Experimental and Numerical Study of a Geodesic Dome Under Static and Dynamic Loads and the Influence of Nodal Connections

Geodesic domes are 3D reticulated structures used to cover large areas. As lightweight structures, they are sensible for dynamic effects. The structural behaviour of domes is affected by the kind of connections between their members. Semi -rigid joints produce loss of stiffness compared with rigid joints. Dynamic tests may capture the effect of semi-rigid joints. The objective of this work is to conduct both static and dynamic tests on a Geodesic Dome at the laboratory scale and compare the results with a linear elastic FE model. The research method involved designing, building and testing a prototype constructed of aluminum wit h overall dimensions of 2000 mm in diameter and 800 mm in height. A 3D finite element model was developed using beam and shell elements. Experimental and numerical results were compared in terms of displacements and frequencies. Load—displacement curves are presented for the static loading. The dynamic behaviour is evaluated by hitting an impact hammer on members and nodes to allow measurement of accelerations. An FFT technique is used to determine the frequency spectrum. The results show that the laboratory prototype presented about 20% less stiffness than predicted by the linear elastic numerical model. The difference is attributed to the transmissibility condition between nodal connectors and emphasizes the influence of semi-rigid joints. Despite being largely used to assess dome structures, standard FE models are shown to be insufficient in capturing local non-linearities.