THE FORMATION OF VISCOUS DAMPING MATRICES FOR DYNAMIC ANALYSIS OF MDOF SYSTEMS

The paper deals with the representation of dissipative effects by mean s of equivalent viscous forces. A brief review of the classical analyt ical treatment of the subject is first presented devoting particular a ttention to the topics of hysteretic and modal damping. The problem of forming viscous matrices in the case of systems which are non-homogen eous from the point of view of dissipation is then addressed; soil-str ucture systems are first considered and some accepted techniques for f orming the structure contribution to the viscous matrix are reviewed. A different technique is then proposed which avoids some of the drawba cks of the previously quoted methods. In the final section of the pape r it is shown how this technique is easily applicable also in the case of systems having internal concentrated dampers of viscous type, this being a situation which is difficult to tackle with usual criteria.