Vibration and acoustic requirements are becoming increasingly important in the design of mechanical structures. The need to vary the structural behaviour to solve noise and vibration problems occurs at design or prototype stage, giving rise to the so-called structural modification problem. Structural dynamic modification (SDM) as an application of modal analysis is a technique to study the effect of physical and geometrical parameter changes of a structural system on its dynamic properties which are mainly in the forms of natural frequencies and mode shapes. The fundamental approaches and formulations to SDM of vibrating systems are introduced. The changes of dynamical behaviour of a structure by modification of mass, damping and stiffness parameters of the structure are presented. The SDM of the real engineering structures is demonstrated. For these structures, it is more important to determine the structural modification in terms of physical and geometrical parameter changes related to mass, damping and stiffness parameters of vibrating structure. In this paper, the design and technological treatments are considered to achieve suitable vibration and acoustical properties of vibrating system. The modal properties of selected structures under physical parameters modification are studied.
structural dynamic modification, modal analysis, damping, natural frequency, mode shape