Nowadays, the Underwater Remotely Operated Vehicle (ROV) has captivated the interest of researchers, given its widespread applications in both military and marine industries. However, establishing a standardized model...
详细信息
Nowadays, the Underwater Remotely Operated Vehicle (ROV) has captivated the interest of researchers, given its widespread applications in both military and marine industries. However, establishing a standardized model for use in challenging conditions, such as the presence of added mass, poses a significant challenge. The ROV serves a crucial role in oceanographic research, contributing to data collection, image recording, and deep-sea surveys. The development of a standard model holds promise for enabling researchers to design ROVs suitable for diverse tasks across varying ocean depths. In this study, for the first time, propose a natural frequency analysis of an ROV, considering added mass. Additionally, conduct a strength analysis for the ROV under critical boundary conditions, including displacement in a dry environment and Stuck in the sludge of the sea. The natural frequency analysis of the underwater environment, considering the acoustic properties of water fluid, is performed using ABAQUS software. The natural frequency of an object in water, indicating the frequency of vibrations per second, depends on factors such as temperature, pressure, and density of the surrounding water. This analysis, integral to structural dynamics, provides valuable insights into how vibrations propagate, facilitating the design of more stable structures. Furthermore, the study investigates the effects of added mass on different vibration modes of the ROV in the MATLAB Environment. Stress analysis results demonstrate that the ROV, submerged in critical boundary conditions due to hydrostatic forces, drag, and equipment weight, possesses sufficient strength for movement in deep-sea environments. Natural frequency analysis in water reveals a reduction in the impact of surrounding fluid and added mass in high-frequency modes. To enhance evaluations of fluid dynamics around the structure, fluid dimensions are considered until the structure’s frequency and resulting frequencies converge
Macroscale rolling/sliding conditions are in the superlubricity,a little-studied topic so *** purpose of this paper is to examine the formation of elastohydrodynamic lubrication(EHL)films by water-based lubricants(gly...
详细信息
Macroscale rolling/sliding conditions are in the superlubricity,a little-studied topic so *** purpose of this paper is to examine the formation of elastohydrodynamic lubrication(EHL)films by water-based lubricants(glycerol and polyethylene glycol(PEG)),providing superlubricous *** were carried out on an optical ball-on-disc tribometer under rolling/sliding *** film thickness was measured by the thin film colorimetric interferometry,and the viscosity of liquids was measured by rotational and high-pressure falling body *** results show that tribochemical reactions are not the mandatory reason for friction to reach the superlubricity level when using the water-based *** studied liquids themselves are almost *** the addition of water,the signs of shear thinning behavior disappear even *** conditions for this type of lubricant can be predicted using the known Hamrock–Dowson *** anomaly in the thickness of the lubricants was observed as an abrupt change at certain *** more PEG there is in the lubricant,the higher the thickness at the beginning of the jump.
This study introduces a new rotary draw bending method that utilizes a variable curvature bending die. Unlike traditional methods that bend tubes with a fixed radius, this method gradually deforms the tube from a larg...
详细信息
The constant amplitude loading fatigue tests were carried out on the 6061/7075 aluminum alloy TIG fillet welded lap specimens in this study,and the weld seam cross-section hardness was *** experimental results show th...
详细信息
The constant amplitude loading fatigue tests were carried out on the 6061/7075 aluminum alloy TIG fillet welded lap specimens in this study,and the weld seam cross-section hardness was *** experimental results show that most specimens mainly failed at the 7075 side weld toes even though the base material tensile strength of 7075 is higher than that of *** maximum stress-strain concentration in the two finite element models is located at the 7075 side weld toe,which is basically consistent with the actual fracture *** weld zone on the 7075 side experiences severe material softening,with a large ***,the Vickers hardness value on the 6061 side negligibly changes and fluctuates around 70 *** obvious defects are found on the fatigue fracture,but a large number of secondary cracks *** germinate from the weld toe and propagate in the direction of the plate *** reinforcement has a serious impact on fatigue *** life will decrease exponentially as the weld reinforcement increases under low *** is found that the notch stress method can give a better fatigue life prediction for TIG weldments,and the errors of the predicted results are within the range of two factors,while the prediction accuracy decreases under low *** equivalent structural stress method can also be used for fatigue life prediction of TIG weldments,but the errors of prediction results are within the range of three factors,and the accuracy decreases under high stress.
This paper proposed an optimal approach to disperse the composite conductive agent which is composed of carbon black(CB)and graphene(Gr)within lithium-ion battery(LIB)slurry with different mixing speeds and mixing ***...
详细信息
This paper proposed an optimal approach to disperse the composite conductive agent which is composed of carbon black(CB)and graphene(Gr)within lithium-ion battery(LIB)slurry with different mixing speeds and mixing *** internal structures of LIB slurry are characterized by Electrochemical Impedance Spectroscopy,Scanning Electron Microscopy,and Raman ***,a composite conductive solution is prepared by mixing the composite conductive agent with NMP solvent under the conditions of five different mixing speeds n_(1)(n_(1)=1000,1100,1200,1300,1400 rpm)in the case of mixing time t_(1)=10 ***,LIB slurry is prepared by blending the composite conductive solution,LiCoO_(2)and PVDF-NMP solution under the conditions of five different mixing speeds n_(2)(n_(2)=1000±280,1100±280,1200±280,1300±280,1400±280 rpm)in the case of mixing time t_(2)=6 *** analyzing the internal structure of different LIB slurries,it shows that in the case of n_(1)=n_(2)=1200 rpm,a conductive network structure is well formed within LIB ***,in order to determine the optimal time to prepare the composite conductive solution for LIB slurry,nine different t_(1)(t_(1)=0,10,20,30,40,50,60,70,80 min)are *** analyzing the internal structure of different LIB slurries,a well-formed conductive network structure and a uniformly distributed composite conductive agent are deduced in LIB slurry when t_(1)=50 ***,it can be concluded that the composite conductive agent composed of CB and Gr is able to be uniformly dispersed in LIB slurry by establishing a well-formed conductive network structure under the optimal mixing speed n_(1)=n_(2)=1200 rpm and the optimal mixing time t_(1)=50 min,t_(2)=6 *** kind of the internal structure has the potential to be used to further analyze the dispersion characterizations of LIB slurry under different composite conductive agent and CB/Gr ratios with the aim of improving the final performance of LIB.
Noise reduction of different airfoils is important because these sections are used in wind turbines,propellers,and aircraft *** methods are used for passive noise reduction of *** of these methods is the use of surfac...
详细信息
Noise reduction of different airfoils is important because these sections are used in wind turbines,propellers,and aircraft *** methods are used for passive noise reduction of *** of these methods is the use of surface *** this research,the effect of the typical surface treatment element(finlets)on the vortex structure at different frequencies in the turbulent flow created on the NACA2412 section is *** this purpose,one-dimensional hot wire probe is *** used surface treatment in this research has a special geometry and the distance between two consecutive finlets is 6 mm(S=6 mm).This study shows that this surface treatment element can be used for noise reduction in high *** result of this research is the suggestion of the most suitable position to install this special surface treatment element to reduce vortex energy in all frequency *** installation location is determined based on a dimensionless parameter(X_(aft)/h).
This study investigates the tribological properties of PLA composites reinforced with copper powder. The composites were made using fused deposition modelling (FDM) technique. The goal is to determine how the addition...
详细信息
In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently *** sliding layers are sometimes applied as a valuable *** diamond-like carbon(DLC)coatings,which are also considered for ce...
详细信息
In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently *** sliding layers are sometimes applied as a valuable *** diamond-like carbon(DLC)coatings,which are also considered for certain applications may show some advantages,as *** material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions,which is crucial for bearings with frequent starts and *** research aimed at studying the performance of fluid film bearings in the specific operating regime,including the transition to mixed friction,is described in the *** tests were carried out on four tilting pad bearings of different material compositions:Steel/bronze,DLC/steel,steel/polyether ether ketone(PEEK),and steel/*** tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values,and observing the changes of friction force during the transition to mixed friction *** of the transition conditions and other results showed clear differences between the tested bearings,illustrating the feasibility of less popular material compositions for bearings operating in specific *** specifically,the DLC/steel bearing was demonstrating superior performance,*** friction,transition to mixed friction occurring at higher load,and more stable performance at start-stop regime over the other tested bearings.
The simultaneous investigation on the parameters affecting the flow of electrically conductive fluids such as volumetric radiation,heat absorption,heat generation,and magnetic field(MF)is very vital due to its existen...
详细信息
The simultaneous investigation on the parameters affecting the flow of electrically conductive fluids such as volumetric radiation,heat absorption,heat generation,and magnetic field(MF)is very vital due to its existence in various sectors of industry and *** present research focuses on mathematical modeling to simulate the cooling of a hot component through power-law(PL)nanofluid convection *** temperature reduction of the hot component inside a two-dimensional(2D)inclined chamber with two different cold wall shapes is *** formulation of the problem is derived with the lattice Boltzmann method(LBM)by code writing via the FORTRAN *** variables such as the radiation parameter(0–1),the Hartmann number(0–75),the heat absorption/generation coefficient(−5–5),the fluid behavioral index(0.8–1.2),the Rayleigh number(103–105),the imposed MF angle(0°–90°),the chamber inclination angle(−90°–90°),and the cavity cold wall shape(smooth and curved)are *** findings indicate that the presence of radiation increases the mean Nusselt number value for the shear-thickening,Newtonian,and shear thinning fluids by about 6.2%,4%,and 2%,*** most cases,the presence of nanoparticles improves the heat transfer(HT)rate,especially in the cases where thermal conduction dominates *** is the lowest cooling performance index and MF effect for the cavity placed at an angle of 90°.The application in the design of electronic coolers and solar collectors is one of the practical cases of this numerical research.
暂无评论