The Experts below are selected from a list of 29232 Experts worldwide ranked by ideXlab platform

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

  • nonlinear recurrent neural networks for finite time solution of general time varying linear matrix Equations
    Neural Networks, 2018
    Co-Authors: Lin Xiao, Bolin Liao, Ke Chen
    Abstract:

    Abstract In order to solve general time-varying linear matrix Equations (LMEs) more efficiently, this paper proposes two nonlinear recurrent neural networks based on two nonlinear activation functions. According to Lyapunov theory, such two nonlinear recurrent neural networks are proved to be convergent within finite-time. Besides, by Solving Differential Equation, the upper bounds of the finite convergence time are determined analytically. Compared with existing recurrent neural networks, the proposed two nonlinear recurrent neural networks have a better convergence property (i.e., the upper bound is lower), and thus the accurate solutions of general time-varying LMEs can be obtained with less time. At last, various different situations have been considered by setting different coefficient matrices of general time-varying LMEs and a great variety of computer simulations (including the application to robot manipulators) have been conducted to validate the better finite-time convergence of the proposed two nonlinear recurrent neural networks.

Hajali Masood - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of the mode I plastic zone size at the crack tip using RKPM and FEM
    2017
    Co-Authors: Abi Shdid Caesar, Hajali Masood
    Abstract:

    In recent years, much research have been done on mesh-free methods for Solving Differential Equation problems including crack and also obtained satisfactory results. Among these methods Reproducing Kernel Particle Method (RKPM) has been used increasingly in fracture mechanic problems. RKPM is a meshfree technology which has proven very useful for Solving problems of fracture mechanics. In this study, it is proposed to obtain the mode I plastic zone size and shape at the crack-tip in a work-hardening material using RKPM. Ramberg-Osgood stress-strain relation is assumed. Results including plastic zone shape are compared with finite element method (FEM) to show the accuracy of RKPM. Results show that the plastic zone size in crack tip for the plane-strain condition is bigger that plane-stress condition. The reason can be stated that in plane-strain condition due to limitations in third dimension, stress is created in the third dimension (z-direction) and cause to increase the daviatoric stress according to J2-Deformational theory and also cause to increase in plastic zone size. The main objective is to obtain the mode I plastic zone shape at the crack-tip in a work-hardening material using RKPM and FEM.N/

  • Comparison between visibility and diffraction criteria on SIF and -Integral value for mode crack using RKPM
    2013
    Co-Authors: Abi Shdid Caesar, Hajali Masood, Nejadpa Arash
    Abstract:

    Recently, mesh-free methods are increasingly utilized in Solving various types of boundary value problems. Much research has been done on mesh-free methods for Solving Differential Equation problems including crack and also obtained satisfactory results. Among these methods, reproducing kernel particle method (RKPM) has been used increasingly in fracture mechanic problems. The -integral and the stress intensity factor (SIF) are the most important parameters for crack problems. In this study -integral has been used to calculate the SIF in the crack tip. The mode SIF at the crack tip in a work-hardening material is obtained for various dilation parameters using RKPM. A comparison between two conventional treatments, visibility and diffraction on SIF and -integral value, is conducted. Visibility and diffraction methods increase the accuracy of RKPM results and effect on the -integral results at the crack tip. In comparing between the visibility and diffraction methods to modify the shape functions, the diffraction criterion seems to have better results for the -integral and SIF value.PublishedN/

  • Comparison between Visibility and Diffraction Criteria on SIF and �-Integral Value for Mode � Crack Using RKPM
    FIU Digital Commons, 2013
    Co-Authors: Hajali Masood, Abi Shdid Caesar, Nejadpak Arash
    Abstract:

    Recently, mesh-free methods are increasingly utilized in Solving various types of boundary value problems. Much research has been done on mesh-free methods for Solving Differential Equation problems including crack and also obtained satisfactory results. Among these methods, reproducing kernel particle method (RKPM) has been used increasingly in fracture mechanic problems. The �-integral and the stress intensity factor (SIF) are the most important parameters for crack problems. In this study �-integral has been used to calculate the SIF in the crack tip. The mode � SIF at the crack tip in a work-hardening material is obtained for various dilation parameters using RKPM. A comparison between two conventional treatments, visibility and diffraction on SIF and �-integral value, is conducted. Visibility and diffractionmethods increase the accuracy of RKPM results and effect on the �-integral results at the crack tip. In comparing between the visibility and diffraction methods to modify the shape functions, the diffraction criterion seems to have better results for the �-integral and SIF value

Abi Shdid Caesar - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of the mode I plastic zone size at the crack tip using RKPM and FEM
    2017
    Co-Authors: Abi Shdid Caesar, Hajali Masood
    Abstract:

    In recent years, much research have been done on mesh-free methods for Solving Differential Equation problems including crack and also obtained satisfactory results. Among these methods Reproducing Kernel Particle Method (RKPM) has been used increasingly in fracture mechanic problems. RKPM is a meshfree technology which has proven very useful for Solving problems of fracture mechanics. In this study, it is proposed to obtain the mode I plastic zone size and shape at the crack-tip in a work-hardening material using RKPM. Ramberg-Osgood stress-strain relation is assumed. Results including plastic zone shape are compared with finite element method (FEM) to show the accuracy of RKPM. Results show that the plastic zone size in crack tip for the plane-strain condition is bigger that plane-stress condition. The reason can be stated that in plane-strain condition due to limitations in third dimension, stress is created in the third dimension (z-direction) and cause to increase the daviatoric stress according to J2-Deformational theory and also cause to increase in plastic zone size. The main objective is to obtain the mode I plastic zone shape at the crack-tip in a work-hardening material using RKPM and FEM.N/

  • Comparison between visibility and diffraction criteria on SIF and -Integral value for mode crack using RKPM
    2013
    Co-Authors: Abi Shdid Caesar, Hajali Masood, Nejadpa Arash
    Abstract:

    Recently, mesh-free methods are increasingly utilized in Solving various types of boundary value problems. Much research has been done on mesh-free methods for Solving Differential Equation problems including crack and also obtained satisfactory results. Among these methods, reproducing kernel particle method (RKPM) has been used increasingly in fracture mechanic problems. The -integral and the stress intensity factor (SIF) are the most important parameters for crack problems. In this study -integral has been used to calculate the SIF in the crack tip. The mode SIF at the crack tip in a work-hardening material is obtained for various dilation parameters using RKPM. A comparison between two conventional treatments, visibility and diffraction on SIF and -integral value, is conducted. Visibility and diffraction methods increase the accuracy of RKPM results and effect on the -integral results at the crack tip. In comparing between the visibility and diffraction methods to modify the shape functions, the diffraction criterion seems to have better results for the -integral and SIF value.PublishedN/

  • Comparison between Visibility and Diffraction Criteria on SIF and �-Integral Value for Mode � Crack Using RKPM
    FIU Digital Commons, 2013
    Co-Authors: Hajali Masood, Abi Shdid Caesar, Nejadpak Arash
    Abstract:

    Recently, mesh-free methods are increasingly utilized in Solving various types of boundary value problems. Much research has been done on mesh-free methods for Solving Differential Equation problems including crack and also obtained satisfactory results. Among these methods, reproducing kernel particle method (RKPM) has been used increasingly in fracture mechanic problems. The �-integral and the stress intensity factor (SIF) are the most important parameters for crack problems. In this study �-integral has been used to calculate the SIF in the crack tip. The mode � SIF at the crack tip in a work-hardening material is obtained for various dilation parameters using RKPM. A comparison between two conventional treatments, visibility and diffraction on SIF and �-integral value, is conducted. Visibility and diffractionmethods increase the accuracy of RKPM results and effect on the �-integral results at the crack tip. In comparing between the visibility and diffraction methods to modify the shape functions, the diffraction criterion seems to have better results for the �-integral and SIF value

Andrey B. Prokofiev - One of the best experts on this subject based on the ideXlab platform.

  • the finite element technique for modelling of pipe vibroacoustical characteristics based on space time joint type two node elements
    2015
    Co-Authors: Tatiana Mironova, Andrey B. Prokofiev
    Abstract:

    The finite element technique of vibroacoustical pipeline characteristics are developed. In this technique linear finite elements were used. The technique allows calculations allows calculations of a complex configuration pipe system. The technique is developed for pipeline diameter much smaller than acoustic wavelength in a fluid. The technique is based on the Solving Differential Equation system of interaction between solid and oscillating fluid in the pipeline. Solution was done for non-stationary nonlinear Differential Equation system. The Equation system includes: the equilibrium condition for a curvelinear pipeline part, elastic displacements dependency from forces and moments, acting bulk force Equations, and the expression for fluid motion in elastic pipe. The pipeline is considered like a beam. The flexural vibrations are considered to be prevailing, and the radial cross-section deformations are neglected. Partial discretization and weighted residual methods were used to solve this Equations.The Differential Equation system contains the 6th derivative on vibration displacement was transformed to linear Differential Equation system. The weighted residual approximation with relations for a Galerkin finite element solutions were done. The linear Differential Equation system was solved in time domain by the finite elements method with account to boundary conditions, using the Crank-Nicolson scheme. The boundary conditions for fluid is a parameter combination of complex pressure oscillation amplitude of pipeline inlet section, complex pressure oscillation amplitude of pipeline outlet section, complex velocity oscillation amplitude of pipeline inlet section, complex velocity oscillation amplitude of pipeline outlet section, load impedance, input impedance. The boundary conditions for solid are pipeline supports.In this technique new two node element was proposed. The new space-time joint type elements based on linear basis function. The joint type of finite element are used for modeling vibroacoustical interaction between solid and oscillating fluid. Time response of the pipeline vibration are resulted from this technique. The mathematical technique computational time less than available finite element techniques.

  • the finite element model of vibroacoustical characteristics of pipe system under force excitation by oscillating fluid flow
    8th FPNI Ph.D Symposium on Fluid Power, 2014
    Co-Authors: Tatiana Mironova, Andrey B. Prokofiev, Victor Sverbilov
    Abstract:

    The finite element mathematical technique of vibroacoustical pipeline characteristics are developed. The technique allows calculations vibroacoustical characteristics of pipe with the axial line lying in one plane under force excitation by oscillating fluid flow. The technique is based on the Solving Differential Equation system of interaction between solid and oscillating fluid in the pipeline. Solution was done for transient non-stationary nonlinear Differential Equation system. The weighted residual approximation with relations for a Galerkin finite element solutions were done. The boundary conditions for fluid is a parameter combination of complex pressure oscillation amplitude of pipeline inlet section, complex pressure oscillation amplitude of pipeline outlet section, complex velocity oscillation amplitude of pipeline inlet section, complex velocity oscillation amplitude of pipeline outlet section, load impedance, input impedance. The boundary conditions for solid is bonding of the pipeline. In this technique new seven node element were proposed. The new space-time single type elements based on Lagrange basis function. The single type of finite element are used for modeling vibroacoustical interaction between solid and oscillating fluid. Time response and amplitude spectrum of the pipeline vibration are resulted of these techniques. The mathematical technique computational coast is 3 orders less than available finite element techniques. The convergence estimate of experimental data and simulation results are made. The method is developed for pipeline diameter much smaller than acoustic wavelength in a fluid. It is actual for aircraft pipelines, pipes of power plants, mobile machines and pipes of stationary processing machines.Copyright © 2014 by ASME

Lin Xiao - One of the best experts on this subject based on the ideXlab platform.

  • nonlinear recurrent neural networks for finite time solution of general time varying linear matrix Equations
    Neural Networks, 2018
    Co-Authors: Lin Xiao, Bolin Liao, Ke Chen
    Abstract:

    Abstract In order to solve general time-varying linear matrix Equations (LMEs) more efficiently, this paper proposes two nonlinear recurrent neural networks based on two nonlinear activation functions. According to Lyapunov theory, such two nonlinear recurrent neural networks are proved to be convergent within finite-time. Besides, by Solving Differential Equation, the upper bounds of the finite convergence time are determined analytically. Compared with existing recurrent neural networks, the proposed two nonlinear recurrent neural networks have a better convergence property (i.e., the upper bound is lower), and thus the accurate solutions of general time-varying LMEs can be obtained with less time. At last, various different situations have been considered by setting different coefficient matrices of general time-varying LMEs and a great variety of computer simulations (including the application to robot manipulators) have been conducted to validate the better finite-time convergence of the proposed two nonlinear recurrent neural networks.