Analysis of Nonlinear Vibrations of Impact Dampers in Boats

Safety and comfort are two important aspects that should be considered in designing a good transportation system such as a high speed boat. One important thing that affects this consideration is the shock vibration when a wave impacts the boat. The shock vibration will induce great acceleration that could be felt by the boat crews. Moreover, in severe cases a crack could spread out at the bottom of the boat. Impact damper is a kind of vibration absorber which decreases unwanted vibration amplitude in a short time by using momentum exchange principle and energy dissipation. This paper studies the operation of an impact damper to attenuate the undesirable vibration of a boat by using the two variable expansion method. It aims at considering the effective factors on impact duration, coefficient of restitution and reducing the amplitude of vibration of the main mass by using the two variable expansion method. The results of analytical computations of this study are compared with other researches and confirm their findings; in addition, it shows that the two variable expansion method is accurate in solving nonlinear problems.