Vibrations are a part of our environment and daily life. Many of them are useful and are needed for many purposes, one of the best example being the hearing system. Nevertheless, vibrations are often undesirable and have to be suppressed or reduced, as they may be harmful to structures by generating damages (possibly leading to dramatic and spectacular accidents such as the case of the Aloha 243 fl ight or the bridge of Tacoma Narrows) or compromise the comfort of users through noise generation of mechanical wave transmission to the body
