A modified mathematical model for simulating gear crack from root with linear growth path in a pinion is developed, which an improved potential energy method used to calculate the time-varying meshing stiffnesses of pair while we also take deformation gear-body into consideration. The formulas stiffness are deduced when grows as pinion. 16DOF dynamic one-stage spur system study response considering and different levels growing As vibration signals induced by tooth buried normal at early...

A multi-wavelength Erbium-doped fiber (EDF) laser based on four-wave-mixing is proposed and experimentally demonstrated. The 5 km single mode in the cavity enhances to suppress homogenous broadening of erbium-doped get stable comb. lasing stability investigated. When pump power 300 mW, has 5-lasing lines maximum fluctuation output about 3.18 dB. At same time, a with 110 m high nonlinear (HNFL) it 7-lasing (above -30 dBm) 0.18dB.

Abstract In the drilling process of oil and gas extraction, safety accidents such as well blowouts surges are prone. The team needs a large amount spare weighted fluid to realize rapid pressure ensure process. To reduce energy consumption mixing work improve efficiency aggravated fluids, new static cyclone mixer is proposed in this paper. paper, numerical simulation carried out by using computational dynamics (CFD) method simulate effects diameter number blades on effect, respectively. have...

Purpose The purpose of this paper is to reduce the drag loss and study effects operating conditions groove parameters such as flow rate temperature automatic transmission fluid, clearance between plates, depth ratio on torque a wet clutch for vehicles, parametric analysis model multi-plate friction with consideration. Design/methodology/approach Both experimental numerical research was carried out in work. Parametric models, full film lubrication pressure distribution are established...

The detection of flaw echoes in backscattered signals ultrasonic nondestructive testing can be challenging due to the existence backscattering noise and electronic noise. In this article, an empirical mode decomposition (EMD) methodology is proposed for echo enhancement. signal was first decomposed into several intrinsic functions (IMFs) using EMD or ensemble (EEMD). sample entropies (SampEn) all IMFs were used select relevant modes. Otsu’s method interval thresholding mode, a window...

This study aims to investigate the hysteresis characteristics of a pneumatic braking system for multi-axle heavy vehicles (MHVs). Hysteresis affects emergency performance severely. The fact that MHVs have large size and complex structure leads more nonlinear coupling property compared normal two-axle vehicles. Thus, theoretical analysis simulation are not enough when studying hysteresis. In this article, brake an eight-axle vehicle in situation is studied based on novel test bench. A servo...

Condition monitoring (CM) is used to assess the health status of wind turbines (WT) by detecting turbine failure and predicting maintenance needs. However, fluctuating operating conditions cause variations in monitored features, therefore increasing difficulty CM, for example, frequency-domain analysis may lead an inaccurate or even incorrect prediction when evaluating WT components. In light this challenge, paper proposed a method evaluation components based on vibration signals. The...

Aiming at the problems of poor tracking accuracy, low convergence speed, weak robustness a 6-DOF electro-hydraulic suspension test system under uncertainties and external disturbance, this article proposes double closed-loop control scheme. In outer loop controller, designs new decoupled adaptive fast nonsingular terminal sliding mode (DAFNTSM) to achieve rate, high accurate disturbances estimation during trajectory tracking. Additionally, coupling force compensator based on RBF neural...

A band-pass filter based on mechanically-induced multi-π-shifted long-period fiber gratings is proposed. The pass band width of the depends number N sub-gratings divided by π-shifts in grating. depth two lateral rejection bands can be changed amount pressure applied to fiber. This paper demonstrates a grating created pressing between periodically grooved plates. For = 7 and LP12 mode coupling, extinction ratio 22.22 dB, loss 0.85 dB. varies from 14.23 nm 39.31 when increases 2 10.

A numerical model is established to investigate the effects of influencing factors such as design parameters and operating conditions on performance behavior engagement process wet clutch based Navier–Stokes equations, contact mechanics, heat transfer theory. finite element called KE used analyze rough during thermal effect viscosity considered The integration grooving into simulation method coupled by domain decomposition groove ungrooved areas are put forward facilitate analysis....

This article investigates the volume change law of trapped fluid in meshing process and flow characteristics external gear pumps under following two cases: pump design with without relief groove. In this study, a mathematical modeling pairs is deduced based on theory complete set equations tooth profile, rate equation derived conservation mass across changing boundaries control volume. During process, function displacement established, which formed by parts: space addition, using approach,...

This paper presents a new fractal seepage model to study the decrease in capacity caused by fluid erosion and pressure changes porous media. The normalized permeability obtained our is good agreement with experiments models literature has high accuracy usability. results demonstrate that: (1) larger instability coefficient, higher particle stability, better of medium, later decreases, slower it goes down, (2) dimension solid skeleton set mainly affects porosity media, independent stability...

In remote measurement systems, the lead wire resistance of sensor will produce a large error. order to ensure accuracy measurement, novel lead-wire-resistance compensation technique is proposed, which suitable for two-wire temperature detector. By connecting zener diode in parallel with detector (RTD) and an interface circuit specially designed it, value can be accurately measured by virtue constant voltage characteristic when reverse breakdown occurs, thereby made calculating RTD. Through...

This paper introduced the good characteristic of morphological filter and its application in pulse noise removing vibration signal. The was used to eliminate interference when signal detected. Using combination open-closing close-opening operations, local original could be kept noises removed effectively. There is no need consider signalpsilas spectrum using de-noise corrupted To verify effectiveness filter, median employed process a simulated results by were more stationary smoother than...

Dual-motor Electric Drive Tracked Vehicles (DDTVs) have attracted increasing attention due to their high transmission efficiency and economical fuel consumption. A test bench for the development validation of new DDTV technologies is necessary urgent. How load vehicle on a exactly same as real road crucial issue when designing bench. This paper proposes novel dynamic emulation method address this problem. The adopts dual dynamometers simulate both inertia that are imposed independent drive...

The load simulation test bench plays an important role in tracked vehicle development. stability and accuracy of the system have a vital impact on experimental results. To accurately reproduce power performance platform, this paper aims to investigate model, control, calibration method bench. Firstly, dynamic model under complex driving conditions is analyzed established, which takes torque as input wheel speed output. Then, considering uncertainties disturbances 2-degree-of-freedom (2-DOF)...