Final Report on the Department of Energy Grant DE - FG 02 - 97 ER 54395 “ Investigation of the Spherical Steliarator Concept ”

DEPARTMENT OF ENERGY Final Report Grant # : DE - FGO 7 - 98 ER 62708

On the convergence of Newton iterations to non-stationary points

We study conditions under which line search Newton methods for nonlinear systems of equations and optimization fail due to the presence of singular non stationary points These points are not solutions of the problem and are characterized by the fact that Jacobian or Hessian matrices are singular It is shown that for systems of nonlinear equations the interaction between the Newton direction and...

Feasibility Control in Nonlinear Optimization Report Otc 2000/04 Optimization Technology Center

We analyze the properties that optimization algorithms must possess in order to prevent convergence to non stationary points for the merit function We show that demanding the exact satisfaction of constraint linearizations results in di culties in a wide range of optimization algorithms Feasibility control is a mechanism that prevents convergence to spurious solutions by ensuring that su cient ...

Buckling Analysis of Functionally Graded Shallow Spherical Shells Under External Hydrostatic Pressure

The aim of this paper is to determine the critical buckling load for simply supported thin shallow spherical shells made of functionally graded material (FGM) subjected to uniform external pressure. A metal-ceramic functionally graded (FG) shell with a power law distribution for volume fraction is considered, where its properties vary gradually through the shell thickness direction from pure me...

Parametric investigation of autofrettage process in thick spherical vessel made of functionally graded materials

In this paper, the effect of autofrettage process parameters on the ultimate pressure that functionally graded spherical vessel can tolerate are investigated. FGM properties and autofrettage pressure are considered as important parameters. Assumptions are variation of properties of FGM in radial direction, the residual stress in the absence of Bauschinger effect with the operation of variable m...