Modelagem por elementos finitos de sistemas dinâmicos combinando materiais viscoelásticos e materiais com memória de forma para o controle passivo de vibrações e ruído

Abstract

It is widely known that the damping mechanisms of most traditional damping materials applied as passive control of vibrations such as elastomers are highly dependent upon environmental and operational parameters such as the excitation frequency and temperature. Regarding this later, variations due to the self-heating phenomenon can jeopardize the damping capability in critical systems, which lead to the requirement of conceiving damping systems with the desired effectiveness at higher temperatures. Shape memory alloys present potential advantages over the traditional elastomers due to their large pseudoelastic hysteresis loop in stress-strain relationship and it can be used as damping material and structural elements in various engineering applications. In this work, a time-domain modeling procedure of structures containing viscoelastic materials and shape memory alloys is addressed. The main goal is the development of methodology based on FEM, implemented in Matlab, in order to perform the analysis of engineering structures treated by passive constraining damping layers and pseudoelastic shape memory alloy wires for passive damping augmentation. Since the mechanical properties of viscoelastic materials are frequency- and temperature-dependent, a four-parameter fractional derivative model has been retained. To model the hysteresis response of the shape memory alloy, a suitable phenomenological simplified model for performing the parametric study of such dynamic system has been used. After the discussion of various theoretical aspects, the time-domain responses are calculated for a three-layer sandwich beam containing viscoelastic materials and shape memory alloy wires and the main features of the methodology are highlighted.