Question

1. Find the stress distribution for the following structural member by calculating and plotting (to scale) the bending stress at 6 axes, top, below the flange, neutral axis, bottom, 1" and 2” up from the bottom if the bending moment is 8000 ft-lb. Denote which stresses are in tension and which are in compression. + + +

Answer 1

of neutral axis - from the - Hetermination bottom layer - - j A = 4 sq. in A₂ = 4 sq. in 4 q = 4.5 in = 2 in A + A2 1 => y = (4x4.5) + 4+4 (4x2) > f5 = 3.25 in) Azea morient of inentia. I = false + A, 4.=572% 4 fragen + A2 63% - + 4 (4.5-3-251 1+ [4² +4(2-3-2577 72 I = 18-1667 in 4 Bending moment, M = 8000 . =8000 X = 96000 ft-lb. 12 in in - lo et

y = 51-3.25 3 . 2 - )کی کی 7- at top, Stress Stresia = کم) و هه مى ده جا 18- ib ba زين وا ط وا - 242 = ج 2 / ط 2 243 . 43 ك : ته م / طلا 28 - 1337 سه د bottom; flange = 0.75 the at - 3-2 Stress = | کا 6000 18068 - --- = عنود طل و2 ، 333 س لام / طال گی گی 140 ہ ہ ا = = = ال

neutralerisi متر - یه و bottom the from at t" Stress . - 3025 هو هو - - 2 280 1262 ہ | خود طل83 - il883ت 2 مل گیا، l7L243- - - the better ferom at 9" Stress 22 - 2 - 3) و 2000 - h - / طل ك گ ه ه ه - 212 طل 02 - 9 / 30 - = 2 2

Stress at the bottom - of = A x Y . 47 of = - 96000 x 3.25 78.1667 . Of . Oh = -17174.28 lo / sg. in = -2473096-38 lb/ft2

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