Name: LARISSA BASTOS MARTINELLI
Type: MSc dissertation
Publication date: 29/03/2019
Advisor:
Name |
Role |
|---|---|
| ELCIO CASSIMIRO ALVES | Advisor * |
| WALNÓRIO GRAÇA FERREIRA | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ELCIO CASSIMIRO ALVES | Advisor * |
| WALNÓRIO GRAÇA FERREIRA | Internal Examiner * |
Summary: This study addresses the optimization of lattice structures with geometrically nonlinear
behavior under dynamic loading. The formulated optimization problem aims to
determine the cross-sectional area of the bars which minimizes the total mass of the
structure, imposing constraints on nodal displacements and stresses. In order to solve
this optimization problem, it was developed a computational program on MATLAB®,
using the Interior Point method and the Sequential Quadratic Programming method,
the algorithms of which are available on Optimization Toolbox. It was included
routines for grouping the bars and to convert the optimal solution obtained using
continuous design variables in commercial values of structural hollow-sections. The
space truss nonlinear finite element is described by an updated Lagrangian
formulation. The implemented geometric nonlinear dynamic analysis procedure
combines Newmarks method with Newton-Raphson type iterations, being validated
by comparison with solutions available in the literature and with solutions obtained
using ANSYS® software. Examples of plane and space trusses under different dynamic
loading are solved using the developed computational program. The results show that:
the Sequential Quadratic Programming method is the most efficient to solve the
studied optimization problem, consideration of structural damping can lead to a
significant reduction in the total mass, the use of the conversion procedure for
commercial sections provides solutions in favor of security and the grouping of bars
generates a satisfactory duration for the optimization process.
