Numerical analysis of dynamic response of gravels

V želji po zagotovitvi večje prometne varnosti udeležencev v prometu se klasične izvozno-uvozne priključke zamenjuje z izletnimi conami. V diplomskem delu smo preverili, če in kako različna velikost delcev sipkega material vpliva na zaustavitev krogle pri trku z njimi. V programskem paketu LS-DYNA smo naredili numerični model, s katerim smo simulirali padanje ter zaustavljanje krogle v sipkem materialu. Simulacije smo opravili pri treh različnih velikostih delcev in treh različnih začetnih hitrostih krogle. Na podlagi tako dobljenih rezultatov smo ugotovili, da pri nižjih hitrostih velikost delcev pomembno vpliva na pot, ki jo pri zaustavljanju opravi krogla, medtem ko se s povečevanjem hitrosti krogle vpliv velikosti delcev zmanjšuje. Najboljše rezultate smo dobili z uporabo delcev, katerih premer znaša 25 mm.In order to ensure higher road safety for road users when joining and leaving highway, traditional metal fence protected junctions, are replaced with run-off areas. During the diploma we analyse if and how different particle size of gravel influence stopping distance of ball when colliding with them. Numerical model to simulate stopping ball, was made in computer software LS-DYNA. Simulations were made on three different gravel grain sizes and with three different initial ball velocity. Based on results we obtain this way, we found that at lower speed particle size influences the ball stopping distance significantly, while the difference decreases with increasing ball speed. Best results were obtained using particles with a diameter of 25 mm