Question

The JT100 horizontal directional drilling machine applies 220 hp and rotates drill pipe at 100 rpm. During the drilling process, a drill pipe is subjected to the following axial and bending loads 30.0 Axial load, P, of 100 kips 0.70 ft-kips bending load, M, in the y-z plane at 30 degrees from the vertical axis The drill pipe, which is made of AISI 4130 steel, has the following dimensions and material properties (Ref. MIL-HDBK-5J, Table 2.3.1.0(c1)) » Length, L 177-in » Inner Diameter, ID-3.5-in Outer Diameter, OD 4-in Note: For a hollow circular cross-section, o-rt) and J-ły + Iz Area, A-HỤ0-Ti ). Moments of Inertia, 1,-1,--(r * Tensile stress limit, Fty -75 ksi . Elasticity Modulus, E 29.0x103 ksi » Poisson's Ratio, v -0.32 » Shear stress limit, Fsu - 57 ksi . Shear Modulus, G 11.0x103 ksi . Density, p 0.283 lb/in3 a) Determine the location on the circumference of the drill pipe where the longitudinal tensile stress is maximum. Identify this location in terms of degrees from the positive vertical axis. b) Determine the principal stresses. σι, σ2, and 03, applied to the drill pipe at this location. c) Determine the maximum shear stress,Tmax, applied to the drill pipe at this location. d) Determine the factor of safety (FoS) for material failure of the drill pipe.

Answer 1

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