tailieunhanh - Dynamic characteristics of elastically supported beam subjected to a compressive axial force and a moving load

This paper discusses the dynamic characteristics of an elastically supported Euler-Bernoulli beam subjected to an initially loaded compressive force and a moving point load. The eccentricity of the axial force is taken into consideration. The timehistories for beam deflection and the dynamic magnification factors are computed by using the Galerkin finite element method and the implicit Newmark method. | Vietnam Journal of Mechanics, VAST, Vol. 33, No. 2 (2011), pp. 113 – 131 DYNAMIC CHARACTERISTICS OF ELASTICALLY SUPPORTED BEAM SUBJECTED TO A COMPRESSIVE AXIAL FORCE AND A MOVING LOAD 2 Nguyen Dinh Kien1 , Le Thi Ha2 1 Institute of Mechanics Hanoi University of Transport and Communication Abstract. This paper discusses the dynamic characteristics of an elastically supported Euler-Bernoulli beam subjected to an initially loaded compressive force and a moving point load. The eccentricity of the axial force is taken into consideration. The timehistories for beam deflection and the dynamic magnification factors are computed by using the Galerkin finite element method and the implicit Newmark method. The effects of decelerated and accelerated motions on the dynamic characteristics are also examined. The influence of the axial force, eccentricity and the moving load parameters on the dynamic characteristics of the beams is investigated and highlighted. Keywords: Elastically supported beam, axial force, moving load, Newmark method, dynamic factor. 1. INTRODUCTION Many structures in practice are subjected to moving loads. Railways, runways, bridges, overhead cranes are typical examples of such structures. Different from other dynamic loads, the position of moving loads varies with time, and this characteristic makes moving load problems a special topic in structural dynamics. Analysis of the moving load problems by using an analytical or a numerical method, thus requires techniques different from that of the conventional dynamic problems. A large number of researches on moving load problems has been performed. The early and excellent reference is the monograph of Frýba [1], in which a number of closedform solutions for the moving load problems has been developed by using the Fourier and Laplace transforms. Following the same approach employed by Frýba, in recent years a number of investigations on beams subjected to moving loads has been carried out. AbuHilal et al. .