Autor: Liu, Liu - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Analysis of dynamic characteristics of an experimental bench of high-pressure water fracturing assisted cutting
Autorzy:: Liu, Zhiming
Zhang, Qiang
Sun, Yuliang
Liu, Junming
Powiązania:: https://bibliotekanauki.pl/articles/2200892.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: high-pressure water fracturing
experimental bench
dynamic characteristics
Opis:: Aiming at the problem that the cutting efficiency of a drum shearer is low when mining hard coal seams, an experimental bench of high-pressure water fracturing assisted cutting is designed. Compared with normal ones, the maximum equivalent stress of the improved experimental bench is reduced by 55.38%, and the maximum total deformation is reduced by 27.23%. According to the results of dynamic response analysis, it is concluded that the experimental bench of high-pressure water fracturing assisted cutting is stable and reliable under extreme working conditions, and meets design requirements for strength and stiffness.
Źródło:: Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 317--330
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 2.

Tytuł:: Influence of pre-tension on torsion of microscale Cu wires: a study via strain gradient theory
Autorzy:: Ma, Xinbing
Liu, Jinxing
Powiązania:: https://bibliotekanauki.pl/articles/280360.pdf
Data publikacji:: 2019
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: nonproportional loading
strain gradient plasticity
size effect
cyclic response
Opis:: Nonproportional plastic deformations on the microscale are an emerging topic. A simplified theory of strain gradient elasto-plasticity is developed to study the evolution of yield strength in a copper wire sequentially experiencing tension and torsion. The pre-tension deformation and stress are inherited to the upcoming torsion process, resulting in a nonproportional loading condition. With consideration of the extra hardening effect due to strain gradient, pre-tension weakens the extra hardening effect of the strain gradient and the dependence on the wire radius. Cyclic torsion behavior is also investigated. Anomalous Bauschinger effect and plastic softening are found.
Źródło:: Journal of Theoretical and Applied Mechanics; 2019, 57, 4; 1055-1065
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 3.

Tytuł:: A control strategy of a permanent magnet synchronous motor for an electric vehicle
Autorzy:: Xie, Jianxin
Liu, Zimeng
Powiązania:: https://bibliotekanauki.pl/articles/2200826.pdf
Data publikacji:: 2022
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: PMSM
SVPWM method
argument
voltage difference
Opis:: The traditional modulation method of the inverter in a permanent magnet synchronous mo- tor (PMSM) is lengthy and computationally intensive. Based on this, a simplified sinusoidal pulse width modulation method is proposed. In this method, voltage space vectors in each sector are synthesized, and the sector in which the synthesized vector is located is determined by the rotation angle of the resultant vector, and then the acting time of the basic vector is calculated by the voltage difference of the phase voltage. The problem of trigonometric functions and coordinate conversion is not involved in the whole calculation process, the calculation model is simple, and it is easy to realize digitization. Mathematical modeling is carried out by using the simulation software Matlab, and the correctness of the calculation method after optimization is verified, which provides an idea for the later research of the inverter modulation method.
Źródło:: Journal of Theoretical and Applied Mechanics; 2022, 60, 4; 673--685
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 4.

Tytuł:: Dynamic analysis of a mechatronic drive system with an induction motor
Autorzy:: Cao, Yongdi
Liu, Xiaohong
Powiązania:: https://bibliotekanauki.pl/articles/2200885.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: dynamic model
electromechanical system
vector control
optimization
rotor
Opis:: The paper presents research findings in the modelling and optimization of dynamic parameters of mechatronic systems with an induction motor. A mathematical model was developed to analyze currents in dynamic states of squirrel-cage rotors in the case of a line-to-line fault. The findings were verified experimentally using calculations for a 1.5 kW three-phase induction motor. The equations for a stationary 0x, 0y coordinate system relating to the stator were derived. The set of design variables selected in the optimization process contained parameters describing design features of the gear shafts and control units settings.
Źródło:: Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 245--258
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 5.

Tytuł:: Establishment of constitutive model and dynamic parameter analysis of rubber conveyor belt
Autorzy:: Chen, Hongyue
Liu, Siyuan
Powiązania:: https://bibliotekanauki.pl/articles/2200896.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: rubber conveyor belt
wire rope core
kinetic parameters
fitting curve
mathematical model
Opis:: A rubber conveyor belt is an essential piece of equipment in coal mine transportation. Its current motion and performance are directly affected by dynamic parameters. In this paper, a constitutive model has been established to study a rubber conveyor belt in order to analyze its dynamic characteristics. The covered rubber was considered as a classical solid model. The wire rope core was used as a Kelvin model, and a generalized constitutive mathematical model was established. Using Matlab, compariso of the fitting curve and the experimental curve was carried out to ensure reliability in an appropriate way. Meanwhile, the influence of different factors on dynamic parameters of rubber conveyor belts was also discussed by controlling the loading frequency and amplitude as well as external temperature. Finally, the experiment with the fitting curve was compared and verified, and the research results can provide a reference for this engineering field.
Źródło:: Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 365--378
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 6.

Tytuł:: A fully-coupled three-dimensional fluid-structure interaction study on the externally-pressurized collapsible tube and the internal flow
Autorzy:: Zhang, Sen
Liu, HaoFei
Powiązania:: https://bibliotekanauki.pl/articles/2200900.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: fluid structure interaction
stability
eigenvalue problem
bifurcation
Opis:: We study the behavior of a collapsible tube conveying a fluid subject to external pressure that could occur in many physiological applications. The method of rotating spines is developed to enable an automatic mesh adaptation when the tube is deformed largely. We examine bifurcation diagrams when the tube is collapsed under a pressure driven condition and reveal that multiple solutions exist for a range of the Reynolds number. The stability characteristic of the system is discovered by determining stability of these solutions by the eigenvalue method for the first time, which is validated by solving a time-dependent problem of the system.
Źródło:: Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 395--406
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 7.

Tytuł:: Structural optimization on the design of an automobile engine intake pipe
Autorzy:: Xie, Jianxin
Liu, Zimeng
Powiązania:: https://bibliotekanauki.pl/articles/2104764.pdf
Data publikacji:: 2022
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: engine
intake pipe
Fluent
optimization design
Opis:: The engine intake pipe is an important part of the engine. A reasonable layout of the intake pipe can prolong service life of the engine and improve engine power. The optimization of design of the intake pipe has a great impact on the overall performance of the engine. The design of the intake pipe based on experience is subjective and unilateral, and the design cycle and experimental period are long. Ansys Fluent software is used to simulate the design, which can more intuitively reflect the air flow condition of the intake pipe and enable selection of the best layout. First of all, a three-dimensional model of the intake pipe is simulated and the airflow characteristics are studied and analyzed. The streamline diagram and velocity contour under various conditions are obtained. Then, compared with the simulation results, the position of the intake pipe is optimized. Finally, the optimized intake pipe is simulated and verified. According to the experimental results, the intake performance of the optimized intake pipe is greatly improved.
Źródło:: Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 449--461
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 8.

Tytuł:: Parametric analysis of the whole loading process of translation-torsion coupled vibration characteristics of the multi-layer bi-directional eccentric frame structure
Autorzy:: Kuang, Yuping
Liu, Yanshan
Powiązania:: https://bibliotekanauki.pl/articles/2104768.pdf
Data publikacji:: 2022
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: eccentric structure
translation-torsion coupled
vibration characteristics
eccentricity
uncoupled torsion to lateral frequency ratio
Opis:: Earthquake investigations confirm that irregular structures suffer more damage than their symmetric counterparts. The vibration mode of irregular structures is affected by the cou- pling of lateral and torsional vibration characteristics. The analysis of the lateral-torsional coupling effect is mainly limited to unidirectional eccentric structure or single-layer eccentric design. To fill this gap, this paper presents a parametric study of the whole loading pro- cess, exploring lateral-torsional coupling vibration characteristics of multi-layer bi-directional eccentric structures. The performed nonlinear static analysis revealed that the natural fre- quency of eccentric frames with different layers exhibited a general pattern with a three-stage evolution from elastic to elastic-plastic stages. Accordingly, three different elastic-plastic de- velopment stages of parametric analysis were defined. The effects of the uncoupled torsion-to- -lateral frequency ratios Ω and stiffness eccentricities on the translation-torsion coupled vi- bration characteristics in the above three stages were simulated via self-compiled programs on the MATLAB platform. The results obtained show that the range of Ω controlling the vibration characteristics was related to the eccentricities. Therefore, it was proposed to set different limit values of Ω in designing and analyzing the structures with different bi- directional eccentric degrees. At Ω = 1.1 ∼ 1.2, the coupling effect between bi-directional eccentricities led to transformation between the first- and second-order vibration modes, while the direction with the lowest lateral stiffness could not be directly judged as the structure first-order principal vibration direction. In the third stage, when the bi-directional eccentricities reached or even exceeded 0.3, the second and third modes transformed into each other.
Źródło:: Journal of Theoretical and Applied Mechanics; 2022, 60, 3; 479--494
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 9.

Tytuł:: On the yield surface of a typical bending-dominant periodic lattice metamaterial
Autorzy:: Wang, Yongjun
Liu, Jinxing
Powiązania:: https://bibliotekanauki.pl/articles/2200879.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: bending-dominant periodic lattice
BDPL
yield
metamaterial
strain energy equivalence
Opis:: A theoretical method for analyzing the initial yield of a typical bending-dominant peri- odic lattice (BDPL) is established. Based on the principle of strain energy equivalence, the macroscopic effective stiffnesses of lattices are calculated. An empirical formula is employed to consider the contributions of both the axial force and bending moment. The initial yield surface of BDPL can be figured out by comparing the effective stress of each strut to the yield strength of the matrix material. The method is applicable to various BDPLs, which we believe is a helpful extension to the method for lattices comprising axial-tension bars in the literature.
Źródło:: Journal of Theoretical and Applied Mechanics; 2023, 61, 1; 175--187
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 10.

Tytuł:: Stochastic hopf bifurcation of quasi-integrable hamiltonian systems with time-delayed feedback control
Stochastyczna bifurkacja Hopfa w quasi-całkowalnych układach Hamiltonowskich sterowanych w pętli sprzężenia zwrotnego z opóźnieniem
Autorzy:: Liu, Z. H.
Zhu, W. Q.
Powiązania:: https://bibliotekanauki.pl/articles/280917.pdf
Data publikacji:: 2008
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: stochastyczna bifurkacja Hopfa
quasi-całkowalny układ Hamiltonowski
sprzężenie zwrotne z opóźnieniem
stochastic Hopf bifurcation
quasi-integrable Hamiltonian system
stochastic averaging
time-delayed feedback control
Opis:: The stochastic Hopf bifurcation of multi-degree-of-freedom (MDOF) quasi-integrable Hamiltonian systems with time-delayed feedback control subject to Gaussian white noise excitations is studied. First, the time-delayed feedback control forces are approximately expressed in terms of the system state variables without time delay, and the system is converted into anordinary quasi-integrable Hamiltonian system. The averaged It�o stochastic differential equations are derived by using the stochastic averaging method for quasi-integrable Hamiltonian systems. Then, an expression for the average bifurcation parameter of the averaged system is obtained approximately, and a criterion for determining the stochastic Hopf bifurcation caused by the time-delayed feedback control forces in the original system as the value of the average bifurcation parameter changing is proposed. An example is worked out in detail to illustrate the above criterion and its validity, and to show the effect of the time delay in the feedback control on the stochastic Hopf bifurcation of the system.
W pracy zajęto się problemem stochastycznej bifurkacji Hopfa quasi-całkowalnych układów Hamiltonowskich o wielu stopniach swobody poddanych wymuszeniu białym szumem z układem sterowania opartym na pętli sprzężenia zwrotnego z opóźnie- niem. Najpierw znaleziono przybliżone wyrażenia na siły sterujące w funkcji zmiennych stanu układu bez opóźnienia, a następnie przetransformowano go postaci quasi- całkowalnej, Hamiltonowskiej. Wyprowadzono stochastyczne równania różniczkowe It^o za pomocą metody uśredniania układów quasi-całkowalnych. Znaleziono przybliżoną postać wyrażenia na parametr bifurkacyjny uśrednionego układu i zaproponowano kryterium stwierdzające obecność stochastycznej bifurkacji Hopfa wywołanej siłami sterującymi z opóźnieniem na podstawie wartości zmiany tego parametru. Opracowa- no szczegółowo przykład do ilustracji działania tego kryterium i zakresu jego stosowalności oraz do prezentacji wpływu opóźnienia w pętli sterownia na stochastyczną bifurkację Hopfa badanego układu.
Źródło:: Journal of Theoretical and Applied Mechanics; 2008, 46, 3; 531-550
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 11.

Tytuł:: Numerical investigation of the inner flow in a centrifugal pump at the shut-off condition
Autorzy:: Liu, H.
Wu, X
Tan, M.
Powiązania:: https://bibliotekanauki.pl/articles/281524.pdf
Data publikacji:: 2013
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: centrifugal pump
numerical simulation
shut-off condition
PIV
Opis:: The unsteady flow fields in a centrifugal pump at the shut-off condition (SOC) are simulated by the Unsteady Reynolds Averaged Navier-Stokes (URANS) approach. To improve simulation accuracy and assign the boundary condition, special 3D models are made. Three-dimensional URANS equations are solved on high-quality unstructured grids with the shear stress transport turbulence model by using the computational fluid dynamics (CFD) code CFX-11.0. Furthermore, the numerical simulation results are validated by particle image velocimetry (PIV) measurements. The main goal of the study is, on one hand, the validation of the numerical procedure proposed, and on the other hand, the detailed analysis of the unsteady inner flow field distribution and pressure fluctuation in the centrifugal pump at SOC. In addition, the head of the pump at SOC is predicted based on CFD results. The flow analysis indicates that there exists two eddies in each impeller flow passage, and the velocity at the volute diffusion part is very low. The amplitudes of pressure fluctuation at ƒr (impeller rotation frequency) and 3ƒr dominate in the impeller, while the pressure fluctuation at ƒb (blade passing frequency) is dominant in the volute.
Źródło:: Journal of Theoretical and Applied Mechanics; 2013, 51, 3; 649-660
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 12.

Tytuł:: Study of triaxial compression mechanical properties and pore-fracture characteristics of coal rocks in the Yili Basin, Xinjiang
Autorzy:: Shen, Cheng
Yue, Ling
Liu, Yang
Powiązania:: https://bibliotekanauki.pl/articles/2200886.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: triaxial compression
mechanical properties
mercury injection
pore-fissure characteristics
Opis:: Compressive mechanical properties and pore-fissure characteristics of coal rock specimens from three stably developed coal seams M1, M8 and M12 in the Xinjiang Yili Basin were investigated in detail by a series of tests. The results show that the compressive mechanical properties of coal rocks in the Yili Basin are significantly affected by the confining pressure. The peak axial stress increases and the peak modulus of elasticity decreases as the confining pressure increases. The peak axial strain increases and then remains constant, while the peak circumferential strain and peak volumetric strain increase and then decrease. The confining pressure has almost no effect on Poisson’s ratio of the coal rock specimens. In addition, electron microscopy tests show that the microscopic fraction of the coal rock specimens is predominantly vitrinite, accounting for 83.1%-89.2%, while the percentage of the inertinite group is relatively small, at 10.3%-16.1%. The throat radius of the coal rock is mainly concentrated around 1-2μm, while the pore radius of the coal rock is between 150-200μm. The coal rock has an overall fine throat and low permeability, and the coal rock in the Yili Basin of Xinjiang is a typical low-permeability coal rock.
Źródło:: Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 207--218
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 13.

Tytuł:: Application of a ring coupled double-Duffing oscillator to a scheme for identifying the coulter signal with a low SNR
Autorzy:: Zhao, Zhijie
Liu, Runcong
Wang, Xiaodong
Powiązania:: https://bibliotekanauki.pl/articles/2200898.pdf
Data publikacji:: 2023
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: simulated Coulter signal
pulsed signal identification
ring coupled double-Duffing oscillator
chaotic-transient synchronous mutation
continuous synchronous mutation
Opis:: In order to use chaotic oscillators to identify Coulter signals with a low SNR (SNR⩽0), a Gaussian pulse signal is used to simulate the Coulter signal, and we study the continuous synchronous mutation (CSM) phenomenon of a chaotic ring coupled double-Duffing (RCDD) oscillator to identify the signals. The maximum difference between the two state variables in the oscillator can be used to determine the anti-noise ability of the oscillator and construct a function to identify pulse amplitudes. A Simulink model is constructed to verify that the proposed method can be used to identify pulse amplitudes with a low SNR, which provides an approach for developing a technology of measuring Coulter signals with the low SNR.
Źródło:: Journal of Theoretical and Applied Mechanics; 2023, 61, 2; 379--393
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 14.

Tytuł:: A comparison of objective functions of optimization-based smoothing algorithm for tetrahedral mesh improvement
Autorzy:: Dai, C.
Liu, H.-L.
Dong, L.
Powiązania:: https://bibliotekanauki.pl/articles/279637.pdf
Data publikacji:: 2014
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: objective function
mesh quality metric
optimization-based smoothing
mesh quality improvement
mesh generation
Opis:: The objective function based on mesh quality metric has a major impact on smoothing unstructured tetrahedral meshes. The ability of seven mesh quality metrics to distinguish four kinds of poor-quality elements and their effects on the change of element shape are analyzed in detail. Then, four better mesh quality metrics are chosen to construct objective functions. In addition, the rational determination of searching direction and the optimal step size in the optimization algorithm of solving the objective function are proposed. Finally, comparisons with the other three objective functions are made according to different number of elements, iteration limit, and the desired accuracy in the improved mesh. It is found that with the increase of the number of elements, the time consumed during optimization increases, but the changes of the worst quality element are different. The number of iterations has little effect on the mesh quality and the time cost. The increasing of the desired degree of accuracy will improve the mesh quality and cost more time. Furthermore, the approach using objective function is compared with Freitag’s common approach. It is clearly shown that it performs better than the existing approach.
Źródło:: Journal of Theoretical and Applied Mechanics; 2014, 52, 1; 151-163
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Skocz do pozycji: 15.

Tytuł:: Numerical study of stall inception in a transonic axial compressor rotor based on the throttle model
Autorzy:: Zhu, X.
Liu, B.
Hu, J.
Shen, X.
Powiązania:: https://bibliotekanauki.pl/articles/280516.pdf
Data publikacji:: 2015
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:: stall
axial compressor
throttle
tip clearance flow
Opis:: The goal of the current paper is to investigate inner flow behavior on stall inception in a transonic compressor rotor. The stall inception process is numerically carried out by unsteady 3-D simulations based on the throttle model. The current study shows that stall starts from the tip of the blade, and stall cell extends to the axial, circumferential and radial directions. Through the comparison of flow transition characteristics at different flow rate conditions, the interface between the incoming flow and tip clearance flow shifts forward to the upstream as the mass flow decreases. Eventually, the shock detaches from the blade leading edge, and tip clearance flow spills into the adjacent blade passage, thus stall happens in the affected blade passages.
Źródło:: Journal of Theoretical and Applied Mechanics; 2015, 53, 2; 307-316
1429-2955
Pojawia się w:: Journal of Theoretical and Applied Mechanics
Dostawca treści:: Biblioteka Nauki

Artykuł

Zmień widok

na półce

Informacja

Wyszukujesz frazę "Liu, Liu" wg kryterium: Autor

Źródło danych

Dostawca treści

Kolekcja

Rok wydania

Wydawca

Temat

Autor

Typ dokumentu

Język