hread; d0 - diameter of test piece (d0 < small diameter of external thread); b - threaded length (b>d);lo- 5 do or 5.65 );Рlc - length of straight portion= (lo + do); lt - total length of test piece =(lc + 2R + a+b); li, = final gauge length; F0 - cross-section area;РR - fillet radius (R >4 mm);Рa > 0Р8.2 Tensile test for full-size bolts, screws and studsРThe test is carried out for the purpose of determining the tensile strength of fasteners. Its method is the same with the one for machined test pieces. The calculation of the tensile strength is based on the nominal stress area.РThread stress area:РWhere:Рd 2 = medium diameter of external thread, mm;Рd 3 = calculated diameter of thread = d 1 – H/6, mm;Рd 1 = small diameter of external thread, mm;РH =height of thread original triangle, mm.
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