Estimation of measuring uncertenty for results of static tensile testing

U teoretskom dijelu rada opisan je postupak statičkog vlačnog ispitivanja prema normi HRN EN ISO 6892-1:2009. U drugom poglavlju opisani su zahtjevi za dimenzije i oblik ispitnih uzoraka, brzine ispitivanja, parametri ispitivanja i popis pojmova te njihove definicije. U trećem poglavlju opisana je metoda procjene mjerne nesigurnosti koja je potrebna kako bi se rezultati dobiveni ispitivanjem mogli usporediti s rezultatima dobivenim u drugim laboratorijima. U eksperimentalnom dijelu provedena su statička vlačna ispitivanja na ispitnim uzorcima od istog čelika u dva različita laboratorija. Jedno ispitivanje provedeno je u Laboratoriju za ispitivanje mehaničkih svojstava FSB-a, drugo u tvrtki ZIT d.o.o. Oprema za ispitivanje u laboratorijima bila je različite mjerne sposobnosti, a okolišni uvjeti su bili slični. Nakon ispitivanja provedena je analiza dobivenih rezultata i provedena je procjena mjerne nesigurnosti. Na temelju analize dobivenih rezultata doneseni su određeni zaključci.In this paper the procedure of tensile testing is described according to HRN EN ISO 6892-1:2009. Requirements for dimensions and shape of test pieces, testing speeds, testing parameters and a list of terms and definitions are given. In third chapter a method for estimation of measurement uncertainty is described, so testing results could be compared between different laboratories. In experimental part of the paper tensile testing was conducted, on steel test pieces in two different laboratories. First tensile test was done in Laboratory for mechanical properties testing at Faculty of Mechanical Engineering and Naval Architecture. Second test was done at the firm ZIT d.o.o. Testing equipment in laboratories had different measurement capabilities, but testing conditions were similar. After testing, an analysis of the results was conducted and estimation of measurement uncertainty was evaluated. In the last part of the paper comments and conclusions for obtained experimental results were given