International Journal of Mechanics and Materials in Design最新文献

A three-dimensional constitutive model considering the effects of grain size, porosity, and temperature on the macroscopic behaviors of nanoporous Shape Memory Alloys (SMAs) is developed. A finite three-phase model containing a spherical pore, a shell-mounted grain boundary phase, and a shell-mounted grain-core phase, is firstly applied to nanoporous NiTi SMAs. By using the composite Eshelby tensor to homogenize, the overall stress–strain relationship of nanoporous NiTi SMAs are then obtained. In order to verify the correctness of the constitutive model, the molecular dynamics simulations of the superelastic behavior of nanoporous NiTi SMAs are also investigated in this paper. By comparing the numerical simulation results with the experimental results and molecular dynamics simulations, it is verified that the constitutive model proposed in this paper can better describe the superelastic behavior of nanoporous NiTi SMAs. Finally, the effects of grain size, porosity, and temperature on the superelastic behavior of nanoporous NiTi SMAs are analyzed by combining numerical and molecular dynamics simulations. This study will contribute to the theoretical basis for the application of nanoporous NiTi SMAs.

Conical pin fins significantly enhance heat transfer through optimized flow dynamics and increased surface area. This study provides a detailed analysis of rate of thermal transfer and temperature profile of a conical pin fin constructed from a functionally graded material (FGM) with linear, quadratic, and exponential profiles, and the fin is infused with a trihybrid nanofluid comprising MWCNT, silver, and copper in an (EG-{H}_{2}O) base fluid. The governing equation after being nondimensionalized was solved by employing the efficient Fibonacci wavelet technique. This approach facilitated a thorough investigation of the key parameters including the Peclet number, the generation number, the convection parameter, the radiation parameter, power index, thermogeometric parameter, the internal heat generation parameter, and the wet parameter. The results indicate that a 100% increase in the inhomogeneity coefficient (grading parameter) significantly enhances thermal profiles, raising temperatures by 4.8, 4.3, and 6.5% for the linear, quadratic, and exponential FGM profiles, respectively. Furthermore, a 400% elevation in internal heat generation levels induces a proportional rise in fin temperature, with increases of 3, 3.1, and 2.5% for the linear, quadratic, and exponential FGM profiles, respectively. A critical analysis of contour plots for the heat transfer rate reveals that each FGM distribution exhibits distinct characteristics. The exponential profile provides the highest thermal performance and the most favorable temperature distribution, thereby offering significant benefits for applications in electronics cooling, heat exchangers, and aerospace systems.

The free vibration characteristics of two-dimensional (2D) decagonal quasicrystal (QC) cylindrical shell panels hold significant promise for advancing sensor technologies, energy harvesting systems and lightweight structural components in aerospace and mechanical enginee3ring. To address this need, this work presents the Hamiltonian-based analytical solution for free vibration of 2D decagonal QC cylindrical shell panels with Lévy-type boundary conditions. By introducing a full-state vector as the fundamental unknown, the governing equations are formulated in the Hamiltonian form, which are simplified into a set of low-order ordinary differential equations. This approach enables the direct derivation of analytical solutions for free vibration of 2D decagonal QC cylindrical shell panels. Comparison studies validate the accuracy of the proposed symplectic model. Through a comprehensive parametric analysis, it is found that the geometric parameters, elastic constants of the phonon and phason fields, material parameters of the phason field are the key influencing factors on the natural frequencies and modal deformations of the QC cylindrical shell panels.

This study investigates the thermal behavior of a radial porous fin influenced by a magnetic field and internal heat generation. The nonlinear governing ordinary differential equation (ODE) is solved using two advanced methodologies: The Taylor wavelet method and the physics-informed neural networks (PINNs). The Taylor wavelet method provides a semi-analytical solution by converting the ODE into algebraic equations, ensuring accuracy and computational efficiency. PINNs integrate physical laws directly into the neural network framework, employing automatic differentiation to minimize residual errors while solving the ODE. A comparative analysis of the fin’s thermal performance with and without the magnetic field is conducted. The results demonstrate that the Hartmann number ((H)) significantly enhances the heat transfer rate. Furthermore, higher values of the heat generation parameter ((Q)) lead to elevated temperature profiles, as increased internal heat production slows the rate of temperature decay along the fin’s length. This trend is consistent across both scenarios. The PINN approach offers a notable advantage by embedding physics equations within its architecture, eliminating the need for extensive mathematical computations often required by traditional numerical methods. This capability ensures accurate results with minimal training data, making it a time-efficient and resource-saving solution for complex thermal analyses. This approach effectively addresses complex nonlinear thermal problems with high precision and reliability.

The article addresses the nonlinear stability problem of internally hinged arches. Formulation for uniform and non-uniform arches are both given. In latter case, the stiffness of the cross-section at the sides of the internal pin can be different through the geometry and material, causing asymmetry. An analytical model is derived as per the Euler–Bernoulli hypothesis with von Kármán nonlinearity accounted. For uniform arches, generally higher internal forces rise in the arch-half, which is closer to the pinned end. The slenderness ratio affects lower arch angles more drastically. With non-uniformity introduced, a less stiff left side affects negatively the buckling load. Extreme cases are also addressed.

Porous orthotropic thin-walled I-beams (TWI-Bs) are commonly used in aerospace, civil, and mechanical applications due to their high stiffness-to-weight ratio. However, accurately predicting their lateral-torsional buckling (LTB) behavior remains challenging, especially under non-uniform loading and in the presence of material porosity and orthotropy. Classical beam theories often fail to capture essential deformation mechanisms, particularly shear deformation and warping effects, which become significant in porous and thin-walled configurations. This study develops a novel analytical model for evaluating the LTB response of porous orthotropic doubly symmetric I-beams subjected to non-uniformly distributed transverse loadings. To the author’s knowledge, this study is among the first to integrate an HSDT-based thin-walled beam formulation with porosity-dependent orthotropic constitutive modeling to the elastic lateral–torsional buckling of thin-walled I-beams under various non-uniform transverse loadings. Three trigonometric-based non-uniform porosity distribution patterns are considered. The solution is obtained using Galerkin’s method, and the model is validated against available benchmark solutions. The results reveal that neglecting higher-order shear deformation leads to a significant overestimation of critical buckling loads, especially for beams with high porosity or under non-uniform loading conditions. Among porosity patterns, NUDP1 yields the highest buckling resistance, whereas NUDP2 results in the lowest. The position of the applied load and its distribution type (e.g., TRL, TGL) substantially influence the LTB behavior, particularly in shear-sensitive configurations. Geometric parameters, such as flange and web thickness ratios and the orthotropy ratio, further interact with porosity and loading to affect buckling performance. These findings underscore the importance of incorporating advanced shear deformation models and realistic porosity distributions to ensure accurate LTB predictions and a robust structural design.

Porous orthotropic laminated plates are increasingly used in lightweight structural applications due to their high stiffness-to-weight ratio and tunable mechanical behavior. However, their vibrational performance is strongly affected by the distribution of porosity, the lamination scheme, and interaction with the underlying support medium, particularly when resting on elastic foundations. This study aims to analyze the fundamental natural frequencies of porous orthotropic laminated plates considering various porosity distribution patterns (PDP, UDP, NUDP1-3), lamination sequences, and two types of elastic foundation models: Winkler and orthotropic Pasternak foundations. The equations of motion are derived using Hamilton’s principle and higher-order shear deformation theory (HSDT) and solved analytically via Galerkin’s method. A comprehensive parametric study is conducted to assess the impact of foundation stiffness, shear layer stiffness ratio, porosity coefficient, orthotropy ratio, aspect ratio, side-to-thickness ratio, and fiber orientation angle on the dynamic response. The results reveal that increasing foundation stiffness significantly enhances natural frequencies and reduces the adverse effects of porosity on structural stiffness. Orthotropic shear interactions further amplify frequency gains, particularly in soft porosity distributions. Lamination sequences with higher in-plane stiffness and lower fiber angles exhibit better vibrational capacity. Additionally, geometric and material orthotropy parameters significantly impact the frequency trends, with elastic foundations enhancing configuration-specific behaviors.

This research explores the nonlinear dynamic behaviors of sigmoid functionally graded (SFG) cylindrical shells (CSs) reinforced with spiral stiffeners (SSs) utilizing a semi-analytical approach. The shell is subjected to a temperature distribution along its thickness, and the material properties of both the shell and stiffeners vary continuously across the thickness in accordance with a power-law distribution and temperature-dependent relations. To model the system, classical shell theory (CST), von Kármán nonlinear kinematics, the smeared stiffener approach, and the Galerkin technique are employed. To examine the system’s vibrational behaviors, the method of multiple scales (MMSs) is applied, targeting internal resonances (1:1/2:1/4) and a superharmonic resonance of order 2/1. This leads to the derivation of a six-degree-of-freedom nonlinear averaged system. This study, for the first time, presents a detailed numerical analysis that uncovers key dynamic behaviors of the system, including waveforms, phase portraits, and Poincaré maps, emphasizing how changes in stiffener angles influence the nonlinear response of the SFG-CSs reinforced with SSs under internal and superharmonic resonances. In addition, the results demonstrate that optimizing the angles of SSs is a viable strategy for enhancing the dynamic stability of the current system.

This study presents a hybrid modelling approach for the damped vibration analysis of functionally graded nanoplates supported by generalized viscoelastic foundations. The plates, composed of ceramic–metal mixtures, are described by higher-order shear deformation theory and a newly formulated modified nonlocal strain gradient theory, accounting simultaneously for nonlocal and strain gradient effects. The foundation model extends the visco-Pasternak type to include two stiffness parameters and two damping coefficients. Closed-form Navier solutions are derived and used both for a comprehensive parametric study and as training data for a neural network surrogate model. The surrogate enables rapid vibration predictions without repeating the full analytical process. The results demonstrate strong consistency between the analytical and ANN-based predictions, confirming the reliability of the proposed hybrid approach. Parametric results highlight the coupled influence of size-dependent effects, gradation profiles, and foundation damping on dynamic characteristics. The proposed framework effectively balances theoretical rigor and computational efficiency, providing a practical reference for vibration prediction and preliminary design of micro- and nano-scale structural components.