This paper examines a code-to-code verification between two thermal models. One used a non-commercial code; the other a commercial. A point heat source was applied to one end of a cylindrical geometry. Melting and re-solidfying of a 316 L stainless steel alloy was considered. Temperature dependent material properties and latent heat were included. Mesh independency was achieved. Positive agreement of thermal histories, temperature profiles, melt pool depth and maximum temperature along the rod.
This research investigates the outcome of wire EDM process over the taper cross-sectional workpieces of Titanium Alloy (Ti6Al-4V). The outcomes result in better kerf width, surface finish, wire wear and metal removal rates, which can be controlled by taper angle of the workpiece, current, and pulse-off time. The effect of these parameters over the four outcomes of the wire EDM process have been studied in this research. Mathematical models have been developed to predict the outcomes.
In the field of oil & gas drilling engineering, the Rotary Steerable System (RSS) is very widely used in directional drilling, the whole drillstring is rotated from the surface by a hydraulically driven top drive. In this paper we analysis of the dynamic model of the Rotary Steerable System (RSS) with a single stabilizer and flex-sub and takes a method of the longitudinal and transverse bending continuous beam method to analyse the stress of RSS with the flex-sub.
Commercial greenhouses are the backbone of farming industry in the regions with arid climatic conditions. Design & implementation of the control systems are driving a major opportunity while doing the up-gradation of conventional type commercial greenhouses. The greenhouse control modules have strong interactions between its parameters, experimental results emphasized that good control system selection can provide a revolutionary increase in terms of crop yield with a minimal energy utilization.
To strengthen the convective heat transfer ability of the limited cooling air in the cabin, temperature field homogenization (TFH) in the core flow region of the engine block area was achieved. The TFH optimization model helped minimize the temperature gradient in the core flow region and maximize it at the heat transfer boundary, and the optimum vector field and flow path were obtained. More comprehensive changes to the structural design were made according to the TFH.
To improve the HMCVT gear shifting smoothness of the self-propelled cotton picker, the quadratic orthogonal rotation test was carried out through the HMCVT test bench and control system with engine speed, clutch oil pressure, flow control valve, load torque, displacement ratio as the influencing factors while jerk, dynamic load coefficient, speed drop, weighted acceleration RMS, frictional work as the response indexes.
This paper presents an electromechanical hybrid model combining a driving circuit and a TWUSM. (1) A driving circuit model combining circuit components with the load-dependent equivalent circuit model is proposed to simulate the real electric network. (2) The teeth discretized method is employed to refine the contact status and interaction forces limited to the teeth space, which improves the accuracy of the rotor step response not only in the rising time, but also the steady value.
The bending-torsional-axial coupling nonlinear dynamic model of double-sided meshing nutation drive system has been established. The modal analysis of double circular arc spiral bevel gears is carried out, and the ten order natural frequencies and their corresponding modes are obtained. The natural frequencies of nutation drive system and double circular arc spiral bevel gears are different, and there is no resonance.
Aiming at the problem of moving path planning of a cellular robot on trusses in space station, a triangular prism truss is taken as the research object, and an optimized ant colony algorithm incorporating a gravitational search algorithm is proposed. The simulation results show that the path and planning time of the cellular robot can be effectively reduced when choosing truss path.
Honeycomb sandwich (HS) structure has been widely used in aerospace applications because of its high specific strength and high specific stiffness. The structure of the lightweight HS panel is complex. Thus, establishing an equivalent simplified model is indispensable to improve the efficiency of the dynamic analysis of HS panels. In this paper, three commonly used dynamically equivalent modeling methods for HS panel are studied.
In helicopter flight simulators, the joystick is a key element, which is used to achieving a reliable helicopter driving while providing a force feedback feeling. In the flight control process, the current force of the haptic interface needs to be used as the simulation calculation of the feedback force. This paper proposes a different strategy aiming at avoiding the use of an expansive and complex force/torque sensor.
In the high-precision servo feed system, when the permanent magnet synchronous motor is operated at low speed in the classical drive feed system, the speed fluctuation caused by the motor torque harmonics seriously affects the speed smoothness of the servo system. In this paper, a novel double-drive differential feed system is proposed to effectively suppress the effect of torque harmonics of PMSM on speed fluctuation of a linear feed system at low-speed operation.
The performance of different models of grooves with various tip gap height on NASA rotor 37 is investigated by discretizing 3D RANS equations based on finite volume technique. Rectangular circumferential grooves casing treatment (CGCT) profile and smooth wall casing performances are evaluated. Moreover, the adiabatic efficiencies and the stall margins of smooth wall casing, rectangular grooves and rectangular grooves with fillet and chamfer corners are compared to assess the impacts of profiles
The paper highlights the importance of process parameters in the electromagnetic sheet metal forming process. Aluminium alloy I(Al6061T6) sheets with varying thicknesses were deformed by varying current, voltage and number of turns of the coil. A numerical model was also developed to predict the behaviour of the sheet under different processing conditions. The simulation and experimental results were in good agreement.
The pressure compensation is the most commonly used method at home and abroad to reduce the impact of external seawater pressure on the hydraulic system. The pressure compensator is the key equipment of the pressure compensation system. In this paper, the pressure characteristics of the bellows-type pressure compensator are analyzed. Through the control variable method, the influence of different design parameters on the dynamic characteristics of the pressure compensator is studied.
A novel bench-scale suspension plant, using magnetorheological elastomer (MRE)-based absorbers accompanied with an adaptive and global neural-network-based tracking controller, is introduced. The global adaptive neural network is used to estimate the uncertain dynamics of the quarter-car model. An auxiliary design system was added to the controller to deal with input constraint effects, and the state was analyzed for its tracking stabilization. All the signals are global, uniform, and ultimate.
The increasing number of patients with hand disabilities after strokes or peripheral nerve injuries necessitates the continuous development of rehabilitation system devices to accelerate muscle recovery and to help patients regain the motor functions of their hands. This paper introduces the design of a hand rehabilitation system for patients who have a solitary impairment of their hand extension. The system was designed to be portable, simple, and cheap.
Thickness-utilizing deployable hard stops (ThUDS) block the motion of a mechanism at a desired position. Designed to reside within the thickness of a design, they can be planar or spatial in nature. Various analyses and design techniques were developed and demonstrated using physical prototypes. ThUDS are able to successfully constrain motion, are able to carry loads, and are useable in various folding applications, including origami-based engineering.
The approach in this research includes data visualization and multilinear regression analysis. Multiple linear regression is a standard selection model in the world of data science. The approach turned out to be promising. However, the results reveal that the implemented technique holds a high degree of predictions, and the number of data sets is adequate. It is also observed that errors are in less concentration as the sum of squared errors is zero for every parameter.
The main contribution of this paper is to present a kind of 2 DOF seven-bar SPM containing two five-bar spherical loops, which has the advantages of high reaction speed, accuracy rating, and rigidity. And based on the unusual actuated choices and symmetrical loop structure, an approach is provided to identify singularities and branches of this kind of 2 DOF seven-bar SPM. The proposed method is visual and offers geometric insights into understanding the formation of mobility using branch graphs.
Yuekou locks are the favorites of antique collectors and have six main types including combination locks, regular locks, pull-back locks, maze locks, multi-stage locks, and hidden-keyhole locks. The crafting of Yuekou locks is conducted in four stages: material preparation, molding, shaping, and assembling. This work introduces the historical development of Yuekou locks, summarizes the verbatim interviews, explores the production of Yuekou locks, and analyzes the structures of Yuekou locks.
Liquid-metal direct writing is a cost-effective and green technology, which is very promising for the customized fabrication of flexible circuits and functional devices. The smooth flowing and conveying of liquid-metal ink are still huge challenges that need significant attention. In this paper, the force mechanism of liquid-metal ink transported by ball rotation and translation of the printing head was analyzed. The flexible complex circuit and functional electronic pattern were printed.
In this paper, an effective UKF-based estimation method is proposed to accurately estimate the driving states of vehicles. First, a three degrees of freedom (3-DOFs) vehicle dynamics model is established, and then a vehicle driving state estimation method is designed based on the UKF algorithm. Finally, by using CarSim and MATLAB/Simulink software, the co-simulation and validation are carried out to validate the accuracy of the proposed method under the sinusoidal and fishhook conditions.
In this article, the lightweight design of a palletizing manipulator arm structure is carried out. The optimization target is designed in 3D with Solid Works. To determine the optimization area and the secondary reconstruction model after the structure is optimized, the reliability and cost of the design structure are also considered. The meta-software performs mechanical performance simulation experiments under the corresponding working conditions for the lightweight structural design.
This article examines the historical development of ancient water-powered mechanical clocks. The study begins with a comprehensive analysis and comparison of the different types of ancient clepsydra, their use and development, development of their feedback systems, power systems, and time-reporting systems.
In this paper, a lined pipe was formed through a drawing process. In double-layered pipes, shear strength is the most important design factor. We verified the effect on shear strength by changing the pipe surface roughness. In order to apply the surface roughness in FEM analysis, the surface roughness was converted to the friction coefficient. Through FEM analysis, we obtained a critical value for the change in shear strength.
The temperature distribution of a machine tool spindle is affected by its air gap. The more serious the air gap eccentricity is, the more uneven the temperature field of the spindle is. In the process of machine tool processing, the instability of the spindle temperature field leads to the decline of parts processing quality and unqualified products, which not only wastes materials, but also affects the processing process.
A program is designed for the myoelectric hand with two control pathways, one for the thumb (controlled utilizing medial nerves) and the second for the rest of the fingers (controlled by the side nerves). The robotic hand was first printed with the use of a 3D printer.
This paper describes a dynamic mathematical model of a new type of two-stage nutation drive system with double circular-arc bevel gears. The dynamic displacement-vibration coupling model takes into account the gyro torque and side clearance of the nutating gear. A numerical analysis geometric model of the nutation drive system is developed. The geometric model considers the time-varying and contact deformation of nutation gear meshing.
This paper presents the design of a dynamometer, with a one-spoked wheel elastic component, to measure the drilling thrust force and drilling moment. After manufacturing, a calibration operation is conducted, and tests are performed by measuring the drilling forces, thrust, and torque on American Iron and Steel Institute (AISI) 1020 steel. Tool wear is studied, and the results are presented in the paper. Obtained results demonstrate the efficiency and accuracy of this measuring instrument.
Robots are a hot topic of research nowadays. Making robot action more accurate and faster is the direction of scholars' efforts. Based on the hydraulic quadruped robot designed by the State Key Laboratory of Fluid Power & Mechatronic System, Zhejiang University, this article discusses the lightweight design for manifold mounted on the hydraulic actuator. Through topology optimization and channel optimization, the part is lighter and the drag loss is less.
In order to improve modification effectiveness, a novel UV-assisted chemical modification (UVA-CM) strategy is proposed based on UV photocatalytic theory, which contributes to developing a novel hybrid chemo-mechanical process monocrystalline silicon. A series of comparative experiments was performed to evaluate modification effectiveness among different strategies. The results show that the liquid–solid chemical modification effect is obviously enhanced through UV advanced oxidation reactions.
This study carries out the complex eigenvalue analysis of influence factors of rail corrugation by using the three-dimensional finite-element model of a wheel–rail system based on the theory of friction self-excited vibration. The results show that improving the vertical and lateral stiffnesses of fasteners, controlling the wheel–rail friction coefficient below 0.4, and maintaining balanced superelevation can effectively reduce the occurrence possibility of rail corrugation.
According to the structural characteristics of the blisk, a new adaptive belt tool system for the blisk finishing is developed. Due to the strong nonlinearity of the pneumatic system, a two-dimensional fuzzy PID controller is developed for the pneumatic force control. Finally, the experiments show that the polishing process is very stable and the roughness after polishing is less than 0.4 μm, which proves the effectiveness of the proposed new belt tool system and the fuzzy PID controller.