Article
Engineering, Multidisciplinary
Martin Horak, Antonio J. Gil, Rogelio Ortigosa, Martin Kruzik
Summary: The use of Electro-Active Polymers (EAPs) for soft robotic actuators has seen impressive development, with a focus on advanced three-dimensional actuation and accurate constitutive models. This paper introduces a novel polyconvex transversely isotropic formulation for simulating EAPs at large strains and presents important results in terms of minimizers and material stability.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Javier Bonet, Chun Hean Lee, Antonio J. Gil, Ataollah Ghavamian
Summary: This paper presents a computational framework for the numerical analysis of large strain dynamics and thermo-elastic systems, incorporating constitutive laws, polyconvexity considerations, and hyperbolicity analysis. The research extends to different elastic models and introduces a generalized convex entropy function. Additionally, a stabilised Petrov-Galerkin framework is proposed for the numerical solution of the thermo-elastic system, with various numerical examples provided to assess the formulation's applicability and robustness.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2021)
Article
Multidisciplinary Sciences
M. H. B. M. Shariff, J. Merodio, R. Bustamante
Summary: In the past, fibre stiffness of finite-radius fibres was modelled using nonlinear models based on strain-gradient theory or Kirchhoff rod theory. However, these models have limitations in characterizing the mechanical behaviour of non-polar elastic solids with finite-radius fibres. This paper proposes a simple and realistic constitutive equation for non-polar elastic solids reinforced by embedded fibres, without using the second gradient theory.
SCIENTIFIC REPORTS
(2023)
Article
Mathematics, Applied
Fabio Sozio, Ashkan Golgoon, Arash Yavari
Summary: This study investigates the possibility of elastodynamic transformation cloaking in bodies made of non-centrosymmetric gradient solids, showing that the obstacle to transformation cloaking also exists in non-centrosymmetric gradient solids.
ZEITSCHRIFT FUR ANGEWANDTE MATHEMATIK UND PHYSIK
(2021)
Article
Materials Science, Multidisciplinary
N. Korshunova, G. Alaimo, S. B. Hosseini, M. Carraturo, A. Reali, J. Niiranen, F. Auricchio, E. Rank, S. Kollmannsberger
Summary: This study investigates the manufacturing of complex materials using Selective Laser Melting technology and finds that microstructural variations can influence the mechanical behavior of the materials. By applying the Finite Cell Method to conduct three-dimensional numerical analysis on bending behavior, the study validates the applicability of beam models for predicting bending behaviors of lattice beams.
MATERIALS & DESIGN
(2021)
Article
Engineering, Multidisciplinary
S. Schuss, S. Glas, C. Hesch
Summary: In this paper, we propose a novel space-time formulation for non-linear elasticity that can efficiently calculate large deformations and displacements using structured and unstructured meshes in the space-time cylinder. This formulation allows for the use of Lagrangian shape functions, including tetrahedron and hypertetrahedron or tesseract elements, without changing the required regularity. By treating spatial and temporal directions equally, we are able to overcome the challenge of designing time-stepping schemes in parallel computations, resulting in enhanced stability and robustness compared to classical time-stepping schemes. The superiority of our approach in convergence is demonstrated through various examples, including highly sensitive systems in the context of non-linear elasticity.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Mechanics
Paul Bouteiller
Summary: This paper deals with finite strain isotropic thermo-elasticity without any specific Ansatz regarding the Helmholtz free energy. On the theoretical side, an Eulerian setting of isotropic thermo-elasticity is developed, based on the objective left Cauchy-Green tensor along with the Cauchy stress. The construction of the elastic model relies on a particular invariants choice of the strain measure. These invariants are built so that a succession of elementary experiments, in which the invariants evolve independently, ensures the complete identification of the Helmholtz free energy and thus of the thermo-elastic constitutive law. Expressions idealizing these experimental tests are proposed. A wide range of hyperelastic models are found to be a special case of the model proposed herein.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Mathematics, Applied
Pavan Kumar Asur Vijaya Kumar, Aamir Dean, Shahab Sahraee, Jose Reinoso, Marco Paggi
Summary: This work proposes a thermodynamically consistent framework for coupled thermo-mechanical simulations in thin-walled structures with cohesive interfaces, utilizing solid shell parametrization and locking-free thermo-mechanical solid shell elements. It also extends the interface finite element for geometrical nonlinearities to model thermo-mechanical decohesion events, with computational implementation in ABAQUS. The predictability of the model is demonstrated through several representative examples.
FINITE ELEMENTS IN ANALYSIS AND DESIGN
(2022)
Article
Engineering, Multidisciplinary
Sergei Khakalo, Anssi Laukkanen
Summary: This study combines Mindlin's strain gradient elasticity theory and Gudmundson-Gurtin-Anand strain gradient plasticity theory to form a unified framework, enriching the modeling capabilities by including the gradient of elastic strains. Numerical results show that the elastic length scale parameter controls the slope of the elastic part and causes additional hardening in the plastic part of the material response curves.
COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Matthias Rambausek, Joachim Schoeberl
Summary: This paper addresses the issue of spurious coupling effects in fully coupled magneto-mechanical finite element simulations involving non-magnetic or air-like media. It characterizes these effects and proposes two new methods to eliminate the undesired spurious magneto-mechanical coupling in non-magnetic media. The proposed methods are compared with established methods in different scenarios and found to be accurate, effective, and crucial for simulating compliant structures.
INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING
(2023)
Article
Mathematics, Applied
Hongliang Li, Pingbing Ming, Huiyu Wang
Summary: This paper establishes a new H2-Korn's inequality and its discrete analog, simplifying the construction of nonconforming elements for a linear strain gradient elastic model. Analysis of the Specht triangle and NZT tetrahedron as representatives demonstrates robust nonconforming elements with convergence rate independent of small material parameter. Construction of regularization interpolation operators and enriching operators for both elements is achieved with error estimates under minimal smoothness assumption on the solution. Numerical results for smooth solution and solution with boundary layer are consistent with theoretical predictions.
JOURNAL OF SCIENTIFIC COMPUTING
(2021)
Article
Materials Science, Multidisciplinary
J. Ciambella, P. Nardinocchi
Summary: The paper thoroughly discusses the proper definition of material symmetry group and its evolution with time in developing a theory of anisotropic viscoelastic media at finite strains. It introduces a novel anisotropic remodelling equation compatible with the principle of structural frame indifference to address this issue. The evolution laws of the dissipative process are completely determined by two scalar functions, and the model can be simplified to an anisotropic fluid or hyperelastic solid model under different deformation speeds.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Computer Science, Interdisciplinary Applications
Lars Blatny, Henning Lowe, Stephanie Wang, Johan Gaume
Summary: This study investigates the failure mechanics of porous brittle solids using a stochastic and numerical microstructure method, revealing the elasticity and failure characteristics at different porosities. The study finds that failure onset is described well through second order work, and stress at failure follows a power law similar to the elastic modulus, with plastic deformation governed by an associative plastic flow rule. Additionally, large deformation simulations show a transition in the mode of deformation localization.
COMPUTERS AND GEOTECHNICS
(2021)
Article
Physics, Multidisciplinary
Sonam Singh, A. K. Singh
Summary: This study investigates the dispersion relation of Anti-plane wave propagation in structures with soft material reinforced at the surface or interface, considering the impact of electro-magnetic coupling parameter, imperfectness parameter, and reinforcement of soft & stiff elastic layer. Through numerical computation and graphical portrayal, the electromechanical efficiency and Cut-Off frequencies of both models are discussed.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Mathematics, Applied
Danny Smyl, Liang Chen, Li Lai, Dong Liu
Summary: This method applies non-cooperative game theory to finite element problems, treating each element as a player to reach Nash equilibrium in the overall game. Numerical demonstrations show matching with analytical solutions in linear elasticity and convergence to a prescribed precision in two-player nonlinear problems.
APPLIED NUMERICAL MATHEMATICS
(2021)
Article
Materials Science, Multidisciplinary
Bhavesh Shrimali, Matteo Pezzulla, Samuel Poincloux, Pedro M. Reis, Oscar Lopez-Pamies
Summary: This study investigates the bending response of perforated plates, focusing on thin plates made of isotropic materials with varying porosities. The research finds that the bending response of perforated plates is mainly influenced by porosity, rather than the size or distribution of the holes.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Engineering, Multidisciplinary
Bhavesh Shrimali, Kamalendu Ghosh, Oscar Lopez-Pamies
Summary: This paper presents an analytical and numerical study of the homogenization problem of suspensions of vacuous bubbles in viscoelastic rubber subject to finite quasistatic deformations. The study reveals that the viscoelastic response of the suspensions features the same type of short-range-memory behavior as that of the underlying rubber, with the distinctive differences that their effective elasticity is compressible and their effective viscosity is compressible and nonlinear. A simple yet accurate analytical approximation for the macroscopic viscoelastic response of the suspensions under arbitrary finite quasistatic deformations is also provided.
JOURNAL OF ELASTICITY
(2023)
Article
Materials Science, Multidisciplinary
A. Kumar, K. Ravi-Chandar, O. Lopez-Pamies
Summary: In this paper, a comprehensive macroscopic phase-field theory for fracture in brittle materials is introduced. The theory extends the phase-field approximation to account for material strength and is validated through comparison with experimental results.
INTERNATIONAL JOURNAL OF FRACTURE
(2022)
Article
Engineering, Multidisciplinary
Victor Lefevre, Gilles A. Francfort, Oscar Lopez-Pamies
Summary: This article discusses a conjecture about the homogenized behavior of hyperelastic composite materials and presents a series of results supporting this conjecture. According to analytical and computational results, it is proposed that the homogenized behavior of isotropic incompressible Neo-Hookean composites is itself an incompressible Neo-Hookean material.
JOURNAL OF ELASTICITY
(2022)
Article
Engineering, Mechanical
Victor Lefevre, Oscar Lopez-Pamies
Summary: This study presents a simple explicit result for the effective shear modulus of a random isotropic suspension of rigid spheres. The result is in quantitative agreement with existing theoretical results and computational results for different volume fractions. Additionally, the result can be realized in suspensions with infinitely many sizes. It describes the behavior of both monodisperse and polydisperse suspensions of rigid spheres.
EXTREME MECHANICS LETTERS
(2022)
Editorial Material
Materials Science, Multidisciplinary
Oscar Lopez-Pamies, Blaise Bourdin
INTERNATIONAL JOURNAL OF FRACTURE
(2022)
Article
Materials Science, Multidisciplinary
Kamalendu Ghosh, Oscar Lopez-Pamies
Summary: Recent experimental and theoretical results have identified elastomers filled with liquid inclusions as a promising new type of material with unprecedented properties. The first objective of this paper is to formulate the homogenization problem that describes the mechanical behavior of such filled elastomers under finite deformations. The focus is on the non dissipative case when the elastomer is a hyperelastic solid, the liquid inclusions are hyperelastic fluids, and the interfaces separating them have their own hyperelastic behavior. The second objective is to implement a numerical scheme to generate solutions for a specific type of filled elastomers, and propose a simple approximation for the effective stored-energy function.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Materials Science, Multidisciplinary
Yingqi Jia, Oscar Lopez-Pamies, Xiaojia Shelly Zhang
Summary: It is well-established that simple topology variations can significantly change the fracture response of structures. This paper proposes a density-based topology optimization framework that uses a complete phase-field fracture theory to accurately describe fracture behaviors. The framework optimizes the structure's initial stiffness, the time of fracture nucleation, and the energy dissipated by fracture propagation. The optimized structures exhibit enhanced fracture behaviors compared to conventional stiffness maximization.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Chemistry, Physical
Kamalendu Ghosh, Victor Lefevre, Oscar Lopez-Pamies
Summary: This paper presents a numerical and analytical study on the macroscopic mechanical response of a random isotropic suspension of liquid n-spherical inclusions. The study shows that for this type of suspension, the mechanical response can be characterized solely by an effective shear modulus (n).
Article
Engineering, Mechanical
Bhavesh Shrimali, Oscar Lopez-Pamies
Summary: It is found in pure-shear fracture tests that fracture nucleation in viscoelastic elastomers occurs at a critical stretch independent of the stretch rate. This overlooked experimental finding implies that the Griffith criticality condition for fracture nucleation can be expressed in terms of the intrinsic fracture energy Gc of the elastomer, rather than the loading-history-dependent critical tearing energy Tc.
EXTREME MECHANICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
B. Shrimali, O. Lopez-Pamies
Summary: In a recent study, it was found that the Griffith criticality condition governing crack growth in viscoelastic elastomers can be simplified from its ordinary form to a fundamental form involving only the intrinsic fracture energy of the elastomer. The purpose of this paper is to use this fundamental form to explain the delayed fracture test for viscoelastic elastomers.
INTERNATIONAL JOURNAL OF FRACTURE
(2023)
Article
Mechanics
Bhavesh Shrimali, Oscar Lopez-Pamies
Summary: Shrimali and Lopez-Pamies (2023) have revealed that the Griffith criticality condition governing crack growth in viscoelastic elastomers can be simplified to a form exclusively involving the intrinsic fracture energy G(c). This article utilizes this simplified form to explain the trousers test, a popular fracture test for studying crack growth in viscoelastic elastomers.
JOURNAL OF APPLIED MECHANICS-TRANSACTIONS OF THE ASME
(2023)
Article
Engineering, Multidisciplinary
Kamalendu Ghosh, Victor Lefevre, Oscar Lopez-Pamies
Summary: This paper presents the derivation of homogenized equations for elastomers filled with liquid inclusions, focusing on the non-dissipative case. The macroscopic response of such filled elastomers is that of a linear elastic solid, characterized by an effective modulus of elasticity. Despite the presence of residual stresses and initial surface tension, the effective modulus of elasticity possesses minor symmetries similar to a conventional linear elastic solid. Numerical results are provided for isotropic suspensions of incompressible liquid 2-spherical inclusions embedded in an isotropic incompressible elastomer.
JOURNAL OF ELASTICITY
(2023)
Article
Materials Science, Multidisciplinary
Ignasius P. A. Wijaya, Oscar Lopez-Pamies, Arif Masud
Summary: This paper presents a formulation and numerical solution algorithm for describing the mechanical response of bodies made of a large class of viscoelastic materials undergoing finite deformations. The formulation is based on a Lagrangian setting and a two-potential mixed formulation. The numerical solution algorithm uses a finite-element discretization of space and a finite-difference discretization of time.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Aditya Kumar, Oscar Lopez-Pamies
Summary: While it was previously believed that cavitation in elastomers could be explained solely based on elasticity, recent research has shown that it is primarily a fracture phenomenon. This study aims to use a macroscopic phase-field theory to provide a detailed quantitative explanation of the seminal poker-chip experiments conducted by Gent and Lindley.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
