Modelling of smart structures

摘要

The interest in smart structures has steadily increased during the last 20 years. The reason for this success is that this new generation of structural systems shows special functionalities: sensing, actuation, shape morphing, health monitoring, vibration control. Indeed, smart structures are able to develop special stiffness and strength characteristics not otherwise generally shown in materials. For various purposes, smart materials are used in the realisation of smart structures. The constitutive behaviour of these materials couples their mechanical response (stress and strain) with other physical fields. In this way a mechanical stimulus can be transformed into a non-mechanical effect and, conversely, a non-mechanical stimulus can be converted into a mechanical effect. This is what happens in piezoelectric materials, where the electric behaviour is coupled with the mechanical one due to the direct and converse piezoelectric effect. This effect enables the material to behave as an actuator or a sensor. Other examples of smart materials include magnetostrictive materials, shape memory alloys, elec-trorheological and magnetorheological fluids. The coupled behaviour of smart materials can also be viewed as energy transduction between different physical fields (e.g. elastic and kinetic energy transformed into electrostatic energy or vice versa). For this reason smart structures are a typical example of a mechanical system governed by a multi-physics behaviour.