Pub Date : 2025-08-29DOI: 10.1016/j.ijengsci.2025.104376
Asghar Zajkani , Michael Khonsari
This paper presents an analytical framework for thermodynamical modeling of creep damage and fracture in materials through the lens of entropy production. Building on the second law of thermodynamics and principles of irreversible processes, the study establishes a unified coupling between a phenomenological damage law and continuum damage mechanics. The model links creep deformation to internal entropy generation and introduces a process-dependent damage exponent to ensure physically consistent and mathematically robust damage evolution. A key contribution is to introduce Creep Fracture Entropy (CFE)—a novel, material-specific thermodynamic index that serves as a reliable predictor of creep failure. By deriving time-dependent expressions for strain, strain rate, and entropy production, the model captures the full progression of creep behavior, without requiring empirical stage segmentation. The model is validated against a range of experimental data from various alloys, manifesting strong agreement with the observed strain and entropy trends. Notably, the calculated CFE values remain confined within a narrow range for each material, highlighting their intrinsic nature of constancy and reliability as fracture indicators. The thermodynamic formulation presented here enhances predictive accuracy for creep life assessment, emphasizing entropy as a pivotal damage variable in irreversible thermodynamics.
{"title":"Creep fracture entropy: A thermomechanical damage-based failure index","authors":"Asghar Zajkani , Michael Khonsari","doi":"10.1016/j.ijengsci.2025.104376","DOIUrl":"10.1016/j.ijengsci.2025.104376","url":null,"abstract":"<div><div>This paper presents an analytical framework for thermodynamical modeling of creep damage and fracture in materials through the lens of entropy production. Building on the second law of thermodynamics and principles of irreversible processes, the study establishes a unified coupling between a phenomenological damage law and continuum damage mechanics. The model links creep deformation to internal entropy generation and introduces a process-dependent damage exponent to ensure physically consistent and mathematically robust damage evolution. A key contribution is to introduce Creep Fracture Entropy (CFE)—a novel, material-specific thermodynamic index that serves as a reliable predictor of creep failure. By deriving time-dependent expressions for strain, strain rate, and entropy production, the model captures the full progression of creep behavior, without requiring empirical stage segmentation. The model is validated against a range of experimental data from various alloys, manifesting strong agreement with the observed strain and entropy trends. Notably, the calculated CFE values remain confined within a narrow range for each material, highlighting their intrinsic nature of constancy and reliability as fracture indicators. The thermodynamic formulation presented here enhances predictive accuracy for creep life assessment, emphasizing entropy as a pivotal damage variable in irreversible thermodynamics.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104376"},"PeriodicalIF":5.7,"publicationDate":"2025-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144913286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-20DOI: 10.1016/j.ijengsci.2025.104372
Y.S. Li , B.L. Liu , S. Li
This study investigates free vibration and sound transmission loss of stiffened magnetoelectroelastic (MEE) sandwich plates incorporating negative Poisson's ratio (NPR) cores. Firstly, a novel three-dimensional NPR structure is designed, and the effective material properties of the NPR structure are calibrated via an artificial neural network. Secondly, the equations of motion for stiffened MEE sandwich plates incorporating NPR cores mentioned above are derived using Hamilton's principle, yielding analytical solutions for free vibration under simply supported boundary conditions. Sound transmission loss (STL) under harmonic acoustic wave incidence is subsequently formulated. Finally, numerical case studies analyze the material properties of NPR cores and STL performance of stiffened MEE sandwich plates. This study elucidates the unique mechanical properties of intelligent NPR structures and establishes evaluation methodologies for multifield coupling effects on the acoustic insulation performance of such lightweight adaptive systems.
{"title":"Sound transmission through stiffened magnetoelectroelastic sandwich plates with negative Poisson’s ratio core","authors":"Y.S. Li , B.L. Liu , S. Li","doi":"10.1016/j.ijengsci.2025.104372","DOIUrl":"10.1016/j.ijengsci.2025.104372","url":null,"abstract":"<div><div>This study investigates free vibration and sound transmission loss of stiffened magnetoelectroelastic (MEE) sandwich plates incorporating negative Poisson's ratio (NPR) cores. Firstly, a novel three-dimensional NPR structure is designed, and the effective material properties of the NPR structure are calibrated via an artificial neural network. Secondly, the equations of motion for stiffened MEE sandwich plates incorporating NPR cores mentioned above are derived using Hamilton's principle, yielding analytical solutions for free vibration under simply supported boundary conditions. Sound transmission loss (STL) under harmonic acoustic wave incidence is subsequently formulated. Finally, numerical case studies analyze the material properties of NPR cores and STL performance of stiffened MEE sandwich plates. This study elucidates the unique mechanical properties of intelligent NPR structures and establishes evaluation methodologies for multifield coupling effects on the acoustic insulation performance of such lightweight adaptive systems.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104372"},"PeriodicalIF":5.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-20DOI: 10.1016/j.ijengsci.2025.104368
Géry de Saxcé
Our aim is to develop a general approach for the dynamics of material bodies of dimension represented by a matter manifold of dimension embedded into the space–time . It can be specialized for (pointwise object), (arch if it is a solid, flow in a pipe or jet if it is a fluid), (plate or shell if it is a solid, sheet of fluid), (bulky bodies). We call torsor a skew-symmetric bilinear map on the vector space of affine real functions on the affine tangent space to the space–time. We use the affine connections as originally developed by Élie Cartan, that is the connections associated to the affine group. We introduce a general principle of covariant divergence free torsor from which we deduce 10 balance equations. We show the relevance of this general principle by applying it for from 1 to 4 in the context of the Galilean relativity.
{"title":"Cosserat media in dynamics","authors":"Géry de Saxcé","doi":"10.1016/j.ijengsci.2025.104368","DOIUrl":"10.1016/j.ijengsci.2025.104368","url":null,"abstract":"<div><div>Our aim is to develop a general approach for the dynamics of material bodies of dimension <span><math><mi>d</mi></math></span> represented by a matter manifold <span><math><mi>N</mi></math></span> of dimension <span><math><mrow><mo>(</mo><mi>d</mi><mo>+</mo><mn>1</mn><mo>)</mo></mrow></math></span> embedded into the space–time <span><math><mi>M</mi></math></span>. It can be specialized for <span><math><mrow><mi>d</mi><mo>=</mo><mn>0</mn></mrow></math></span> (pointwise object), <span><math><mrow><mi>d</mi><mo>=</mo><mn>1</mn></mrow></math></span> (arch if it is a solid, flow in a pipe or jet if it is a fluid), <span><math><mrow><mi>d</mi><mo>=</mo><mn>2</mn></mrow></math></span> (plate or shell if it is a solid, sheet of fluid), <span><math><mrow><mi>d</mi><mo>=</mo><mn>3</mn></mrow></math></span> (bulky bodies). We call torsor a skew-symmetric bilinear map on the vector space of affine real functions on the affine tangent space to the space–time. We use the affine connections as originally developed by Élie Cartan, that is the connections associated to the affine group. We introduce a general principle of covariant divergence free torsor from which we deduce 10 balance equations. We show the relevance of this general principle by applying it for <span><math><mi>d</mi></math></span> from 1 to 4 in the context of the Galilean relativity.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104368"},"PeriodicalIF":5.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-20DOI: 10.1016/j.ijengsci.2025.104369
Harold Berjamin, Stephan Rudykh
Layered media can be used as acoustic filters, allowing only waves of certain frequencies to propagate. In soft magneto-active laminates, the shear wave band gaps (i.e., the frequency intervals for which shear waves cannot propagate) can be adjusted after fabrication by exploiting the magneto-elastic coupling. In the present study, the control of shear wave propagation in magneto-active stratified media is revisited by means of homogenisation theory, and extended to nonlinear waves of moderate amplitude. Building upon earlier works, the layers are modelled by means of a revised hard-magnetic material theory for which the total Cauchy stress is symmetric, and the incompressible elastic response is of generalised neo-Hookean type (encompassing Yeoh, Fung-Demiray, and Gent materials). Using asymptotic homogenisation, a nonlinear dispersive wave equation with cubic nonlinearity is derived, under certain simplifying assumptions. In passing, an effective strain energy function describing such laminates is obtained. The combined effects of nonlinearity and wave dispersion contribute to the formation of solitary waves, which are analysed using the homogenised wave equation and a modified Korteweg–de Vries (mKdV) approximation of the latter. The mKdV equation is compared to direct numerical simulations of the impact problem, and various consequences of these results are explored. In particular, we show that an upper bound for the speed of solitary waves can be adjusted by varying the applied magnetic field, or by modifying the properties of the microstructure.
{"title":"Nonlinear dispersive waves in soft elastic laminates under finite magneto–deformations","authors":"Harold Berjamin, Stephan Rudykh","doi":"10.1016/j.ijengsci.2025.104369","DOIUrl":"10.1016/j.ijengsci.2025.104369","url":null,"abstract":"<div><div>Layered media can be used as acoustic filters, allowing only waves of certain frequencies to propagate. In soft magneto-active laminates, the shear wave band gaps (i.e., the frequency intervals for which shear waves cannot propagate) can be adjusted after fabrication by exploiting the magneto-elastic coupling. In the present study, the control of shear wave propagation in magneto-active stratified media is revisited by means of homogenisation theory, and extended to nonlinear waves of moderate amplitude. Building upon earlier works, the layers are modelled by means of a revised hard-magnetic material theory for which the total Cauchy stress is symmetric, and the incompressible elastic response is of generalised neo-Hookean type (encompassing Yeoh, Fung-Demiray, and Gent materials). Using asymptotic homogenisation, a nonlinear dispersive wave equation with cubic nonlinearity is derived, under certain simplifying assumptions. In passing, an effective strain energy function describing such laminates is obtained. The combined effects of nonlinearity and wave dispersion contribute to the formation of solitary waves, which are analysed using the homogenised wave equation and a modified Korteweg–de Vries (mKdV) approximation of the latter. The mKdV equation is compared to direct numerical simulations of the impact problem, and various consequences of these results are explored. In particular, we show that an upper bound for the speed of solitary waves can be adjusted by varying the applied magnetic field, or by modifying the properties of the microstructure.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104369"},"PeriodicalIF":5.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-20DOI: 10.1016/j.ijengsci.2025.104371
Quansheng Zang , Hao Hong , Jun Liu , Yanhui Zhong , Bei Zhang , Bin Li , Lei Gan
This paper proposes an isogeometric boundary element method (IGABEM) to solve the nonlinear liquid sloshing problem in a rectangular container subjected to oscillatory excitation. Based on the semi-Lagrange approach, a fixed global coordinate system and a local Cartesian coordinate system that moves synchronously with the container are defined. Starting from the Laplace equation, the boundary integral equations for the liquid sloshing problem are derived using Gauss’s divergence theorem and the integration by parts technique, while incorporating nonlinear kinematic and dynamic boundary conditions of the free surface. The corresponding boundary element solution system is then formulated. Non-Uniform Rational B-Splines (NURBS) are employed as shape functions to accurately describe the geometric boundaries and approximate the unknown physical fields. This method ultimately produces the discrete equations governing nonlinear liquid sloshing problem in an oscillating container. Compared with traditional polynomial interpolation shape functions, NURBS provide improved continuity both within elements and across element interfaces as well as local support. These properties make them particularly suitable for satisfying the continuity requirements of the liquid surface. For time integration, a second-order Runge–Kutta algorithm is employed for time-stepping to solve the IGABEM system equations, compute variable gradients at each time step, and update the computational grid in real-time. A series of numerical examples are presented, the results are compared with analytical solutions, experimental data, and alternative numerical methods for free and forced liquid sloshing, free surface fluctuations and internal pressures. These comparisons validate the accuracy and robustness of the proposed method. The numerical examples further investigate the effects of external excitation frequency, excitation amplitude, rotation center position, and bottom obstacle height on liquid sloshing responses in the rectangular container. The results indicate that changes in excitation frequency, vertical eccentricity of the rotation center, and obstacle height significantly influence the liquid sloshing behavior.
{"title":"Isogeometric boundary element analysis of nonlinear liquid sloshing in containers under pitching oscillation","authors":"Quansheng Zang , Hao Hong , Jun Liu , Yanhui Zhong , Bei Zhang , Bin Li , Lei Gan","doi":"10.1016/j.ijengsci.2025.104371","DOIUrl":"10.1016/j.ijengsci.2025.104371","url":null,"abstract":"<div><div>This paper proposes an isogeometric boundary element method (IGABEM) to solve the nonlinear liquid sloshing problem in a rectangular container subjected to oscillatory excitation. Based on the semi-Lagrange approach, a fixed global coordinate system and a local Cartesian coordinate system that moves synchronously with the container are defined. Starting from the Laplace equation, the boundary integral equations for the liquid sloshing problem are derived using Gauss’s divergence theorem and the integration by parts technique, while incorporating nonlinear kinematic and dynamic boundary conditions of the free surface. The corresponding boundary element solution system is then formulated. Non-Uniform Rational B-Splines (NURBS) are employed as shape functions to accurately describe the geometric boundaries and approximate the unknown physical fields. This method ultimately produces the discrete equations governing nonlinear liquid sloshing problem in an oscillating container. Compared with traditional polynomial interpolation shape functions, NURBS provide improved continuity both within elements and across element interfaces as well as local support. These properties make them particularly suitable for satisfying the continuity requirements of the liquid surface. For time integration, a second-order Runge–Kutta algorithm is employed for time-stepping to solve the IGABEM system equations, compute variable gradients at each time step, and update the computational grid in real-time. A series of numerical examples are presented, the results are compared with analytical solutions, experimental data, and alternative numerical methods for free and forced liquid sloshing, free surface fluctuations and internal pressures. These comparisons validate the accuracy and robustness of the proposed method. The numerical examples further investigate the effects of external excitation frequency, excitation amplitude, rotation center position, and bottom obstacle height on liquid sloshing responses in the rectangular container. The results indicate that changes in excitation frequency, vertical eccentricity of the rotation center, and obstacle height significantly influence the liquid sloshing behavior.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104371"},"PeriodicalIF":5.7,"publicationDate":"2025-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144865083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-15DOI: 10.1016/j.ijengsci.2025.104356
Gennadi I. Mikhasev , Enrico Radi
The problem of pull-in instability of an electrostatically actuated nanocantilever is investigated here by considering the effect of the residual surface stress and surface attractions. A novel approach is developed by replacing the original differential equation with an equivalent integral equation for the deflection, obtained by using the Green’s function of the nanocantilever. Moreover, the resultant lateral force is approximated by a power function of the axial coordinate containing two unknown parameters, namely the power-law exponent and the tip deflection. These two unknowns can be found from a matching procedure by requiring that the approximated distribution of the lateral force calculated at the midspan and at the free tip must coincide with the actual load distribution calculated from the deflection predicted by the governing integral equation when the approximated load distribution is considered. In this way, a system of two nonlinear algebraic equations for the two unknown parameters as functions of the applied voltage is derived. The maximum attained by the electrostatic voltage then provides the approximated values of the pull-in voltage and the pull-in deflection. The plotted results show the effects of positive and negative residual surface stress and surface attractions on the pull-in parameters. A practical application is also considered for a nanocantilever made of Silicon with crystallographic direction [100] on faces. It is observed that for a very thin Si[100] nanocantilever there exists a critical length at which the nanobeam buckles without any applied electrostatic voltage and for any gap distance between movable and fixed electrodes.
{"title":"Effect of surface stresses on pull-in instability of a nanocantilever under electrostatic and intermolecular forces","authors":"Gennadi I. Mikhasev , Enrico Radi","doi":"10.1016/j.ijengsci.2025.104356","DOIUrl":"10.1016/j.ijengsci.2025.104356","url":null,"abstract":"<div><div>The problem of pull-in instability of an electrostatically actuated nanocantilever is investigated here by considering the effect of the residual surface stress and surface attractions. A novel approach is developed by replacing the original differential equation with an equivalent integral equation for the deflection, obtained by using the Green’s function of the nanocantilever. Moreover, the resultant lateral force is approximated by a power function of the axial coordinate containing two unknown parameters, namely the power-law exponent and the tip deflection. These two unknowns can be found from a matching procedure by requiring that the approximated distribution of the lateral force calculated at the midspan and at the free tip must coincide with the actual load distribution calculated from the deflection predicted by the governing integral equation when the approximated load distribution is considered. In this way, a system of two nonlinear algebraic equations for the two unknown parameters as functions of the applied voltage is derived. The maximum attained by the electrostatic voltage then provides the approximated values of the pull-in voltage and the pull-in deflection. The plotted results show the effects of positive and negative residual surface stress and surface attractions on the pull-in parameters. A practical application is also considered for a nanocantilever made of Silicon with crystallographic direction [100] on faces. It is observed that for a very thin Si[100] nanocantilever there exists a critical length at which the nanobeam buckles without any applied electrostatic voltage and for any gap distance between movable and fixed electrodes.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104356"},"PeriodicalIF":5.7,"publicationDate":"2025-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144841974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-11DOI: 10.1016/j.ijengsci.2025.104317
Lukas Laubert , Felix Weber , Fabrice Detrez , Sebastian Pfaller
The Capriccio method is a computational technique for coupling finite element (FE) and molecular dynamics (MD) domains to bridge their length scales and to provide boundary conditions typically employed in large-scale engineering applications. Earlier studies showed that strain inconsistencies between the coupled domains are caused by the coupling region’s (bridging domain, BD) resistance to spatial motion. Thus, this work examines influences of coupling parameters on strain convergence in Capriccio-coupled setups to study the mechanical behavior of solid amorphous materials. To this end, we employ a linear elastic 1D setup, imitating essential features of the Capriccio method, including force-transmitting anchor points (AP), which couple the domains via linear elastic springs. To assess the effect of more complex interactions in 3D models versus 1D results, we use an interdimensional mapping scheme, allowing qualitative and quantitative comparisons. For validation, we employ both an inelastic polystyrene MD model and a predominantly elastic silica glass MD model, each coupled to a corresponding FE material description. Our 1D results demonstrate that decreasing the conventionally high AP stiffness, along with other less significant measures, diminishes this motion resistance, revealing an optimal ratio between the material stiffness of the coupled domains and the cumulative AP stiffness. The 3D silica setup confirms that these measures ensure decent domain adherence and sufficiently low strain incompatibilities to study the mechanical behavior of elastic models. However, these measures turn out limited and may not ensure sufficient accuracy for studying the deformation and fracture behavior of Capriccio-coupled inelastic models. To overcome this, we employ a modified coupling approach, revising the Capriccio method’s AP concept by introducing a much lower so-called molecular statics stiffness during the FE calculation and a higher AP stiffness during only the MD calculation. Initial results on the 1D setup indicate that essential coupling limitations can be overcome, albeit with the risk of oscillatory strain amplifications depending on the BD’s design. This novel approach may enable a more accurate analysis of the mechanical behavior of coupled inelastic amorphous materials. We recommend evaluating its performance in 3D alongside additional methodological extensions. Overall, our results outline the current limitations of the Capriccio method and lay the groundwork for its targeted extension to study the mechanical behavior and, in particular, fracture phenomena in inelastic amorphous materials.
{"title":"Approaching and overcoming the limitations of the multiscale Capriccio method for simulating the mechanical behavior of amorphous materials","authors":"Lukas Laubert , Felix Weber , Fabrice Detrez , Sebastian Pfaller","doi":"10.1016/j.ijengsci.2025.104317","DOIUrl":"10.1016/j.ijengsci.2025.104317","url":null,"abstract":"<div><div>The Capriccio method is a computational technique for coupling finite element (FE) and molecular dynamics (MD) domains to bridge their length scales and to provide boundary conditions typically employed in large-scale engineering applications. Earlier studies showed that strain inconsistencies between the coupled domains are caused by the coupling region’s (bridging domain, BD) resistance to spatial motion. Thus, this work examines influences of coupling parameters on strain convergence in Capriccio-coupled setups to study the mechanical behavior of solid amorphous materials. To this end, we employ a linear elastic 1D setup, imitating essential features of the Capriccio method, including force-transmitting anchor points (AP), which couple the domains via linear elastic springs. To assess the effect of more complex interactions in 3D models versus 1D results, we use an interdimensional mapping scheme, allowing qualitative and quantitative comparisons. For validation, we employ both an inelastic polystyrene MD model and a predominantly elastic silica glass MD model, each coupled to a corresponding FE material description. Our 1D results demonstrate that decreasing the conventionally high AP stiffness, along with other less significant measures, diminishes this motion resistance, revealing an optimal ratio between the material stiffness of the coupled domains and the cumulative AP stiffness. The 3D silica setup confirms that these measures ensure decent domain adherence and sufficiently low strain incompatibilities to study the mechanical behavior of elastic models. However, these measures turn out limited and may not ensure sufficient accuracy for studying the deformation and fracture behavior of Capriccio-coupled inelastic models. To overcome this, we employ a modified coupling approach, revising the Capriccio method’s AP concept by introducing a much lower so-called molecular statics stiffness during the FE calculation and a higher AP stiffness during only the MD calculation. Initial results on the 1D setup indicate that essential coupling limitations can be overcome, albeit with the risk of oscillatory strain amplifications depending on the BD’s design. This novel approach may enable a more accurate analysis of the mechanical behavior of coupled inelastic amorphous materials. We recommend evaluating its performance in 3D alongside additional methodological extensions. Overall, our results outline the current limitations of the Capriccio method and lay the groundwork for its targeted extension to study the mechanical behavior and, in particular, fracture phenomena in inelastic amorphous materials.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104317"},"PeriodicalIF":5.7,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144810249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-08-11DOI: 10.1016/j.ijengsci.2025.104360
M.H.B.M. Shariff
In this study, we develop a nonlinear framework based on spectral invariants to model the electromagnetic behaviour of fibre-reinforced composites, explicitly accounting for the fibre stiffness of the embedded fibres. Employing Cosserat continuum theory, we derive general constitutive equations for stress and couple stress that capture the interactions between mechanical and electromagnetic fields. These equations also enable a physically meaningful decomposition of the couple stress tensor. To model materials in which fibre bending plays a dominant role, we refine the general constitutive equations by restricting their dependence on fibre direction gradients to directional derivatives along the fibre axis. Prototype forms of the internal energy function are proposed for both the general and specialized cases. We demonstrate the applicability of the specialized model by solving boundary value problems involving fibre bending and inflation, highlighting its physical relevance. The results offer a foundation for the design and simulation of advanced smart materials, particularly in applications where electromagnetic effects and fibre microstructure are strongly coupled.
{"title":"On the electromagnetic Cosserat spectral modelling of fibre-reinforced composites with fibre bending stiffness","authors":"M.H.B.M. Shariff","doi":"10.1016/j.ijengsci.2025.104360","DOIUrl":"10.1016/j.ijengsci.2025.104360","url":null,"abstract":"<div><div>In this study, we develop a nonlinear framework based on spectral invariants to model the electromagnetic behaviour of fibre-reinforced composites, explicitly accounting for the fibre stiffness of the embedded fibres. Employing Cosserat continuum theory, we derive general constitutive equations for stress and couple stress that capture the interactions between mechanical and electromagnetic fields. These equations also enable a physically meaningful decomposition of the couple stress tensor. To model materials in which fibre bending plays a dominant role, we refine the general constitutive equations by restricting their dependence on fibre direction gradients to directional derivatives along the fibre axis. Prototype forms of the internal energy function are proposed for both the general and specialized cases. We demonstrate the applicability of the specialized model by solving boundary value problems involving fibre bending and inflation, highlighting its physical relevance. The results offer a foundation for the design and simulation of advanced smart materials, particularly in applications where electromagnetic effects and fibre microstructure are strongly coupled.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104360"},"PeriodicalIF":5.7,"publicationDate":"2025-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144810248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-31DOI: 10.1016/j.ijengsci.2025.104358
Asif Equbal, Paragmoni Kalita
Hemodynamic variables are vital for understanding the progression of cardiovascular diseases, but their accuracy depends on assumptions about arterial wall behaviour. Although the left anterior descending (LAD) branch of the left coronary artery (LCA) has been reported to be highly susceptible to atherosclerosis, there is a significant lack of studies comparing the effects of different wall models in this context. This study employs two-way fluid-structure interaction (FSI) simulations to investigate the impact of rigid, elastic, and hyperelastic wall models on the hemodynamics of a moderately stenosed LAD branch in an idealised LCA. The non-Newtonian properties of blood are captured using the Carreau viscosity model. Key hemodynamic parameters—primary velocity (), streamwise vorticity, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and fractional flow reserve (FFR)—are evaluated across these models. Results show that the rigid model mostly exhibits higher and TAWSS at the stenosis throat compared to the elastic and hyperelastic models. It overestimates the peak TAWSS by 6.22 % and 14.46 % relative to the elastic and hyperelastic models, respectively, suggesting a higher risk of plaque rupture in rigid walls. In terms of plaque progression, both the pre- and post-stenotic regions of the arterial wall show the most extensive affected areas in the hyperelastic model compared to the rigid and elastic models, indicated by severe negative and critically low values of TAWSS, and critically high values of OSI and RRT. The FFR value is the highest for the hyperelastic model (0.95), followed by the elastic (0.94) and rigid models (0.91). These findings underscore the importance of incorporating arterial wall flexibility in hemodynamic studies to improve risk assessment and clinical accuracy.
{"title":"Effect of wall models on hemodynamics in left coronary artery: A comparative numerical study","authors":"Asif Equbal, Paragmoni Kalita","doi":"10.1016/j.ijengsci.2025.104358","DOIUrl":"10.1016/j.ijengsci.2025.104358","url":null,"abstract":"<div><div>Hemodynamic variables are vital for understanding the progression of cardiovascular diseases, but their accuracy depends on assumptions about arterial wall behaviour. Although the left anterior descending (LAD) branch of the left coronary artery (LCA) has been reported to be highly susceptible to atherosclerosis, there is a significant lack of studies comparing the effects of different wall models in this context. This study employs two-way fluid-structure interaction (FSI) simulations to investigate the impact of rigid, elastic, and hyperelastic wall models on the hemodynamics of a moderately stenosed LAD branch in an idealised LCA. The non-Newtonian properties of blood are captured using the Carreau viscosity model. Key hemodynamic parameters—primary velocity (<span><math><msub><mi>V</mi><mi>p</mi></msub></math></span>), streamwise vorticity, time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), relative residence time (RRT), and fractional flow reserve (FFR)—are evaluated across these models. Results show that the rigid model mostly exhibits higher <span><math><msub><mi>V</mi><mi>p</mi></msub></math></span> and TAWSS at the stenosis throat compared to the elastic and hyperelastic models. It overestimates the peak TAWSS by 6.22 % and 14.46 % relative to the elastic and hyperelastic models, respectively, suggesting a higher risk of plaque rupture in rigid walls. In terms of plaque progression, both the pre- and post-stenotic regions of the arterial wall show the most extensive affected areas in the hyperelastic model compared to the rigid and elastic models, indicated by severe negative <span><math><msub><mi>V</mi><mi>p</mi></msub></math></span>and critically low values of TAWSS, and critically high values of OSI and RRT. The FFR value is the highest for the hyperelastic model (0.95), followed by the elastic (0.94) and rigid models (0.91). These findings underscore the importance of incorporating arterial wall flexibility in hemodynamic studies to improve risk assessment and clinical accuracy.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104358"},"PeriodicalIF":5.7,"publicationDate":"2025-07-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144738286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-07-28DOI: 10.1016/j.ijengsci.2025.104350
Andrea Francesco Russillo, Giuseppe Failla
Analysing elastic wave propagation in periodic small-size structures plays an important role in the design of many micro- and nano-engineering devices. However, as ad hoc size-dependent continuum theories are required to capture size effects, pertinent computational tools shall be developed to characterize the wave propagation properties. In this context, this paper introduces an original computational framework to build the dispersion diagram of periodic 3D small-size solids of arbitrary shape, as modelled by the well-established Eringen’s nonlocal integral theory. The framework makes use of a suitable periodic Bloch ansatz to represent the response variables involved in the weak formulation of the integro-differential free-vibration equilibrium equations of the unit cell. Building on the periodicity of the Bloch ansatz and introducing an appropriate change of variables, it is shown that the integral coupling the response at a given point of the unit cell to the responses at all points of the solid can be reverted to the summation of integrals defined on the domain of the unit cell only. This remarkable result paves the way to solve the wave propagation problem by a finite element formulation of the free-vibration equilibrium equations of the unit cell, which involves a standard mass matrix, a local stiffness matrix and a nonlocal stiffness matrix, with the latter being expressed by the infinite summation of nonlocal matrices accounting for the nonlocal interactions between the unit cell and the surrounding cells of the solid. In fact, the summation can be truncated to a finite order depending on the nonlocal horizon of the kernel function selected for the nonlocal integral model and the dispersion diagram can be obtained from a linear eigenvalue problem, derived enforcing the Bloch conditions in the finite element free-vibration equilibrium equations of the unit cell. Numerical applications substantiate correctness and accuracy of the proposed framework, which enables a consistent application of the Eringen’s nonlocal integral theory to study wave propagation in periodic 3D small-size structures of arbitrary shape, for the first time to the best of authors’ knowledge.
{"title":"A novel computational framework for wave propagation analysis of periodic 3D small-size solids","authors":"Andrea Francesco Russillo, Giuseppe Failla","doi":"10.1016/j.ijengsci.2025.104350","DOIUrl":"10.1016/j.ijengsci.2025.104350","url":null,"abstract":"<div><div>Analysing elastic wave propagation in periodic small-size structures plays an important role in the design of many micro- and nano-engineering devices. However, as ad hoc size-dependent continuum theories are required to capture size effects, pertinent computational tools shall be developed to characterize the wave propagation properties. In this context, this paper introduces an original computational framework to build the dispersion diagram of periodic 3D small-size solids of arbitrary shape, as modelled by the well-established Eringen’s nonlocal integral theory. The framework makes use of a suitable periodic Bloch ansatz to represent the response variables involved in the weak formulation of the integro-differential free-vibration equilibrium equations of the unit cell. Building on the periodicity of the Bloch ansatz and introducing an appropriate change of variables, it is shown that the integral coupling the response at a given point of the unit cell to the responses at all points of the solid can be reverted to the summation of integrals defined on the domain of the unit cell only. This remarkable result paves the way to solve the wave propagation problem by a finite element formulation of the free-vibration equilibrium equations of the unit cell, which involves a standard mass matrix, a local stiffness matrix and a nonlocal stiffness matrix, with the latter being expressed by the infinite summation of nonlocal matrices accounting for the nonlocal interactions between the unit cell and the surrounding cells of the solid. In fact, the summation can be truncated to a finite order depending on the nonlocal horizon of the kernel function selected for the nonlocal integral model and the dispersion diagram can be obtained from a linear eigenvalue problem, derived enforcing the Bloch conditions in the finite element free-vibration equilibrium equations of the unit cell. Numerical applications substantiate correctness and accuracy of the proposed framework, which enables a consistent application of the Eringen’s nonlocal integral theory to study wave propagation in periodic 3D small-size structures of arbitrary shape, for the first time to the best of authors’ knowledge.</div></div>","PeriodicalId":14053,"journal":{"name":"International Journal of Engineering Science","volume":"217 ","pages":"Article 104350"},"PeriodicalIF":5.7,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144713665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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