(Solved): 1- In a bolted assembly, two steel members having different thicknesses are clamped together.The ste ...

****In a bolted assembly, two steel members having different thicknesses are clamped together. The steel washers having \( 3 \mathrm{~mm} \) thickness are used under the bolt heads. The thicknesses of the members are \( 32 \mathrm{~mm} \) and \( 38 \mathrm{~mm} \). The steel bolt has a length of \( 88 \mathrm{~mm} \) and its specification is M16x2 ISO 9.8. A fluctuating external load is applied to the entire joint with \( P_{\max }=450 \mathrm{kN} \) and \( \mathrm{P}_{\min }=125 \mathrm{kN} \). a) Calculate the minimum number of bolts necessary to avoid joint separation. b) In the same bolted assembly, assume 15 bolts are used and calculate the fatigue factor of safety using the Goodman theory. Given Data for the problem: -Elasticity modulus of steel is \( 207 \mathrm{GPa} \). -Applied preload is 75 percent of the proof load \( \left(\mathrm{F}_{i}=0.75 \mathrm{~F}_{\mathrm{p}}\right) \) and \( \mathrm{F}_{\mathrm{p}}=\mathrm{A}_{\mathrm{t}} \cdot \mathrm{S}_{\mathrm{p}} \) -Take \( \mathrm{S}_{\mathrm{c}} \) (Endurance strength) of bolt as \( 332 \mathrm{MPa} \). - \( S_{\mathrm{p}} \) (proof strength), \( S_{u t} \) (ultimate tensile strength), \( A_{t} \) (tensile stress area) of bolt should be found from the corresponding tables in the textbook. The bolt material grade is ISO \( 9.8 \). ****Explain self-locking condition and determine the roles of lead angle and friction coefficient in self-locking.