Influence of shock impulse characteristics on vibration control using nonlinear fluid viscous dampers

Abstract

Energy dissipating damping devices such as fluid viscous dampers (FVDs) often have applications in shock vibration control of structural and mechanical systems. Nonlinear FVDs are more suitable compared to the linear FVDs for applications where large force and velocities are exerted, such as in structures subjected to shock excitations. This paper discusses the influence of shock impulse characteristics on vibration control of a single-degree-of-freedom system with linear and nonlinear fluid viscous dampers for three types of shock excitation profile, viz. half-cycle sine, initial-peak saw tooth and rectangular. The following response parameters have been considered: (1) maximum acceleration of the structure, (2) maximum displacement of the structure, and (3) time required for attenuation of response below a specified threshold. An approximation based on the concept of equal energy dissipation to determine the response of the structure with nonlinear fluid viscous dampers subjected to shock excitation has been proposed. The paper also presents non-dimensional design charts for above shock pulses for linear and nonlinear fluid viscous dampers, which can be used for preliminary decision on damper parameters to be used in design.