CONTRIBUTIONS TO THE DEVELOPMENT OF ELEMENTAL VISCOUS DAMPING MODELS

The aim of this paper is to provide insight into the response of structures modelled with a new elemental viscous damping model. The elemental viscous damping model developed in this study uses the element deformation mode shapes and frequencies to construct a damping matrix for each individual beam or column element. These elemental viscous damping matrices can be used to directly calculate member damping forces or, combined using the direct stiffness method to obtain a global viscous damping matrix. In particular, this study investigates: (1) what relationship exists between the level of viscous damping specified at the element level and the observed global viscous damping ratio for single and multi-storey frames; (2) how damping assigned to different elements affects the observed global viscous damping ratio, and; (3) how variations in the beam/column stiffness affect the observed global viscous damping ratio. Linear free vibration analysis was used to investigate the relationship between the elemental viscous damping factor and the global viscous damping ratio. Three different elemental viscous damping configurations were considered; (1) beam element viscous damping only; (2) column element viscous damping only, and; (3) beam and column viscous damping. This study highlighted that the relationship between elemental viscous damping and the observed damping ratio is complex and is affected by a variety of different variables.