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Dynamic stress concentration in an infinitely long cylindrical cavity due to a point spherical source embedded within a fluid-saturated poroelastic formation of infinite extent

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 139-156页

作者： H.HOSSEINI O.BALILASHAKI Department of mechanical engineering Faculty of EngineeringGolestan University

The effects of a harmonically exciting monopole source on an infinitely long cylindrical cavity embedded entirely within a fluid-saturated poroelastic formation of infinite extent are examined theoretically. It is assumed that the source is located outside the cavity at a specified distance from the borehole axis. The magnitudes of the hoop and radial stresses beside the pore pressures exerted on the interface and inside the porous medium surrounding the borehole are calculated and discussed. Biot's poroelastic modeling along with three types of boundary conditions for the cylindrical interface including the ideal fluid, empty borehole, and rigid inclusion with a hard boundary is employed for the analysis. Utilizing a proper translational addition theorem for expressing the incident spherical wave in terms of cylindrical wave expansions, the proposed boundary conditions at the interface are satisfied. Stresses are formulated by means of wave potential functions in a three-dimensional(3D) manner. The effects of the frequency and the radial distance between the source and borehole on the induced stresses are examined for the first cylindrical modes over frequency spectra. Two permeability conditions for the interface and three types of soils for the porous formation are considered throughout the analysis. To give an overall outline of the study, a numerical example is presented. The results clearly indicate that the distance is a key parameter and has considerable effects on the induced stress values. In addition, the interface permeability condition and soil characteristics play an important role in determining the dynamic response of the borehole. Finally,the obtained results are compared with the relevant analyses existing in the literature for some limit cases, and good agreement is achieved.

关键词： cylindrical cavity O353.4 point source porous medium stress concentration wave-field transformation

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Free vibration and transient response of double curved beams connected by intermediate straight beams

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 37-62页

作者： R.A.JAFARI-TALOOKOLAEI H.GHANDVAR E.JUMAEV S.KHATIR T.CUONG-LE School of mechanical engineering Babol Noshirvani University of Technology Department of mechanical engineering Faculty of Engineering New Uzbekistan University University of Business and Science Center for engineering Application and technology Solutions Ho Chi Minh City Open University

This paper investigates the free vibration and transient response of interconnected structures including double curved beams and intermediate straight beams,which are all constructed from functionally graded porous(FGP) materials. The strain potential and kinetic energies of each beam along with the work done by the external force are calculated. Additionally, a higher-order beam element is introduced to derive stiffness and mass matrices, along with the force vector. The curved and straight beams are discretized, and their assembled stiffness, mass matrices, and force vectors, are *** conditions at the joints are used to derive the total matrices of the entire structure. Subsequently, the natural frequencies and transient response of the system are determined. The accuracy of the mathematical model and the self-developed computer program is validated through the comparison of the obtained results with those of the existing literature and commercial software ANSYS, demonstrating excellent ***, a comprehensive study is conducted to investigate the effects of various parameters on the free vibration and transient response of the considered structure.

关键词： double curved beam finite element method functionally graded porous (FGP) material intermediate straight beam O313 vibration analysis

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Wind Turbine Composite Blades:A Critical Review of Aeroelastic Modeling and Vibration Control

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Fluid Dynamics & Materials Processing 2025年第1期21卷 1-36页

作者： Tingrui Liu Qinghu Cui Dan Xu College of mechanical&Electronic engineering Shandong University of Science&TechnologyQingdao266590China School of mechanical&automotive engineering Liaocheng UniversityLiaocheng252059China

With the gradual increase in the size and flexibility of composite blades in large wind turbines,problems related toaeroelastic instability and blade vibration are becoming increasingly more *** their impact on thelifespan of wind turbines,these subjects have become important topics in turbine blade *** this article,firstaspects related to the aeroelastic(structural and aerodynamic)modeling of large wind turbine blades are ***,two main methods for blade vibration control are outlined(passive control and active control),including the case of composite *** improvement schemes are proposed accordingly,with a specialfocus on the industry’s outstanding suppression scheme for stall-induced nonlinear flutter and a new high-frequencymicro-vibration control ***,future research directions are indicated based on existingresearch.

关键词： Aeroelastic instability vibration control composite blade stall-induced nonlinear flutter high-frequency microvibration

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Analysis of Linear and Nonlinear Vibrations of Composite Rectangular Sandwich Plates with Lattice Cores

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Computers, Materials & Continua 2025年第1期82卷 223-257页

作者： Alireza Moradi Alireza Shaterzadeh faculty of mechanical engineering Shahrood University of TechnologyShahroodP.O.Box ***Iran

For the first time,the linear and nonlinear vibrations of composite rectangular sandwich plates with various geometric patterns of lattice core have been analytically examined in this *** plate comprises a lattice core located in the middle and several homogeneous orthotropic layers that are symmetrical relative to *** this purpose,the partial differential equations of motion have been derived based on the first-order shear deformation theory,employing Hamilton’s principle and Von Kármán’s nonlinear displacement-strain ***,the nonlinear partial differential equations of the plate are converted into a time-dependent nonlinear ordinary differential equation(Duffing equation)by applying the Galerkin *** the solution of this equation,the natural frequencies are ***,to calculate the non-linear frequencies of the plate,the non-linear equation of the plate has been solved analytically using the method of multiple ***,the effect of some critical parameters of the system,such as the thickness,height,and different angles of the stiffeners on the linear and nonlinear frequencies,has been analyzed in *** confirmthe solution method,the results of this research have been compared with the reported results in the literature and finite elements in ABAQUS,and a perfect match is *** results reveal that the geometry and configuration of core ribs strongly affect the natural frequencies of the plate.

关键词： Free vibration composite sandwich plate lattice core galerkin method Duffing equation multiple scales method

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A comprehensive investigation on nonlinear vibration and bending characteristics of bio-inspired helicoidal laminated composite structures

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 81-100页

作者： S.SAURABH R.KIRAN D.SINGH R.VAISH V.S.CHAUHAN School of mechanical and Materials engineering Indian Institute of Technology Mandi

Bio-inspired helicoidal composite laminates, inspired by the intricate helical structures found in nature, present a promising frontier for enhancing the mechanical properties of structural designs. Hence, this study provides a comprehensive investigation into the nonlinear free vibration and nonlinear bending behavior of bio-inspired composite plates. The inverse hyperbolic shear deformation theory(IHSDT) of plates is employed to characterize the displacement field, with the incorporation of Green-Lagrange nonlinearity. The problem is modeled using the C0finite element method(FEM), and an in-house code is developed in the MATLAB environment to solve it numerically. Various helicoidal layup configurations including helicoidal recursive(HR), helicoidal exponential(HE), helicoidal semi-circular(HS), linear helicoidal(LH), and Fibonacci helicoidal(FH)with different layup sequences and quasi-isotropic configurations are studied. The model is validated, and parametric studies are conducted. These studies investigate the effects of layup configurations, side-to-thickness ratio, modulus ratios, boundary conditions, and loading conditions at different load amplitudes on the nonlinear vibration and nonlinear bending behaviors of bio-inspired composite plates. The results show that the laminate sequence exerts a substantial impact on both nonlinear natural frequencies and nonlinear bending behaviors. Moreover, this influence varies across different side-to-thickness ratios and boundary conditions of the bio-inspired composite plate.

关键词： bio-inspired composite plate finite element method (FEM) Green-Lagrange helicoidal inverse hyperbolic shear deformation theory (IHSDT) nonlinear O322

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Comparative Evaluation and Performance Analysis of Heat Exchangers Featured with Peened Surface

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Journal of Thermal Science 2025年第1期34卷 50-61页

作者： DINESHBABU Chinnadurai SHIVA SANKARAN Nallasamy VENKATESH RAJAKrishnan VENKATESH Rathinavelu Department of mechanical engineering Kongunadu College of Engineering and TechnologyTamil Nadu-621215India Department of mechanical engineering Selvam College of TechnologyNamakkalTamil Nadu-637003India Department of mechanical engineering Sona College of TechnologySalemTamil Nadu-636005India Department of mechanical engineering Saveetha School of EngineeringSaveetha Institute of Medical and Technical Sciences(SIMATS)Saveetha UniversityChennai 602105TamilnaduIndia

Heat exchangers have the potential for various engineering applications,and their performance is enriched by surface *** proposed system enriches the heat exchanger's performance by adapting a peened stainless steel(SS)surface blasted with copper,grinding,sand,and *** influences peened SS surface modified with a copper blast,grinding,sandblast,and iron blast on the surface morphology of shell and tube heat exchanger surface(STHE)is analyzed via tungsten heated cathode electron gun featured scanning electron microscope and observed coarse grain *** SS surface featured STHE performance is experimentally evaluated by different flow rates(30,60,90,and 120 L/min)underwater fluid medium functioned by the temperature ranges of 25-75℃ and its results are compared with computational fluid dynamic(CFD)/heat transfer research(HTRI)analyzed *** 60 L/min flow rate was spotted as an optimum value for both shell and tube side *** STHE is operated with a 60 L/min flow rate under the different peened surfaces and evaluated its Stanton number,Nusselt number,logarithmic mean temperature difference(LMTD),overall heat transfer coefficient,number of transfer units(NTU),effectiveness,and exergy *** iron blasted SS peened surface was observed to have better SHTE performance like Stanton number(0.0012),Nusselt number(2180),reduced LMTD of 31℃,improved overall heat transfer co-efficient of 2400 W/(m^(2)·K),better NTU of 0.5532,good effectiveness value of 0.45162,and hiked exergy efficiency of 10% respectively.

关键词： penned surface performance analysis stainless steel shell and tube heat exchanger

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Dynamic behaviors of graphene platelets-reinforced metal foam piezoelectric beams with velocity feedback control

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Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 63-80页

作者： Jie CHEN Xinyue ZHANG Mingyang FAN School of Mathematics Statistics and Mechanics Beijing University of Technology College of mechanical & Energy engineering Beijing University of Technology

Graphene platelets(GPLs)-reinforced metal foam structures enhance the mechanical properties while maintaining the lightweight characteristics of metal foams. Further bonding piezoelectric actuator and sensor layers on the surfaces of GPLs-reinforced metal foam beams enables active vibration control, greatly expanding their applications in the aerospace industry. For the first time, this paper investigates the vibration characteristics and active vibration control of GPLs-reinforced metal foam beams with surfacebonded piezoelectric layers. The constant velocity feedback scheme is used to design the closed-loop controller including piezoelectric actuators and sensors. The effects of the GPLs on the linear and nonlinear free vibrations of the beams are numerically *** Newmark-β method combined with Newton's iteration technique is used to calculate the nonlinear responses of the beams under different load forms including harmonic loads,impact loads, and moving loads. Additionally, special attention is given to the vibration reduction performance of the velocity feedback control on the responses of the beam.

关键词： active vibration control metal foam nonlinear free vibration O341 piezoelectric material velocity feedback control

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Few-shot learning for screening 2D Ga_(2)CoS_(4-x) supported single-atom catalysts for hydrogen production

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Journal of Energy Chemistry 2025年第1期100卷 665-673页

作者： Nabil Khossossi Poulumi Dey Department of mechanical engineering(ME) Delft University of Technology2628 CD DelftThe Netherlands

Hydrogen generation and related energy applications heavily rely on the hydrogen evolution reaction(HER),which faces challenges of slow kinetics and high *** electrocatalysts,particularly single-atom catalysts (SACs) on two-dimensional (2D) materials,are *** study presents a few-shot machine learning (ML) assisted high-throughput screening of 2D septuple-atomic-layer Ga_(2)CoS_(4-x)supported SACs to predict HER catalytic ***,density functional theory (DFT)calculations showed that 2D Ga_(2)CoS4is inactive for ***,defective Ga_(2)CoS_(4-x)(x=0–0.25)monolayers exhibit excellent HER activity due to surface sulfur vacancies (SVs),with predicted overpotentials (0–60 mV) comparable to or lower than commercial Pt/C,which typically exhibits an overpotential of around 50 m V in the acidic electrolyte,when the concentration of surface SV is lower than 8.3%.SVs generate spin-polarized states near the Fermi level,making them effective HER *** demonstrate ML-accelerated HER overpotential predictions for all transition metal SACs on 2D Ga_(2)CoS_(4-x).Using DFT data from 18 SACs,an ML model with high prediction accuracy and reduced computation time was *** intrinsic descriptor linking SAC atomic properties to HER overpotential was *** study thus provides a framework for screening SACs on 2D materials,enhancing catalyst design.

关键词： Hydrogen production Electrocatalyst 2D material Density functional theory Machine learning Surface sulfur vacancy

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Flow field distribution and overpressure characteristics inside the crew compartment of a truck-mounted howitzer under the effect of muzzle blast

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Defence technology(防务技术) 2025年第2期44卷 190-205页

作者： Shengcheng Wei Linfang Qian Yadong Xu Qiang Yin Xinyu Xiong School of mechanical engineering Nanjing University of Science and TechnologyNanjing210094China Northwest Institute of mechanical and Electrical engineering Xianyang712099China

The muzzle blast overpressure induces disturbances in the flow field inside the crew compartment(FFICC)of a truck-mounted howitzer during the artillery *** overpressure is the primary factor preventing personnel from firing artillery within the *** investigate the overpressure characteristics of the FFICC,a foreign trade equipment model was used as the research object,and a numerical model was established to analyze the propagation of muzzle blast from the muzzle to the interior of the crew compartment under extreme firing *** comparative verification,the muzzle blast experiment included overpressure data from both the flow field outside the crew compartment(FFOCC)and the FFICC,as well as the acceleration data of the crew compartment structure(Str-CC).The research findings demonstrate that the overpressure-time curves of the FFICC exhibit multi-peak characteristics,while the pressure wave shows no significant *** enclosed nature of the cab hinders the dissipation of pressure wave energy within the FFICC,leading to sustained high-amplitude *** frameskin structure helps attenuate the impact of muzzle blast on the ***,local high overpressure caused by the convex or concave features of the cab's exterior significantly amplifies the overpressure amplitude within the FFICC.

关键词： Truck-mounted howitzer Muzzle blast Flow field inside the crew compartment(FFICC) Overpressure characteristics Flow-structure interaction

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One-dimensional wave theory analysis of factors and characteristics influencing errors in two-wave method data processing in SHPB

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Acta Mechanica Sinica 2025年第1期41卷 128-140页

作者： Minghui Ma Guangfa Gao School of mechanical engineering Nanjing University of Science and TechnologyNanjing 210094China

A simplified calculation of the specimen’s stress-strain curve is generally conducted using the two-wave method by the split Hopkinson pressure bar(SHPB),which aligns the onset of the transmitted and reflected ***,this approach neglects the travel time of elastic waves within the *** the travel time of elastic waves,this study quantitatively investigates the error characteristics and patterns of stress,strain,and strain rate in the specimen under different conditions using the theoretical two-wave method,and compares the results with those obtained using the onset-aligned twowave *** study reveals that the stress-time curves derived from the theoretical two-wave method are lower than the actual stress curves,whereas those obtained from the onset-aligned two-wave method are consistently higher than the actual stress curves,with the stress deviation approximating a constant value when the dimensionless time exceeds *** starting point of the stress-strain curves obtained by the theoretical two-wave method is not zero but a point on the strain axis,whereas the onset-aligned two-wave method always starts at ***,the slopes of the stress-strain curves obtained by both methods differ from the actual Young’s modulus of the material,and functional relationships between the slopes and the actual Young’s modulus are *** research offers theoretical guidance for the refined design of SHPB experiments and the accurate processing of data.

关键词： SHPB Stress wave effect Assumption of stress uniformity Dynamic stress-strain curve

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