Estudo teorico-experimental do comportamento dinamico de telhas de aço trapezoidais formadas a frio

Abstract

Cold-formed steel roofing sheets are applied over closings and coverings with several types of engineering structures. The connection between the structure and the sheets are often carried out through fixing purlins. The fixation between the sheets is normally done by using simple overlapping of the adjacent longitudinal edges, but it can also be done by means of rivets. Several times, it becomes dificult to evaluate the influence of the boundary conditions on the stiffness of these system types. For this reason, in the present work, the assessment of structural performance of trapezoidal steel roofing sheets regarding different boundary conditions has been carried out. In order to reach this aim, the natural frequencies and associated vibration modes for each studied case have been evaluated. A theoretical and experimental study has been developed to prove that the dynamical properties of the sheets can allow us to describe their structural behaviour. The theoretical model has been carried out by using the Finite Element Method. The comparison between theoretical and experimental results in terms of natural frequencies and eigenmodes associated with them has made it possible to calibrate the finite element models. A detailed analysis of different boundary conditions cases has permitted to arrive at some conclusions about the sheets characteristics, for example: the fixing of the sheets longitudinal edges does not affect its global stiffness, and the restriction level of the sheets edges directly determines the stiffness in some specific regions of the sheets. Discussion on the obtained results and conclusions are then presented. DYNAMIC BEHAVIOUR OF COLD-FORMED TRAPEZOIDAL STEEL ROOFING SHEETS: EXPERIMENTAL AND THEORETICAL ANALYSIS.

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