Acta Mechanica最新文献

{"title":"Static extension and vibration analysis of piezoelectric semiconductor nanobars based on two-phase local/nonlocal integral models","authors":"Huidiao Song,&nbsp;Hai Qing","doi":"10.1007/s00707-025-04535-y","DOIUrl":"10.1007/s00707-025-04535-y","url":null,"abstract":"<div><p>In this study, the size-dependent static tensile and axial vibrational responses of piezoelectric semiconductor nanobars are investigated using strain-driven and stress-driven dual-phase local/nonlocal integral constitutive models. A linearized one-dimensional phenomenological framework for piezoelectric semiconductors is employed to establish the governing equations. The two-phase local/nonlocal integral formulation is implemented, which is subsequently transformed into differential formulations with corresponding constitutive constraints. A few dimensionless variables are introduced to streamline mathematical derivations. The general differential quadrature method is utilized to obtain the numerical solutions. The influence of nonlocal parameters on the static extension displacement, electric potential, and undamped natural frequencies of piezoelectric semiconductor nanobar are investigated under different boundary and loading conditions. Critical comparisons between strain-driven and stress-driven modeling paradigms are highlighted to elucidate their distinct predictive capabilities in nanoscale electromechanical coupling phenomena.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"299 - 315"},"PeriodicalIF":2.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancement of capacitive micromachined ultrasonic transducer performance via porous graphene-reinforced PDMS dielectric gap fillers for ultrasound retinal stimulation","authors":"Mohammad Homaei,&nbsp;Mohammad Fathalilou,&nbsp;Ghader Rezazadeh","doi":"10.1007/s00707-025-04527-y","DOIUrl":"10.1007/s00707-025-04527-y","url":null,"abstract":"<div><p>Ultrasound stimulation has emerged as a promising noninvasive approach for vision restoration, yet conventional capacitive micromachined ultrasonic transducers (CMUTs) face limitations such as high actuation voltages and insufficient pressure output. This study introduces an innovative CMUT design incorporating a soft porous graphene-reinforced polydimethylsiloxane (PDMS) gap-filling material to address these challenges. Unlike conventional uniform or non-porous gap materials, the porous graphene-PDMS composite simultaneously enables lower operational voltages with improved sensitivity and mechanical stability. A comprehensive nonlinear electromechanical model, leveraging the physically gradient descent-based learning method, captures the complex coupling between the displacement-dependent dielectric properties and the nonlinear plate dynamics. This integrated approach uniquely predicts enhanced resonance responses and acoustic output, providing valuable insights for designing high-performance CMUTs in biomedical applications. The integration of graphene nanoplatelets improves the dynamic response and reduces actuation voltage, optimizing performance for retinal stimulation. Key results include a 32.7% increase in transversal displacement, a 24.3% reduction in actuation voltage, and a 46.2% enhancement in first harmonic resonance amplitude. The proposed CMUT generates 2.4 times higher acoustic pressure at 2 MHz, with a 100-element array achieving 55 Pascals for photoreceptor stimulation and a 1600-element array producing 35 Pascals for ganglion and bipolar cells. These findings highlight the potential of porous graphene-reinforced PDMS to advance CMUT-based retinal prosthetics, offering improved efficiency, safety, and precision for noninvasive therapeutic applications.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"181 - 204"},"PeriodicalIF":2.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915729","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of flexoelectricity on the nonlinear thermo-electro-mechanical response of piezoelectric functionally graded porous graphene platelets-reinforced plates resting on the Kerr foundation","authors":"Xinjie Zhang,&nbsp;Xie Zhao,&nbsp;Yanqing Li,&nbsp;Hongtao Wang,&nbsp;Shijie Zheng","doi":"10.1007/s00707-025-04529-w","DOIUrl":"10.1007/s00707-025-04529-w","url":null,"abstract":"<div><p>This paper investigates the nonlinear free vibration of functionally graded porous graphene platelets-reinforced composite (FGP-GPLs) plates resting on the Kerr foundation, with piezoelectric sheets integrated on the upper and lower surfaces. The material model of the composite layer incorporates three types of porosity and three distinct patterns of graphene platelets distribution. To determine the effective material properties of the composite layer, the Halpin–Tsai micromechanical model, the rule of mixture, and the closed-cell Gaussian random field scheme are employed. The numerical model of the piezoelectric smart laminated structure is developed, carefully considering the effects of the piezoelectricity and flexoelectricity, temperature, and von Kármán nonlinear assumption. This is done in conjunction with the higher-order shear deformation theory (HSDT), the modified couple stress theory (MCST), and isogeometric analysis (IGA) techniques. The nonlinear response of the numerical model is solved using a direct iterative method. The accuracy and effectiveness of the model and solution approach have been validated through comparison with results from the available literature. Lastly, a comprehensive discussion is provided on the effects of various parameters, including the distribution patterns of porosity and graphene platelets, the porosity coefficient, the weight fraction of graphene platelets, the temperature rise, the stiffness of the elastic foundation, the flexoelectric effect, and the size-dependent effect on the nonlinear free vibration of the piezoelectric functionally graded porous graphene platelets-reinforced laminated plate resting on the foundation.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"205 - 237"},"PeriodicalIF":2.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915725","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Free vibration analysis of smart piezoelectric GPL-reinforced FGM microplates placed on Winkler–Pasternak foundation","authors":"Van-Loi Nguyen,&nbsp;Thanh-Binh Chu,&nbsp;Minh-Tu Tran,&nbsp;Jaroon Rungamornrat","doi":"10.1007/s00707-025-04517-0","DOIUrl":"10.1007/s00707-025-04517-0","url":null,"abstract":"<div><p>Graphene-reinforced composites are increasingly employed as core layers in smart microplates due to their exceptional mechanical and functional properties. Although graphene or graphene platelets (GPLs) are typically used to reinforce homogeneous matrices, integrating GPLs into conventional functionally graded materials (FGMs) represents a novel approach. This study proposed a new material model comprising a GPL-reinforced FGM core with piezoelectric coating layers. The composite matrix is continuously graded through the thickness following a power-law distribution, and five distinct GPL dispersion patterns are examined. The core’s material properties are determined using the modified Halpin–Tsai model in conjunction with the rule of mixtures. Based on variants of a four-unknown refined plate theory (RPT4) combined with the modified couple stress theory (MCST), governing equations for smart GPL-reinforced FGM microplates with two piezoelectric layers resting on a Winkler–Pasternak foundation are derived. A Navier-based analytical solution is then employed to compute the natural frequencies of the piezoelectric microplate. The performance of the proposed model and the different RPT4 variants is assessed, and the influences of material parameters, piezoelectric layer thickness, length scale, and foundation parameters on the natural frequency are thoroughly investigated.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"153 - 179"},"PeriodicalIF":2.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Phase-field theory of adiabatic shear","authors":"J. D. Clayton","doi":"10.1007/s00707-025-04536-x","DOIUrl":"10.1007/s00707-025-04536-x","url":null,"abstract":"<div><p>A geometrically nonlinear framework is constructed for modeling material failure by adiabatic shear. Mechanisms encompassed include nonlinear thermoelasticity pertinent for high-pressure and high-temperature states, dynamic plasticity from combined actions of dislocation glide and twinning, initial and evolving porosity, rotational dynamic recrystallization (DRX), and localized material degradation from softening and ductile fracture. An order parameter of phase-field type accounts for softening mechanisms at a microstructure length scale too small to be resolved in structural mechanics applications. Phase-field regularization sets the finite width of a shear band or ductile crack, analogous to application of phase-field theory for regularizing sharp cracks in brittle fracture. The framework depicts the reduction in resistance to shear banding with (initial) defects or pores, and DRX, in a physically motivated scheme different from prior theory. Model calculations reproduce experimental observations on shear localization and fracture in steel and titanium, the latter with and without initial pores and DRX, under dynamic shear-dominant loading. Further results predict decreased shear stability from void growth under tensile pressure. Compressive pressure increases flow strength, leading to higher temperature and earlier localization in some cases, but later localization in others due to suppressed thermoelastic expansion. Higher loading rates can increase stability due to rate dependence of flow stress, transient phase-field kinetics, and possible inertial effects.\u0000</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"239 - 273"},"PeriodicalIF":2.9,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915744","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of damage and dynamic loading on deflection responses of hybrid structural composite (fibre-reinforced metal laminates) and experimental verification","authors":"Libin Chakkata Thomas,&nbsp;Vikash Kumar,&nbsp;Gaurav Kumar,&nbsp;Sandhyarani Biswas,&nbsp;Mukesh Thakur,&nbsp;Subrata Kumar Panda,&nbsp;Ashish Kumar Meher","doi":"10.1007/s00707-025-04528-x","DOIUrl":"10.1007/s00707-025-04528-x","url":null,"abstract":"<div><p>This research focuses on developing a numerical model for predicting time-varying displacement responses of damaged fibre-metal laminate (FML) hybrid structural components using a higher-order mathematical model, including pre-damage. The numerical solution accuracy obtained using a customized computational code (MATLAB) through the mathematical model is verified with experimental dynamic deflection data. The numerical transient responses are computed through Newmark’s (average acceleration) integration technique in association with the isoparametric finite element approach. Additionally, the pre-damage (crack) is introduced through a variable crack closure technique (VCCT) in a simulation tool (ABAQUS), and the mesh details, including the nodal information, are imported to the MATLAB platform using the compatibility code. For experimental validation purposes, a few hybrid FML (glass fibre epoxy panels joined with aluminium plates) are fabricated and utilized for experimentation, including the experimental material properties. The numerical model accuracies are initially verified with previously published transient values of the laminated composite. After fulfilling the necessary convergence criteria and the validation, the computational model is extended to work out a few parametric analyses to understand the significance of damage and limiting factors (curvature ratio, geometric shapes, and modular ratios) in designing such FML components. It can be concluded from the numerical experimentation that the geometrical parameters (curvature ratio, stacking sequence, and aspect ratio) largely influence the dynamic deflections, i.e. the responses vary from 4–8% (increase in peak displacement). Meanwhile, the values upsurge by 32%, while the structural end-restrained conditions are less (for a cantilever case: CFFF). Finally, a set of recommendations is listed to understand the advantages of the proposed model for the analysis of FML structure, including the damage effects.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"135 - 152"},"PeriodicalIF":2.9,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915728","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wave-based analysis and parametric study of vibration in fluid-filled periodic pipe structures","authors":"Dongze He,&nbsp;Shuang Du","doi":"10.1007/s00707-025-04532-1","DOIUrl":"10.1007/s00707-025-04532-1","url":null,"abstract":"<div><p>Considering the increasing demand for vibration and noise control in fluid-conveying pipeline systems, this study presents the wave-based analytical model for investigating the vibration behavior of periodic pipe structures filled with internal fluids. The model is formulated by integrating Timoshenko beam theory with the wave-based method. Governing differential equations are derived, considering both cross-sectional deformation and shear effects. A fluctuation-type solution is employed to obtain the displacement fields. Based on the displacement and force continuity conditions at the interfaces of adjacent units, together with the appropriate boundary conditions, the global dynamic equations of the periodic fluid-filled pipe structure are derived.The model’s accuracy is validated through comparison with finite element method (FEM) results. Subsequently, a parametric analysis is performed to examine the effects of fluid velocity, structural geometry, and material properties on the bandgap characteristics. The proposed framework offers theoretical insights and practical guidance for the design and vibration control of fluid-filled periodic pipeline systems.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"117 - 134"},"PeriodicalIF":2.9,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dynamic stress analysis of semi-elliptical notches in PZT media under SH wave interaction using Mathieu functions","authors":"Fatemah Mofarreh,&nbsp;Sarika Panwar,&nbsp;Abdulkafi Mohammed Saeed,&nbsp;Ganesh V. Radhakrishnan,&nbsp;Saroj Date,&nbsp;N. S. Alharthi,&nbsp;Abdul Hamid Ganie,&nbsp;Abhinav Singhal","doi":"10.1007/s00707-025-04520-5","DOIUrl":"10.1007/s00707-025-04520-5","url":null,"abstract":"<div><p>This work develops a rigorous analytical framework to examine the scattering behavior and dynamic stress response of semi-elliptical notches in piezoelectric half-planes subjected to anti-plane shear (SH) waves. The framework unifies the treatment of cracks, circular holes, and notches within a consistent wave–defect interaction model, while explicitly incorporating piezoelectric coupling and nanoscale surface/interface effects. The analysis employs the complex function method in combination with the Helmholtz equation and wavefield superposition theory, resulting in an infinite system of equations that rigorously enforces continuity and boundary conditions. A systematic truncation scheme is then applied to ensure stable and convergent solutions. The results reveal that surface/interface effects play a crucial role in suppressing the dynamic stress concentration factor (DSCF), particularly under vertical SH-wave excitation, while sharper resonance peaks emerge at low modulus ratios and higher piezoelectric constants, such as PZT-5H and BaTiO₃. In the absence of piezoelectric coupling, the formulation seamlessly reduces to classical elasticity, ensuring strong theoretical consistency. Validation is achieved through recovery of benchmark solutions (semicircular notch and edge crack), graphical comparisons with prior results, and the rapid convergence of the truncated system, confirming the model’s accuracy and robustness. The findings hold significant implications for structural health monitoring, non-destructive evaluation, and the design of advanced piezoelectric composites, where accurate prediction of stress amplification and defect evolution is essential. Although the present study focuses on semi-elliptical notches in half-plane geometries under SH-wave loading, the approach can be readily extended to more general defect shapes and mixed-mode disturbances. The novelty of this work lies in capturing piezoelectric surface/interface effects within an exact analytical framework, thereby enhancing predictive capability for defect-induced stress concentrations and providing a reliable basis for the design and durability assessment of high-performance piezoelectric materials.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"89 - 115"},"PeriodicalIF":2.9,"publicationDate":"2025-09-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermal and mechanical post-buckling analysis of the composite truncated conical shells reinforced with the lattice core","authors":"M. S. Sajjadi,&nbsp;A. R. Shaterzadeh","doi":"10.1007/s00707-025-04525-0","DOIUrl":"10.1007/s00707-025-04525-0","url":null,"abstract":"<div><p>In this study, the thermal post-buckling behavior of a truncated composite conical shell with a lattice core and two composite layers is investigated. The shell is subjected to a uniform and linear temperature rise in thickness direction with simply supported boundary conditions at both ends. The shell is assumed to have an initial geometric imperfection and a lattice core composed of three stiffeners types: longitudinal (stringer), radial (ring), and helical with constant helical angles. The governing equations are derived based on the classical shell theory, incorporating nonlinear stress–strain relations under thermal loading. The compatibility equations are solved using the Galerkin method and the method of undetermined coefficients to predict the thermal buckling loads and post-buckling response. Numerical results validate the proposed model by comparison with previous studies and show that the reinforcement pattern significantly affects the thermal buckling performance. Among the configurations, the helical stiffeners yield the highest thermal resistance.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"67 - 88"},"PeriodicalIF":2.9,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915649","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influences of complex surface conditions on reflection behavior of coupled waves in a piezoelectric solid with void","authors":"Shuang Jia,&nbsp;Yueqiu Li,&nbsp;Hong Wang,&nbsp;Ying Li,&nbsp;Changda Wang","doi":"10.1007/s00707-025-04521-4","DOIUrl":"10.1007/s00707-025-04521-4","url":null,"abstract":"<div><p>The reflection behavior of a multiple physical fields coupled waves for four kinds of possible surface conditions of piezoelectric solid with void is studied in this paper. First, the dispersion equation for multiple physical fields coupled waves propagation in the piezoelectric porous media is derived through inserting the multiple physical fields coupled constitutive equations into the general governing equation. Different from the classic piezoelectric medium, there are four coupled elastic waves in the piezoelectric material with void. Due to the consideration of porous effects of the piezoelectric material, the surface conditions can be proposed in different forms. These surface conditions, which include the free surface and elastic surface, electrical short circuit and electrical open circuit, as well as zero volume fraction disturbance surface and zero equivalent force surface, are then used to determine the reflection coefficients of reflection waves. The numerical results are provided for incident QP wave and incident QSV wave, respectively, and are validated by the energy conservation law. Based on these numerical results, the influences of the four kinds of surface conditions on the reflection behavior of multiple physical fields coupled waves are discussed.</p></div>","PeriodicalId":456,"journal":{"name":"Acta Mechanica","volume":"237 1","pages":"53 - 65"},"PeriodicalIF":2.9,"publicationDate":"2025-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}