Components and structures exposed to elastic dynamic loading respond with elastic strains on the surface of the material. Mechanical response could be monitored by deformations on the surface. The measurements and monitoring of these parameters could be performed with electronic devices for on-line measurements, controlled by computerized systems. Fatigue induced flaw growth was monitored on a 4-point specimen, loaded by cyclic dynamic bend forces. The flaw growth was monitored by strain gauges with standard resistance of 120Ω. After performance of fractal-graphical measurements, a flaw growth analysis was performed to determine the shape, propagation and cross sections of the crack. To determine the stress intensity factor a FEM model was developed based on measured crack shapes and material properties and cyclic loading data of the actual tested specimen. The investigation results showed that derived calibration curve could be used to predict surface deformations as a result of crack propagation and growth. With the determination of surface deformation, one could follow propagation of the crack on the surface and also propagation through the depth of the material. The goal of this paper is to describe methodology and results based on experimental and FME methods during crack propagation and potential use of this technique for online monitoring purposes.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 17811734Slovenian transmission grid operator ELES is trying in last decade to design and develp sofisticated electric tansmission system. ELES introduces relaible system for controling and maintance of transmission system with modern solutions and inovative approaches. The new pilot projects are running on facilities for testing and real high voltage transmission grid network as results of collaboration between academic institutions, industrial companies and ELES. One project is aimed to analysis of efficiency system for on-line thermal rating, weather conditions and calculation of allowed thermal current. Since last winter had significant impact on failure of 110, 220 and 400 kV electricity transmissions grid, the Slovenian ELES company looking for possibility of on-line monitoring including ice alarm. Proposed computer added software in OTLM system can provide horizontal forces change vs. Temperature and incline of line in frame of regular operating conditions and in case of ice as well. Final goal of presented project is on-time worrying of distribution center about ice on the transmission network system.
B.03 Paper at an international scientific conference
COBISS.SI-ID: 18258198