Question

the cantilevered tube shown in fig 5-17 is to be made of 2014 aluminium alloy treated to obtain a specified minimum yield strength of 276MPa. we wish to select a stock size tube from table A-8 using a design factor nd=4. the bending load is F=1.75kN , the axial tension is P=9kN and torsion T=72Nm. What is the realized factor safety?

Answer 1

to be at the The maximum Stress will be expected fixed support of cantilevered tube: Hence, the internal loading at the fixed support can be shown m figure below: F T 120 mm Efn=0,N=P Efy = 0, V-F & M2=0, M + F d = 0 = M = - Fd & Tu=oIT The whe at the top surface of the maximum stresses at the origin: tube ou M₂ C (210) (do/2) + + A I zz A Izz The torsional stress at the same point is : Tr 72 (do/2) J J Tuz = Using the Distortion - energy theory 6 = (ou + six2) where by=0 On the basis of the given design factor, 276 = 69 MPa 6 < Sy nd 4