Untitled in english

Author(s)

Wilfredo Montealegre Rubio

• Document type: Master's Dissertation
• Press: São Paulo. , ilustrações.
• Institution: Universidade de São Paulo (USP). Escola Politécnica (EP/BC)
• Defense date: 2005-09-30

Examining board members

Emilio Carlos Nelli Silva; Ricardo Cury Ibrahim; Renato Pavanello

• Advisor: Emilio Carlos Nelli Silva
• Field of knowledge: Engineering - Mechanical Engineering
• Indexed in: Banco de Dados Bibliográficos da USP-DEDALUS; Biblioteca Digital de Teses e Dissertações - USP
• Location: Universidade de São Paulo. Biblioteca Central da Escola Politécnica; EPBC/FD-4159; Universidade de São Paulo. Escola Politécnica. Biblioteca de Engenharia Mecânica, Naval e Oceânica; EPMN/FD-4159

Abstract

MEMS are MicroElectroMechanical Systems designed in micrometric scale. A very common type of MEMS are the electrothermomechanical MEMS, which couples electrical, thermal and mechanical field to generate displacements. In these MEMS an electrical current is converted to heat by Joule effect and the heat causes thermal strain, which in turn causes structural deformation. Electrothermomechanical MEMS are designed as compliant mechanisms; they attain their mobility from flexibility of their structure as opposed to rigid body structure that attains their mobility from hinges, bearings and sliders. Design of electrothermomechanical MEMS is not an easy task to be accomplished by using trial and error methods; therefore, in this work Topology Optimization Method (TOM) is applied, which combines optimization algorithms with Finite Element Method to design the best structure topology, distributing the material in the interior of a fixed domain according to cost criteria. In electrothermomechanical MEMS, this cost criteria consists of maximizing the output displacement, with the least weight, when an electric potential is applied to the structure. The main goal of this work is to design electrothermomechanical MEMS using the Topology Optimization Method. A material model based on the traditional SIMP model is adopted and the optimization algorithm is constructed based on sequential linear programming (SLP). A filtering technique is applied to control the meshdependency and the checkerboard problem. An alternative way is applied to control the checkerboard problem: TOM based on the method of continuous approximation of material distribution - CAMD. Several examples of optimized two-dimensional electrothermomechanical MEMS are included. In addition, the influence of different values of optimization parameters upon the final topology is discussed. (AU)