Dynamic analysis of stiffened Plated Structures Under Moving Forces and Masses

Abstract

Dynamic analysis of structures under moving forces and masses has been one of the most important challenges for engineers during the last few years. The vast application of this time-varying position of forces and masses in many fields of industry has intensified the importance of evaluating the dynamic response of vibrant structures under moving loads. Hence in the present work, the dynamic behavior of rectangular and curved stiffened plated structures are studied. The free vibration and dynamic response analyses of bare and stiffened plates under moving forces and masses are carried out using the finite element method. The stiffened plates depending on their use, accommodate various stiffeners that are placed either concentrically or eccentrically. The stiffener’s orientation in a particular direction is important because of its strength contribution to the plate. Moreover, the stiffener’s size and shape play a crucial role in strengthening the plates keeping the structure’s weight low. All these parameters – stiffener’s disposition, orientation, size, shape, and type contribute productively to the dynamic analysis of the stiffened plates with much significance. Hence, a parametric study for the free vibration characteristics of stiffened plates having various boundary conditions and considering all the above parameters is carried out. The dynamic responses of stiffened plates subjected to moving forces and masses are also investigated using the Newmark integration method. The displacements, velocities and accelerations for each time interval are computed using this approach. The influence of single or multiple moving forces and masses travelling on the plate in a straight or arbitrary path is also reported. An isoparametric quadratic plate bending element with shear deformation is considered to accomplish this task. The plate and stiffener’s stiffness and mass matrices are developed separately and assembled to form the entire structure’s global matrices. A finite element based MATLAB code is established to offer an efficient solution to these analyses. The results are validated with the published ones and the FEAST (Finite Element Analysis of STructures) software solution wherever possible to show the present method’s efficacy. Various numerical examples of unstiffened and stiffened rectangular and curved plates and bridge decks with concentric and eccentric stiffeners for different boundary conditions are presented to show the formulation’s versatility. Some new results obtained by the proposed method are also presented.