Shape optimization using a matrix - free
نویسنده
چکیده
In tackling the problem of minimizing the deformation of a loaded structure, by varying the shape of the original structure, past second order optimization efforts have focused on general Newton techniques like the Davidon-Fletcher-Powell (DFP) update formula and the BroydenFletcher-Goldfarb-Shanno (BFGS) formula which iteratively build estimates of the structure's Hessian. This thesis bypasses the above mentioned need for explicit estimation of the Hessian by exploiting the inherent symmetry of the problem and, thus, is able to use a matrix-free Krylov subspace method like GMRES as the Newton solver. In addition to this computationally efficient solver, the thesis algorithm also uses stochastic perturbations to escape from its Newton stalls. Results will be presented to illustrate the algorithm's convergence. Thesis supervisor: Jacob K. White Title: Assoc. Prof., Dept. of E.E.C.S.
منابع مشابه
THIN WALLED STEEL SECTIONS’ FREE SHAPE OPTIMIZATION USING CHARGED SYSTEM SEARCH ALGORITHM
Graph theory based methods are powerful means for representing structural systems so that their geometry and topology can be understood clearly. The combination of graph theory based methods and some metaheuristics can offer effective solutions for complex engineering optimization problems. This paper presents a Charged System Search (CSS) algorithm for the free shape optimizations of thin-wall...
متن کاملInvestigation of Utilizing a Secant Stiffness Matrix for 2D Nonlinear Shape Optimization and Sensitivity Analysis
In this article the general non-symmetric parametric form of the incremental secant stiffness matrix for nonlinear analysis of solids have been investigated to present a semi analytical sensitivity analysis approach for geometric nonlinear shape optimization. To approach this aim the analytical formulas of secant stiffness matrix are presented. The models were validated and used to perform inve...
متن کاملA Free Line Search Steepest Descent Method for Solving Unconstrained Optimization Problems
In this paper, we solve unconstrained optimization problem using a free line search steepest descent method. First, we propose a double parameter scaled quasi Newton formula for calculating an approximation of the Hessian matrix. The approximation obtained from this formula is a positive definite matrix that is satisfied in the standard secant relation. We also show that the largest eigen value...
متن کاملMonte Carlo Simulation for Treatment Planning Optimization of the COMS and USC Eye Plaques Using the MCNP4C Code
Introduction: Ophthalmic plaque radiotherapy using I-125 radioactive seeds in removable episcleral plaques is often used in management of ophthalmic tumors. Radioactive seeds are fixed in a gold bowl-shaped plaque and the plaque is sutured to the scleral surface corresponding to the base of the intraocular tumor. This treatment allows for a localized radiation dose delivery to the tumor with a ...
متن کاملConvex Surface Visualization Using Rational Bi- cubic Function
The rational cubic function with three parameters has been extended to rational bi-cubic function to visualize the shape of regular convex surface data. The rational bi-cubic function involves six parameters in each rectangular patch. Data dependent constraints are derived on four of these parameters to visualize the shape of convex surface data while other two are free to refine the shape of s...
متن کاملNatural Boundary Conditions for Smoothing in Geometry Processing
In geometry processing, smoothness energies are commonly used to model scattered data interpolation, dense data denoising, and regularization during shape optimization. The squared Laplacian energy is a popular choice of energy and has a corresponding standard implementation: squaring the discrete Laplacian matrix. For compact domains, when values along the boundary are not known in advance, th...
متن کامل