Over the last years the structural health monitoring (SHM) systems investigations have been focused on providing structures with similar functionality as the biological nervous system. There are numerous studies that have investigated this. In those studies a large number of sensors collects an extensive amount of data. In this study we demonstrate a novel effective SHM (eSHM) system which can monitor a structure with one single pressure sensor. The eSHM system can detect cracks by means of a system of capillaries integrated in a structure. This structure with the integrated capillaries can be produced by 3D printing, also known as additive manufacturing (AM). The principle of the eSHM system is monitoring the pressure variations in a network of capillaries. The effectiveness of this system is linked with the greatest strength of AM, which is the capability to create complex geometrical structures. Before the implementation in real structures, it is of crucial importance to be sure that the capillaries do not negatively influence the fatigue behaviour of the structures and the crack initiation. For this, the main objective of this study is to investigate different locations for a straight capillary incorporated into a four-point bending test specimen. The investigated titanium specimens with the integrated eSHM system are produced by AM. The capillary is located in the longitudinal dimension of the test specimen on the tension area of a four-point bending setup. We evaluate three different distances of the capillary to the outer surface of the test specimens. Furthermore, the results are also obtained by finite element simulations. We can conclude that –for the considered structure– the presence of the capillary does not influence the fatigue life negatively. On the other hand, cracks nucleate in the capillary region. Our future work will focus on the improvement of the capillary’s robustness. Other parameters like roughness effect and residual stresses should be also taken into account.
doi: 10.12783/SHM2015/22