University:
Michigan State University
Course:
ERG 100 | Introduction to Engineering Design
Academic year:

2021
Views:

9

Pages:

1
Author:

Alexa Livingston

PROBLEM 1.33 A steel pipe of 12-in. outer diameter is fabricated from 14 -in.-thick plate by welding along a helix that forms an angle of 25° with a plane perpendicular to the axis of the pipe. Knowing that the maximum allowable normal and shearing stresses in the directions respectively normal and tangential to the weld are σ = 12 ksi and τ = 7.2 ksi, determine the magnitude P of the largest axial force that can be applied to the pipe. SOLUTION 1 d = 6 in. 2 o ri = ro − t = 6 − 0.25 = 5.75 in. d o = 12 in. ro = A0 = π ( ro2 − ri2 ) = π (62 − 5.752 ) = 9.228 in2 θ = 25° P Based on σ = 12 ksi: σ = cos 2 θ A0 P = Based on τ = 7.2 ksi: τ = P= A0σ (9.228)(12 × 103 ) 3 = = 134.8 × 10 lb cos2 θ cos2 25 ° P sin 2θ 2 A0 2 A0τ (2)(9.288)(7.2 × 10 3) 3 = = 174.5 × 10 lb sin 2θ sin 50 ° The smaller calculated value of P is the allowable value. P = 134.8 × 103 lb P = 134.8 kips W