20.500.12556/RUL-101436 Vpliv poliuretanske pene na dušenje nosilnih struktur The influence of polyurethane foam on the damping of beam structures V magistrski nalogi je predstavljen vpliv poliuretanske pene na dušenje nosilnih struktur. Raziskovalo se je, v kolikšni meri poliuretanska pena zmanjša amplitude nihanja cevnih jeklenih nosilcev. Najprej je predstavljen analitični izračun lastnih frekvenc nosilca po Euler-Bernoullijevi teoriji upogibnega nihanja nosilcev. Izbrani nosilec je cev kvadratnega prereza, ki je na eni strani fiksno vpet, na drugi strani pa ima prosti konec. V programu NX Nastran se je po metodi končnih elementov izvedla modalna analiza nosilca, pri kateri so rezultat lastne oblike in lastne frekvence nosilca s polnilom in brez polnila iz poliuretanske pene. Teoretično pridobljeni rezultati so se preverili še z eksperimentom. Nihanja preizkušancev s polnilom in brez polnila iz poliuretanske pene, so bila izmerjena s pospeškomerom ADXL377 in s hitrotekočo kamero Fastcam Photron Ultima 512. V rezultatih raziskave je predstavljen vpliv polnila iz poliuretanske pene na povečanje dušilnih karakteristik jeklenih cevnih nosilcev. V prilogi je dodan izpis analitičnega izračuna lastnih frekvenc nosilca po Euler-Bernoullijevi teoriji upogibnega nihanja nosilcev, ki je narejen v programu Mathematica. The master's thesis introduces the influence of polyurethane foam on the damping of beam structures. It was researched, how much polyurethane foam reduces the amplitudes of vibrations of tubular steel beams. At first is introduced an analytical calculation of the natural frequencies of the beam based on the Euler-Bernoulli theory of bending oscillation of the beams. The selected hollow square cross-section beam is fixed on one side and on the other side it has the free end. With the finite element method in the NX Nastran software is carried out the modal analysis of the beam that results are natural shapes and natural frequencies of beam with filling and without filling from polyurethane foam. Theoretically gained results were also checked with experiment. The vibrations that appear on prepared samples with filling and without filling from polyurethane foam, were measured out with an accelerometer ADXL377 and with the high speed camera Fastcam Photron Ultima 512. In results of research is presented influence of filling from polyurethane foam to increase damping characteristics of the tubular steel holder. In attachment is added the display of the analytical calculation of the natural frequencies according to the Euler-Bernoulli theory of bending oscillation of the beams, which is made in the Mathematica software. poliuretanska pena nosilec Euler-Bernoullijeva teorija modalna analiza metoda končnih elementov pospeškomer hitrotekoča kamera dušilna karakteristika polyurethane foam beam Euler-Bernoulli theory modal analysis finite element method accelerometer high speed camera damping characteristic true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2018-06-02 07:45:35 2018-06-02 07:45:37 2023-10-18 09:22:44 0000-00-00 00:00:00 2018 0 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 1970-01-01 204529 1711.pdf 1711.pdf 1 F763433C29A2CDEA98B953E16C79C0A5 99f2813e8ad37aad75ab85c62eac2b389f06091a2d5337ef9e14766af50023f8 436fc50f-a1b5-11eb-a523-00155dcfd717 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=111458 Fakulteta za strojništvo 0 0 0