Analysis of dynamical response to large deformation of piles with initial displacements

In this paper, a nonlinear mathematical model for analyzing dynamical response to the large deformation of piles with initial displacements is firstly established with the arc-coordinate, and it is a set of nonlinear integral-differential equa- tions, in which, the Winkeler model is used to simulate the resistance of the soil to the pile. Secondly, a set of new auxiliary functions are introduced. The differential-integral equations are transformed into a set of nonlinear differential equations, and the differential quadrature method （DQM） and the finite difference method （FDM） are applied to discretize the set of nonlinear equations in the spatial and time domains, respectively. Then, the Newton-Raphson method is used to solve the set of discretization algebraic equations at each time step. Finally, numerical examples are presented, and the dynamical re- sponses to the deformation of piles, including configuration, bending moment and shear force, are graphically illuminated. In calculation, two types of initial displacements and dynamical loads are applied, and the effects of parameters on the dynamical responses of piles are analyzed in detail.

The Existence and Uniqueness of the Solution for Perio dical Boundary Value Problems of 2k th Order Differential Equations with Resonance

In this paper, a new set of sufficient conditions related to an initial value problem and global homeomorphism is obtained in discussing the existence and uniqueness of 2π-periodic solution for 2kth order differential equations with resonance. The key role is played by nonnegative auxiliary scalar coercive function. The result of this paper generalizes some existed theorems.

Using Inverter-Based Renewable Generators to Improve the Grid Power Quality-A Review

With the increasing penetration of renewable power in the grid,renewable generators are expected to play more important roles rather than merely working as active power sources.Considering the high controllability and considerable idle capacity of the inverter-based renewable generators,various auxiliary functions for them have been studied to benefit the grid.Among these auxiliary functions,the grid power quality improvement is very promising.This paper presents a review of the emerging control strategies for inverter-based renewable generators to improve grid power quality.The related papers are classified with different power quality issues and technical routes,and a comprehensive comparison is presented.The future trends of this research area are also discussed.

A Class of New Special Solution of Nonlinear Diffusion Equation

One of the most interesting problems of nonlinear differential equations is the construction of partial solutions. A new method is presented in this paper to seek special solutions of nonlinear diffusion equations. This method is based on seeking suitable function to satisfy Bernolli equation. Many new special solutions are obtained.

QUADRATIC INTEGRABILITY AND BOUNDEDNESS OF THE SOLUTIONS FOR SECOND ORDER NONLINEAR DELAY DIFFERENTIAL EQUATIONS

In this paper, by means of auxiliary functions and inequalities, we obtain some sufficient conditions of second order nonhomogeneous delay differential equation belonging to the L.S. or L.S. ∩ L.C..