DYNAMIC ANALYSIS OF STRUCTURES SUPPORTING A MOVING MASS, EXPOSED TO EXTERNAL AND INTERNAL DAMPING

Abstract

In the dynamic analysis of structures supporting a moving load, for the sake of simplifi- cation, the mass either of the moving load or the supporting structures is neglected. In earlier papers, examples for reckoning with the timely variation of the mass are found only for simple structures. It is well known that dynamic stress values are influenced by exter- nal and internal damping. Their combined effects are only reckoned with in free vibration and in exciting by harmonic forces, in cases where the dynamic system has a constant mass matrix. There is an adequate numerical method for the analysis of structures with several degrees of freedom, with permanent mass matrix, under external damping. An algorithm has been presented in this paper for the analysis of dynamic excess displace- ments of structures, for cases both the effects of moving mass and of internal friction have to be reckoned with. The developed algorithm and numerical method have been tested on examples. The mentioned factors showed important effects, justifying to be reckoned with in the analysis of real structures.