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Chang Tao - One of the best experts on this subject based on the ideXlab platform.

  • nonlinear dynamic responses of fiber metal laminated beam subjected to moving harmonic loads resting on tensionless elastic foundation
    Composites Part B-engineering, 2017
    Co-Authors: Yang Chen, Jun Zhong, Chang Tao
    Abstract:

    Abstract The nonlinear dynamic responses of the fiber-metal laminated beam resting on a tensionless elastic foundation and subjected to a moving harmonic load and thermal load are investigated in the paper. The beam-foundation interaction force that only reacts in compression is established by introducing the hyperbolic tangent function, and the steady temperature field is deduced by solving the one-dimensional steady-state heat transfer equation. The nonlinear governing equations are derived by application of Hamilton principle and solved by finite difference Method, Newmark Method and Newton-Raphson Method. In numerical results, FML beams constrained by different boundary conditions are selected to reveal the dynamic properties of FML beams. The effects of some parameters are discussed in detail, and some meaningful conclusions are concluded.

  • dynamic analysis for cracked fiber metal laminated beams carrying moving loads and its application for wavelet based crack detection
    Composite Structures, 2017
    Co-Authors: Chang Tao, Ting Dai
    Abstract:

    Abstract The present study considered the free and forced vibration of cracked fiber metal laminated (FML) beams with a damper subjected to a moving load, and the detection of the cracks by using continuous wavelet transform (CWT). The beam is regarded as multi segments which are assumed to obey the Euler-Bernoulli beam hypothesis and the crack is modeled as rotational spring with sectional flexibility. The modal expansion theory and Newmark Method are employed to solve the dynamic responses of FML beam numerically. Two classes of boundary conditions are considered and the dynamic responses at the tip of a FML cantilever beam with a single crack are obtained for various load velocity, and the outcome results have been compared to the results obtained by literature. The influences of crack depth, crack location, ply angle of the fiber layer, stiffness coefficient of the damper and velocity of the moving load on free vibration and forced vibration of FML cantilever beams are investigated. Numerical results indicate that the above-mentioned effects play a very important role on both free vibration and dynamic responses of the beam. In the end of the numerical examples, continuous wavelet transform is used to detect the location of the cracks of a clamped-clamped FML beam.

Yang Chen - One of the best experts on this subject based on the ideXlab platform.

  • nonlinear dynamic responses of fiber metal laminated beam subjected to moving harmonic loads resting on tensionless elastic foundation
    Composites Part B-engineering, 2017
    Co-Authors: Yang Chen, Jun Zhong, Chang Tao
    Abstract:

    Abstract The nonlinear dynamic responses of the fiber-metal laminated beam resting on a tensionless elastic foundation and subjected to a moving harmonic load and thermal load are investigated in the paper. The beam-foundation interaction force that only reacts in compression is established by introducing the hyperbolic tangent function, and the steady temperature field is deduced by solving the one-dimensional steady-state heat transfer equation. The nonlinear governing equations are derived by application of Hamilton principle and solved by finite difference Method, Newmark Method and Newton-Raphson Method. In numerical results, FML beams constrained by different boundary conditions are selected to reveal the dynamic properties of FML beams. The effects of some parameters are discussed in detail, and some meaningful conclusions are concluded.

Tahar Fakhfakh - One of the best experts on this subject based on the ideXlab platform.

  • study of a spur gear dynamic behavior in transient regime
    Mechanical Systems and Signal Processing, 2011
    Co-Authors: Mohamed Taoufik Khabou, Fakher Chaari, Noussa Bouchaala, Tahar Fakhfakh
    Abstract:

    Abstract In this paper the dynamic behavior of a single stage spur gear reducer in transient regime is studied. Dynamic response of the single stage spur gear reducer is investigated at different rotating velocities. First, gear excitation is induced by the motor torque and load variation in addition to the fluctuation of meshing stiffness due to the variation of input rotational speed. Then, the dynamic response is computed using the Newmark Method. After that, a parameter study is made on spur gear powered in the first place by an electric motor and in the second place by four strokes four cylinders diesel engine. Dynamic responses come to confirm a significant influence of the transient regime on the dynamic behavior of a gear set, particularly in the case of engine acyclism condition.

  • Effect of manufacturing defects on the dynamic behaviour for an helical two-stage gear system
    Mecanique & Industries, 2009
    Co-Authors: L. Walha, Tahar Fakhfakh, Yassine Driss, Mohamed Haddar
    Abstract:

    The modelling of the dynamic behaviour of three-dimensional model of two-stage gear system is formulated for general helical gears location. The excitation is induced by the periodic variation of the mesh stiffnesses. This case describes the real working of the gearings. First, the modal analysis of the system is treated. Then, the calculation of the dynamic response is performed by a step-by-step time integration Method (Newmark Method). Finally, two types of manufacturing defects on the gears are introduced in the model: eccentricity and profile defect. An analysis of the effects of these defects on the gear system dynamic behaviour is then treated.

  • dynamic behaviour of hydrodynamic journal bearings in presence of rotor spatial angular misalignment
    Mechanism and Machine Theory, 2009
    Co-Authors: Slim Bouaziz, Molka Attia Hili, Mohamed Mataar, Tahar Fakhfakh
    Abstract:

    Abstract In this work, the dynamic behaviour of misaligned rotor is presented. The rotor is mounted in two hydrodynamic journal bearings and has two degrees of freedom. Reynolds’ equation is obtained by considering the effect of mass transfer across the fluid film. This is discretized by means of the finite difference Method and solved numerically. By integrating the oil pressure distribution, the hydrodynamic forces are calculated. The elasticity of the fluid film is modelled by stiffness and damping matrices. The motion equations have been established for the rotor bearings system and simulated with Newmark Method. The effect of bearings geometry on the dynamic coefficients is presented. A theoretical model describing the angular misalignment defect is analysed in order to survey the vibratory response of the misaligned rotor. Numerical simulation results are presented and discussed.

Ting Dai - One of the best experts on this subject based on the ideXlab platform.

  • hygrothermal mechanical behaviors of a porous fg crc annular plate with variable thickness considering aggregation of cnts
    Composite Structures, 2019
    Co-Authors: Ting Dai, Yang Yang, Hongliang Dai, Hong Tang, Zhongyan Lin
    Abstract:

    Abstract Experiment in literature has shown the aggregation phenomenon in carbon nanotube (CNT) reinforced polymeric composites. In this paper, considering the aggregation effect of CNTs and porosity in both polymeric matrix and aggregated CNT clusters, a mechanical model to investigate the coupled conduction of temperature and moisture as well as the hygrothermal mechanical behaviors of a porous functionally graded CNT reinforced composite (FG-CRC) rotating annular plate with variable thickness is built. Numerical results of the temperature and moisture fields as well as the hygrothermal mechanical responses are achieved by combining the differential quadrature Method (DQM), the Runge-Kutta Method and the Newmark Method. Several useful conclusions as follow are obtained through numerical examples and discussions. In the numerical examples, influences of the aggregation effect of CNTs, coupled effect of temperature and moisture, material property (graded index and porosity parameters), geometric parameters as well as the rotating conditions to the hygrothermal mechanical responses of the porous FG-CRC annular plate are studied in detail. The theoretical process and conclusions will be helpful to the design and manufacture of novel porous graded materials and structures applying in hygrothermal environment and conditions.

  • dynamic analysis for cracked fiber metal laminated beams carrying moving loads and its application for wavelet based crack detection
    Composite Structures, 2017
    Co-Authors: Chang Tao, Ting Dai
    Abstract:

    Abstract The present study considered the free and forced vibration of cracked fiber metal laminated (FML) beams with a damper subjected to a moving load, and the detection of the cracks by using continuous wavelet transform (CWT). The beam is regarded as multi segments which are assumed to obey the Euler-Bernoulli beam hypothesis and the crack is modeled as rotational spring with sectional flexibility. The modal expansion theory and Newmark Method are employed to solve the dynamic responses of FML beam numerically. Two classes of boundary conditions are considered and the dynamic responses at the tip of a FML cantilever beam with a single crack are obtained for various load velocity, and the outcome results have been compared to the results obtained by literature. The influences of crack depth, crack location, ply angle of the fiber layer, stiffness coefficient of the damper and velocity of the moving load on free vibration and forced vibration of FML cantilever beams are investigated. Numerical results indicate that the above-mentioned effects play a very important role on both free vibration and dynamic responses of the beam. In the end of the numerical examples, continuous wavelet transform is used to detect the location of the cracks of a clamped-clamped FML beam.

F W Williams - One of the best experts on this subject based on the ideXlab platform.