Article
Engineering, Multidisciplinary
Michael Neunteufel, Astrid S. Pechstein, Joachim Schoeberl
Summary: This paper extends the TDNNS method to nonlinear elasticity by lifting the distributional derivatives of the displacement vector to a regular strain tensor using the Hu-Washizu principle. Three different methods are introduced using either the deformation gradient, the Cauchy-Green strain tensor, or both as independent variables. The good performance and accuracy of the methods are demonstrated through numerical examples where stress and strain variables are locally eliminated in linear sub-problems, resulting in an equation system solely in terms of displacement variables.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Computer Science, Interdisciplinary Applications
Alireza Beheshti, Reza Ansari
Summary: This paper focuses on the geometrically nonlinear analysis of laminated composite shells using the finite element method. A higher-order shell model with extensible directors possessing twelve parameters is used to extract the exact Green-Lagrange strains and the three-dimensional second Piola-Kirchhoff stress tensor based on the base vectors of the shell mid-surface. The weak form of governing equations is derived using the principle of virtual work. A computationally efficient four-node shell element is designed to address locking problems and the ANS approach and assumed strain scheme are employed. Standard benchmarks for isotropic materials with geometric nonlinearity are solved to examine the performance of the proposed shell element, and results of thin and thick layered composite structures are presented.
ENGINEERING WITH COMPUTERS
(2023)
Article
Computer Science, Software Engineering
Simon Duenser, Bernhard Thomaszewski, Roi Poranne, Stelian Coros
Summary: Many flexible structures have a small number of compliant modes, but predicting these modes is challenging. To address this, we propose Nonlinear Compliant Modes, an extension of linear eigenmodes for large-deformation analysis. Our method correctly predicts nonlinear effects that linear eigenanalysis fails to capture.
ACM TRANSACTIONS ON GRAPHICS
(2023)
Article
Engineering, Multidisciplinary
Bartosz Borzeszkowski, Izabela Lubowiecka, Roger A. Sauer
Summary: This paper presents a Finite Element Model Updating method based on an efficient isogeometric shell formulation for reconstructing heterogeneous material distributions. With nonlinear hyperelastic material models and bilinear element discretization, as well as flexible incorporation of experimental data, accurate reconstructions are achieved.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Mechanical
Keisuke Otsuka, Yinan Wang, Koji Fujita, Hiroki Nagai, Kanjuro Makihara
Summary: This study developed a novel consistent strain-based multifidelity modeling framework to address the problems in conventional multifidelity modeling. By leveraging new vector-strain transformations, all fidelity models obtained from the proposed framework consistently use the same external force model. The framework was validated using a hydrodynamic force model, and the simulation results concurred with conventional models and experiments. The reduction in calculation time provided by low-fidelity models has significant implications for conceptual and initial designs.
JOURNAL OF COMPUTATIONAL AND NONLINEAR DYNAMICS
(2022)
Article
Mechanics
D. Bertrand, S. Grange, F. Bourrier, T. Langlade
Summary: This paper presents a formulation of a finite element to model cable-based structures in dynamics conditions while maintaining specific internal mechanical equilibrium. By using the concept of macro finite element, complex mechanical systems can be embedded and solved within the element boundaries, allowing easy implementation within classical commercial codes.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Review
Engineering, Mechanical
Hossein B. Khaniki, Mergen H. Ghayesh, Rey Chin, Marco Amabili
Summary: This paper presents a critical review of the nonlinear dynamics of hyperelastic structures and materials, including an introduction to the constitutive laws of hyperelasticity, continuum mechanics techniques, and the application of hyperelasticity to model the nonlinear dynamics of polymeric structures. This review is of great importance for stimulating the development of more accurate and reliable models.
NONLINEAR DYNAMICS
(2022)
Article
Engineering, Civil
Yacine Ben-Youssef, Youcef Kerboua, Aouni A. Lakis
Summary: This paper presents a numerical model for analyzing the aeroelastic stability of a thin cylindrical shell subjected to external supersonic airflow, taking into account the effect of geometric nonlinearity on the dynamic behavior of the structure. Numerical studies are conducted to validate the accuracy of the model.
THIN-WALLED STRUCTURES
(2022)
Article
Engineering, Multidisciplinary
Pavan Kumar Asur Vijaya Kumar, Aamir Dean, Jose Reinoso, Marco Paggi
Summary: This passage reviews the research on fracture phenomena of thin-walled structures in recent decades, introduces the development of a thermodynamically consistent framework for thin-walled structures under the influence of temperature, and the method of using fully-integrated solid shell finite elements for coupled thermo-mechanical phase-field modeling.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Civil
Haowen Hou, Wei Wang, Shiye Wang
Summary: This paper provides both continuum finite element (CFE) modeling and fiber-based modeling methods for the nonlinear cyclic analyses of double-skin composite walls (DSCWs). The models are validated by experimental results, achieving good agreement. Two modification methods for the enhancement of confining effect due to interactional constraints of concrete in continuous multi-cavities are proposed. The reliability of the RSMM parameters that control the buckling and fracture of steel fibers is verified.
THIN-WALLED STRUCTURES
(2023)
Article
Multidisciplinary Sciences
Mauricio C. Vanzulli, Jorge M. Perez Zerpa
Summary: This article presents a novel approach for the computation of aerodynamic forces in frame structures by coupling the co-rotational framework with the quasi-steady theory, providing accurate solutions for challenging problems.
Article
Mechanics
Zahra Ghadimi, Behrooz Hassani
Summary: This paper investigates the geometrically nonlinear analysis of laminated and piezolaminated shells using the isogeometric method. The initial director vectors at control points are obtained by solving a defined system of equations at the Greville points, resulting in an efficient convergence for high-order NURBS. The formulation is based on the Reissner-Mindlin assumption and an updated Lagrangian approach. An analytical integration is performed in each layer to reduce computational cost.
Article
Engineering, Civil
M. Kohansal-Vajargah, R. Ansari
Summary: The paper presents a free vibration analysis of three-dimensional micropolar structures with different geometries and studies the effects of length scale parameter on the dimensionless natural frequencies of micropolar structures with various geometries.
THIN-WALLED STRUCTURES
(2021)
Article
Engineering, Aerospace
Dimitris Varelis, Dimitris A. Saravanos
Summary: This paper investigates the nonlinear electromechanical response of shallow piezoelectric laminated shells under mechanical pressure loads, predicting the transition between stable and unstable states using a coupled nonlinear mechanics model. The results demonstrate the predictive capability and complexity of the electromechanical behavior of the shells.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Mechanics
Alireza Beheshti, Reza Ansari
Summary: The current study focuses on the transient dynamic analysis of composite shells with geometric nonlinearity. A 12-parameter shell model suitable for thick composite structures is used to extract strains and stresses. The weak form is constructed based on Hamilton's principle, and the nonlinear finite element method, total Lagrangian scheme, and composite time integration approach are employed to solve the dynamic problem. Approaches are taken to overcome numerical anomalies related to the four-node shell element, such as transverse shear, membrane, and curvatures-thickness locking. Several problems are solved to assess the newly developed shell element, comparing it with available literature data.
COMPOSITE STRUCTURES
(2023)
Article
Chemistry, Multidisciplinary
Tobias Keplinger, Falk K. Wittel, Markus Rueggeberg, Ingo Burgert
Summary: Wood-derived cellulose materials obtained through structure-retaining delignification exhibit excellent mechanical properties and potential as renewable cellulose scaffolds. However, for faster progress in the field, a more comprehensive characterization of the developed materials is needed.
ADVANCED MATERIALS
(2021)
Correction
Materials Science, Composites
Ahmad Rafsanjani, Dominique Derome, Falk K. Wittel, Jan Carmeliet
COMPOSITES SCIENCE AND TECHNOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Eashan Saikia, Nino F. Laubli, Jan T. Burri, Markus Ruggeberg, Christian M. Schleputz, Hannes Vogler, Ingo Burgert, Hans J. Herrmann, Bradley J. Nelson, Ueli Grossniklaus, Falk K. Wittel
Summary: Insects become prey to the Venus flytrap when they touch the sensory hairs on the flytrap lobes, triggering trap closure. The mechanical stimulus from the touch induces an electrical response in sensory cells of the trigger hair, with mechanosensitive ion channels opening due to membrane tension changes. A multi-scale hair model was used to investigate how stimuli act on sensory cells, revealing high-stretch regions localized in the interior of the cell wall rather than at the notch periphery. Different cell shape variants were also studied to understand the influence of morphology on these high-stretch regions and potentially provide new insights into mechanotransduction activity in the flytrap.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
Article
Chemistry, Physical
Pavel S. Iliev, Falk K. Wittel, Hans J. Herrmann
Summary: Freestanding columns built with loose gravel and continuous strings can be stable at several meters in height and withstand vertical loads that can severely fragment the core grains. Dynamic simulations using rigid particles and elastic chains explain this counter-intuitive behavior, revealing fundamental intrinsic differences compared to the well-studied case of confining silos.
EUROPEAN PHYSICAL JOURNAL E
(2021)
Article
Biophysics
Eashan Saikia, Nino F. Laeubli, Hannes Vogler, Markus Rueggeberg, Hans J. Herrmann, Ingo Burgert, Jan T. Burri, Bradley J. Nelson, Ueli Grossniklaus, Falk K. Wittel
Summary: The study investigates the cellular-level kinematics of Venus flytrap's sensory hairs in response to stimuli, finding that viscoelasticity and intercellular fluid transport, along with angular velocity, play a role in the plant's rate-dependent response. The research also establishes a multi-scale kinematic link between angular velocity and cell wall stretch, suggesting that mechanosensitive ion channels in the plasma membrane of sensory cells may be sensitive to the rate of stretch application.
BIOMECHANICS AND MODELING IN MECHANOBIOLOGY
(2021)
Article
Multidisciplinary Sciences
Roman Vetter, Dagmar Iber
Summary: Morphogen gradients encode positional information during development. This study shows that the observed precision of progenitor domain boundaries can be achieved with a single gradient, and the patterning mechanism can generate even greater precision in progenitor cell numbers.
NATURE COMMUNICATIONS
(2022)
Article
Biology
Mustafa Basaran, Y. Ilker Yaman, Tevfik Can Yuece, Roman Vetter, Askin Kocabas
Summary: Research suggests that complex interactions and biomechanical factors regulate the bacterial orientation and formation of ordered structures during colony growth. The velocity profile and growth geometry play a significant role in determining the orientation of bacteria. The dynamics of these ordered structures depend on bacterial length and can enhance bacterial survival around nutrient-rich areas.
Article
Physics, Multidisciplinary
Dagmar Iber, Roman Vetter
Summary: Pseudostratified epithelia have irregular cell shapes along the apical-basal axis, which are determined by fundamental geometric relationships that minimize lateral cell-cell contact energy. This understanding provides a new perspective on epithelial cell organization and can be utilized in the development of 3D simulation frameworks for studying epithelial dynamics.
FRONTIERS IN PHYSICS
(2022)
Article
Cell Biology
Dagmar Iber, Roman Vetter
Summary: Researchers have investigated the underlying mechanisms that ensure the precision and robustness of developmental outcomes. Recent studies have provided new insights into the basis of precise development by quantifying chemical gradients and epithelial cell shapes.
CURRENT OPINION IN GENETICS & DEVELOPMENT
(2022)
Article
Forestry
Jonas Matthias Maas, Phillipe Groenquist, Jennifer Furrer, Vanessa Studer, Anselmo Malvetti, Markus Rueggeberg, Falk K. Wittel
Summary: This paper proposes a novel approach to assess residual stresses caused by moisture introduced by adhesives in modern timber engineering. By using wooden bilayers as a reporter system and determining the stress-driving parameters, the residual stresses in adhesive bondlines can be calculated, emphasizing the approach's scale independence and general applicability to larger scale structures.
WOOD SCIENCE AND TECHNOLOGY
(2022)
Article
Developmental Biology
Jan A. Adelmann, Roman Vetter, Dagmar Iber
Summary: Tissue patterning during embryonic development is highly precise. By numerical analysis, we found that the positional error of morphogen gradients increases with gradient length, cell diameter, and readout position. This precision enables high patterning precision over developmental time, especially in epithelial tissues with small cross-sectional cell areas. Our findings also suggest that enhanced precision may have led to the emergence of pseudostratification in epithelia.
Article
Biology
Jan Andreas Adelmann, Roman Vetter, Dagmar Iber
Summary: Morphogen gradients help cells determine their position in tissue. Cell-based simulations were used to compare the positional error of linear and non-linear morphogen decay. The study found that non-linear decay reduces positional error near the source, but increases it significantly far from the source in tissues with flux barriers. These findings suggest that morphogen decay dynamics may not play a significant physiological role in patterning precision.
Article
Multidisciplinary Sciences
Yuchong Long, Roman Vetter, Dagmar Iber
Summary: This study finds that transverse diffusion effects can enhance the precision of pattern formation in epithelial tissues patterned by morphogen gradients. The positional error decreases in wider tissues but saturates beyond a width of about ten cells. This research demonstrates that gradient-based patterning in two-or higher-dimensional systems can achieve even greater precision than predicted by 1D models, highlighting the potential of noisy morphogen gradients for high-precision tissue patterning.
Article
Multidisciplinary Sciences
Veerle de Goederen, Roman Vetter, Katie McDole, Dagmar Iber
Summary: This study investigates the biomechanical mechanism of mammalian neural tube formation using a mechanical finite element model. The researchers achieved neural tube closure by simulating mesoderm expansion, nonneural ectoderm expansion, and neural plate adhesion to the notochord. They propose that the biomechanical force for dorsolateral hinge point formation comes from zippering.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Correction
Construction & Building Technology
D. Derome, A. Rafsanjani, S. Hering, M. Dressler, A. Patera, C. Lanvermann, M. Sedighi-Gilani, F. K. Wittel, P. Niemz, J. Carmeliet
JOURNAL OF BUILDING PHYSICS
(2021)
