Influence Of Different Loads Research Articles

Behavior of container berth structure under the influence of environmental and operational loads

Abstract Container docks, which are an essential component of the marine berth, are exposed to loads from various sources, such as self-weight, operation, and environment. In this study, four sets of combined loads to which the container berth is exposed were selected at the Um-Qaser Port in southern Iraq. The berth was constructed more than 40 years ago, which has to be verified according to latest specifications, and each set of combined loads was analyzed in three cases. In the first case, the piles were assumed to be fixed at the seabed, and in the second and third cases the piles were modeled as embedded in elastic and elasto-plastic sandy soil, respectively. The general-purpose finite-element software ABAQUS was used to model the various components to determine the maximum stresses, displacements, axial forces, shear forces, and bending moments due to dead, live, operate, berthing, mooring, waves, and seismic loads. It has been demonstrated that the impact loads of ships have a more significant impact on the structure compared to other loads. The calculated displacement when the piles are assumed to be fixed at the seabed level may be reduced by 50–94% of that calculated when the soil is modeled, meaning that assuming fixed piles yields inaccurate results, especially for deck displacements. However, this assumption was verified to yield reasonable results for shear forces at the pile head. It could also be noted that the elasto-plastic model of soil was more sensitive than the elastic model in displacement by 0.4–8% and bending moment by 0.3–34%, while it is less sensitive in axial force by 3–8%. The aim of this study is to obtain knowledge on the behavior and efficiency of container berth under the influence of different loads and the environmental conditions surrounding it.

The influence of different load distribution considering geometric error on the fatigue life of ball screw

The ball screw pair is a precision drive component that converts rotary motion into linear motion. In practical applications, because the feed system usually has rotational torque and geometric errors, it may increase the contact load of the ball screw pair and reduce the fatigue life. In order to study the influence of different loads and geometric errors on the maximum contact load and fatigue life of ball screw pairs, the following research work was carried out. Firstly, based on the composite load and rotational torque, the ball load distribution model is established, and the accuracy of the model is verified by finite element modeling analysis. Then, the influence of different composite loads, rotation times and geometric errors (including ball size error, lead error and raceway tooth profile error) on the ball load distribution is analyzed. Finally, the influence of compound load, rotating torque and geometric error on the fatigue life of ball screw pairs is studied. The results show that the rotational torque and lead error have a great influence on the load distribution and fatigue life of the ball, and the influence of lead error on load distribution is greater than that of dimension error and tooth profile error. The fatigue life of the ball screw pair with non-uniform load distribution is shorter than that of the ball screw pair with uniform load distribution.

Adaptive Equivalent Factor-Based Energy Management Strategy for Plug-In Hybrid Electric Buses Considering Passenger Load Variations

Energy management strategies (EMSs) are one of the key technologies for the development of plug-in hybrid electric buses (PHEBs). This paper addresses the issue of optimal energy distribution for PHEBs under significant variations in passenger load at different bus stations, which cannot be solved by a single equivalent factor equivalent fuel consumption minimization energy management strategy (ECMS). An adaptive equivalent factor equivalent fuel consumption minimization energy management strategy (A-ECMS) considering passenger load is proposed. First, the powertrain system of the PHEB is modeled, and the accuracy of the model is verified in a simulation environment. Then, the reference SOC descent trajectory of the battery is obtained using a dynamic programming (DP) algorithm, the recursive least squares (RLS) method is employed to identify the passenger load, and the influence of different loads on the state of charge (SOC) trajectory under a single equivalent factor is analyzed. Finally, a genetic algorithm (GA) is used to establish the correspondence between passenger load, bus station, and equivalent factor, enabling the actual SOC to follow the reference SOC descent trajectory, thereby achieving optimal energy distribution. Simulation results demonstrate that the A-ECMS reduces fuel consumption of the PHEB per 100 km by 2.59% and 10.10% compared to the ECMS and rule-based EMS, respectively, validating the effectiveness of the proposed strategy.

Finding the Weight Difference of a Rectangular Structure with a Parabolic Arc for Mathematical Models Made of Steel and other Composite Materials

The most popular materials for lightweight constructions, including building and aircraft structures, industrial, military, and aerospace technology, are armored composites. Composites made of carbon fiber are typically employed in lightweight applications. The ANSYS program was used to produce four mathematical models. Steel is used in the construction of the first and second versions whereas composite materials are used in the third and fourth variants. To find all the deformations, stresses, and strains that appear on the four models, as well as to calculate the weights of those four structures and compare them, these four models were tested with the ANSYS 15.0 program to obtain equal deformation resistance for all models under the influence of different loads. The results show that the composite models had lower strains, stresses, and deformations than the steel models. Among other results, it was discovered that the weight of the third model made of composite materials decreased by (32.72%) compared to the steel-based first model, and after doing the necessary calculations and assessing the results, the fourth model made of composite materials' weight was reduced by (19.21%) when compared to the second model made of steel.

Metal-Organic-Framework-based nanofiltration membranes for selective multi-cationic recovery from seawater and brines

Nanofiltration (NF) is gaining a role of increasing importance in Zero Liquid Discharge (ZLD)/Minimal Liquid Discharge (MLD) systems, enhancing the efficiency of downstream technologies to recover valuable minerals from seawater and brines. However, often the purity of the recovered minerals does not meet market specifications, making ZLD/MLD currently economically unfeasible. To such end, in this study, a novel positively charged NF membrane was developed to enhance magnesium and calcium selectivity. The membrane comprised: (i) an ultrafiltration substrate and (ii) an active layer that incorporated NH2-MIL-101(Al) and ZnO nanoparticles in a chitosan matrix. The influence of different loadings of NH2-MIL-101(Al) and ZnO on membrane structure, selectivity and water permeability was investigated. Initial filtration tests with single-salt solutions at 1000 ppm (NaCl, Na2SO4, MgCl2, CaCl2) showed that the membrane with 35%wt of ZnO presented the highest rejections of MgCl2 (90.10%) and CaCl2 (86.49%). Selectivity towards MgCl2 and CaCl2 was higher than those of commercial membranes (NF90 and NF270) and the positively charged membranes introduced in recent literature. The novel synthesized membrane in this work was also tested with synthetic seawater and brine at a trans-membrane pressure of 30 bar. Results highlighted the intriguing competitiveness of the novel membrane in terms of magnesium and calcium selectivity with NF90 and NF270 within the field of both seawater and brine valorization.

Influence of different loads on PCDD/F removal by SCR during municipal solid waste incineration

This study was conducted on a full-scale (500 t/d) municipal solid waste incinerator (MSWI), investigating the influence of different loads on the emission of polychlorinated dibenzodioxins and polychlorinated dibenzofurans (PCDD/Fs) and their removal by selective catalytic reduction (SCR) system. The total concentration of PCDD/Fs at the SCR inlet under 100% load was higher than that under 80% load. The changing loads caused different distribution characteristics of PCDD/Fs at the SCR inlet, and the dominant congeners changed from high-chlorinated PCDDs (80% load) to low-chlorinated PCDFs (100% load). Moreover, the increased load enhanced the removal efficiency of PCDD/Fs by SCR from 17.3% to 64.2%, which was influenced by the inlet PCDD/F distribution and the moisture content. The high-chlorinated PCDD/Fs with the more stable structure were more difficult to be deteriorated and the high moisture content can weaken the catalytic activity of SCR catalysts. Correlation analysis was used to study the relationship between major air pollutants and PCDD/F emissions. The results showed that HCl positively correlated with PCDD/F emission concentrations, while NOx and SO2 negatively correlated. The results of this study can provide a reference for MSWI to operate properly under variable loads.

Extension of an In Vitro Spine Test Rig to Track Load‐dependent Biomechanics of the Lumbar Spine under Physiological Conditions

AbstractLow back pain is a major cause of chronic health problems and is often related to loading history. A test rig was developed at the Institute of General Mechanics, RWTH Aachen University to investigate the influence of duration and intensity of spinal loading using in vitro experiments on spinal cadavers. In this work, several extensions of this spine test rig are presented: (1) a hydraulic cylinder with a force measuring unit was added to apply axial compression; (2) a new follower load principle system was developed to achieve uniform compression of the naturally curved spine; (3) the specimen is immersed in phosphate‐buffered saline with protease inhibitors during the testing period to allow osmotic interactions on the one hand and the investigation of the influence of different loading and rest cycles on the other hand; (4) a fiber‐optic pressure measurement system was added to successfully measure the intradiscal pressure during the test series. The first results obtained using these test rig extensions and the new pressure measurement system show their functionality. The new test rig enables the investigation of a wide range of load scenarios and further measurement parameters.

Influence of different loads and temperatures on solid lubricant-filled micro-dimples existing on both cylinder liner and piston ring

In order to meet the increasing demands of friction reduction and wear resistance in heavy-duty diesel engines, the refined design of surface topography of cylinder liner and piston ring (CLPR) has been a major concern. Based on electrolytic micro-texturing and electrochemical deposition methods, micro-dimples filled with solid lubricant have been separately applied to the CLPR surfaces. This double-sided textured design of CLPR exhibited significantly lower friction coefficient and wear depth than the non-dimpled CLPR when the lubricating oil containing zinc dialkyldithiophosphates (ZDDP) was used under different strengthening loads and temperatures. Solid lubricants were released from the double-sided textures, forming mutually transferable solid lubricant films on the sliding surface. Although various products containing molybdenum oxides, molybdenum sulfides, phosphate of different chain lengths, zinc compounds, iron sulfide, etc. Appeared in the tribochemical reactions of ZDDP and MoS2 with increasing temperature and load, but the lubricating effect was still maintained. These results can provide some insight into the design of CLPR surfaces in order to achieve a high quality tribofilm under heavy load conditions.

Simulation Analysis of Skew Collision of Needle Roller Bearing Used in Precision Cycloid Reducer

In order to improve the service life of the needle roller bearing used in a precision cycloid reducer, and to reveal the skew and collision phenomenon of the needle roller bearing, based on the force analysis of the transmission mechanism of the cycloid reducer and considering the friction between the cycloid wheel, needle roller, cage, and crank shaft, the dynamic contact between the rolling bodies is simulated by the Hertz elastic contact, where the contact between the cage pocket hole and needle roller is equivalent to the spring and damping, and a nonlinear dynamic model of the needle roller bearing is established. The influence of different load and cage clearances on the deflection impact of the rotating needle roller bearing is calculated. The results show that the inclination of rollers is different under different pocket clearances, and the larger the pocket gap, the greater the fluctuation of the roller inclination angle; the action force of the crank shaft on the roller suppresses the deflection of the roller; the impact force of the roller on the cage has periodicity, which is consistent with the impact force of the crank shaft on the roller. The impact force of the cage is different under different loads, and the greater the load, the more rollers there are in the bearing area, the larger the impact force is, and the smaller the impact force of the rollers in the middle of the bearing zone is, compared with that of the rollers on the two sides; when the load is small, a pocket cage gap of 0.3 mm is selected, and when the load is heavy, a pocket cage gap of 0.2 mm is selected in order to make the bearing run more smoothly.

Effect of blade tips ice on vibration performance of wind turbines

There are abundant wind resources in cold regions. Therefore, it is essential to systematically study some icing situation of wind turbines blades (especially the blade tip area) to reduce the loss of wind turbines blades caused by faults, which has important significance to the development and utilization of superior wind power resources in alpine regions in the future. An S8025 airfoil blade was used as this research object to research this influence of different loads on this typical vibration performance of a wind turbines with blade tip icing. The results display that the tip area of these wind turbines will be covered with ice because of the small chord length. Blade tip icing results in an increase in blade mass, blade stiffness, blade torsional stiffness, and other parameters, and the low-order vibration frequencies decreases while the high-order vibration frequencies increases. The centrifugal force load significantly affects the vibration performance of a wind turbines with blade tip icing. The results can be used as a reference to improve the deicing of wind turbines blade tips.

Molecular dynamics simulation of hyaluronic acid hydrogels: Effect of water content on mechanical and tribological properties

Background and objectiveRecently conducted biomedical studies have shown that the drug diffusivity of hyaluronic acid hydrogel plays an important role in the treatment of joint diseases. The drug diffusivity is closely related to the water content of hydrogel. In addition, different water content will not only affect its mechanical and tribological properties, but also change the effect of drug release. MethodsIn this work, a Molecular dynamics simulation was used to investigate the effect of water content on spatial distribution, tribological and mechanical properties of a hyaluronic acid hydrogel network. This paper focuses on the analysis and calculation of the radial distribution function of 20, 40, 60, and 80% water content model and the friction force and mechanical parameters under the influence of different load and friction speed. ResultsThe results show that at 20 and 40% water content, the spatial distribution is loose and the intermolecular force is not strong, resulting in a major lack in tribological and mechanical properties; whereas at 60 and 80% water content, the spatial distribution becomes gradually compact and the intermolecular force is gradually increased. The tribological and mechanical properties manifest a marked improvement. ConclusionsThe calculations reveal that the hydrogel model has the best wear resistance, pressure resistance, and plastic deformation resistance at 80% water content. In the range of 20–80% water content, the mechanical properties and friction properties of hydrogels become better and better with the increase of water content.

Research on the sharpness of combustion noise of three-cylinder GDI engine based on adaptive cyclic Wiener filter method

In order to analyze the sharpness of combustion noise of the gasoline direct injection (GDI) engine, the in-cylinder pressure and noise of different loads and speeds of a three-cylinder GDI engine are measured. An adaptive cycle Wiener filter method is proposed to separate the combustion noise. The result indicated that the proposed method can overcome the drawbacks of the original Wiener filter method and is able to separate high-frequency combustion noise components more accurately and effectively. The sharpness of the combustion noise is calculated by the Zwicker method and Aures method, and the comparison results show that the Aures method is more suitable for evaluating combustion noise. The influence of different loads and speeds on the sharpness of combustion noise is investigated by the proposed method systematically. The results indicated that at low speed (1500 r/min), the combustion noise and sharpness will increase with the load while at medium (3000 r/min) and high (5500 r/min) speeds, the combustion noise under half load (50%) has the highest sharpness. Excessive high load (100%) and too low load (0%) both suppress the generation of combustion noise. As for the same engine load, a higher engine speed will lead to higher combustion noise and sharpness.

Modeling and Experiments of an Annular Multi-Channel Magnetorheological Valve

With the increasing number of cars, the demand for vehicle maintenance lifts is also increasing. The hydraulic valve is one of its core components, but there are problems with it such as inaccurate positioning and failure. In order to improve the service performance of vehicle maintenance elevators, a novel annular multi-channel magnetorheological (MR) valve structure was creatively proposed based on intelligent material MR fluid (MRF), and its magnetic circuit was designed. The influence of current, damping gap and coil turns on the pressure drop performance of the annular multi-channel MR valve was numerically studied and compared with ordinary type magnetorheological valve pressure drop performance through contrast and analysis. The influence of different loads and currents on the pressure drop performance of annular multi-channel magnetorheological valve was verified by experiments, and the reliability of numerical analysis results was verified. The results show that the single winding excitation coil is 321 to meet the demand. The pressure drop performance of the annular multi-channel magnetorheological valve is 5.6 times that of the ordinary magnetorheological valve. The load has little influence on the regulating range and performance of pressure drop of the MR valve. Compared with the common type, the pressure drop performance of the annular multi-channel MR Valve is improved by 3.7 times, which is basically consistent with the simulation results.

Influence of Ti3AlC2 content and load on the tribological behaviors of Ti3AlC2p/Al composites

In this study, Ti 3 AlC 2 particles doped aluminum matrix composites were prepared by ultrasonic agitation casting method. Microstructure, mechanical properties, and tribological properties of pure aluminum and Ti 3 AlC 2p /Al composites were characterized. Influence of different loads (10, 20, 30, and 40 N) and Ti 3 AlC 2 contents (1.0, 2.0, 3.0, and 4.0 wt%) on the tribological behaviors of the composites were studied. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Energy dispersion spectroscopy (EDS), and 3D laser confocal were used to assist the analysis. The results indicated that fine and uniformly microstructure and the optimum comprehensive mechanical properties were exhibited on 2.0 wt%-Ti 3 AlC 2p /Al composites. The abrasive grooves were widened and deepened with an increase in the load. The abrasion performance of composites improved distinctly with the addition of the Ti 3 AlC 2 particles, which changed the wear mechanism from adhesive wear to abrasive wear. The 30 N load and the composites of 2.0 wt% Ti 3 AlC 2 revealed the optimum tribological properties. The improvement of the tribological behavior of composites was attributed to the refinement of microstructure, the improvement mechanical properties and the three dimensional layered Ti 3 AlC 2 phases with self-lubricating properties.

Study on the film-forming ability of water in oil emulsion with water concentration

This paper mainly explores the influence of different loads on the lubrication performance of point contact under pure rolling conditions and the abrasion phenomenon of water-containing emulsion on the contact area under pure sliding condition. The laboratory apparatus is point contact lubrication friction test equipment and the lubricant is water-containing emulsion.

Wrist angle prediction under different loads based on GA‐ELM neural network and surface electromyography

AbstractIn sEMG (surface electromyography) pattern recognition, most of the research focuses on the static pattern recognition of different limbs, ignoring the importance of changing load intensity, and joint angle movement information. Traditional static qualitative pattern recognition cannot adjust the motion amplitude and load intensity, so it is of great significance to study the continuous prediction of wrist angle under different load intensities. Based on the correlation between the surface EMG signal and the joint angle signal, the article is based on the neural network to identify and predict the wrist angle under different loads continuously quantitatively. The sEMG signal in this article was collected with the approval and review of the Ethics Committee and the people's informed consent. Since qualitative pattern recognition cannot adjust the wrist movement range and the different load training intensity, the article establishes an angle prediction model based on a genetic algorithm to optimize the extreme learning machine (ELM). In addition, the article analyzes the influence of different loads on the continuous prediction accuracy of the wrist angle, realizes the continuous quantitative angle of the precise wrist prediction. Experimental analysis shows that the wrist joint angle predicted by the ELM optimized based on genetic algorithm is close to the actual angle, and the average error is about 5.96 degrees.

A melamine‐based covalent organic framework nanomaterial as a nanofiller in polyethersulfone mixed matrix membranes to improve separation and antifouling performance

AbstractThis research reported developing a polyethersulfone (PES) membrane using covalent organic frameworks (COFs) nanoparticle with a mean dimension of 30 nm. The SNW‐1 (Schiff‐based network) COF was synthesized using precursors of melamine and terephthalic acid and then characterized by XRD, SEM, TEM, and FTIR analyses. The influence of different loadings of the COF was evaluated on the permeability, antifouling behavior and dye/salt rejection. The addition of SNW‐1 caused a reduction in surface roughness and an improvement in hydrophilicity of the nanocomposite membranes, which improved their flux and fouling resistance considerably. The improvement of water flux, 2.6 times, was observed by adding 0.5 wt% COF to the membrane matrix. The 0.5 wt% COF membrane presented the best water permeability, 38.9 L/m2 h bar BSA solution flux, dye rejection of 98.7% for Reactive Green 19 and 62.6% for Reactive yellow 39, 52.9% Na2SO4 and 24.5% NaCl salt rejections. Zeta potential and salt rejection trend indicated a negative surface charge on the nanocomposite membrane. Fouling experiments by BSA protein solution exhibited that the FRR reached 88.9% for 2 wt% COF membrane. Thus, employing SNW‐1 into PES matrix resulted in a promising nanofiltration membrane for dye separation and moderate salt separation with suitable antifouling properties.

Study of the Lifetime Testing of Spherical Rubber Isolators

This study aims to identify the fatigue lifetime of a thin-walled hollow spherical rubber isolator subjected to harmonic and random vibrations. Firstly, the nonlinear characteristics of the rubber materials are tested and analyzed through vibration experiments. The relationship among the nonlinear stiffness, nonlinear damping, and relative displacement amplitude is established. Secondly, an accelerated lifetime experiment under random excitation is carried out. The correlation between the root-mean-squared acceleration response of the random vibration system and the stiffness attenuation of the rubber isolator is established and modeled. A lifetime prediction method for rubber isolators is proposed based on the model. Finally, the influence of different loads on the lifetime of the rubber isolator is investigated. These methods provide an additional rationale for the further theoretical research and practical engineering application of rubber damping systems.

Fatigue crack propagation behavior of high-strength steel under variable amplitude loading

In this paper, aimed at high strength steel for marine structures, a series of crack propagation tests were designed and carried out, and the influence of different load forms on crack growth has been investigated. At first, a series of fatigue crack propagation experiments were designed for compact tension specimens made of AH36 High-strength steel, and the influences of overload ratio, interval of overloads, and load sequence on fatigue crack growth rate were investigated. Besides, storm model loading and superimposed loading were applied to further investigate crack growth behavior under more complex loading condition. The research indicates fatigue crack growth behavior under variable amplitude loadings deviates apparently. The difference is mainly caused by the sequence of variable amplitude loadings and the retardation/acceleration when tensile/compressive overloads are applied. Moreover, digital image correlation technique was adopted to obtain the strain fields and residual strain around crack tip. The mechanism of fatigue crack growth behavior under variable amplitude loadings was investigated by analyzing the transformation of strain fields in crack tips. Extended finite element method to calculate the plastic zone size around crack tip was proposed and verified to be accurate and applicable. In the end, the plastic zone size obtained by digital image correlation technique, which shows better accuracy, was applied to improve the modified Wheeler model, and the fatigue crack growth behavior under variable amplitude loadings was predicted by the improved modified Wheeler model, and was in good agreement with experiment results.

An Experimental and Analytical Study of the Distribution of Heat in Concrete Columns

Fire is one of the most devastating disasters that have caused human damage, prompting researchers to conduct numerous studies on the behavior of fire-prone elements and take action to minimize damage. With the development of computer simulation theories, it is possible to study the behavior of structures under the influence of different loads (static, dynamic, thermal ... etc), and this leads to saving time, effort and money cost instead of performing laboratory experiments. Thermal loads are considered one of the most dangerous loads to which concrete structures are exposed. Hence it is very important to know the thermal distribution in the cross section of the element exposed to high temperature. Whereas, by knowing the thermal distribution, the designed load and the expected failure load of the structural element can be calculated and thus take the necessary measures to reduce the fire risk as much as possible. In this research, an experimental and analytical study was conducted on models of reinforced concrete columns, where thermocouple were used in different places to monitor the temperature at the specified points, The experimental thermal distribution was compared with the analytical results of the ANSYS Workbench program. The analytical results showed a great accuracy compared to the experimental results. Consequently, an analytical model was simulated to simulate the experimental, through which it is possible to know the thermal distribution of the model. Keywords : thermal distribution, thermal analysis, thermocouple, ANSYS Workbench. DOI: 10.7176/CER/13-1-01 Publication date: January 31 st 2021