Computational Geometry of Period-3 Hyperbolic Components in the Mandelbrot Set

A parametric theoretical boundary equation of a period-3 hyperbolic component in the Mandelbrot set is established from a perspective of Euclidean plane geometry. We not only calculate the interior area, perimeter and curvature of the boundary line but also derive some relevant geometrical properties. The budding point of the period-3k component, which is born on the boundary of the period-3 component, and its relevant period-3k points are theoretically obtained by means of Cardano’s formula for the cubic equation. In addition, computational results are presented in tables and figures to support the theoretical background of this paper.

Barrier Solutions of Elliptic Differential Equations in Musielak-Orlicz-Sobolev Spaces

In this paper, we study the solution set of the following Dirichlet boundary equation: − div a 1 x , u , D u + a 0 x , u = f x , u , D u in Musielak-Orlicz-Sobolev spaces, where a 1 : Ω × ℝ × ℝ N ⟶ ℝ N , a 0 : Ω × ℝ ⟶ ℝ , and f : Ω × ℝ × ℝ N ⟶ ℝ are all Carathéodory functions. Both a 1 and f depend on the solution u and its gradient D u . By using a linear functional analysis method, we provide sufficient conditions which ensure that the solution set of the equation is nonempty, and it possesses a greatest element and a smallest element with respect to the ordering “≤,” which are called barrier solutions.

Elliptic Equation of Plastic Area Boundary around the Circular Laneway in Nonuniform Stress Field

In order to obtain the analytical solution of the plastic area boundary of circular laneway surrounding rock in nonuniform stress field, we studied the evolution of the plastic area shapes of the circular laneway surrounding rock from circular to elliptical and derived the analytical solutions of the boundary radii in the elliptical shape. The results show that (1) with the increase of the confining pressure ratio from 1, the major axis radius of the plastic area increases gradually, the minor axis radius decreases gradually, and the shape of the plastic area gradually evolves from circular to elliptical; (2) on the basis of the Mohr–Coulomb strength criterion, the analytical expressions of major axis and minor axis radii of the elliptical plastic area are derived, and the elliptic equation of the plastic area boundary of circular laneway in nonuniform stress field is established; and (3) the confining pressure ratio is the key factor affecting the shape of the plastic area. When the confining pressure ratio is less than 1.6, the plastic area of the circular laneway surrounding rock is elliptical, and the elliptic boundary equation is applicable. When the confining pressure ratio is greater than 1.6, the plastic area is butterfly shaped, and the elliptic boundary equation is no longer applicable.

Computational Bifurcations Occurring on Red Fixed Components in the λ-Parameter Plane for a Family of Optimal Fourth-Order Multiple-Root Finders under the Möbius Conjugacy Map

Optimal fourth-order multiple-root finders with parameter λ were conjugated via the Möbius map applied to a simple polynomial function. The long-term dynamics of these conjugated maps in the λ -parameter plane was analyzed to discover some properties of periodic, bounded and chaotic orbits. The λ -parameters for periodic orbits in the parameter plane are painted in different colors depending on their periods, and the bounded or chaotic ones are colored black to illustrate λ -dependent connected components. When a red fixed component in the parameter plane branches into a q-periodic component, we encounter geometric bifurcation phenomena whose characteristics determine the desired boundary equation and bifurcation point. Computational results along with illustrated components support the bifurcation phenomena underlying this paper.

R-function Theory for Bending Problem of Shallow Spherical Shells with Polygonal Boundary

The governing differential equations of the bending problem of simply supported shallow spherical shells on Winkler foundation are simplified to an independent equation of radial deflection. The independent equation of radial deflection is decomposed to two Laplace operators by intermediate variable. The R-function theory is applied to describe a shallow spherical shell on Winkler foundation with concave boundary, and then a quasi-Green’s function is established by using the fundamental solution and the normalized boundary equation. The quasi-Green’s function satisfies the homogeneous boundary condition of the problem. The Laplace operators of the problem are reduced to two simultaneous Fredholm integral equations of the second kind by the Green’s formula. The singularity of the kernel of the integral equation is eliminated by choosing a suitable form of the normalized boundary equation. The integral equations are discretized into the homogeneous linear algebraic equations to proceed numerical computing. The singular term in the discrete equation is eliminated by the integral method. Some numerical examples are given to verify the validity of the proposed method in calculating simple boundary conditions and polygonal boundary conditions. A comparison with the ANSYS finite element (FEM) solution shows a good agreement, and it demonstrates the feasibility and efficiency of the present method.

Charged radiating stars with Lie symmetries

We consider the general model of an accelerating, expanding and shearing radiating star in the presence of charge. Using a new set of variables arising from the Lie symmetries of differential equations we transform the boundary equation into ordinary differential equations. We present several new exact models for a charged gravitating sphere. A particular family of solution may be interpreted as a generalised Euclidean star in the presence of the electromagnetic field. This family admits a linear barotropic equation of state. In the uncharged limit, we regain general relativistic stellar models where proper and areal radii are equal, and its generalisations. Our group theoretical approach selects the physically important cases of Euclidean stars and equations of state.

NUMERICAL SOLUTION OF PLANE PROBLEM OF ELASTICITY THEORY USING BOUNDARY EQUATION METHOD

The stress-strain state of a two-dimensional problem under the conditions of plane deformation is investigated using the method of boundary equations. A rectangular plate rigidly clamped into the base under conditions of plane deformation is studied under horizontal load distributed along the vertical face. Numerical experiments are carried out to analyze the stability of the solution, the convergence, and the accuracy of results obtained.

Application of Trefftz method for the solution of two-dimensional Poisson’s problem taking into account material properties

The aim of this paper is theoretical and numerical analysis of one of the nonsingular Trefftz method. Two-dimensional boundary value problem governed by Poisson’s equation is taken as the example. Domain boundary equation is obtained by transformation of classical formulation of the boundary problem with the use of weighted residual method. In this paper the original variation formulation is considered. The solution of the problem is assumed as the superposition of Trefftz functions, which satisfy Laplace’s equation. Taking the same functions as the weighting functions one obtains equations of the Galerkin version of the Trefftz method with symbolic name OS;TT. The paper contains the theoretical analysis of the OS;TT method which is confirmed with numerical example. .