1270 KB50 KB199920252016Boltežar, MihaČesnik, MartinSlavič, Jankoletnik:62številka:nr. 7/8str. 471-482ISSN:0039-2480COBISSID_HOST:14742043URN:URN:NBN:SI:doc-NL9YHIY1enZveza strojnih inženirjev in tehnikov Slovenije etc.Strojniški vestnikfrekvenčne števne metodenaključno kinematsko vzbujanjeparametri utrujanjapreizkus vibracijskega utrujanjaAssessment of the fatigue parameters from random vibration testing| application to a rivet joint|In order to estimate a structure's fatigue life when excited with an acceleration profile the fatigue parameters must be known. However, material's fatigue exponent and fatigue strength are not always readily available, especially for complex structures that include riveted or welded joints for which additional fatigue tests are needed. This study introduces a new fatigue-parameter assessment method based on random vibration loading and its application to a blind-hole rivet joint that diminishes the need for additional fatigue tests. The presented procedure requires a simple experimental setup; however, a more extensive analysis of the experimental results is necessary. The method of fatigue parameter assessment is presented and applied on real, experimentally obtained data from vibration tests of rivet-joint specimens, excited with a random base-vibration load in the frequency range of a single natural frequency. Special attention was given to the modelling of the rivet joint and the uncertainties arising from the riveting process were considered. With the presented procedure it is possible to obtain the fatigue parameters solely from the results of random-vibration testing with different acceleration profiles and therefore diminishing the need for additional classic fatigue tests. The obtained fatigue parameters indirectly include the stress concentration factor and the damping-loss- factor increase during the damage accumulation. Additionally, by applying the random-vibration load the influences of the natural-frequency shift and the small nonlinearities of the structure are reduced, which can present a major issue in classic harmonic-vibration fatigue testingVibracijsko utrujanje dinamske strukture je, poleg neželenega pojava prekomernih vibracij in hrupa, poglavitni razlog za izvajanje numeričnih in eksperimentalnih dinamskih analiz izdelka. Dinamski odziv sistema vnese v izdelek določeno napetostno stanje; v primeru neugodnih dinamskih lastnosti izdelka lahko že nizke vibracijske obremenitve hitro privedejo do odpovedi izdelka zaradi utrujanja materiala. Eksperimentalno preverjanje ustreznosti izdelka je ustaljen postopek vibracijskega testiranja prototipov, v zadnjem času pa se veliko raziskovalnega dela usmerja v numerično analizo vibracijskega utrujanja. Namen predstavljene raziskave je vzpostavitev metodologije, ki bo na podlagi eksperimentalnih rezultatov vibracijskih preizkusov omogočila pridobitev parametrov utrujanja za obravnavano strukturo oziroma materialTEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaUniverza v Ljubljani, Fakulteta za strojništvo