The wind turbine tower is an important component of the system that collects wind energy. The tower is built as a series of tapered pipes with decreasing thickness upward, which makes the joint connections play a significant role in the global structural integrity of the tower. A tower failure may trigger a global failure, as it might be followed by the rotor’s collapse, resulting in significant losses in maintenance expenditure. This study investigates the collapse behavior of the wind turbine tower with and without a bolt joint. The tower response was analyzed using the Finite Element Method (FEM) implemented in ABAQUS. Initially, a benchmarking analysis was conducted to verify the simulation procedures. After verification, numerical simulations were performed for the selected case configurations to evaluate the tower’s behavior under combined axial compression, shear force, and bending moment. Numerical simulation results show that the torsional loading of Loading Case 2 (LC2) significantly reduces the Load Proportionality Factor (LPF), with Loading Case 1 (LC1) having an LPF of 2.89 and LC2 having an LPF of 1.39, resulting in a weakening effect of torque on stability. Meanwhile, Material Nonlinear Analysis (MNA) and Geometric and Material Nonlinear Analysis (GMNA), which account for material plasticity and geometric nonlinearity, provide more realistic predictions with LPFs of 1.89 and 1.24 for LC1 and 1.95 and 1.29 for LC2. In addition, bolt pretension improved stress redistribution and structural stability, resulting in a more uniform load transfer within the jointed system. Therefore, these results contribute to the design and optimization of tower structures, emphasizing the importance of considering both material and geometric nonlinearities, as well as bolt pretension, in structural analysis.
Excessive solar exposure can result in elevated temperatures on solar photovoltaic (PV) panels, therefore decreasing their efficiency. To address this issue, passive cooling techniques utilizing vortex generators (VGs) can be employed to maintain optimal thermal conditions for the solar panel. The current study presents a numerical analysis using computational fluid dynamics to analyze the impact of varying the aspect ratio of the delta winglet VGs on the cooling of a solar PV system as a preliminary study. The aspect ratio was modified by altering the base width of the delta winglet while maintaining fixed heights of 20 mm and 10 mm. The investigation focused on the Nusselt number, convective heat transfer coefficients, and flow visualization to evaluate the heat transfer characteristics. The proposed method has been validated against empirical correlation for the heat transfer coefficient and Nusselt number. The findings indicate that variations in aspect ratio significantly influence heat transfer performance. Notably, the highest increase in the Nusselt number was observed for an aspect ratio of 3.0, with a height of 20 mm and a width of 60 mm, yielding an enhancement of 58.57 %. Flow visualization revealed that the adjusted aspect ratio modifies the flow distribution, thereby generating vortices within the flow.
The article presents a novel analytical machine learning (ML)-based hybrid framework for studying vibration behavior of advanced composite cylindrical microshells based on butterfly-shaped auxetic cores and functionally graded triply periodic minimal surface (FG-TPMS) face layers reinforced using graphene platelet reinforcements (GPLRCs). The analytical framework combines first-order shear deformation theory (FSDT) with modified strain gradient theory (MSGT) to account for the effects of size that are present in microstructures. Hamilton’s concept is used to find dynamic governing equations, and Fourier series expansions are used to solve them analytically. The butterfly-shaped auxetic core signifies a notable improvement over traditional re-entrant auxetic designs, providing increased stiffness and greater structural stability while preserving negative Poisson’s ratio properties. The FG-TPMS face layers deliver optimal strength-to-weight ratios through mathematically engineered periodic structures, further enhanced by strategically positioned GPL reinforcements. An extreme gradient boosting (XGBoost) technique is designed and trained on a comprehensive dataset of 48,600 simulation points to enhance the analytical approach and facilitate swift design optimization. The collection includes essential design characteristics such as MSGT length scale parameters, TPMS pattern variations, butterfly-auxetic geometric ratios, GPL distribution patterns, porosity distributions, weight fractions, and porosity factors.
This research focuses on the size optimization of fuselage frame structures for Medium Altitude Long Endurance Unmanned Aerial Vehicle (MALE UAV), constructed from carbon fiber composites, to reduce mass while maintaining structural integrity. The optimization process utilizes finite element method (FEM) simulations and targets thickness and ply orientation angle variables. Constraints such as failure indices based on the Tsai-Hill criterion, displacement limits, and symmetry composite design requirements are strictly adhered to. The optimization process often results in the elimination of unnecessary layers, particularly middle laminates like layer 5, and adjusts fiber orientations, typically favoring 90° for outer layers and 0° or ±45° for middle layers, to improve stress distribution and load management. FEM simulations comparing the initial and final frame designs show mass reductions ranging from 10 to 11 % in certain frames. However, in some cases, mass remains unchanged, with only fiber orientations being modified to enhance performance. This size optimization not only reduces mass but also ensures that the structural performance meets strength and rigidity requirements under operational loads. The findings contribute to aerospace engineering by offering strategies that balance performance, reliability, and mass efficiency in composite material applications.
This study investigates the ultimate bending moment of box girders within ship structures, dissecting the impact of geometrical parameters, initial imperfections, and the direction of bending moment. Employing the Finite Element Method (FEM) analysis, this investigation navigates through the complex interplay among these variables to unravel profound insights into structural behavior. Initially, a comprehensive benchmarking analysis conducted to evaluate the accuracy of computational models against experimental data. The results demonstrated a high degree of precision, with discrepancies being limited to approximately 2 %. The examination of geometrical parameters unveils their significant role in shaping the structural integrity of box girders, shedding light on how variations in dimensions can influence the ultimate bending moment. Moreover, the study scrutinizes the effect of initial imperfections, recognizing their potential to trigger structural vulnerabilities and alter load-bearing capacities. The investigation reveals significant correlations between geometrical parameters and the ultimate bending moment. Increasing the span/bay ratio from 1 to 6 results in a 70 % decrease in the ultimate bending moment with a constant initial imperfection of 100 %. In contrast, raising the b/t ratio from 35 to 70 leads to a reduction of approximately 65 % in the ultimate bending moment at an imperfection of 250 %.
The purpose of this article is to analyze the deformation, equivalent elastic strain, and safety factor of a bracket. The research applies a numerical study of topology optimization of evaluation for the structures by using a finite element analysis (FEA) and using aluminum alloy 6061 T6 and cast iron EN GJL 100 materials. The benchmarking of mesh condition by comparing the result with the reference’s data is in good agreement, with error correction less than 5%. On the other hand, the results of the bracket evaluation show that aluminum alloy is more elastic and durable than cast iron. However, cast iron has a higher safety factor than aluminum alloy. The safety factor indicates the structural integrity of a certain material by limiting the maximum force that may be applied. The FEA and optimization results showed that the optimization reduced deformation by 15%. Strain decreased by 21% after optimization. Stress experienced a 25% reduction due to optimization. In this specific topology, weight reduction occurs consistently, resulting in a 31% decrease. This means the topology optimization is effective to evaluate the design structure, such as the bracket caliper, and also shows the reduction in iteration time when the finite element method is applied.
In this work, an enhanced MITC3+ approach enriched by a constant in-plane strain correction is proposed in the analysis of functionally graded (FG) porous plates. The approach involves formulating the corrected in-plane strain field through the utilization of corrected nodal derivatives in the concept of discrete divergence consistency (DDC). The DDC for the in-plane strain field is obtained through the orthogonality condition derived from the three-field variational principle (Hu-Washizu), which arises from the difference between resultant in-plane stress and in-plane strain. In carefully examining the static analysis of the FG porous plate with different elements, our investigation delves into the influence of length-to-thickness ratios, power-law indices, and porosity distributions. This comprehensive examination aims to illuminate their combined influence on the numerical outcomes. The proposed approach demonstrates superior performance in addressing FG shell problems, outperforming the original MITC3+ method.
This comprehensive study meticulously analyzes the hydrodynamic performance of various patrol boat designs to enhance maritime security in the Arafura Sea, Indonesia. We evaluated three hull types – monohull, catamaran, and trimaran – based on resistance, stability, seakeeping, and passenger comfort. The study generated nine hull variations using regression analysis. The multi-attribute decision making method and sensitivity analysis were applied to determine the optimal design. The results, a testament to our thorough approach, showed that Catamaran Hull C had the best performance, with the lowest resistance, better stability, and improved seakeeping characteristics. This design is recommended for patrol operations in the Arafura Sea, supporting maritime security and the achievement of the Sustainable Development Goals.
Friction stir processing (FSP) has emerged as an effective technique for enhancing the mechanical and microstructural properties of metal matrix composites. This study investigates the influence of FSP parameters on the mechanical characteristics and microstructure of AZ31B magnesium alloy reinforced with silicon carbide particles of size APS < 80 nm. The method employed here is a hole method for reinforcement and designed with an L9 orthogonal array to analyze the effects of tool geometry, rotational speed, traverse speed, and hole diameter. The experimental findings indicate that a cylindrical threaded tool pin profile, a 0.8-mm hole diameter, a rotational speed of 765 revolutions per minute, and a traverse speed of 31.5 mm/min resulted in the most optimal combination of mechanical properties, including improved tensile strength, micro-hardness, and elongation. Microstructural analysis revealed a uniform distribution of SiC particles, leading to grain refinement and enhanced material performance. These results demonstrate that FSP is a sustainable approach for fabricating high-performance magnesium-based composites, making them suitable for applications in aerospace, automotive, and biomedical industries.
Electricity consumption is expected to increase significantly by 2050. It is essential to ensure that as the increase occurs, there is also a corresponding increase in the proportion of renewable energy sources in the electricity supply. Wind energy has great potential as a promising source of renewable energy. One alternative method for harvesting wind energy is the use of Savonius turbines, which can help expand the collaboration between renewable energy and conventional resources. The critical parts in deploying the Savonius are the consideration of the curved geometrical factor. Thus, this study aims to assess how the geometrical factors of the Savonius turbine affect its performance, and the findings from this research can offer valuable insights for designing an optimal Savonius rotor that aligns with specific requirements. As part of geometrical variations, three different shapes are being modeled and analyzed: one with a phase-shift angle (PSA) of 0°, another with 25°, and a third with 35°. To produce the calculation results, the research employed advanced three-dimensional modeling techniques and the computational fluid dynamics (CFD) method, considering steady conditions and the shear stress transport model. A factorial design analysis was then conducted based on the obtained CFD results to validate the significance of the data research results regarding the impact of these factors on performance. Based on the summarized result trends, the type-1 rotor, with a PSA of 25°, exhibits excellent CPmax performance, achieving a value of 0.32. The results of the factorial design approach analysis indicate that the blade shape, tip-speed ratio, and PSA factors have a significant influence on the performance of the Savonius Rotor.
This work presents an analytical derivation for the stress and deformation formulations under combined mechanical and thermal loading in rectangular functionally graded curved beams. The mechanical load consists of a double couple, while the thermal load corresponds to a steady-state temperature distribution. Using Timoshenko beam theory and thermo-elastic theory, the governing equations incorporate an exponential material gradient in the radial direction, assuming a constant Poisson’s ratio. The Mathematica software was utilized to evaluate the stress and deformation formulations for the thermo-mechanical analysis. Meanwhile, Matlab software was used to perform the results. The results of normalized stresses (including radial, tangential, and von Mises components) and deformations are presented at different variations of temperatures for two different materials that are plotted. The results for the two considered FGM materials, Aluminum/steel and Ti-6Al-4V/ZrO2 are compared, demonstrating lower stresses for Ti-6Al-4V/ZrO2 under identical conditions. The study highlights the influence of temperature and material gradients that affect stress and deformation, with strong agreement between analytical results and finite element analysis (ANSYS simulations), validated through MATLAB plots.
This study explores the relationship between the variable nonlocal parameter and material variations in functionally graded (FG) nanobeams incorporating the influence of unsteady aero thermal and magnetic load defined by the first-order Piston theory. The governing equations of FG Euler nanobeams are derived using Eringen’s nonlocal elasticity theory. These equations are then numerically tested using the Bernstein-based Rayleigh-Ritz method. A comparison with previously published results is conducted to validate the accuracy of the findings. Additionally, the study investigates the effects of nonlocal ceramic, nonlocal metal parameters, Mach number, and aerodynamic force on various physical parameters of FG nanobeam.
Grounding is an accident on the ship that can hit the bottom ship, propeller, rudder, and other ship structure. Notch is a defect often appearing in ship structures, aircraft structures, bridges, welded joints, and even microstructures. The most formed notch shape is a notch with a V-like shape called a V-notch. The present study relies on the finite element approach to analyze the impact of the V-notch defect on the grounding penetration simulation on a stiffened bottom plate. This study models 28 distinct scenarios distinguished by the quantity, size, and distance between V-notches. Study outputs in reaction force, resistance, and plate deformation due to penetration, stress concentration, and penetration depth of grounding impact on the stiffened bottom plate are obtained using dynamic explicit simulation in the form of penetration. The outcomes of the numerical simulation demonstrate that the existence of V-notch defects causes stress concentration, reducing the plate structure’s resistance and allowable penetration. The plate with one V-notch defect can reduce the resistance to 29.7% of the resistance of the plate without defects. Besides that, the resistance of the plate with two defects drops by only 5.2%, while when there are three defects simultaneously on the stiffener plate, the plate resistance is reduced by 31.4%. This research shows that the number of V-notches does not determine resistance in a plate, but the position of the V-notch on the plate is close to the penetration area, which is about 100 mm from the center of the plate. V-notch defects with smaller opening angles reduce resistance by 34.38% compared to larger opening angles, which only reduce resistance by 29.77%. Therefore, reducing the strength of the ship in grounding will increase the possibility of losing ship buoyancy, cargo leaks, engine and electrical failure, and loss of propulsion.
The present study used analytical and numerical methods to conduction works in functional graded material fin that is exposed to progressive boundary cooling and heating. The fin length was chosen as a direction to vary thermal characteristic in functionally graded material, and the physical properties were ascertained by the linear model. In heat sink, two approximation analytical techniques are employed to evaluated the thermal performance: one based on a mean value problem and the other strategy based on principle of the equivalent qualities. ANSYS APD’s numerical solution was based on a stepwise modification of characteristics. The outcomes indicated that the thermal conductivity ratio significantly influences temperature levels, with the terminal temperature levels of the functionally graded fin varying exponentially in relation to the thermal conductivity ratio. The influence of material index begins with the length of functionally graded material-fin where the fin’s terminus experiences the largest effect. A 6.756% is the maximum absolute error between numerical and analytical findings, which indicating a strong concordance between the two analysis methods.
The possibility of damage caused by explosive loading in above-ground tanks due to not being covered is much higher compared to buried and semi-buried concrete and steel tanks. In order to evaluate the real behavior of above-ground tanks, it is necessary to pay attention to fluid and structure interaction. Therefore, investigating the behavior of above-ground tanks under the blast load, taking into account the effects of fluid-structure interaction is the main goal of the study. For this purpose, the main variables are the amount of fluid in the tank (empty, half full, and full) and the distribution of fluid pressure on the tank (uniform and nonuniform pressure). Also, the investigated responses include maximum von Mises stress, maximum displacement created in the tank, kinetic energy, and failure index. The results show that considering the tank as empty of fluid, increased the responses of maximum stress, maximum displacement, kinetic energy, and failure index by 18.1, 31.2, 4.1, and 17%, respectively. Also, filling the tank with fluid has caused a decrease of 41, 90, 8.9, and 15.4% in the responses of maximum distributed stress, maximum displacement, kinetic energy, and failure index of the tank, respectively. Other results show that the nonuniform distribution of fluid pressure in the tank increases the maximum responses of stress and failure index in the tank by 35.6 and 2.5%, respectively. In this condition, the maximum responses of displacement and kinetic energy decrease by 84.3 and 4.3%, respectively.
Design optimization of a liquefied natural gas (LNG) ISO tank is essential to ensure structural integrity while minimizing weight. This approach enables the identification of efficient material distributions under critical loading conditions, enhancing safety, compliance with ISO 1496 standards, and overall transport efficiency without compromising strength. This study proposes a topology optimization for the Bakelite support structure of a 40 ft LNG ISO tank that balances structural strength and weight efficiency. The optimization process incorporates two main strategies: strain energy minimization and mass retain, defined as the objective function and constrained within a 90–50% mass retain range. To ensure structural integrity and regulatory compliance, the resulting designs are evaluated under the ISO 1496 standard loading scenarios, including lifting, stacking, and racking. Initial mesh convergence study of the proposed finite element analysis model shows optimum mesh selection with optimum computational time. The topology optimization results with mass retain ranging from 90 to 50% in all loading scenarios achieved a substantial weight reduction in the Bakelite support, between 4.81 and 81.41%, by eliminating the Bakelite application in the middle support of the pressure vessel. The optimized Bakelite support slightly increases stress and deformation in both the pressure vessel and the Bakelite support, remaining within the standard criteria limits. The proposed optimization is promising in maintaining structural strength compliance with ISO 1496 standards.
The propeller shaft inclination angle is one of the critical parameters influencing the speed of a fishing boat. This study assesses how the propeller shaft inclination angle impacts the speed of composite fishing boats through experimental and numerical analyses. The model used for testing is a scaled-down version of a 24.0 m × 6.5 m × 3.5 m fishing boat, constructed at a 1:12 scale using composite materials (polyester resin and fiberglass). The model allows for the propeller shaft angle adjustment from 0° to 15°. The model was tested at the design speed of 2.9 knots to measure the vessel’s speed corresponding to various inclination angles. Additional tests were conducted at lower (2.31 knots) and higher (3.46 knots) speeds to validate the results. The model was also simulated using computational fluid dynamics (CFD) software to compare and assess the reliability of the experimental results. Subsequently, the CFD software was employed to simulate the actual vessel and evaluate its performance. The results of the experiments and simulations demonstrate significant variations in vessel speed as the inclination angle increases from 0° to 15°. The maximum speed was achieved when the propeller shaft inclination angle ranged between 6° and 7° (reaching 3.05 knots). The vessel speed decreased substantially when the inclination angle increased from 9° to 15°. The speed variation patterns for the 2.31 knot and 2.9 knot cases were similar, whereas the 3.46 knot case exhibited notable differences. The optimal propeller shaft inclination angle range for achieving high speeds for the studied vessel lies between 3° and 8°.
The aim of this work is to investigate gallium arsenide, a particular kind of semiconductor. The study employs a three-layer asymmetric slab waveguide structure, where a thin gallium arsenide (GaAs) film is deposited on a glass substrate, and above the film is a dielectric cladding, such as air. To enable complete internal reflection at the interfaces, the guiding slab’s index of refraction has to be greater than that of the cover material (cladding) or the substrate material. Further investigated are the effects of the thickness of GaAs on transverse electric/transverse magnetic (TE/TM) propagation modes typically. Every method was shown with specific settings. The thickness of GaAs affects the number of TE/TM modes. Cut-off wavenumber and attenuation decrease for a particular applied wavelength (0.6328 µm) due to decreasing propagation wavenumber. Simulation findings clearly reveal that the basic mode has the biggest incidence angle and lowest penetration depth; the highest mode has the incidence angle very near the critical angle and the best penetration depth. The design of integrated optical devices depends on optical waveguides, which calls for consistent and accurate findings for defining the waveguide’s properties prior to manufacturing.
The transient response of thermoelastic materials subjected to a time-decaying thermal field is presented in this article using a nonlinear analysis. The basic equations provided are based on a generalized thermoelastic model under changing thermal conductivity, which is incorporated into the formulations. This problem is solved using the finite-element techniques instead of the Kirchhoff transforms since solving non-linear equations is quite difficult. Laplace transformation and the eigenvalue approaches are used to solve the problems in the linear context of the Kirchhoff transforms. The study investigates and compares the impact of varying thermal conductivity both with and without employing Kirchhoff’s transform. The numerical outputs are graphically shown to display the displacement, temperature, and stress variations.
A visual scripting approach for limit analysis of masonry walls subjected to out-of-plane loads is proposed. To this aim, within a visual scripting framework, an interactive CAD representation of the structure and of the acting loads, boundary conditions, and restraints is coupled with an optimization algorithm to calculate the collapse load multiplier and visualize the related predicted collapse mechanism. The proposed approach can be useful for practical purposes, indeed it allows us to quickly identify the key factors that influence the structural response and, through the tuning of some input data, can furnish some hints for design purposes. The effectiveness of the promoted tool is verified by application to eight well-known benchmark cases.
