This article details the experimental and numerical results on the energy absorption performance of square tubular profile with circular discontinuities drilled at lengthwise in the structure. A straight profile pattern was utilized to compare the absorption of energy between the ones with discontinuities under quasi-static loads. The collapse mode and energy absorption conditions were modified by circular holes. The holes were drilled symmetrically in two walls and located in three different positions along of profile length. The results showed a better performance on energy absorption for the circular discontinuities located in middle height. With respect to a profile without holes, a maximum increase of 7% in energy absorption capacity was obtained experimentally. Also, the numerical simulation confirmed that the implementation of circular discontinuities can reduce the peak load (P max ) by 10%. A present analysis has been conducted to compare numerical results obtained by means of the finite element method with the experimental data captured by using the testing machine. Finally the discrete model of the tube with and without geometrical discontinuities presents very good agreements with the experimental results.

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In this paper, mathematical descriptions of the static and dynamic behaviour of the bladed disc with the undamaged and damaged lacing wire are briefly explained. For a steam turbine disc with 70 axial blades coupled by the lacing wire, the centrifugal static analysis is performed. Then, the free and forced vibrations are computed to find differences in vibrations of the bladed disc with and without a failure in the lacing wire. The tip timing measurement is considered as an experimental tool for identifications of possible failures. According to the obtained FE results, a failure of the lacing wire in the rotating disc assembly can be identified by monitoring the centrifugal deformations of the blade tips, resonance frequencies and response amplitudes of the whole bladed disc. The dynamic behaviours of the failure-free disc and with cracked wire connection are compared to each other to outline differences in the known nodal diameter and dispersion curve definition.

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