Question

Part Design/size the rectangular cross section of a steel bar which is fixed at one end and carries an axial force of 95 kip at the other end (the weight of the bar itself can be assumed to be small and negligible). The height h of the cross section shall be 1.3 times larger than the base b of it (i.e., h 1.3xb). After finding b and h, round each one of them up to the nearest half of an inch. The bar length is 15 ft. The yield stress is 36 ksi, and the modulus of elasticity is 30000 ksi. Use a factor of safety of 2 against yielding. Part 2 Since the calculated values of b and h have been rounded up to the nearest half of an inch, analyze the actual system (i.e., the one with the rounded-up b and h values) to find the stress in the bar as well as the displacement at the end of it. Also, determine the associated factor of safety against yielding

Answer 1

PART 1 →P= 95 kip 15 Ft here, for a rectangular bar of Steel we have Height of section =h . width of section = b Also, h= 1.36 length of bar, l=15ft = 12x15 inch = 180 inches yield séuess fy = 36 ksi Modulus of elasticity, E = 30000 ksi factor of lifety against yielding = 2.0. Now, as we know Allowable Huess = field stuess = 36 ksi safety - Factor of = 18ksi Fa Also = - load Aula de Их Б section ce cross - - For Safety, of Fa »95 <b² 1.3X18 4.0599 562 9 0.014 Sb 2 h), 2,6193 inch

AL - Take a steel bar, Height, h= 3.0 inch width, b = 2.5 inch PART 2 :- Actual stress and Elongaban. go kips linen? Actual Stuess ;0= = 3x2.5 = 12.67 ksi Elongation of bae, 5= PL - 95% 180 mnm inch 1 = 0.076 inch factor of safety associated = yield stress Actual stuess = 36 ksi 12.67 ksi = 1.842