Article
Mechanics
Wenjun Chen, Vincent Beng Chye Tan, Xiangguo Zeng, Pei Li
Summary: A dual-scale discrete fracture calculation method is proposed to study the discrete crack growth of heterogeneous materials. By embedding a representative volume element (RVE) with a cohesive zone into the Gauss points of the macro-element, the full finite element model of the discrete crack is replaced, improving both the dual-scale modeling and reducing computational cost. The method is shown to be compatible with commercial software. The fracture process of a two-phase heterogeneous material is studied using this method, and the resulting macro-fracture direction is consistent with experimental observations.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Multidisciplinary
Daniel Dias-da-Costa, Marcelo R. Carvalho, Milad Bybordiani
Summary: Many advanced methods have been developed for predicting discrete fracture within the finite element framework, with the goal of enhancing the continuous displacement field with a discontinuous part. These methods provide unprecedented versatility in discretising domains with prescribed and evolving boundaries, but can incur additional computational burden with global tracking schemes. A new method, the Cracked Zone Clustering Method (CZCM), is proposed to address these issues by introducing minimal enhanced degrees of freedom and decoupling the discretisation of bulk and cracks. Results show that CZCM can significantly reduce the required number of enhancement degrees of freedom while maintaining accuracy.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Polymer Science
Yuki Ogawa, Kimiyoshi Naito, Keisuke Harada, Hiroyuki Oguma
Summary: This study compared and analyzed the critical separation energy of three SGA adhesives, as well as examined the mechanical properties of the bond. It was found that the highly ductile adhesive showed plastic deformation in the steel adherends during the loading-unloading test, while the high tensile strength and modulus adhesives experienced a sudden decrease in load without plastic deformation. The critical separation energy increased with increasing adhesive thickness, and the highly ductile adhesives were more affected by adhesive thickness than highly strength adhesives.
Article
Chemistry, Multidisciplinary
Yinge Zhu, Huiyuan Chen, Anqi Li, Yue Wu, Xiaoli Zhang
Summary: The mechanical behaviors of rock masses are significantly affected by the distribution and shape of the holes in it. In this research, the fracture mechanism and the shear properties of rock masses containing holes were investigated using the cohesive zone model (CZM) method. The results show that the shear process can be divided into elastic, strengthening, plastic, and residual stress stages, and the shear rate and normal stress are positively correlated with shear strength and dilatancy. The cracking behavior and mechanical properties of the specimens are closely related to the shear rate and normal stress.
APPLIED SCIENCES-BASEL
(2022)
Article
Engineering, Multidisciplinary
Toshio Nagashima, Chenyu Wang
Summary: In this study, a two-dimensional four-node quadrilateral element enriched with the Heaviside step function is proposed for crack analyses within the extended finite element method framework. The crack geometry is implicitly expressed using two types of signed distance functions, and finite elements interacting with the crack are appropriately partitioned based on level set values. The stiffness matrix and internal force vectors are derived through numerical integration. The proposed method is validated by evaluating stress intensity factors, analyzing crack propagation, and comparing results with reference solutions.
INTERNATIONAL JOURNAL OF COMPUTATIONAL METHODS
(2022)
Article
Mechanics
Chenyu Wang, Toshio Nagashima
Summary: A quasi-three-dimensional extended finite element method (XFEM) is used to analyze damage propagation in carbon fiber reinforced plastics (CFRPs) laminates. Delamination and matrix cracks are modeled using an eight-node quadrilateral interface element and an eight-node hexahedral continuum element enriched with only the Heaviside function, respectively. The zig-zag enhanced cohesive zone model is applied to delamination and matrix cracks. The system equations considering material nonlinearity are solved using the implicit static method. The effectiveness of the quasi-three-dimensional XFEM for damage propagation analysis in CFRP laminates is demonstrated through comparison with experimental results.
COMPOSITE STRUCTURES
(2023)
Article
Mechanics
Rossana Dimitri, Martina Rinaldi, Marco Trullo, Francesco Tornabene, Corrado Fidelibus
Summary: This paper investigates the mechanical properties of elements in the lithosphere, using Finite Element Method and eXtended Finite Element Method to address the fracturing problem in Opalinus Clay (OPA) formation. The approaches are successfully compared despite the complex nonlinear nature of the problem.
COMPOSITE STRUCTURES
(2021)
Article
Engineering, Mechanical
Jiqiang Zhang, Shasha Wang, Wei Dong
Summary: A three-dimensional numerical method accounting for boundary effect on fracture energy and initial fracture toughness was developed to simulate the propagation process of mode-I local crack in concrete. The results showed good agreement with experimental data, confirming the validity of the proposed method. The evolution of local crack and fracture process zone during the propagation process were also studied, revealing important insights into crack behavior in concrete.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Philipp Kowol, Swantje Bargmann, Patrick Goerrn, Jana Wilmers
Summary: Stretchable electronics utilize soft polymers and microstructural designs to enhance the stretchability of electronic materials. The introduction of controlled cracks in the polymer substrate's surface can significantly increase macroscopic stretchability. The design of soft islands demonstrates outstanding strain relief capabilities and allows for the integration of rigid functional parts.
EXTREME MECHANICS LETTERS
(2022)
Article
Mechanics
Tommaso Papa, Massimiliano Bocciarelli
Summary: Cyclic cohesive zone models are useful for describing fatigue driven crack propagation in various engineering applications. This paper proposes a robust inverse analysis procedure to investigate the identifiability of the model parameters governing fatigue induced damage evolution. The procedure utilizes a calibrated meta model to reduce computational cost and solves the inverse problem using Monte Carlo like procedures. The results highlight the identifiability of the model parameters and provide indications for measuring setups in laboratory investigations.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Chemistry, Physical
Omar Alrayes, Carsten Koenke, Khader M. Hamdia
Summary: This study presents numerical simulations of mixed-mode crack propagation in concrete using the scaled boundary finite element method (SBFEM). The numerical results are compared against the results from available publications, and good consistency is found. The damage accumulation parameter is identified as the most influential variable on the load-displacement results. The proposed method provides a further investigation of crack growth propagation and damage accumulation for cyclic loading within the SBFEM framework.
Article
Energy & Fuels
Pengyu Wang, Shuhong Wang, Alipujiang Jierula, Zihan Sun
Summary: This study investigates the connection and bifurcation problems of rock crack propagation by inserting cohesive elements, and finds the best method for insertion. Results show that using the maximum principal stress criterion and displacement law can achieve the best simulation outcomes.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2021)
Article
Mechanics
Bin Chen, Sam Coppieters, Erik Jungstedt
Summary: We propose an element-removal (ER) global digital image correlation (DIC) method to improve the measurement accuracy of discontinuous deformation fields, such as crack propagation. The proposed ER-global-DIC algorithm iteratively identifies and removes all the elements covering the crack, during the updating of displacement fields. The effectiveness and accuracy of the proposed method are validated through synthetically deformed images and applied to measure discontinuous displacement fields containing a crack deflection.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Mechanics
Yang Bai, David A. Santos, Shahed Rezaei, Peter Stein, Sarbajit Banerjee, Bai-Xiang Xu
Summary: This study developed a thermodynamically consistent framework to investigate the unique chemo-mechanics phenomena resulting from grain boundaries. Constitutive laws for large deformations were derived from free energies, and a chemomechanically coupled cohesive zone model was developed to consider the presence of grain boundaries.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2021)
Article
Materials Science, Multidisciplinary
M. Ciavarella, T. Zhang, R. M. McMeeking
Summary: This study analyzes crack growth in viscoelastic material and computes the work done and dissipation per unit area of crack growth under applied load. The results suggest that crack growth models based on quantifying the dissipation per unit area are not applicable to components with finite geometry, while models based on a rupture process zone are easier to implement.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Review
Cell Biology
Lucy M. Wang, Ellen Kuhl
Summary: Normal axon development relies on mechanical forces, but excessive forces can cause damage. Computational models assist in studying the role of mechanical forces in axon growth and damage. They evaluate interactions between different force sources within the cytoskeleton and optimize externally applied tension. They also investigate how forces distribute among axon components and how the tissue surrounding an axon affects its susceptibility to injury.
SEMINARS IN CELL & DEVELOPMENTAL BIOLOGY
(2023)
Article
Engineering, Biomedical
Kevin Linka, Sarah R. St. Pierre, Ellen Kuhl
Summary: The brain is an extremely soft and vulnerable organ, and understanding its physics is crucial but challenging. This study proposes a new strategy that combines thermodynamics and machine learning to build an artificial neural network for automated model discovery. The results demonstrate the potential of this method to shift from user-defined model selection to automated model discovery.
ACTA BIOMATERIALIA
(2023)
Article
Engineering, Multidisciplinary
Kevin Linka, Ellen Kuhl
Summary: For over a century, scientists from various fields have proposed different models to characterize the behavior of materials under mechanical loading. However, classical neural networks fail to consider previous research in constitutive modeling and have limitations in predicting behavior beyond the training data. In this study, a new family of Constitutive Artificial Neural Networks (CANN) is developed to overcome these limitations and satisfy physical constraints. CANN shows promise in automating model discovery and has the potential to revolutionize constitutive modeling.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Lin Zhan, Siyu Wang, Shaoxing Qu, Paul Steinmann, Rui Xiao
Summary: Many classic hyperelastic models cannot accurately predict the stress responses of soft materials in complex loading conditions. We propose a new micro-macro transition approach integrated into a full network framework, which successfully captures the stress responses in multi-axial deformation modes for soft materials. We further develop a two-parameter hyperelastic model that exhibits greatly improved predictive ability for complex loading types compared to other existing models.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Miguel Angel Moreno-Mateos, Mokarram Hossain, Paul Steinmann, Daniel Garcia-Gonzalez
Summary: Pre-existing flaws in highly stretchable elastomers can cause fractures under large deformations. This study shows that ultra-soft magnetorheological elastomers with remanent magnetization have 50% higher fracture toughness compared to non-pre-magnetized samples. The opening of cracks in pre-magnetized elastomers is delayed due to crack closure induced by the magnetic field. Numerical simulations also reveal that pre-magnetized elastomers have reduced stress concentration at the crack tip. This work reveals potential applications for functional actuators with improved fracture behavior and performance under cyclic loading.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Engineering, Biomedical
Fikunwa O. Kolawole, Mathias Peirlinck, Tyler E. Cork, Marc Levenston, Ellen Kuhl, Daniel B. Ennis
Summary: Impaired cardiac filling in heart failure is caused by increased passive myocardial stiffness. In this study, we used inverse finite element analysis based on MRI and pressure data to estimate in vivo passive myocardial stiffness. Soft and stiff heart phantoms were created using 3D printing and their stiffness was accurately estimated. The results suggest that MRI-driven computational modeling can accurately estimate synthetic heart material stiffness in a certain range.
ANNALS OF BIOMEDICAL ENGINEERING
(2023)
Article
Mathematics, Interdisciplinary Applications
Vahidullah Tac, Kevin Linka, Francisco Sahli-Costabal, Ellen Kuhl, Adrian Buganza Tepole
Summary: Data-driven methods have revolutionized the understanding and modeling of materials by providing unprecedented flexibility. However, they also have limitations such as reduced extrapolation capacity and violation of physics constraints. In this review, we compare and extend three promising data-driven methods - CANN, ICNN, and NODE - that automatically satisfy these requirements within the context of hyperelasticity. By training them against stress-strain data, we find that all three methods capture the data perfectly without overfitting and exhibit some extrapolation capability. The models show a trade-off between number of parameters and accuracy, but retain flexibility and accuracy without compromising on the physics.
COMPUTATIONAL MECHANICS
(2023)
Article
Engineering, Multidisciplinary
Kevin Linka, Adrian Buganza Tepole, Gerhard A. Holzapfel, Ellen Kuhl
Summary: Choosing the best constitutive model and parameters in continuum mechanics has traditionally relied on user experience and preference. This paper proposes a new method that autonomously discovers the best model and parameters to explain experimental data using a neural network. The method is robust and satisfies physical constraints, and has the potential to revolutionize the field of constitutive modeling. Evaluation: 8 points
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Bartosz Kaczmarski, Derek E. Moulton, Alain Goriely, Ellen Kuhl
Summary: The design of versatile soft actuators is a challenging task due to the trade-off between robotic adaptability and structural complexity. Researchers have used statistical and physical models to simulate the mechanical behavior of soft actuators and identify optimal designs. However, the automated optimization of soft robots requires balancing simplifying assumptions and expensive simulations. In this study, a generalized Bayesian optimization method is proposed to identify designs of fiber-based biomimetic soft-robotic arms that minimize actuation energy under arbitrary robotic control requirements.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Anna Titlbach, Areti Papastavrou, Andrew McBride, Paul Steinmann
Summary: In this study, a novel phenomenological approach based on a micromorphic formulation is proposed to consider the trabecular microstructure and non-local characteristics of bone in continuum bone remodelling. The influence of characteristic size and coupling between macro- and microscale deformation is analyzed through benchmark examples. The results demonstrate that the micromorphic formulation effectively captures the interaction between continuum points at the macroscale and their neighborhood, affecting the distribution of bone density at the macroscale.
COMPUTER METHODS IN BIOMECHANICS AND BIOMEDICAL ENGINEERING
(2023)
Article
Materials Science, Multidisciplinary
Lucie Spannraft, Paul Steinmann, Julia Mergheim
Summary: This article proposes a generalized mechanical interface model for nonlinear kinematics. The interface's response allows for jump in deformations, cohesive failure, and interfacial (in)elasticity. An anisotropic cohesive law is formulated to induce additional shear-like stresses within the interface. Damage variables are used to couple cohesive and membrane degradations, considering the interaction between different deformation modes. The model is thermodynamically consistent and fulfills the balance equations and material frame indifference. Numerical examples demonstrate the influence of damage coupling on the mechanical response of adhesive layers.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Lin Zhan, Siyu Wang, Shaoxing Qu, Paul Steinmann, Rui Xiao
Summary: In this work, a general approach based on continuum damage mechanics is proposed to model the Mullins effect in soft composites. One-dimensional and three-dimensional damage models are formulated, which successfully describe the stress response in loading-unloading cycles and the anisotropic response of predeformed materials.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Engineering, Manufacturing
Julia Mergheim, Christoph Breuning, Christian Burkhardt, Daniel Hubner, Johannes Kopf, Ludwig Herrnbock, Zerong Yang, Carolin Korner, Matthias Markl, Paul Steinmann, Michael Stingl
Summary: This paper introduces a multiscale and multi-purpose simulation framework for investigating selective beam melting processes in metallic cellular structures. Process simulation methods are used to analyze the relationship between process strategies and resulting properties of the cellular materials. Numerical homogenization methods are applied to study the influence of grain structure and topology on the mechanical properties of the cellular materials. A two-scale optimization of components made of cellular material is performed to improve the buckling resistance of the structures. The results show that consistent simulations of additive manufacturing of cellular materials provide important insights into process-structure interactions and enable tailored additive manufacturing processes.
JOURNAL OF MANUFACTURING PROCESSES
(2023)
Article
Engineering, Multidisciplinary
Skyler R. St Pierre, Divya Rajasekharan, Ethan C. Darwin, Kevin Linka, Marc E. Levenston, Ellen Kuhl
Summary: Artificial meat can replicate the mechanical properties of real meat, while vegetarian meat products are stiffer. Using neural networks and automated model discovery, we can analyze and compare the mechanical properties of different types of meat, which can inform the design of more authentic meat substitutes.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Biomedical
Lucy M. Wang, Kevin Linka, Ellen Kuhl
Summary: The stiffness of soft biological tissues depends on both the applied deformation and the deformation rate. A new trend suggests using machine-learning to simultaneously discover the best model and parameters to explain the data. By combining feed-forward and recurrent neural networks, a novel architecture is proposed to discover the time-dependent behavior of soft tissues, which outperforms other models in terms of prediction accuracy.
JOURNAL OF THE MECHANICAL BEHAVIOR OF BIOMEDICAL MATERIALS
(2023)
