Answers to Chapter Questions

Units

Problem 1: σa = 200 MPa; σb = 31 ksi

Problem 2: Wa = 46×103 N; Wb = 10.9×103 lb

Stress and Strain

Problem 1: Stress = 10.1 MPa; Strain = 0.05×10-3 (hint, pipe full)

Problem 2: Load = 5655 lb.

Problem 3: It is safe (hint, σ = 115 MPa)

Problem 4: Sy = 44 ksi, any material with Sy > 44 ksi will be adequate

Problem 5: σ rod = 127 ksi, σ cylinder = 25 ksi, ε rod = 4.2×10-3, ε cylinder = 8.9×10-4

Thermal Expansion

Problem 1: 6.34 cm below tank top

Problem 2: 468 MPa; 0.00234; 919 kN

Problem 3: 20 m; 186.3 MPa, using -54ºC in the winter, α = 11.7×10-6 /ºC

Problem 4: 21.45 ksi; 180.2 kips, assuming Carbon Steel E = 30×106 psi, α = 6.5×10-6 /ºC

Problem 5: σ steel = 1727 psi; σ copper = 7895 psi

Pressure Vessels

Problem 2: DN500 Schedule 10 pipe

Problem 3: MAWP = 690 psi

Problem 4: Does not meet specifications

Properties of Areas

Problem 1: 7132.9 cm4; 1761.9 cm4

Problem 2: 112.85 in4; 30.7 in4

Problem 3: 44.32 cm4

Beam Reactions and Diagrams

Problem 1:  SFmax = 58.8 kN; BM max = 44.14 kN×m

Problem 2:  SFmax = 4347 lbs; BM max = 18263 lbs×ft

Problem 3:  SFmax = 35.98 kN; BM max = 83.6 kN×m

Problem 4:  SFmax = 293.6 kips ; BM max = 2420.6 kips×ft

Beam Stress due to Bending Moments

Problem 1:  72.3 MPa, safe

Problem 2:  Sx = 766.9×103 mm3, W410×46.1

Problem 3:  128.6 lb/ft

Problem 4:  Various solutions, example: Side beams Hemlock for Smin = 126 in∴ choose 4″×16″; deck boards 2″×12″ σreq = 497.6 psi ∴ choose Eastern White Pine

Beam Deflection

Problem 1:  1.9 cm

Problem 2:  0.26″

Problem 3:  3.54″

Problem 4:  depends on location, 37 cm @ 5.27 m from left end

Torsion in Round Shafts

Problem 1:  0.66×OD, 66% weight savings

Problem 2:  182.4 MPa, 162.97 MPa

Problem 3:  224.6 mm

Problem 4:  75.38 MPa, 39.95 MPa

Bolted and Welded Joints

Problem 1:  TBD

Problem 2:  TBD

Problem 3:  TBD

Problem 4:  TBD

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