the method is uniquely robust in capturing the interface-related processes of biofilm formation especially erosion. The fact is that SPH is a versatile tool owing to its adaptive Lagrangian nature in the problems whose geometry is temporarily varying (dynamic). Moreover, its mesh-less feature is considered to be favorable in interpreting the method as a particle based one. Hence, it is quite straight forward to incorporate complex interactions and ad-hoc rules at the particle level into the method. This is the case for the problems with coupled governing equations with different time and length scale. In this thesis all different physics which account for biofilm formation have been implemented in the framework of SPH and one can say that this tool is purely SPH based. Besides the numerical simulation, experiments were conducted by our partners in the medical school of Hannover. The obtained numerical results show a good agreement with experimental and published data which demonstrates that the model is capable of predicting overall spatial and temporal evolution of the biofilms. The developed tool can be employed in either controlling the detrimental biofilms or harnessing the beneficial ones.
      Led by: Peter Wriggers
      Team: Meisam Soleimani, Peter Wriggers, Meike Stiesch
      Year: 2013
    • Gekoppelte Simulation von Aerosolströmungen in asthmatischen Bronchien
      Das Ziel dieses Projektvorhabens ist es, auf Basis eines gekoppelten 3D Mehrfeldmodells die partikelbeladene Luftströmung in gesunden sowie in asthmatisch verengten Bronchien anhand von numerischen Simulationen zu studieren.
      Led by: P. Wriggers, B. Avci
      Team: J. Stasch, J.-P. Fürstenau
      Year: 2014
      Funding: Leibniz Universität Hannover, Wege in die Forschung
    • Advanced multiscale computational mechanics for physiopathological behavior analysis of tissues and organs
      The physiological functionalities of large biological structures are highly affected by the mechanics of living tissues which is, in turn, related to microstructural arrangement of histological constituents and biochemical environment at nanoscale. Present research activity aims to develop a novel tissue multiscale description, including also inelastic mechanisms, coupled with an advanced computational formulation under finite strain and large-displacement assumptions. As a result, an innovative in-silico tool for simulation of organs and large biological structures will be developed, allowing to predict pathology-related damage or pharmacological-related healing and providing novel diagnostic and clinical indications for highly patient-specific medical treatments.
      Led by: P. Wriggers, M. Marino
      Year: 2015
      Funding: Alexander von Humboldt-Stiftung
    • Patient-Specific FSI Analysis of the Blood Flow in the Thoracic Aorta
      The complexity of numerical modeling and simulation of blood flow in patient-specific thoracic aorta geometries leads to a number of major computational challenging issues. For instance, for an adequate simulation of the flow and pressure field, the incompressible Navier-Stokes equations have to be solved with the assumption that the relatively thin blood vessels suffer large displacements and undergo large elastic or visco-elastic deformations caused by the pulsatile blood flow. Subsequently, inaccurate predictions would be obtained for the hemodynamic quantities with the very simplifying rigid-wall assumption (CFD modeling). Moreover, when applying only the CFD modeling approach the essential phenomena of pressure wave propagation in cardiovascular systems are disregarded, however these phenomena are of major relevance for clinical practice. Accordingly, strongly coupled FSI schemes are inevitable for comprehensive blood flow simulations in arterial systems, and as blood and vascular walls have comparable densities, monolithic or at least partitioned strongly coupled FSI schemes are required for solving the multi-physics problem with its inherent significant added-mass effects.
      Led by: P. Wriggers, B. Avci
      Team: B. Avci
      Year: 2016
    • Red blood cell simulation using a coupled shell-fluid analysis purely based on the SPH method
      If the rheological behavior of a Red-Blood-Cell (RBC) changes, for example due to some infection, it is reflected in its deformability when it passes through the microvessels. It can severely affect its proper function which is providing the oxygen and nutrient to the living cells. In this research project, a novel 3D numerical method has been developed to simulate RBCs based on the interaction between a shell-like solid structure and a fluid. RBC is assumed to be a thin shell encapsulating an internal fluid (Cytoplasm) which is submerged in an external fluid (blood plasma). The approach is entirely based on the smoothed particle hydrodynamics (SPH) method for both fluid and the shell structure. The method was motivated by the goal to benefit from the Lagrangian and meshless features of SPH in order to handle several complexities in the problem due to the coupling between the RBC membrane as a deformable elastic shell and interior/exterior fluids.
      Led by: Peter Wriggers
      Team: Meisam Soleimani
      Year: 2017
      Duration: 3 Jahre
    • Computational modeling of in-stent restenosis
      This project aims to develop a computational tool for the modeling of the long-term behaviour of stent deployment, with a special focus on both current and prospective approaches. A multiscale description of arterial constitutive behaviour will be employed, including possible damage due to the stenting procedure. Moreover, the chemo-biological mechanisms underlying the growth and remodelling due to wound healing in tissues will be introduced. Therefore, a multiphysics computational framework will be developed and applied for the analysis of both metal and drug-eluting stents. The project will allow to identify the dominant mechanisms driving in-stent restenosis, deciphering the role of the different molecular species in the pathological remodeling of arteries. The final target is to optimise the clinical outcome of current approaches and propose targeted therapeutic approaches.
      Led by: M. Marino
      Year: 2017
      Funding: Masterplan SmartBiotecs, MWK (Lower Saxony, Germany)

    High Performance Computing (HPC)

    • In many cases, massive parallel large-scale computations are indispensable for solving problems of practical interest. The numerical treatment of such class problems requires not only highly efficient scalable parallel solvers, moreover, efficient parallel algorithms covering the whole simulation pipeline – also including pre- and post-processing, mesh generation and design solvers considering uncertainties – are essential to model and to simulate large-scale or exascale class problems. The specific goal of this project is therefore the development and implementation of new parallel algorithms and methods that will allow to solve large-scale class problems with high efficiency.
      Led by: P. Wriggers, B. Avci
      Team: B. Avci
      Year: 2014
      Funding: FP7 of the EU
    • ISPH-based Simulation of the Selective Laser Melting Process
      Development of a thermo-mechanical model for the simulation of the SLM process.
      Led by: Christian Weißenfels, Peter Wriggers
      Team: M.Sc. Jan-Philipp Fürstenau
      Year: 2017

    Fracture Mechanics/ XFEM

    Multiscale and multiphysics material modelling of polycrystalline metals and forming processes

    • Water-induced damage mechanisms of cyclic loaded high-performance concretes
      The use of offshore wind energy is expanding and fatigue-loaded concrete structures are built that are submerged in water. This currently already applies to so-called grouted joints, where high-strength fine-grained concrete (grout) is used in the steel support structures of offshore wind turbines. Such constructions are subjected to several hundred million load cycles within their service life. An increased water content in the concrete results from the offshore exposure which is principally different to onshore constructions,. Comparatively few investigations of fatigue-tested concrete specimens immersed in water are documented in the literature. Despite the fact, that considerably scatterings occur in these results a clear tendency can be observed. Specimens that are immersed in water have a significantly lower fatigue resistance compared with specimens tested in air. Some investigations also show that fatigue-loaded concrete specimens immersed in water have a significant change in their fracture behaviour compared with specimens tested in air. This can be seen, in tests, for example, by ascending air bubbles, wash-outs of fine particles and premature crack initiation.Water-induced damage mechanisms in fatigue-loaded concrete have indeed been recognised in the past, but they were not identified and described with sufficient precision. Consequently, they cannot be quantified reliably. Based on the existing knowledge gap, the vast majority of these mechanisms have currently escaped numerical modelling and simulation.The aim of this research project is to understand, analyse and quantify macroscopically water-induced damage mechanisms of fatigue-loaded high-performance concretes in the Experimental-Virtual-Lab (EVL) with complementary very latest state-of-the-art experimental methods. At the same time, models will be created and numerically implemented on a micromechanical basis that enables proving of hypotheses that will be derived from the experimental investigations. The structural data serve for the validation of these models; the data will be determined by µCT scans, NMR measurements and mercury intrusion porosimetry.After a first clarification of the origin of mechanisms by the EVL, modelling at the macroscopic level will be attempted on the basis of the micromechanical investigations. In this way it will be verified, how the water influences the degradation behaviour of fatigue-loaded high-performance concretes and which additional active, water-induced damage mechanisms are decisively involved in the degradation process. It will be possible for the first time to carry out a prediction of the degradation behaviour of fatigue-loaded high-performance concretes immersed in water based on microstructurally orientated parameters.
      Led by: Fadi Aldakheel, Peter Wriggers
      Year: 2020
      Funding: DFG SPP 2020, zweite Förderperiode
      Duration: 3 Jahre

    Contact mechanics

    • MULTISCALE CONTACT HOMOGENIZATION OF GRANULAR INTERFACES
      Dry granular third bodies are frequently encountered at multiple scales of contact interfaces in contexts that range from mechanical problems of tire traction and semiconductor manufacturing to biological problems of wear debris generation and mobility in implant joints. The investigations that are envisaged within this proposal will provide further insight into the modeling and simulation of third body effects in a fully nonlinear three-dimensional virtual setting that accounts for inelastic phenomena.
      Led by: P. Wriggers, I. Temizer
      Team: R. Weidlich
      Year: 2009
    • Mutiscale FEM approach for rubber friction on rough surfaces
      Understanding the frictional behaviour of elastomers on rough surfaces is of high practical importance in many industrial applications. For example the traction of a tire is directly linked to the material properties of the considered elastomer and the surface conditions of the road track. One goal of our studies is to gain a deeper understanding of the underlying contact physics at all length scales. Another aim is to determine a macroscopic coefficient of friction for varying material and surface properties and to validate the results with experimental data.
      Led by: P. Wriggers
      Team: P. Wagner
      Year: 2012
    • Contact models for soil mechanics
      The installation of foundations influences strongly the load bearing capacity of the soil. The large discrepancy between experimental and numerical results, using Coulomb friction law for modeling the soil structure interaction, points out that new strategies to solve this kind of problems are necessary. Experimental observations show that for rough surfaces of the structure the friction angle at the contact zone corresponds to the friction angle of the soil. This leads to the conclusion that the contact zone lies completely within the soil. A way to improve the friction laws for soil structure interactions is to project the soil models onto the contact surface which is the motivation of this work. </a></p>
      Led by: P. Wriggers
      Team: C. Weißenfels
      Year: 2012
    • Application of the Virtual Element Method to Non-Conforming Contact Interfaces
      When using standard Finite Elements the discretization is subject to limitations depending on the element geometry. In contrast to this the Virtual Element Method offers the possibility for elements with an arbitrary number of nodes and special geometries like non-convex polygons or hanging nodes. In this Project the application of the Virtual Elements to different problems is investigated. Here it is used to create an efficient contact discretization.
      Led by: P. Wriggers
      Team: W. Rust
      Year: 2014
    • Towards multiscale modeling of Abrasive wear
      The work is motivated towards understanding wear as a multiscale-multiphysics approach. A 3D framework is developed to simulate cracks propagation in a microstructure due to contact loading to eventually predict wear trends in filled elastomeric compounds.
      Led by: P. Wriggers
      Team: A. B. Harish
      Year: 2015

    Additive Manufacturing

    Discrete Elements and Molecular Dynamics

    • Discrete Element Method
      This project is concerned with the development of a discrete element method (DEM) code for the simulation of large particle systems in 3-D, where also complex moving boundary geometries can be taken into account. The DEM is a well established numerical method to simulate systems consisting of granular matter. Granular mixing, tumbling mills, transport of particles via conveyor belts or screw conveyors are just some examples of important particulate processes in industry sectors like mining, pharmaceutical and food industries. For such systems, the optimization of the design variables as well as the appropriate choice of the operating parameters is still a difficult and a challenging task.
      Led by: P. Wriggers
      Team: B. Avci
      Year: 2011

    Artificial Intelligence

    • Using Machine Learning to Improve the Modelling of Machining and Cutting Processes
      Metal cutting is a fundamental process in industrial production. The fast and accurate on-line prediction of metal cutting processes is crucial for the Intelligent Manufacturing (IM). With the advent of high-speed computing, robust numerical algorithms and machine learning technology, computational modelling serves as a tool for not only accurate but also fast predicting the complex machining processes and understanding the complex physics. In this work, the machine learning based numerical model is developed for simulation of metal cutting processes.
      Led by: C. Weißenfels, P. Wriggers
      Team: M.Sc. Dengpeng Huang
      Year: 2018
      Funding: China Scholarship Council (CSC)
    • Physics-Informed Data-Driven Simulation
      This project investigates to what extent simulation with neural networks on the one hand and data-based empirical modeling on the other hand can be combined in a symbiotic manner. The ultimate goal is the generation of reliable models for complex dynamical systems known as digital twins.
      Led by: H. Wessels, P. Wriggers
      Team: H. Wessels
      Year: 2020

    Finite element technology

    • Large Deformation Cohesive-Zone Element for Fracture in Rubbery Polymers
      In this work, a 3D cohesive zone element is developed considering material and geometric nonlinearities and suitable for modeling large deformations and rotations.
      Led by: P. Wriggers
      Team: A. B. Harish
      Year: 2015
    • The stress and fatigue analysis of the transportation line
      The conveyor of the production line in Salzgitter Flachstahl GmbH which carries the steel coils is going to be subjected to an extra load due to the bigger coil size. The objective is to do a structural analysis of the conveyor to see if the safety factor of structure is still in the allowable region. Since, the loading condition is naturally variable due to continuously feeding the moving conveyor with steel coils, a fatigue analysis is required in addition to an ordinary static analysis.
      Led by: Peter Wriggers
      Team: Meisam Soleimani
      Year: 2018

Publications

Showing entries 611 - 620 out of 639
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1991

Note on finite-element implementation of pressure boundary loading. / Simo, J. C.; Taylor, R. L.; Wriggers, Peter.

In: Communications in Applied Numerical Methods, Vol. 7, No. 7, 10.1991, p. 513-525.

Research output: Contribution to journal › Article › Research › peer review

More...

Nonlinear computational mechanics : state of the art. / Wriggers, Peter.

Berlin : Springer Nature, 1991.

Research output: Book/Report › Monograph › Research

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1990

Nonlinear stability-analysis of shell and contact-problems including branch-switching. / Stein, E.; Wagner, W.; Wriggers, Peter.

In: Computational mechanics, Vol. 5, No. 6, 11.1990, p. 428-446.

Research output: Contribution to journal › Article › Research › peer review

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A fully non-linear axisymmetrical membrane element for rubber-like materials. / Wriggers, Peter; Taylor, R. L.

In: Engineering computations, Vol. 7, No. 4, 01.04.1990, p. 303-310.

Research output: Contribution to journal › Review article › Research › peer review

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A general procedure for the direct computation of turning and bifurcation points. / Wriggers, Peter; Simo, J. C.

In: International Journal for Numerical Methods in Engineering, Vol. 30, No. 1, 07.1990, p. 155-176.

Research output: Contribution to journal › Article › Research › peer review

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Finite element formulation of large deformation impact-contact problems with friction. / Wriggers, Peter; Vu Van, T.; Stein, E.

In: Computers and Structures, Vol. 37, No. 3, 1990, p. 319-331.

Research output: Contribution to journal › Article › Research › peer review

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1989

Theory and numerics of thin elastic shells with finite rotations. / Gruttmann, F.; Stein, E.; Wriggers, Peter.

In: Ingenieur-Archiv, Vol. 59, No. 1, 01.1989, p. 54-67.

Research output: Contribution to journal › Article › Research › peer review

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Interaktive Steuerung von nichtlinearen Finite-Element-Algorithmen mittels eines Expertensystems. / Wriggers, Peter; Tarnow, N.

In: Bauingenieur Berlin, Vol. 64, No. 2, 1989, p. 57-65.

Research output: Contribution to journal › Article › Research › peer review

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Thin shells with finite rotations. Theory and finite element formulation. / Wriggers, Peter; Gruttmann, F.

Anal Comput Model Shell Presented Winter Ann Meet ASME. Publ by ASME, 1989. p. 135-159 (Anal Comput Model Shell Presented Winter Ann Meet ASME).

Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review

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1988

A simple method for the calculation of postcritical branches. / Wagner, W.; Wriggers, Peter.

In: Engineering computations, Vol. 5, No. 2, 01.02.1988, p. 103-109.

Research output: Contribution to journal › Review article › Research › peer review

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Showing entries 611 - 620 out of 639
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Last Change: 13.03.23 Print

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