DYNAMIC ANALYSIS OF RECTANGULAR-PLATES WITH STEPPED THICKNESS SUBJECTED TO MOVING LOADS INCLUDING ADDITIONAL MASS

This paper presents a simplified analytical method for rectangular pla tes with arbitrarily- and eccentrically-stepped thickness, such as bui lding slabs, subjected to moving loads, including the effect of the ad ditional mass. The discontinuous variation of the bending stiffness an d mass of the plate due to the variation of the thickness can be expre ssed continuously by means of a characteristic function, which is defi ned as a Dirac function existing continuously in a prescribed region, as proposed by the author's previous work. Since the bending stiffness used here is given exactly by the actual bending stiffness at each po int, a modification of the bending stiffness used in an equivalent pla te analogy is unnecessary. It is clarified from numerical computations that the effect of the additional mass due to moving loads is signifi cant for heavy-weight additional mass but is negligible for usual addi tional mass with 65 kg. Then, approximate but accurate solutions for a current plate subjected to stationary and moving loads are proposed b y excluding the effect of additional mass. The numerical results obtai ned from the proposed theory for simply-supported and clamped plates w ith stepped thickness, excluding the effect of additional mass, show g ood agreement with results obtained from the finite element method usi ng FEM code NASTRAN.