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The main objective of this study is to develop a numerical model based on Isogeometric Analysis to study the dynamic behavior of multi-directional functionally graded plates with variable thickness.

A numerical study was conducted on the dynamic behavior of multi-directional functionally graded plates. Rectangular and circular plates with variable thickness are taken into investigation. The third-order shear deformation plate theory of Reddy is used to describe the displacement field, while the equation of motion is developed based on the Hamilton's principle. Isogeometric Analysis approach is employed as a discretization tool to develop the system equation, where NURBS basis functions are used. The famous Newmark method is used to solve time-dependent problems.

The results obtained from this study indicated that the thickness gradation has a more considerable effect than in-plane variation of materials in MFGM plates. Additionally, the influence of the damping factor is observed to affect the vibration amplitude of the plate. The results obtained from this study could be used for future investigations, where the viscous elasticity and other dynamic factors are considered.

Although there have been a number of studies in the literature devoted to analyzing the linear static bending and free vibration of FGM and MFGM plates with variable thickness, the study on dynamic response of FGM and MFGM plate is still limited. Therefore, this study is dedicated to the investigation of the dynamic behavior of multi-directional functionally graded plates.

Unconventional machining processes, particularly ultrasonic vibration cutting (UVC), can overcome such technical bottlenecks. However, the precise mechanism through which UVC affects the in-service functional performance of advanced aerospace materials remains obscure. This limits their industrial application and requires a deeper understanding.

The surface integrity and in-service functional performance of advanced aerospace materials are important guarantees for safety and stability in the aerospace industry. For advanced aerospace materials, which are difficult-to-machine, conventional machining processes cannot meet the requirements of high in-service functional performance owing to rapid tool wear, low processing efficiency and high cutting forces and temperatures in the cutting area during machining.

To address this literature gap, this study is focused on the quantitative evaluation of the in-service functional performance (fatigue performance, wear resistance and corrosion resistance) of advanced aerospace materials. First, the characteristics and usage background of advanced aerospace materials are elaborated in detail. Second, the improved effect of UVC on in-service functional performance is summarized. We have also explored the unique advantages of UVC during the processing of advanced aerospace materials. Finally, in response to some of the limitations of UVC, future development directions are proposed, including improvements in ultrasound systems, upgrades in ultrasound processing objects and theoretical breakthroughs in in-service functional performance.

This study provides insights into the optimization of machining processes to improve the in-service functional performance of advanced aviation materials, particularly the use of UVC and its unique process advantages.

This article focuses on the low-velocity impact (LVI) output of carbon nanotubes (CNTs)’ reinforcement circular plates, considering agglomeration size effect and clumping of CNTs’ inner side of the agglomerations.

A representative volume element (RVE) is used to determine the nanocomposite properties reinforced with agglomerated CNTs with random orientation. First-order shear deformation theory (FSDT) is used to obtain the motion equations of LVI analysis. These equations are handled by developing a Ritz method and Lagrangian mechanics. To extract the mass and stiffness matrices, terms with second and higher degrees are ignored.

Formulation validation is performed by providing various examples, including comparisons with other research and ABAQUS FE code. The effects of agglomeration size, clumping of CNTs’ inner side of the agglomerations, CNT volume fraction and impact location on the responses of impact load, projectile displacement and plate deflection are analytically studied. These achievements illuminate how the influence of agglomeration size is very small on the impact response. Also, the influence of clumping of CNTs’ inner side of the agglomerations is significant, and as it increases, the displacement values and impact time increase, and the impact force decreases.

In this article, to avoid additional calculations, the parameters of the mass matrix and the stiffness coefficients are linearized to obtain the equations of motion of the impact on the circular plate.

The purpose of this paper is to evaluate the effect of film cooling holes on the vibration characteristics of a turbine blade, and provide the design basis for the blade, which may reduce computing costs.

Modal analysis of the blades with and without film cooling holes is performed to evaluate the effect of film cooling holes on its natural frequency. Harmonic analysis of the blade is performed to calculate the stress concentration factors of film cooling holes for different modes.

The frequency differences between two blades with and without film cooling holes are insignificant, while the differences of the vibration stress cannot be neglected. For the first three modes of the blades, the stress concentration factor is sensitive to the hole’s shape and position on the blade. With the help of the stress concentration factor defined in this work, the concentration of stresses induced by different film cooling holes can be accurately described when evaluating HCF life of the turbine blade.

The effect of film cooling holes on a turbine blade's natural frequencies was confirmed to be insignificant and the stress concentration factors around the holes are calculated. Therefore, the simplified model of the blade without film cooling holes can be used to evaluate the natural frequencies and vibration stress, which saves a lot of time and cost.

Abnormal vibrations often occur in the liquid oxygen kerosene transmission pipelines of rocket engines, which seriously threaten their safety. Improper handling can result in failed rocket launches and significant economic losses. Therefore, this paper aims to examine vibrations in transmission pipelines.

In this study, a three-dimensional high-pressure pipeline model composed of corrugated pipes, multi-section bent pipes, and other auxiliary structures was established. The fluid–solid coupling method was used to analyse vibration characteristics of the pipeline under various external excitations. The simulation results were visualised using MATLAB, and their validity was verified via a thermal test.

In this study, the vibration mechanism of a complex high-pressure pipeline was examined via a visualisation method. The results showed that the low-frequency vibration of the pipe was caused by fluid self-excited pressure pulsation, whereas the vibration of the engine system caused a high-frequency vibration of the pipeline. The excitation of external pressure pulses did not significantly affect the vibrations of the pipelines. The visualisation results indicated that the severe vibration position of the pipeline thermal test is mainly concentrated between the inlet and outlet and between the two bellows.

The results of this study aid in understanding the causes of abnormal vibrations in rocket engine pipelines.

The causes of different vibration frequencies in the complex pipelines of rocket engines and the propagation characteristics of external vibration excitation were obtained.

The purpose of this study is to analyse the magnetic field effect on Fe₃O₄/H₂O Ferrofluid flowing in a sudden expansion tube, which has specific behaviour in terms of rheology, with convex dimple fins. Because the investigation of flow separation is a prominent application in performance, the effect of magnetic field and convex dimple on the thermo-hydraulic performance of sudden expansion tube are examined, in detail.

During the solution of the boundary conditions of the sudden expansion tube, finite volume method was used. Analyses have been conducted considering the single-phase solution, steady-state, incompressible fluid and no-slip condition of the wall under forced convection conditions. In the analyses, it has been assumed that the flow was developing thermally and has been fully developed hydrodynamically.

The present study focuses on exploring the influence of the magnetic field, nanofluid concentration and convex dimple fins on the thermo-hydraulic performance of sudden expansion tube. The results indicate that the strength of the magnetic field, nanofluid concentration and convex dimple fins have a positive effect on the convective heat transfer in the system.

The authors conducted numerical studies, determining through a literature search that no one had yet investigated enhancing heat transfer on a sudden expansion tube using combinations of magnetic fields, nanofluids and convex dimple fins. The results of the numerical analyses provide valuable information about the improvement of heat transfer and system performance in electronic device cooling and heat exchangers.

In the present study, a steel lifting lug is replaced with a composite (carbon fiber-reinforced epoxy [CFRP]) lifting lug made of a carbon/epoxy composite. The purpose of this paper was to obtain a composite lifting lug with a higher level of strength that is capable of carrying loads without failure.

The vibration and static behaviors of steel and composite lifting lugs have been investigated using finite element analysis (FEA), ANSYS software. The main consideration in the design of the composite (CFRP) lifting lug was that the displacement of both steel and composite lugs was the same under the same load. Hence, by using the FEA displacement result of the steel lifting lug, the thickness of the composite lifting lug is determined using FEA.

Compared to the steel lifting lug, the composite (CFRP) lifting lug has much lower stresses and much higher natural frequencies. Static behavior was experienced by the composite lifting lug, showing a reduction in von Mises stress, third principal stress and XZ shear stress, respectively, by 48.4%, 34.6% and 89.8%, respectively, when compared with the steel lifting lug. A higher natural frequency of mode shape swaying in X (258.976√1,000 Hz) was experienced by the composite lifting lug when compared to the steel lifting lug (195.935√1,000 Hz). The safe strength of the design composite lifting lug has been proven by FEA results, which showed that the composite (CFRP) lifting lug has a higher factor of safety in all developed stresses than the steel lifting lug. According to von Mises stress, the factor of safety of the composite lifting lug is increased by 76% when compared to the steel lifting lug. The von Mises stress at the edge of the hole in the composite lifting lug is reduced from 23.763 MPa to 20.775 MPa when compared to the steel lifting lug.

This work presents the designed composite (CFRP) lifting lug, which will be able to carry loads with more safety than a steel one.

This paper addresses a significant research gap in the study of Rayleigh surface wave propagation within a piezoelectric medium characterized by piezoelectric properties, thermal effects and voids. Previous research has often overlooked the crucial aspects related to voids. This study aims to provide analytical solutions for Rayleigh waves propagating through a medium consisting of a nonlocal piezo-thermo-elastic material with voids under the Moore–Gibson–Thompson thermo-elasticity theory with memory dependencies.

The analytical solutions are derived using a wave-mode method, and roots are computed from the characteristic equation using the Durand–Kerner method. These roots are then filtered based on the decay condition of surface waves. The analysis pertains to a medium subjected to stress-free and isothermal boundary conditions.

Computational simulations are performed to determine the attenuation coefficient and phase velocity of Rayleigh waves. This investigation goes beyond mere calculations and examines particle motion to gain deeper insights into Rayleigh wave propagation. Furthermore, this investigates how kernel function and nonlocal parameters influence these wave phenomena.

The results of this study reveal several unique cases that significantly contribute to the understanding of Rayleigh wave propagation within this intricate material system, particularly in the presence of voids.

This investigation provides valuable insights into the synergistic dynamics among piezoelectric constituents, void structures and Rayleigh wave propagation, enabling advancements in sensor technology, augmented energy harvesting methodologies and pioneering seismic monitoring approaches.

This study formulates a novel governing equation for a nonlocal piezo-thermo-elastic medium with voids, highlighting the significance of Rayleigh waves and investigating the impact of memory.

This study aims to comprehensively investigate the process-structure-property correlation of acrylonitrile butadiene styrene (ABS) parts manufactured by the overheat material extrusion (Mex) method. This study considers the relationships between the tensile and impact strength with temperature profiles, mesostructures and fracture behaviors of the ABS-printed parts.

The overheat printing condition was generated by using the highest possible printing temperature of the Mex printer used in this study together with cooling fan turned off. Temperature profiles of the polymer rasters were measured to characterize the diffusion time of the deposited rasters. Thermogravimetric analysis, differential scanning calorimetry and melt flow index were performed to study the thermal properties of the ABS feedstock. The mesostructures of the printed ABS samples were characterized by using an optical microscope, while their fracture surface was investigated using a field emission scanning electron microscope. The authors performed the tensile and impact tests following ASTM D3039 and D256-10A, respectively.

The use of the overheat Mex printing could offer better raster diffusion with reduced cooling rate and prolonged diffusion time. Consequently, the overheat printed ABS parts possessed a porosity as low as 1.35% with an increase in the weld length formed between the adjacent rasters of up to 62.5%. More importantly, the overheat printed ABS parts exhibited an increase of up to 70%, 84% and 30% in tensile strain at break, tensile toughness and impact strength, respectively, compared to their normal printed counterparts.

This study provides a facile but effective approach to fabricate highly dense and strong polymeric parts printed by Mex method for end-use applications.

The purpose of this paper is to study the effect of surface salt spray duration on the fretting wear and electrochemical corrosion behaviors of Inconel 690 alloy.

A high-temperature steam generator was applied to salt spray test samples, a fretting wear rig was used to realize the damage behavior tests, an electrochemical workstation was applied to analysis the changes of each sample’s corrosion dynamic response before and after fretting wear.

The thickness of the oxide film that formed on sample surface was increased with the salt spray duration, and somewhat it could act as lubrication during the fretting wear process; however, the corrosive chloride would accelerate the fretting mechanical damage behavior.

In a salt steam spray condition, the fretting tribo-corrosion behaviors of Inconel 690 alloy surface was studied.