The originality of this paper is in the presentation of the experimental results on tension splices in steel S690 with three or four bolts, positioned in the direction of loading. The tests were also numerically simulated to evaluate the stress and deformation state in the steel plates due to localized pressure of the bolts. It was shown that the distribution of forces between bots may be non-uniform and as such it is not included in any of the Eurocode rules. The results were compared to the Eurocode bearing resistance formula and it was proven that the bearing resistance is not properly defined and it also does not properly limit the bolt-hole deformation. Moreover, the unfavourable initial position of the bolts due to fabrication tolerances did not significantly affect the force distribution or the resistance. The new bearing resistance formula is also presented in the paper. The new formula is defined consistenly to the Eurocode and differs between failure types. It gives better results than Eurocode bearing resistance formula if compared to the test results.
COBISS.SI-ID: 5173345
The paper presents numerical simulations of flame straightening procces applied on a steel beam. The simulations are very complex due to difficult evaluation of the input parameters. The flame, that presents the thermal load, changes in space and in time, the material characteristics that are temperature dependent have to be defined, the boundary conditions should be correctly defined. Transient, fully coupled temperature-displacement, geometrically nonlinear problems were solved by state-of-the-art features in Abaqus finite element software. Even though the flame straightening process is demanding in terms of numerical simulation, the appropriate approach gives reasonable results. The presented numerical results explain the test performed in the framework of RFCS project OPTISTRAIGHT very well. The flame straightening was also simulated with a simplified numerical model, where the temperature as a boundary condition was prescribed instead of heat flux. The time of calculation was considerably shorter, but uniform increase of the temperature in the V heat does not explain the phenomena correctly. The local increase of temperature under the flame is crucial for the correct mechanical response of a steel beam. The simplified analyses were used for the derivation of an analytical method based on the uniform temperature field. Such method is presented in the final report of the RFCS project OPTISTRAIGHT in a form for the application in the workshop.
COBISS.SI-ID: 5700961