The flexibility of steel hollow tubular sections subjected to thermal and mechanical loads

Numerical analysis of hollow tubular sections is used as a starting tool to establish the reliability assessment of these elements when mechanically or thermally loaded. To quantify the material deformation behaviour of these elements resulting from ground motion, crack propagation, effects from high temperatures, theoretical and experiments analyses can be used for testing a service reliable guarantee. Structural hollow sections have excellent static properties, not only with regard to buckling and torsion, but also in the overall design of members. They can offer economic advantages compared to open sections. It is possible to change the strength by varying the wall thickness or filling the section with other material without changing the external geometry. Flexibility is an important parameter in hollow tubular systems when subjected to thermal or mechanical loads. This work presents a numerical analysis technique based on the finite element method for thermal and mechanical nonlinear behaviour. Temperature field will be calculated according to non-steady conditions when submitted to standard ISO834 and non-linear material properties foreseen in Eurocode standards (EC1 and EC3). This work will present a complete study of the flexibility analysis for a wide range of pipe dimensions, and the obtained results are then compared with design rules.temperature, equivalent stress, tubular section, flexibilit