This paper proposes a model prediction method for tracking wear trajectories under lubricated conditions, based on the Archard wear model and the theory of elastohydrodynamic lubrication. Tracking wear in such a syste...
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This paper proposes a model prediction method for tracking wear trajectories under lubricated conditions, based on the Archard wear model and the theory of elastohydrodynamic lubrication. Tracking wear in such a system was challenging due to the random nature of the tooth surface condition and the unstable force. The Archard wear model usually ignored the change in wear depth at the pitch point as it was inherently dedicated to the relationship between relative sliding distance and normal force. To overcome these problems, the proposed approach embedded the force analysis model of the micro convex body with time-varying reference into the constrained optimization process of the Archard model. The model was therefore called the Archard wear optimization model. By embedding the time-varying characteristics of the micro convex into the wear model, the wear depth at the pitch point was calculated and the model was optimized. In addition to inheriting the advantages of the Archard wear model, the proposed model ensures accurate tracking of key points, and is experimentally evaluated. Meanwhile, lubricating oil supply coefficient have been introduced to study tooth surface wear under different lubrication conditions.
A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered de...
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A winding system is a time-varying system that considers complex nonlinear characteristics,and how to control the stability of the winding tension during the winding process is the primary problem that has hindered development in this field in recent *** nonlinear factors affect the tension in the winding process,such as friction,structured uncertainties,unstructured uncertainties,and external *** terms severely restrict the tension tracking *** tension control strategies are mainly based on the composite control of the tension and speed loops,and previous studies involve complex decoupling *** to the large number of calculations required for this method,it is inconvenient for practical engineering *** simplify the tension generation mechanism and the influence of the nonlinear characteristics of the winding system,a simpler nonlinear dynamic model of the winding tension was *** adaptive method was applied to update the feedback gain of the continuous robust integral of the sign of the error(RISE).Furthermore,an extended state observer was used to estimate modeling errors and external *** model disturbance term can be compensated for in the designed RISE *** asymptotic stability of the system was proven according to the Lyapunov stability ***,a comparative analysis of the proposed nonlinear controller and several other controllers was *** results indicated that the control of the winding tension was significantly enhanced.
Forging is one of the techniques traditionally used in the manufacture of knee implants. As the material deforms, stress develops during forging. When these stresses exceed a threshold, it can render a product defecti...
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This study investigated the effects of zigzag-flow channel bending angle in printed circuit heat exchangers(PCHEs) using a computational fluid dynamics method with ANSYS-FLUENT *** three-dimensional model of PCHE with...
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This study investigated the effects of zigzag-flow channel bending angle in printed circuit heat exchangers(PCHEs) using a computational fluid dynamics method with ANSYS-FLUENT *** three-dimensional model of PCHE with a 15° curved,zigzag channel was conducted for preliminary *** comparisons between the CFD simulation results and the experimental data showed good agreement with some discrepancies in the heat transfer and pressure drop *** addition,different bending angle configurations(0°,3° to 30°) of zigzag channels were analyzed to obtain better thermal-hydraulic performance of the zigzag channel PCHE under different inlet mass flow *** criteria of heat transfer and frictional factor were applied to evaluate the thermal-hydraulic performance of the *** results showed that the 6° and 9°bending channel provided good thermal-hydraulic *** correlations were developed using the 6°and 9° bending channel angles in PCHE designs to predict the Nusselt number and friction factor.
The purpose of this review is to explore the intersection of computational engineering and biomedical science,highlighting the transformative potential this convergence holds for innovation in healthcare and medical *...
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The purpose of this review is to explore the intersection of computational engineering and biomedical science,highlighting the transformative potential this convergence holds for innovation in healthcare and medical *** review covers key topics such as computational modelling,bioinformatics,machine learning in medical diagnostics,and the integration of wearable technology for real-time health *** findings indicate that computational models have significantly enhanced the understanding of complex biological systems,while machine learning algorithms have improved the accuracy of disease prediction and *** synergy between bioinformatics and computational techniques has led to breakthroughs in personalized medicine,enabling more precise treatment ***,the integration of wearable devices with advanced computational methods has opened new avenues for continuous health monitoring and early disease *** review emphasizes the need for interdisciplinary collaboration to further advance this *** research should focus on developing more robust and scalable computational models,enhancing data integration techniques,and addressing ethical considerations related to data privacy and *** fostering innovation at the intersection of these disciplines,the potential to revolutionize healthcare delivery and outcomes becomes increasingly attainable.
Used extensively in the aerospace industry,the superalloy Inconel 718 is deemed hard to cut because of its rapid work hardening,low thermal conductivity,and excessive shear *** here is patterning Inconel 718 with micr...
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Used extensively in the aerospace industry,the superalloy Inconel 718 is deemed hard to cut because of its rapid work hardening,low thermal conductivity,and excessive shear *** here is patterning Inconel 718 with micro-dimples using electrochemical machining and electrical discharge machining prior to conventional *** this micro-dimple patterning influences the machinability of Inconel 718 is analyzed via orthogonal cutting experiments,and with the optimal parameters,the cutting temperature is lowered by 45.5%and the cutting forces are reduced significantly,i.e.,the tangential cutting force and the thrust force are reduced by 61.1% and 47.1%,*** predictions of finite-element simulations agree with experimental observations,and it is concluded that dimpled Inconel 718 offers significantly improved tool wear and surface integrity.
This study examines the wear and corrosion characteristics of Al7079 alloy matrix composites that are strengthened with boron nitride (BN) and aloe vera particles. These composites are produced using the stir casting ...
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In engineering applications,the notch effect and size effect significantly influence the evaluation of fatigue performance in components,necessitating special attention in life *** study proposes a new probabilistic m...
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In engineering applications,the notch effect and size effect significantly influence the evaluation of fatigue performance in components,necessitating special attention in life *** study proposes a new probabilistic model,based on the theory of critical distance(TCD),to predict fatigue life,with the aim of quantitatively assessing the impact of notch effect and size *** stress distribution on the critical plane is first characterized using a sixth-order multinomial function,and the relative stress gradient function is utilized to calculate the value of the critical ***,the effect of the ratio of shear strain to normal strain on fatigue life under multiaxial loading is ***,the integration of the Weibull distribution into the TCD is employed for conducting probabilistic modeling of fatigue ***,fatigue experiments are conducted on notched specimens of Q355D steel,demonstrating that the life prediction results under 50%survival probability are superior to the traditional TCD method.
Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling ca...
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Research of capture mechanisms with strong capture adaptability and stable grasp is important to solve the problem of launch and recovery of torpedo-shaped autonomous underwater vehicles(AUVs).A multi-loop coupling capture mechanism with strong adaptability and high retraction rate has been proposed for the launch and recovery of torpedo-shaped AUVs with different morphological ***,the principle of capturing motion retraction is described based on the appearance characteristics of torpedo-shaped AUVs,and the configuration synthesis of the capture mechanism is carried out using the method of constrained chain ***,the screw theory is employed to analyze the degree of freedom(DoF)of the capture ***,the 3D model of the capture mechanism is established,and the kinematics and dynamics simulations are carried *** with the capture orientation requirements of the capture mechanism,the statics and vibration characteristics analyses are carried ***,considering the capture process and the underwater working environment,the motion characteristics and hydraulics characteristics of the capture mechanism are ***,a principle prototype is developed and the torpedo-shaped AUVs capture experiment is *** work provides technical reserves for the research and development of AUV capture special equipment.
Laser-Induced Graphene (LIG) is regarded as a promising sensor carrier due to its inherent three-dimensional porous structure. However, as two mutually exclusive properties of the pressure sensor, sensitivity and work...
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Laser-Induced Graphene (LIG) is regarded as a promising sensor carrier due to its inherent three-dimensional porous structure. However, as two mutually exclusive properties of the pressure sensor, sensitivity and working range are difficult to be further improved by the single porous structure. Inspired by the unique geometry of Oxalis corniculata L. leaves, we here propose a novel method consist of laser pre-etching and inducing steps to fabricate LIG-based electrodes with a two-stage architecture featuring microjigsaw and microporous structures. The following injection of liquid-silicone significantly improves the friction resistance and bending reliability of LIG materials. The interface contact between external microjigsaw structures induces substantial resistance changes, and the internal microporous structure exhibits reversibility during dynamic deformation. Consequently, the jigsaw-like pressure sensor achieves a balanced performance with sensitivities of 3.64, 1.20 and 0.03 kPa^(- 1) in pressure range of 0 -20, 20 - 40 and 40 - 150 kPa, respectively. The bionic LIG-based pressure sensor serves as the core component and further integrated with an all-in-one wireless transmission system capable of monitoring various health parameters such as subtle pulse rates, heartbeat rhythms, sounds, etc., indicating broad prospects in future wearable electronics.
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