International Journal of Mechanics and Materials in Design最新文献

The complex relationship between multiple design parameters and several crashworthiness indices introduces substantial complexities in the structural design of variable-thickness rolled blank (VRB) and orthogonal woven glass fiber-reinforced polymer (OW-GFRP) hybrid hat-shaped beams under transverse impacting. The complexity arises from two primary factors: the direct relationship between structural parameters and crashworthiness indices remains unclear; and the sensitivity of structural parameters to crashworthiness indices can vary markedly across different design schemes, leading to prolonged design cycles and elevated costs. Therefore, we introduce two intermediate field variables, internal energy density (IED) and its mean square error (delta _{IED}), to systematically quantify structural energy distribution patterns enabling the exploration of nonlinear relationship and the sensitivity analysis via spatially IED gradient. This approach constructs a unified framework for the optimization design of structural crashworthiness. The effects of structural parameters on crashworthiness indices, internal energy density and its mean square error are carried out by the numerical models validated by three-point bending experiments of hat-shaped beams. It is found that a more homogeneous IED distribution leads to better crashworthiness indices. Moreover, sensitivity analysis of design parameters to crashworthiness indices has been performed through the surrogate model constructed by the response surface method. The results indicate that the thickness of VRB thick zone (t) has the most pronounced effect on crashworthiness indices, with the number of OW-GFRP plies (n) also playing a significant role, while the influence of middle position of transition zone (p) and the ply angle of OW-GFRP plies ((theta)) is comparatively limited. Finally, a design criterion for homogenizing the IED distribution is proposed to inform the structural design of hybrid beam, which has been successfully applied to a VRB/OW-GFRP hybrid bumper, achieving both excellent crashworthiness and significant mass reduction.

The present work involves a finite element simulation of Glass-reinforced aluminium laminate (GLARE) subjected to quasi-static loading to predict the damage modes using a cohesive zone model (CZM) while considering frictional effects between interfaces as well as indentor and laminate. The CZM, which involves cohesive elements and cohesive surface accompanied with frictional effect is the novelty of the work. Considering frictional effects at every dissimilar interfaces such as Al and composites as well as between the indentor and the surface of the laminate improves the accuracy of the damage prediction. Also, the addition of the in-plane failure modes of the composite in the GLARE laminate using continuum shell element, enabled us to study the combined effect between in-plane damage and out-of-plane delamination simultaneously. The response of CZM was governed by bilinear traction separation law to predict the initiation of damage based on quadratic failure criterion and evolution of damage was predicted based on mixed mode B-K criteria, which used a linear function of average through-thickness stresses. Prediction of plasticity, ductile and shear modes for damage of  the aluminium alloy were obtained by using Johnson–Cook and shear criteria respectively. Initiation of failure of the  composites were predicted by Hashin damage criteria. While the damage evolution of aluminium and composite were predicted using fracture toughness applying linear softening behaviour. A finite element model was developed based on the crack band theory and viscous regularization scheme respectively using the commercially available Abaqus/Explicit finite element solver. The experimentally obtained force versus displacement (F-D) curves for the quasistatic loading were analysed, to obtain the type and sequence of the damage. The FE simulation predicted results for type and sequence of damage which were compared with experimental results. Considering the frictional effect resulted in high delamination at the bottom layers and less delamination at the top layer as compared with prediction without frictional effect which is better prediction with experimental results. In addition, the extent of the damage was investigated using ultrasonic A and C-scan techniques. The numerical and experimental results in terms of F-D curves, size and shape of the delamination were found to be in good agreement.

The Ritz method is highly effective for analysing various structural elements, including plates, shells, panels, and frames. However, its use in analysing functionally graded porous curved (FGPC) beams remains relatively insufficiently explored. This paper presents a novel approach utilising Laguerre functions-based Ritz method to examine the bending, buckling, and free vibration characteristics of FGPC beams. A higher-order shear deformation theory is adopted to accurately model the displacement field pertinent to the problem. Lagrange’s equations are employed to derive the governing equations of motion. The investigation encompasses FGPC beams subjected to three distinct boundary conditions and incorporates two types of porosity distributions. Numerical examples are conducted to evaluate the proposed methodology’s accuracy and efficiency. Moreover, the study meticulously explores the effects of slenderness ratio, boundary condition, porosity distribution, porosity ratio, power-law index, and curvature on the bending, buckling, and vibrational responses of FGPC beams, providing comprehensive analyses and discussions. The results indicate that the methodology proposed herein is straightforward and effective for comprehensively analysing FGPC beams. Furthermore, the boundary condition and the porosity factor significantly impact the bending, buckling, and vibration behaviours of FGPC beams. This research yields several innovative findings that establish a benchmark for subsequent investigations. Additionally, the outcomes of this study enhance the safe and efficient design of engineering systems that integrate FGPC structures.

The manufacturing industry has undergone a remarkable shift with the advent of Metal Additive manufacturing (AM) technology, which offers unmatched design and optimization flexibility. The Wheel hub, which is a vital component in an automobile, transmits power from the driveshaft to the wheel for which the component must be of great strength and durability. The present work aims to develop a high-performance wheel hub for automotive applications utilizing the Aluminum-based alloy AlSi10Mg. Using AM for automotive parts enhances its importance in smart manufacturing which offers freedom for complex designing resulting in reduced weight. The study uses physical testing and a numerical approach to assess the wheel hub performance and force calculations to attain a real-life applicable component. It was found that AlSi10Mg is one of the most suitable materials that can be used to fabricate a wheel hub. The present work is done by designing, followed by topology optimization based on force calculations in Ansys. The experimental testing leads to results that are taken as input for calculations. Future research will be concentrated on identifying better ways to optimize the existing wheel hub design and, if relevant, adopt a better production process. After analysis, It was found out that the maximum von-Mises stress is 110–120 MPa and the deformation ranges from 0.15 to 0.25 mm with FOS ranging in 2.5–2.8 which falls under the real-life application which resulted in a weight reduction of 32.62% by using topology optimization, increasing the vehicle’s performance and efficiency.

Optimizing the design of composite cylinders is crucial for balancing structural integrity, weight reduction, and cost-effectiveness, especially with the widespread use of fiber-reinforced materials in many engineering applications. This study presents a novel approach using Genetic Algorithms to optimize liquefied petroleum gas (LPG) composite cylinders for maximum failure pressure by MATLAB software. Inspired by natural selection, the Genetic Algorithm efficiently explores design variations, considering different materials and cylinder geometries. The main goal of this study is to find the best ply angle and stacking sequence to maximize failure pressure for hybrid and non-hybrid composite cylinders. The maximum stress and Tsai–Wu criteria are used together to predict failure. The algorithm converges towards an optimal design through iterative generations, evaluated using fitness functions based on classical laminate theory. The results demonstrate the effectiveness of this approach in achieving an optimal design under mechanical and thermal loads. The optimization process exhibits strong sensitivity to the selected failure criterion, with the Tsai-Wu and Maximum Stress theories generating fundamentally different optimal configurations. For example, design I under mechanical loads, the Tsai-Wu failure criterion based GA finds that the optimal solution for carbon epoxy is [-89/-50/56/-50/-51/-50₃/56₃/-50/56/-50/57/-50₂/56₅/57/-50₂/56]_s. In contrast, for the maximum stress failure criterion based GA, the optimal solution is [51₂ /-50/51₂/-50₂/51/-50/51/-50/52₂/-50₂/52₃/-50₂/52/-50/51/-50₃]_s. The analysis under combined mechanical and thermal loading highlights significant performance constraints driven by temperature variations, uncovering distinct operational regimes. Within a limited thermal range, several viable stacking sequences are achievable; however, outside this window, only simplified—yet less optimal—designs remain feasible. For example, carbon epoxy, both GA identified that [90₂₆]_s is the optimal configuration. Numerical findings provide insights for hybrid and non-hybrid composite cylinders, assessing the best design based on cylinder structural efficiency and the cylinder cost.

Anchor loss is a critical factor affecting the performance of bulk acoustic wave resonators. It refers to the dissipation of acoustic energy from the resonator into the surrounding substrate or support structures through the anchors holding the resonator. This paper presents an approach to enhance the quality factor and reduce the anchor loss of a thin-film piezoelectric-on-silicon MEMS resonator by using a BOX-shaped Phononic Crystal structure. The BOX-shaped Phononic Crystal (BOX-PnC) creates a bandgap, effectively preventing wave transmission through the tether to the resonator anchors. This bandgap frequency range extended from 92 to 274 MHz with a width of 182 MHz, representing 99% gap-mid gap percentage. The results demonstrate that applying BOX-PnC on resonator anchors reduces the insertion loss from 2.6 to 0.8 dB, improves the anchor quality factor from 36,000 to 1,250,000, and increases the unloaded Q-factor from 8,463 to 94,033, achieving enhancements of 34.7-fold and 3.25-fold, respectively.

In this study, the thermomechanical buckling behavior of sandwich smart nanoplates with magneto-electro-elastic surface layers was modeled and examined together with high-order plate theory and nonlocal strain gradient elasticity theory. It consists of a functionally graded material (FGM) metal-ceramic foam structure containing four different foam distributions in the core layer of the sandwich nanoplate. FGM core structure includes pure metal, pure ceramic, pure ceramic–metal and pure metal-cerasssmic combinations. The equations of motion were obtained by Hamilton’s principle as a result of the electro-elastic and magneto-strictive coupling effects, as well as the reflection of thermal loads, spring foundation and shear foundation effects into the energy equations, and the equations of motion were solved by the Navier method. Thermal effects, foundation effects, the effects of electric and magnetic potentials applied to the smart surface layers, and the effects of the properties of the foam structure in the core layer on the thermo-mechanical buckling behavior of the smart sandwich nanoplate have been examined in a broad framework. It is thought that the results of this study will be beneficial in the design and production of smart nano electro-mechanical systems that are intended to operate in high temperature environments. The buckling behavior of the smart plate can be adjusted with the properties of the core layer, the properties of the foundation coefficients and the applied external electric and magnetic potentials for a desired temperature operating environment.

Hybrid nanofluid, a unique type of operational fluid, has gained considerable recognition due to its exceptional thermal conductivity. This study focuses on the thermal analysis of a shifting fin when a hybrid nanofluid is present with a constant flow rate U. It is considered that the fin’s thickness changes as it grows longer. As a result, several fin identities, including convex, triangular, and rectangular shapes, have been taken into consideration. Two types of nanoparticles, namely graphene oxide ((Go)), and molybdenum disulphide ((Mo{S}_{2})), are used in a benzene-water solution (({C}_{6}{H}_{6}{O}_{2}-{H}_{2} O)). The specified conditions resulted in the development of an ordinary differential equation for the fin model. The equation was then changed to a form without dimensions. The Hermite wavelet method was utilized for the first time to address the challenge of a mobile fin submerged in a hybrid nanofluid. To confirm the outcomes, the obtained results were compared systematically with numerical simulations. Three fins with various shapes have been compared and contrasted. It is discovered that the temperature decrease rate is speedier in the triangular and convex fin compared to that of the rectangular fin. This study not only highlights the potential of hybrid nanofluids but also pioneers the application of HWM in fin design, advancing the field of thermal management technologies. An increase of 400% in the convection parameter results in a temperature decrease of 4.926% for the rectangular fin, 5.339% for the convex fin, and 5.599% for the triangular fin. Conversely, when the Peclet number increases by 400%, the temperature distribution along the fin tip rises by 7.1346% for the rectangular profile, 11.428% for the convex profile, and 12.298% for the triangular profile.

In this paper, two sampling techniques are proposed to improve the accuracy of surrogate models used to solve optimization problems involving computationally expensive objective functions. Both techniques depend on random walks and the acceptance criterion of the simulated annealing algorithm to ensure a balance between exploration and exploitation. Moreover, a genetic algorithm is used to locate the global optimal point of the so-far constructed surrogate model. This is to further enhance the search capabilities of our proposed techniques. A simple cubic radial basis function is used as a surrogate model in our experiments. The proposed surrogate-based optimization approach is applied to the marine propeller design problem, where the objective function is an expensive, black-box function. The design variables are the chord lengths and thicknesses for every blade, while the design objective is to achieve the maximum efficiency of the marine propeller. The obtained results improve on those previously reported in literature.

In this study, the axial vibration analysis of radially functionally graded composite nanotubes in an elastic medium based on Bishop's theory is investigated. The material parameters used change functionally from the inside to the outside for the hollow section, as described in the literature. Eringen’s nonlocal elasticity theory in differential form is applied to study higher-order effects in the nano-scale. First, the equation of motion and boundary conditions for the problem in the axial direction are established. The Fourier coefficient is determined by combining the Fourier sine series with the equation of motion. With higher-order boundary conditions, an eigenvalue problem is formulated using the Stokes' transform. In this eigenvalue problem, the elastic medium parameter, rigidities of axial springs at the boundaries, nonlocal parameter, and the volume fraction index are incorporated. From this perspective, the study of these parameters in compact form is possible. The results obtained are compared with those of similar studies in the literature, showing excellent agreement. The effects of several parameters are detailed through various graphs and tables.