The subject of the invention is the method for determining additional mechanical loads of transmission power line conductor on the basis of monitoring the change in the angle of inclination of the conductor and the measurements of conductor temperature or, more specifically, the algorithm for numerical iterative calculation of the geometry of the conductor catenary due to the change in the tensile force, depending on the conductor temperature and on the change in the inclination angle in the area of attachment of the conductor. Furthermore, the method that, in addition to the calculation of tensile forces in the conductor and of the inclination of the conductor, enables also the determination of the value of the additional load of the conductor due to ice or a fallen tree on the basis of the recorded catenary geometry, depending on the current conductor temperature, the inclination of the conductor and the weather conditions at the location of the tramission power line. The technical problem solved by this invention is such a method for determining additional mechanical loads of a transmission power line conductor that will enable the calculation of forces in the conductor and of the sagging of the conductor at an optional point of span between two transmission power line towers, depending on the change in temperature. Also it will enable the control of a safe clearance distance, the calculation of tensile forces at the spot of attachment of the conductor to a console on the tower, furthermore, monitoring of the conductor geometry and of tensile forces in the conductor and determination of input data to define the time of melting of ice on the conductor. In addition, it will ensure safe operation of the transmission power line and monitoring of additional tensile forces in the conductor.
F.33 Slovenian patent
COBISS.SI-ID: 20704534Structure integrity assessment of pipeline requires limit load solutions for variety of crack depth in order to predict loading capacity of pipeline or resistance to crack growth and initiation. Standard fracture toughness testing of thin walled pipeline is often difficult to perform in order to complete standard requirements. Therefore, the new simple pipe-ring specimen for fracture toughness testing has been proposed. In order to determine normalized fracture toughness of pipe-ring specimens the limit load is necessary to determine. The limit load is influenced by geometry of specimen and loading manner. The limit load assumed load when ligament at the deepest point of crack is fully yielded. The ligament yielding of pipe-ring specimens containing through thickness axial crack under combined loads is going to be calculated by the finite element method. In order to provide limit load expressions the finite elements analyses and compared with experimental results, what shows good agreement.
B.05 Guest lecturer at an institute/university
COBISS.SI-ID: 20288278Fatigue behaviour of structural components depends on material's conditions at the end of thermomechanical treatment. During manufacturing process the physical and mechanical properties are different than delivered materials. Metastable stainless austenitic steel AISI 316L is widely using in chemical and processing industry. Bending process the billet is partly deformed to tension and compression where compress-tension residual stresses remain. During combined fatigue tensile-bending loading the process of martensitic transformation continued and residual stress distribution is rearranged. It caused change of stress loading amplitude and loading ratio, too. Aim of paper is presented model for determination stress loading amplitude in order to create S-N curve and determine fatigue limit of pre-deformed component.
B.05 Guest lecturer at an institute/university
COBISS.SI-ID: 21803542The OTLM-SMART system calculates the tensile forces in the conductor as well the angle and compare calculated values with measurement of the conductor temperature. Applying thus features, it is possible use as well for estimating the additional weight on the conductor due to ice, wet snow or foreign bodies (e.g. fallen trees or objects…). Combined with weather condition it is possible to estimate the cause of the additional weight. The added weight causes interior forces responsible for permanent elongation of the conductor. On the basis of laboratory measurements for determining this permanent elongation for specific conductor types it is possible to estimate the elongation of the power line and the new sag height. The OTLM system of online monitoring sends the data to the OTLM centre, which actually calculates the individual sag heights for critical sections along the power line, and for every span. The results of these calculations give guidance for additional courses of action, such a re-mounted conductor by shorting length and increasing conductor’s tensile force. Laboratory testing of fatigue life limit is going to provide maximum allowed strain of specific conductor. Comparison between laboratory conductor cyclic testing results and tensile behaviour of conductor on transmission line is going to provide condition of conductor and his life limit.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 20562198The research showed that the main reason for the formation of cracks on the axis is the residual stresses, which, by taking into account regular operating voltages, exceed the permanently dynamic strength of the material. Accordingly, we propose that a non-contactless contactless measurement of residual stresses (eg with the Rentgen method) is carried out regularly in the area of transition of the axis between the bearing surface of the monoblock hub and the smaller diameter of the axle of the freight wagon. Measurement of residual stresses must be carried out on the new axes prior to commissioning, and also after the auditory mounting of the monoblock hub on the supporting surface of the axis, where the measured tensions can only be in the range of the torsional stress on the axis, as shown by numerical simulations. In the event that the residual tensile stresses are high and exceed the value of + 40 MPa in the axial direction, measures must be taken to reduce them.
F.30 Professional assessment of the situation
COBISS.SI-ID: 21172502