Question

Required Information For a bolted assembly with six bolts, the stiffness of each bolt is kb - 24 Mibf/in and the stiffness of the members is km 13 Mlbflin per bolt. An external load of 80 kips is applied to the entire joint. Assume the load is equally distributed to all the bolts. It has been determined to use 1/2 in-13 UNC grade 8 bolts with rolled threads. Assume the bolts are preloaded to 75 percent of the proof load. Determine the yielding factor of safety. The yielding factor of safety is

Answer 1

0-1419 in) area Givers data :- External load applied (P) = so kips Bolt stiffness (Kb) = 2.4 Mebflin. Mensbes stiffress (km) 13 Milflin. Dianetes of bolte d) = {in-13 UNC Trade 8 Number of bolto (n) = 6 from standard table for unified screar threads UNC and UNF corresponding tensile storess (AL) Forom standard table she specifications for steel bolts for grade 8 obtained, Minimum proof strength (Sp) = 120 kpsi Minimum tensile stress oth (Sut) = 150 kpsi load Pes each bolt is written as P = 6 P= 13.333 Kips We know that The expression for Preload is given by 0.75 Sp AL 0.75 X 120 X 0.1419 Now, So kips Fi LL- IC 12.771 kip

C = C = C= stiffness constant i8 givers by Kb km tkb 2.4 13+ 2.4 0.15584 Now, the yielding factor of safety in Written by using the relation Sp X AL no CP + F 120 X 0.1419 ПР (0.15584% 13.333) +12.771 i8 np 10146758