Kargarnovin - Professor, Sharif University of Technology, Tehran, Iran
Saeedi - Graduate Student, Sharif University of Technology, Tehran, Iran

In this paper dynamic response of an Euler-Bernoullibeam with a constant cross section, finite length and specified support conditions on an intermittent elastic foundation under the influence of a moving force has been studied using modal analysis technique. It is assumed that the beam is at rest when the moving force starts its motion over the structure. It is further assumed that the force will be in full contact with the beam during its motion, i.e. no separation occurs and moving force velocity is constant. The present analysis in its general form may well be applied to beams on any kind of non-uniform foundation. However, the results from the computer simulation model given in this paper are for beams on intermittent foundation. It should be noted that intermittent elastic foundation leads to changes in the stiffness of system along the length of the beam and influences the natural frequencies and mode shapes. Taking into account the effect of foundation new eigenfunctions are obtained. The obtained results from this study such as natural frequencies, shear force and bending moment distributions are compared with those obtained by conventional method. It is shown that our developed method yields to more accurate results.

elastic foundation، modal analysis، Euler-Bernoulli beam، moving force