Junhong Zhang

Junhong Zhang
Tianjin University | tju · State Key Laboratory of Engines

About

60
Publications
11,835
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492
Citations
Citations since 2016
45 Research Items
458 Citations
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100
2016201720182019202020212022020406080100

Publications

Publications (60)
Article
The effect of vibration magnitude on frequency-dependence of discomfort of human body is always overlooked with respect to the comfort equivalence contours, particularly for high-magnitude vibration in wideband frequency. In this study, the magnitude effect of vertical vibration on discomfort of human body is investigated experimentally. Nineteen m...
Conference Paper
An accurate and efficient method of identifying noise sources can provide guidance for acoustic improvement and troubleshooting of diesel engines. Due to the complexity and impact of diesel engine acoustic and vibration signal, the current signal decomposition methods are not adaptive enough in dealing with diesel engine acoustic signal, and it is...
Conference Paper
People are exposed to whole-body vibration involving multiple directions during daily life especially travelling in vehicles. This study carries out experimental research on human response to dual-axis lateral and roll vibration. Random and sinusoidal vibration defined at 1 Hz are employed as the stimuli. Corresponding apparent inertia and root mea...
Article
Full-text available
Due to complicated transfer paths and strong background noise interference, the fault pattern information deeply hides in common features of the vibration signal at the engine surface. In this study, the refined composite multiscale fuzzy entropy (RCMFE) used to measure the irregularity and self-similarity of time series is proposed to quantify the...
Article
The biodynamic response of 14 subjects to sinusoidal dual-axis vibration in lateral and roll directions is studied. The root mean square of human response is detected by measuring the torque at the seat pan. The effects of phase difference, magnitude, and frequency on the biodynamic responses are investigated. The consistency between human response...
Article
Full-text available
In order to accurately predict the damping characteristics of a hydraulic shock absorber under piston inclination and eccentricity conditions, especially, considering effects of piston surface construction. In present work, taking account of piston slight inclination and eccentricity, a more detailed mathematical model was developed to estimate eff...
Article
Abstract The aim of this paper is to analyze local autoignition induced by secondary flame acceleration. The secondary flame acceleration process and the local autoignition formation mechanism at the condition of the secondary flame acceleration propagation were investigated by utilizing an improved designed constant volume combustion bomb (CVCB) w...
Article
Human beings are exposed to whole-body vibration during daily life, which may cause discomfort or even sickness. Rotational vibration especially the roll vibration produces conspicuous discomfort. To promote the understanding of biodynamic characteristics of human body under roll vibration experimental research is carried out with 8 subjects expose...
Article
Full-text available
Bird strikes are a common, serious, and devastating event in aviation accidents, and multi-bird strikes are also frequently reported. A numerical multi-bird-strike simulation was performed to investigate the effect of flocking birds striking on engine blades. The smooth particle hydrodynamics (SPH) method was adopted in the hemispherical-ended bird...
Article
Full-text available
Bird strikes are one major accident for aircraft engines and can inflict heavy casualties and economic losses. In this study, a smoothed particle hydrodynamics (SPH) mallard model has been used to simulate bird impact to rotary aero-engine fan blades. The simulations were performed using the finite element method (FEM) at LS-DYNA. The reliability o...
Article
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Axial compressor blades with a deformed initial torsion angle caused by aerodynamic excitation resonated at the working speed and changed the rule of fatigue damage accumulation. The fatigue life of a blade has a prediction error, even causing serious flight accidents if the effect of torque causing damage deterioration of the blade fatigue life is...
Conference Paper
To study the effect of blockage on the film cooling performance, film cooling plate models with cylindrical hole, compound hole, and fan-shaped hole under the all-round blockage, leading-edge blockage, and trailing-edge blockage were established respectively. The anti-blockage performance of three kinds of the hole was compared. The result shows th...
Conference Paper
Sound quality (SQ) plays important role in automobile competitiveness, in which the high frequency characteristics of tones are prominent when internal combustion engines are replaced by fuel cells or batteries. Hence, it is of great significance to explore the influence of tones on the SQ of such electric vehicles. At the moment, the prominence of...
Conference Paper
A multi-objective optimization method is proposed to overcome the shortcomings of the traditional method which establish the multi-body dynamic model frequently. A multi-body dynamic model of a McPherson front suspension with composite transverse leaf spring is developed in ADAMS/Car. The parallel travel simulation result shows the toe angle, cambe...
Article
Full-text available
To study the effect of a bird striking engine fan on the rotor system, a low-pressure rotor system dynamic model based on a real aero-engine structure was established. Dynamic equations were derived considering the case of the bird strike force which transferred to the rotor system. The bird strike force was obtained from the bird strike process si...
Article
The sound quality (SQ) of a diesel engine varies with scenario and operating condition, therefore, the traditional evaluation method based on fixed operating points may not be able to reflect the SQ flexibly. Besides, it is difficult to effectively quantify the SQ performance due to the differences of application scenarios, which is not conducive t...
Article
In the proton exchange membrane fuel cell (PEMFC), the uneven distribution of contact pressure on the gas diffusion layer (GDL) will lead to the increase in local contact voltage, thus increasing the ohmic loss of the stack, and will affect the porosity to change the reaction gas concentration. Therefore, it is essential to optimize the consistency...
Article
The crack growth behavior of Hastelloy X under creep-fatigue interaction at high temperature is investigated by a nonlinear creep-fatigue interaction damage model. Multiaxial stress is considered both in the fatigue and creep damage models. The effect of the variance of fatigue damage parameters is analyzed in a quantitative method and some linear...
Conference Paper
Leaf springs play an important role in the handling stability and ride comfort of vehicle. End rubber gaskets are widely used to reduce the friction between leaves, but they also have considerable effect on the stiffness of the suspension assembly. The ride comfort may deteriorate with the stiffness of leaf spring changes. In this paper the influen...
Article
Full-text available
Within 30 Hz, the discomfort caused by whole-body vibration in rotational direction is higher than vertical vibration at similar equivalent magnitude. Roll vibration, in particular, produces greater discomfort comparing with pitch and yaw vibrations. It is critical to understand the biodynamic characteristics of seated human body under roll vibrati...
Article
In this paper, a dynamic model of a “0-2-1” rotor system with rubbing fault between blade and abradable coated casings is developed. The sub-model of rubbing force considers scraping work energy of coating, casing stiffness, and initial clearance between blade tip and casing. A rotor rig is established and samples of abradable coatings are introduc...
Article
Due to limitations in the generalisation ability of currently proposed improved variational mode decomposition (VMD) methods, it is hard to precisely and efficiently discern signal characteristics from different power systems. Meanwhile, it is difficult to separate non-order noise sources in current studies. To address this issue, a novel scheme is...
Article
Full-text available
: The compression of the gas diffusion layer (GDL) greatly affects the electrochemical performance of proton exchange membrane fuel cells (PEMFCs) by means of both the equivalent value and distribution of contact pressure, which depends on the packing manner of the fuel cell. This work develops an intelligent approach for improving the uniformity a...
Article
A fluid-structure interaction model is developed to investigate the combustion and cooling performance of an aero-engine combustor. Cylindrical holes, conical holes, fan-shaped holes and console holes are introduced to reduce the thermal load of thermal barrier coatings (TBCs) in combustor, respectively. To reduce the coolant consumption, the numbe...
Article
Full-text available
The mean stress effect in fatigue life varies by material and loading conditions. Therefore, a classical low cycle fatigue (LCF) model based on mean stress correction shows limits in asymmetric loading cases in both accuracy and applicability. In this paper, the effect of strain ratio (R) on LCF life is analyzed and a strain ratio-based model is pr...
Article
Failure analysis on an aero-engine combustor is carried out for the cranking failure of combustor liner during its service period. Crack macroscopic observation and microscopic observation are performed. Fluid-structure coupling simulation of aero-engine combustor under typical working conditions is carried out to obtain the temperature distributio...
Article
Full-text available
In order to investigate the mechanism of a rotor system with unbalance and blade-casing rubbing coupling faults, the vibration and rub force in a rotor system resulting from unbalance and blade-casing rubbing coupling faults are simulated. At first, a dynamic model of 0-2-1 form rotor is established, and a blade-casing model, which considered blade...
Article
In this work, a new method of using a magnetorheological damper to improve the self-adaptive ability of a rotor system to rub-impact is developed. To validate the feasibility of this method, a finite element model of the rub-impact rotor system with magnetorheological damper is investigated. A revised formula describing the relationship between the...
Article
Failure mechanism analysis of thermal barrier coatings (TBCs) on an ex-service aero-engine combustor is carried out. Microstructure, chemical composition, phase composition, and Young's modulus of TBCs are detected for three typical spallation areas as well as an as-sprayed sample for reference. A fluid-structure interaction simulation for the turb...
Article
Full-text available
Magnetorheological damper (MRD), a semi-active control device, has the stability of the passive control device and the adaptive ability of the active control device. It is considered to be an ideal replacement for the squeeze film damper (SFD) and has been extensively investigated. However, the effect mechanism of MRD to a rotor system is still unc...
Article
With increasing fuel injection pressure, maximum firing pressure and corresponding vibration, the high-pressure fuel pipe of diesel engine is prone to failure due to the increase of operation load. In order to dig out the failure mechanism of the high-pressure fuel pipe, this paper studies the vibration modes, fracture surface, frequency response a...
Article
Full-text available
In this paper, a novel fuzzy-based analytic hierarchy process (FAHP) is proposed for identifying noise sources of diesel engine and sorting their contributions. The hierarchy tree consists of 5 levels including the component level, the frequency band level, the test point level, the operating condition level, and the overall noise level. The variat...
Article
The vibration from transport vehicles may negatively affect the ride comfort in the cab and the product safety in the carriage. A 15 degrees of freedom vehicle model consisted of a cab, a carriage, a chassis, and mounts and suspensions between them are introduced to present the vibration behavior of a three-axle vehicle. Two indices, the coupling f...
Article
Full-text available
Most fatigue theories neglect the loads below fatigue limit in damage accumulation, which leads to inconsistency between the predicted and the actual fatigue lives. In this study, a novel damage model is proposed to take into account the loads below fatigue limit from two aspects: the strengthening effect and the cumulative damage. The strengthenin...
Article
Full-text available
The engine cooling system must be able to match up with the stable operating conditions so as to guarantee the engine performance. On the working cycle level, however, the dynamic thermo-state of engines has not been considered in the cooling strategy. Besides, the frequent over-cooling boiling inside the gallery changes the cooling capacity consta...
Article
Full-text available
Bubble diameter is important for the three-dimensional nucleate boiling two-phase flow simulation. However, the bubble diameter is rarely considered as a variable because it is difficult to estimate. In this paper, a novel bubble diameter model is proposed for the boiling flow. The heat transfer growth, the breakup or coalescence of collision and t...
Article
Full-text available
This study aims to investigate the effect of loading factors on damage accumulation under variable amplitude vibration (VAV). Vibration fatigue experiments are conducted under both constant amplitude vibration (CAV) and VAV loading cases. The effects of loading sequence, loading amplitude, stress difference, and cyclic ratio on damage accumulation...
Article
Full-text available
The lubrication performance of journal bearings with different sorts of uniformly distributed micro-spherical textures are studied in this paper. Geometries and dynamic models of journal bearings with pure concave/convex textures are developed. The validity of the proposed models is verified against the oil film pressure distribution from the liter...
Article
Full-text available
In rotor-bearing system, the misalignment can lead to secondary faults, such as the rub-impact fault. How the development of misalignment could affect the rub-impact force and other dynamic responses is important for the vibration control and fault diagnosis of rotor system. In this paper, a mathematical model of a two-shaft rotor-bearing- gear cou...
Article
A three-dimensional electrochemical-thermal coupling model of LiFePO4 battery was developed based on the real multi-layer structure. The model was developed to describe the discharge process of the battery in four modes: the constant current, constant overpotential, constant voltage and maximum power discharge processes. The electric conductivity o...
Article
Full-text available
In this paper, the dynamic behavior of a rotor-bearing-SFD system with the inner race defect of bearing is investigated. The contact force between the rolling element and the race is calculated in Hertzian contact and elastohydrodynamic lubrication condition. The supporting force of the SFD is simulated by integrating the pressure distribution deri...
Article
Full-text available
In this paper, a simulation method based on an orthogonal anisotropic material is proposed. A numerical example using a simple plate is presented to show the difference in the static performance between the orthogonal anisotropic and the isotropic models. Comparing with the tested modal data of a diesel engine oil cooler cover made by glass fiber r...
Article
Full-text available
The injection molding process parameters strongly affect plastic production quality, manufacturing cost, and molding efficiency. In this study, the effects of the process parameters, including the valve gate open timing, the molding temperature, the melt temperature, the injection time, the packing pressure, the packing time, and the cooling time,...
Article
As the essential foundation of noise reduction, many noise source identification methods have been developed and applied to engineering practice. To identify the noise source in the board-band frequency of different engine parts at various typical speeds, this paper presents an integrated noise source identification method based on the ensemble emp...
Article
A mathematical model describing the dynamics of road transport vehicle is proposed in this paper. The system consists of a cab, a carriage, a chassis, the road, and mounts/suspensions between them. The coupled correlations between substructures are studied using the state space theory. A factor, coupling coefficient, for describing the coupling eff...
Article
Full-text available
Diesel engine-radiated noise quality prediction is an important topic because engine noise has a significant impact on the overall vehicle noise. Sound quality prediction is based on subjective and objective evaluation of engine noise. The integrated satisfaction index (ISI) is proposed as a criterion for differentiate noise quality in the subjecti...
Article
The structural circumferential periodicity of inertial excitation produced by concentrated mass was utilized to establish the mathematical model of thin circular plate carrying eccentric concentrated mass and to analyze its transverse vibration. The fundamental frequency coefficient, natural frequency and mode shape function are determined by this...
Article
Fatigue fracture is one of the main failure modes of Ti-6Al-4V alloy, fracture toughness and crack closure have strong effects on the fatigue crack growth(FCG) rate of Ti-6Al-4V alloy. The FCG rate of Ti-6Al-4V is investigated by using experimental and analytical methods. The effects of stress ratio, crack closure and fracture toughness on the FCG...
Article
In order to achieve accurate diagnosis for rotating machinery automatically and considering that test data under actual fault conditions are rather difficult to obtain, a novel fault diagnosis strategy based on rotor dynamics and computational intelligence was proposed in this paper. Considering the nonlinear restoring force of ball bearing, the dy...
Article
Piston ring dynamics play an important role in the lubricant characteristics of reciprocating engines that lead to engine wear and high consumption of lubricating oil. Due to the complexity of realistic test and working conditions, a study of cavitation with surface roughness and its effect on piston ring lubrication was conducted in a simulation p...
Article
The dynamic and lubrication characteristic analyses of the crankshaft–bearing system is quite a complex problem, and it is important to avoid asperity contact which may lead to bearing wear and increase of friction loss significantly in dynamic lubrication condition. In this paper, the dynamic characteristic that has an essential impact on lubricat...
Article
Full-text available
To comprehensively consider the effects of strength degeneration and failure correlation, an improved stress–strength interference (SSI) model is proposed to analyze the reliability of aero-engine blades with the fatigue failure mode. Two types of TC4 alloy experiments are conducted for the study on the damage accumulation law. All the parameters i...
Article
The performance and particulate emission of a diesel engine are affected by the consumption of lubricating oil. Most studies on oil consumption mechanism of the cylinder have been done by using the experimental method, however they are very costly. Therefore, it is very necessary to study oil consumption mechanism of the cylinder and obtain the acc...
Article
Full-text available
There are more researches on engine fan noise control focusing on reducing fan noise level through optimizing fan structure, and a lot of research achievements have been obtained. However, researches on the effect of fan noise to engine noise quality are lacking. The influences of the effects of fan structure optimization on the engine noise qualit...
Article
Vibration signals from diesel engine contain many different components mainly caused by combustion and mechanism operations, several blind source separation techniques are available for decomposing the signal into its components in the case of multichannel measurements, such as independent component analysis (ICA). However, the source separation of...
Article
Full-text available
Fatigue life and reliability of aero-engine blade are always of important significance to flight safety. The establishment of damage model is one of the key factors in blade fatigue research. Conventional linear Miner’s sum method is not suitable for aero-engine because of its low accuracy. A back propagation neutral network (BPNN) based on the com...
Conference Paper
The self-adaptive control strategy, which is applied to NC machining processes, is one of the most important approaches to improve production efficiency. It can be realized by two steps. Firstly, the dynamic model of servo subsystem and milling force is deduced in frequency domain, and is discretized in terms of Z — transform so as to approach the...

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