Article
Materials Science, Multidisciplinary
S. E. Alavi, J. F. Ganghoffer, H. Reda, M. Sadighi
Summary: This paper revisits higher-order homogenization schemes towards micromorphic media based on variational principles and an extension of Hill macrohomogeneity condition. By deriving complete homogeneous microscopic displacement field, it leads to a higher-grade micromorphic theory with relative stress and hyperstress tensors including second-order and third order polynomials. The numerical applications show that the higher-order moduli converge quickly with unit cell size.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Mechanics
S. E. Alavi, M. Nasimsobhan, J. F. Ganghoffer, A. Sinoimeri, M. Sadighi
Summary: A homogenization methodology is proposed for constructing effective Cosserat substitution media for heterogeneous materials, applicable to various architected materials exhibiting micropolar chiral effects. The method provides size-independent higher-order effective moduli and is validated through computation of effective micropolar moduli for periodic lattice materials.
Article
Materials Science, Multidisciplinary
S. Ehsan Alavi, Jean-Francois Ganghoffer, Mojtaba Sadighi
Summary: This contribution aims to build chiral Cosserat effective models of architectured media prone to such effects, using dedicated homogenization methods. A variational principle and a decomposition of the microscopic displacement are employed to obtain the effective Cosserat model. The accuracy of the homogenized chiral Cosserat model is evaluated based on the energy of the fluctuating displacement.
MATHEMATICS AND MECHANICS OF SOLIDS
(2022)
Article
Mechanics
Ignacio Romero, Christina Schenk
Summary: This article presents a new variational principle for connecting beam models and deformable solid models, and provides its mathematical analysis. Despite the differences between the two types of governing equations, it is shown that the equilibrium of combined beam-solid systems can be obtained from a constrained variational principle, and the resulting boundary-value problem is well posed.
Article
Mechanics
Marco Colatosti, Nicholas Fantuzzi, Patrizia Trovalusci, Renato Masiani
Summary: This study analyzed particle composite materials with various microstructures, consisting of rigid particles and elastic interfaces. Different textures were examined, and static analyses compared discrete, micropolar, and classical models. The effectiveness of micropolar continuum theory in describing such materials was demonstrated through the performed analyses.
Article
Materials Science, Multidisciplinary
J. F. Ganghoffer, H. Reda
Summary: A methodology is proposed for constructing effective strain gradient media for heterogeneous materials, combining linear elasticity variational principle and extended Hill lemma. The method decomposes the microscopic displacement field of the heterogeneous continuum into a polynomial homogeneous part in the generalized kinematic measures of the strain gradient effective continuum and a periodic fluctuation, and computes strain gradient effective moduli for composite materials.
MECHANICS OF MATERIALS
(2021)
Article
Mechanics
Aleksey A. Vasiliev, Igor S. Pavlov
Summary: The dynamics of tetrachiral Cosserat lattices are investigated through discrete and generalized continuum models, with detailed analysis and comparison of their characteristics. Derived dispersion relations provide insights into long-wavelength and gradient micropolar approximations, particularly for slowly varying deformations. The two-field models offer accurate frequencies for both long-wavelength and short-wavelength deformations, making them useful for directional frequency filtering in continuum mechanics.
MECHANICS RESEARCH COMMUNICATIONS
(2021)
Article
Engineering, Multidisciplinary
Andrea Bacigalupo, Luigi Gambarotta
Summary: This paper focuses on dynamic homogenization of lattice-like materials with lumped mass at nodes to obtain energetically consistent models for accurate descriptions of the discrete system's acoustic behavior. By utilizing proper mapping and enhanced continualization, equivalent continuum models with non-local terms are derived, achieving energy-consistent differential equations for effective representation of the system's behavior.
INTERNATIONAL JOURNAL OF ENGINEERING SCIENCE
(2021)
Article
Mechanics
Jean-Francois Ganghoffer, Abdallah Wazne, Hilal Reda
Summary: In the last two decades, there has been significant research activity on architected materials due to their unique effective properties. The challenge lies in up-scaling the mechanical response to achieve continuum behavior, which may differ from the micro-level properties. Continuum models beyond Cauchy's theory are needed for artificial materials called meta-materials, which exhibit static and dynamic attributes not found in natural materials. This article reviews the scientific issues and challenges of higher-order homogenization methods and proposes solutions for enriched models in both static and dynamic regimes.
MECHANICS RESEARCH COMMUNICATIONS
(2023)
Article
Physics, Condensed Matter
Tyler DeValk, Jonah Hestetune, Roderic S. Lakes
Summary: In this study, it was observed that the chiral gyroid lattice exhibits temperature-induced twist with the direction of twist corresponding to the sense of chirality. The Poisson's ratio of the gyroid is known to be about 0.3 with minimal dependence on size.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Mathematics, Applied
A. Aguirre, R. Codina, J. Baiges
Summary: This paper investigates the numerical locking problem of Reissner-Mindlin's and Timoshenko's theories when approximated using the standard Galerkin finite element method for thin structures. To address this issue, a Variational Multiscale stabilization method is proposed, including two different approaches: Algebraic Sub-Grid Scale formulation and Orthogonal Sub-Grid Scale formulation. The stability and convergence of both approaches are proved, with the Orthogonal Sub-Grid Scale approach performing better. The Orthogonal Sub-Grid Scale approach is shown to be stable and optimally convergent, regardless of the thickness of the solid, unlike the sensitive and suboptimal Algebraic Sub-Grid Scale approach.
FINITE ELEMENTS IN ANALYSIS AND DESIGN
(2023)
Article
Mechanics
S. E. Alavi, J. F. Ganghoffer, M. Sadighi, M. Nasimsobhan, A. H. Akbarzadeh
Summary: This paper evaluates the mechanical properties of repetitive lattice materials using Timoshenko beam models and a continualization method. It also proposes a surface formulation to quantify the edge effects in lattice structures. The results show that the proposed method is accurate and computationally efficient.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Engineering, Mechanical
Gaojian Lin, Jiaqi Li, Pengwan Chen, Weifu Sun, Sergei A. Chizhik, Alexander A. Makhaniok, Galina B. Melnikova, Tatiana A. Kuznetsova
Summary: Three-dimensional chiral mechanical metamaterials exhibit a unique compression-twisting coupling effect, which can lead to global buckling under external compressive load exceeding a critical value. A novel constitutive model and homogenization method were developed to describe and quantify the size dependency of chirality in these materials. The study revealed the effects of chirality on buckling strength and mode.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Mathematics, Applied
Minyi Zhu, Guobin Gong, Jun Xia
Summary: The study uses the variational method to analyze cantilever tapered beams with tip loads and end displacements to determine optimized shapes and materials that minimize weights. By applying energy theorems and isoperimetric problems, width variation curves and minimum masses are derived for two beam types. The study shows that material properties and beam length significantly impact the minimization of mass for cantilever beams.
ADVANCES IN APPLIED MATHEMATICS AND MECHANICS
(2021)
Article
Materials Science, Multidisciplinary
S. Grytsiuk, S. Bluegel
Summary: The ground state of the B20 FeGe chiral magnet is a superposition of twisted helical spin-density waves formed by different sublattices of the crystal, giving rise to new contributions to the micromagnetic energies of the exchange and DM interactions. The magnitude of the spin-spiral twist in B20 FeGe is found to be similar to global spiraling, and the energy difference between twisted spirals and the ferromagnetic state agrees well with experimental results.Further experiments are suggested to explore the ground state properties of B20 chiral magnets.
Article
Materials Science, Multidisciplinary
Baihong Chen, Changyue Liu, Zengting Xu, Zhijian Wang, Rui Xiao
Summary: In this study, both polydomain and monodomain liquid crystal elastomers (LCEs) were synthesized and their shape change with temperature under a certain stress level was characterized. A thermo-order-mechanical coupling model was developed to predict the shape change of LCEs, showing good consistency with experimental results.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Peng Wang, Fei Xu, Yiding Wang, Jun Song, Cheng Chen
Summary: This study investigates the interplay of super-screw dislocations and coherent twin boundary (CTB) in Ni3Al using molecular dynamics simulations and dislocation continuum theory. Various interaction mechanisms are observed depending on the stress and dislocation gliding pathways. A continuum model framework is developed to evaluate the critical shear stress required for CTB to accommodate dislocations along different pathways, considering the effects of anti-phase boundary (APB) and Complex Stacking Fault (CSF). The study suggests that the resistant force of CTB against all gliding dislocations is a more appropriate metric for quantifying its strength.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Chenyu Du, Haitao Cui, Hongjian Zhang, Zhibin Cai, Weikuo Zhai
Summary: A thermal-elastoplastic phase field model was developed to simulate thermal fatigue crack growth. The accuracy and availability of the model were verified through typical examples. The results indicate that the proposed model effectively simulates the process of thermal fatigue crack propagation in elastoplastic solids. The appropriate regularization length needs to be determined based on experimental results.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
J. Carlsson, A. Kuswoyo, A. Shaikeea, N. A. Fleck
Summary: The sensitivity of the compressive strength of a polymeric Kelvin lattice to the presence of an epoxy core is investigated both experimentally and numerically. The study shows that the epoxy core prevents the formation of crush bands in the lattice and changes its deformation mode. At finite strain, the strength of the lattice is degraded by bending failure and cracking of the struts and adjacent core, leading to the formation of vertical fissures.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Saptarshi Paul, Anurag Gupta
Summary: In this study, we investigate the geometry and mechanics of the buckled orthotropic von Karman elastic plate with free boundary condition, in the presence of an isolated positive or negative disclination. The shape of the buckled plate is cone-like for a positive disclination and saddle-like for a negative disclination. With increasing orthotropy, the shape of the buckled plate becomes more tent-like and the Gaussian curvature spreads along the ridge of the tent. The stress fields are focused in the neighborhood of the defect point and the ridge, indicating that most of the stretching energy is accommodated in these singular regions.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Antu Acharya, Vikram Muthkani, Anirvan DasGupta, Atul Jain
Summary: This study proposes filler-based and infill-based strategies for creating auxetic lattices with enhanced stiffness. The elastic properties of the sinusoidal re-entrant honeycomb lattice are developed and validated using finite element models. Parametric studies are conducted to find combinations leading to enhanced stiffness with minor loss in auxeticity. The results demonstrate the possibility of achieving a significant increment in stiffness while retaining significant auxeticity. The proposed approaches outperform existing approaches in terms of stiffness and auxeticity.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Biswajit Pal, Ananth Ramaswamy
Summary: This study presents a multi-scale approach to simulate the shrinkage and creep of concrete, addressing the limitations of existing macroscopic prediction models due to the heterogeneous nature of concrete. The model is validated with experimental data and compared to national codes and macroscopic models, demonstrating its effectiveness in overcoming the gaps in existing models.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Akash Kumar Behera, Mohammad Masiur Rahaman, Debasish Roy
Summary: Ceramics have attractive properties but low fracture toughness is a major drawback. There is interest in improving the mechanical performance of ceramics by tailoring residual stresses. However, there is a lack of computational models that can accurately predict crack paths and quantify the improved fracture toughness.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Bineet Kumar, Sandeep Kumar Dubey, Sonalisa Ray
Summary: This study aims to develop an energy-based theoretical formulation for predicting the evolution of the fracture process zone in concrete under fatigue loading. Experimental results and calibrations indicate that the specimen size and aggregate size affect the fracture behavior and process zone length of concrete.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Zheliang Wang, Hao Sheng, Xinyi Lin, Yifan Rao, Jia Liu, Nanshu Lu
Summary: In this study, an analytical framework is proposed for investigating the behavior of laminated beams with any number of layers under various bending conditions, and the theory is validated through finite element analysis. It was found that the number of layers, applied deformation, layer properties, and layer aspect ratio have an impact on the equivalent flexural rigidity.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Michael Schwaighofer, Markus Konigsberger, Luis Zelaya-Lainez, Markus Lukacevic, Sebastian Serna-Loaiza, Michael Harasek, Florian Zikeli, Anton Friedl, Josef Fussl
Summary: In this study, nanoindentation relaxation tests were re-evaluated on five industrial lignins extracted from different feedstocks. It was found that the viscoelastic properties of all tested lignins were practically identical and independent of the feedstock and the extraction processes.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Tian Han, Dandan Qi, Jia Ma, Chaoyang Sun
Summary: In this study, a generative design method was used to propose new modified lattice structures suitable for tensile and compressive loading conditions. By conducting experimental and finite element analyses, it was confirmed that the derived structures have improved load-bearing capacity and energy absorption compared to the original structures. The effects of shape parameters on mechanical properties were also discussed.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Wenbin Zheng, Jay Airao, Ramin Aghababaei
Summary: Spinodal decomposition of Ti1-xAlxN crystal structure significantly affects their physical properties. This study uses three-dimensional molecular dynamics simulations to investigate the phase transformation mechanism and surface finish during material removal in TiAlN. The simulations reveal that the aluminum content and cutting depth have a significant influence on the phase transformation process through spinodal decomposition.
MECHANICS OF MATERIALS
(2024)
Article
Materials Science, Multidisciplinary
Atasi Ghosh
Summary: The micro-mechanism of low cycle fatigue deformation behavior has been summarized and the recent development in the approach of numerical simulation of cyclic stress-strain behavior of polycrystalline metallic materials at multi-scale has been discussed.
MECHANICS OF MATERIALS
(2024)