International Journal of Mechanics and Materials in Design最新文献

This study investigates the free vibration behavior of a highway bridge system modeled as a prestressed axially functionally graded (AFG) tapered Euler-Bernoulli beam under simply supported - simply supported and clamped - clamped boundary conditions. The model integrates the influences of initial strain, material gradation represented by a power-law exponent, and geometric tapering specified by the taper ratio. The Galerkin approach employing orthonormal polynomials is applied to address both forward and inverse vibration issues. To ensure the credibility of the obtained results, convergence behavior is carefully examined, and comparisons are also made with existing solutions in some specific cases. The results indicate that prestressing significantly enhances the values of the fundamental frequency parameter, whereas higher vibration modes demonstrate reduced sensitivity. The inverse formulation accurately estimates the initial strain parameter from frequency data, converging effectively with a sufficient number of basis functions. Mode shape analysis shows that initial strain strongly influences the fundamental mode, whereas tapering affects all vibration modes. The findings demonstrate the effectiveness of the presented Galerkin-based approach for vibration analysis and inverse parameter identification in prestressed AFG tapered beam structures. Also, it provides valuable insights for the design and health monitoring of the highway bridge structures. Moreover, the proposed framework supports the development of safer, longer-lasting, and more sustainable infrastructure systems through optimized material usage and reduced maintenance demands.

Because of their remarkable mechanical and physical properties, including their high strength-to-weight ratio, tunable stiffness and strength, and negative Poisson's ratio, functionally graded graphene origami-enabled auxetic metamaterial structures have demonstrated great promise for a range of engineering applications. This is one of the first studies where the IGA method was used to analyze the free and forced vibration behaviors of FG-GOEAM non-uniform thickness microplates subjected to different types of dynamic loads and resting on a visco-elastic foundation. A genetic programming-based micromechanics model is used to calculate the GOEAM's material characteristic, such as its Young's modulus, and Poisson's ratio. The governing equations of motion are established using the higher-order shear deformation theory, modified couple stress theory, and Hamilton's principle. The impacts of GOri's folding degree, distribution, weight fraction, length-scale parameter, and micro-plate dimensions on the free vibration and transient response of non-uniform thickness FG-GOEAM micro-plate are shown by a thorough parametric research. The analysis, design, and optimization of FG-GOEAM structures in civil engineering, microelectronics, aerospace, semiconductor chips, and nuclear power applications are anticipated to benefit from these discoveries.

This study introduces a novel configuration in which piezoelectric layers with variable spanning angle along the pipe length are employed on a fluid–conveying pipe to analyze energy harvesting performance. The modeling framework is based on Euler–Bernoulli beam theory combined with von–Karman nonlinear strain–displacement relations. The piezoelectric pipe is resting on a nonlinear viscoelastic foundation and simply supported at both ends, is subjected to external harmonic excitation near its primary resonance. Hamilton’s principle is employed to derive the governing equations of motion, which are subsequently reduced to a set of ordinary differential equations using the Galerkin method. The harmonic balance method is then utilized to derive analytical expressions for the frequency and force response of amplitude, voltage output and harvested power. The effects of damping coefficient, excitation force, excitation frequency, pipe length and load resistance on the system’s response are investigated in detail. The results reveal that there exists an optimal spanning angle of PZT layers that maximizes the electrical output; hence, using larger spanning angle does not necessarily lead to greater energy harvesting.

In this paper, the size-dependent bending and buckling behaviors of a piezoelectric semiconductor nanobeam are investigated using both strain-driven and stress-driven two-phase local/nonlocal integral models. The governing equations are derived based on a linearized one-dimensional phenomenological theory of piezoelectric semiconductors. The two-phase local/nonlocal integral formulation is implemented, and the integral equations are transformed into differential forms with corresponding constitutive constraints. Several dimensionless variables are introduced to simplify the formulations. The general differential quadrature method is employed to obtain numerical solutions. Based on the results, the influence of nonlocal parameters on the bending deflection, electric potential, and buckling loads of the piezoelectric semiconductor nanobeam is examined under various 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.

Surface Acoustic Wave (SAW) sensors are gaining importance in contemporary technology due to their distinctive characteristics, adaptability, and extensive application spectrum. The present study focuses on enhancing SAW sensor performance by improving their mass loading sensitivity and addressing interfacial imperfections, aiming to elevate their efficiency and precision. The study investigates the dynamic behavior of Love-type waves in piezoelectro-magnetic fiber-reinforced composite (PEMC) structures, analyzing two models: one with an air medium (Model-A) and another with a coated thin film mass loading (Model-B). Five sub-models of interfacial imperfections are explored: Mechanically compliant dielectrically weakly conducting and magnetically weakly permeable (DWMW), highly conducting and magnetically highly permeable (DHMH), low dielectric and magnetic permeability (LDLP), grounded metallic with magnetic grounding (GMMG), and ideal contact interfaces. A micromechanical model of the PEMC is developed, from which material constants of the composite are derived using the strength of materials and the rule of mixtures technique. Using precise boundary conditions for interfacial imperfections, velocity equations are derived and illustrated graphically under four electric-magnetic scenarios: electrically-magnetically short (ESMS), electrically short-magnetically open (ESMO), electrically open-magnetically short (EOMS), and electrically-magnetically open (EOMO). This analysis highlights the impact of electro-mechanical and magneto-mechanical interactions, as well as mass loading, volume fractions, and interfacial imperfections, on Love-type wave velocities in advanced composites. The outcomes of this research could revolutionize detection technologies in SAW devices, thereby enhancing their application across diverse sectors.

This study proposes a robust mathematical and computational framework for investigating the dynamic response of multidirectional functionally graded viscoelastic beams (MDFGVBs) on elastic foundations under moving loads. To capture the time-dependent behavior of viscoelastic materials, the Kelvin–Voigt constitutive model is adopted to capture both stiffness and damping effects. The beam's material properties vary continuously and independently along the axial, transverse, and thickness directions, governed by a generalized spatial gradation function, reflecting realistic material heterogeneity. The governing equations of motion are systematically derived using both Euler–Bernoulli and Timoshenko beam theories, incorporating bending, shear deformation, and rotary inertia effects. The Ritz method is employed for spatial discretization under various classical boundary conditions, whiletransient dynamic responses are computed using the unconditionally stable Newmark-β scheme. Model accuracy and numerical stability are validated through rigorous comparisons with established benchmark solutions. A comprehensive parametric study is conducted to explore the influence of foundation stiffness, viscoelastic damping coefficients, and material gradation indices on both free and forced vibrations. The results reveal significant coupled effects between the foundation parameters and the spatially varying viscoelastic and elastic properties. These findings provide practical guidance for designing functionally graded beam components, for instance in aerospace wing structures and precision robotic arms, where controlling vibration amplitudes and dynamic deflections is critical for structural integrity and operational accuracy. The study also aids in selecting appropriate material gradation profiles and foundation stiffness to achieve targeted dynamic performance.

The current study presents a significant advancement in the elastic bending analysis of hybrid composite sandwich curved beams with re-entrant auxetic cores by introducing a general beam model that more accurately reflects straight and curved beams. The main contribution of this study is the use of a computationally efficient 2D higher-order shear deformation theory without thickness-stretching effects, that develops a reduced kinematic representation through integral expressions of the three displacement variables for the mechanical analysis of hybrid sandwich curved beam with FG face sheets and re-entrant auxetic core. In this study, a new configuration of curved sandwich beam structures with a re-entrant auxetic honeycomb core is presented. In which the negative Poisson’s ratio behavior, promotes transverse expansion during axial extension, providing enhanced mechanical performance compared with traditional sandwich beam systems with core materials that have a positive Poisson’s ratio, while the virtual work principle is used to obtain the equilibrium governing equations. A closed-form solution is used to determine the transverse and axial displacements and internal forces of the composite sandwich beams. The accuracy and strength of the proposed mathematical model were validated through a comparison study with existing numerical results. A detailed parametric study was conducted to examine the effects of different parameters, including material gradation, length-to-thickness ratio, sandwich configuration schemes, and geometric properties of the auxetic core, on the bending behavior of curved beams. The numerical results provide new insights into the elastic bending characteristics of hybrid sandwich beams with re-entrant auxetic cores, highlighting the significant role of auxetic cores in the bending behavior of curved beams.

Thermal performance is significantly better in hybrid nanofluids compared to traditional nanofluids and leading to advancements in industrial processes, medical equipment, and nanomaterials engineering. The ongoing study explores the hybridized fluid flow dynamics over a bidirectional stretching surface, emphasizing their thermal flow properties under various impacts. The study explores not only achieving higher heat conduction compared to traditional nanofluids but also highlights the shape effects capabilities offered by the single-walled and multi-walled carbon nanotube nanoparticle combination in water. The partial differential equations concerning momentum and energy transport have been rendered into a set of ordinary differential equations using a similarity transformation. The transformed nonlinear dimensionless ODEs were solved using the bvp5c solver, a boundary-value problem tool available in MATLAB, and the obtained profiles were further refined and validated using MATLAB’s bvp5c solver. The visualizations represent the results for flows, heat transmission characteristics, which are obtained via the utilization of many important physical features. The present numerical data were validated by comparing special cases of the model with former published results, and display admirable agreement. Outcomes reveal that both hybrid volume fraction and nanoparticle rotation strengthen the axial velocity but damp transverse motion, showing a directional partiality in momentum transport. The temperature fields are remarkably raised by increasing the Biot number, radiation, hybrid nanoparticle concentration, and heat source factor, depicting the hybrid nanofluid’s thermal performance. These findings are applicable in the cooling of rotating machinery, microchannel thermal systems, solar collectors, and nano-manufacturing technologies.

Fins are essential components in many thermal management systems due to their flexible geometry and high efficiency in heat transfer. They are used in applications such as electronic devices, nuclear reactor cooling, and solar energy systems. Among various fin shapes, pyramidal spine fins received attention because of their capacity to improve CPU heat sink performance. Motivated by these applications, the present study investigated the thermal characteristics of an inclined pyramidal spine fin subject to a convective-radiative environment. Additionally, the spine is considered a porous surface, and its interaction with the surrounding fluid is demonstrated using Darcy’s model. By introducing suitable non-dimensional terms, the governing heat equation is transformed into a dimensionless ordinary differential equation (ODE). The resultant equation was solved semi-analytically using a shifted Vieta-Pell polynomial collocation method (SVP-PCM). The novel SVP-PCM approach is distinguished by its close agreement with results from known numerical techniques, showing its robustness and reliability when compared with existing data. Key thermal parameters and their effects are shown graphically. The outcomes reveal that the enhancing values of radiation parameter (from 0 to 3) and convection-conduction parameter (from 2 to 4) improve heat transmission efficiency by 29.82% and 69.28% respectively. Conversely, an increase in the ambient temperature parameter (from 0.2 to 0.5) leads to a decrement of heat transfer rate by 37.5%.

Isaac Newton's contributions laid the foundation for modern mechanics, science, and engineering. This paper explores the historical context in which Newton developed his theories, particularly his three laws of motion, and highlights how they reshaped the scientific understanding of nature and progress. In this paper. we first introduce Newton’s key contemporaries during that era of ground-breaking scientific advances, whose work greatly influenced his discoveries. Then, we focus on the contributions of Newton’s laws of motion to modern mechanics, especially in fields that have received less attention in previous studies. For example, in continuum mechanics, Newton’s laws describe the equilibrium state, dynamic behavior and interactions of particles/systems under external forces. Newton’s contribution also extends to atomistic mechanics. In molecular dynamics simulations, Newton’s second law governs the motion of atoms, which allows us to examine the system behavior under load at the atomistic scale. Furthermore, the paper examines the evolution of classical mechanics into more general formulations, namely Lagrangian and Hamiltonian mechanics, which are central to modern physics. These energy-based approaches provide a more flexible framework to analyze complex systems and serve as a bridge to advanced topics such as statistical mechanics and quantum mechanics. Finally, we examine the limitations of Newtonian mechanics in problems involving relativistic effects, quantum phenomena, and non-inertial reference frames. We briefly introduce the corresponding theories that extend Newton’s framework to address these problems.