A fractionating column used in chemical industry, 14 m long, is made of 300 mm inside...

  

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A fractionating column used in chemical industry, 14 m long, is made of 300 mm inside diameter standard steel pipe of thickness 10 mm, weighing 75 kg/m. This pipe is operating in vertical position as shown in the figure, where it is all-around welded to the base plate before erection on site. The pipe is internally pressurized to 4 MPa and subjected to maximum wind load of 600 N/m. a- Calculate the minimum weld size considering the static and fatigue loading due to wind. (Neglect the effect of shear and the effect of stress discontinuity) b- An elliptical surface crack of 10 mm length and 2 mm depth is detected at location A. If the fracture toughness of the pipe material is 15 MPa m¹, determine the margin of safety against brittle fracture. 1/2 c- Estimate the safe life cycle of the pipe. (Consider Paris law and assume that the crack aspect (a/2C) ratio remains constant) The pipe and weld material data is steel of the following properties: 12 m 600 Nim 14 m Crack- Weld Yield stress σ = 350 MPa, Ultimate strength σ = 500 MPa, Endurance limit σ = 200 MPa, v = 0.3, da/dN = 11 × 10" (AK) 35 (MPa - m-cycle units). The average configuration correction factor for bending loading is 1.12 while for tension is 1.12/0. pipe thickness 10 mm 0/201 2C 0.4 0.3- 0.2- 0.1- 1.0 1.5 2.0 2 K mm Elliptical crack at location A For elliptical crack: f(a/W) = 1.12/0 a A fractionating column used in chemical industry, 14 m long, is made of 300 mm inside diameter standard steel pipe of thickness 10 mm, weighing 75 kg/m. This pipe is operating in vertical position as shown in the figure, where it is all-around welded to the base plate before erection on site. The pipe is internally pressurized to 4 MPa and subjected to maximum wind load of 600 N/m. a- Calculate the minimum weld size considering the static and fatigue loading due to wind. (Neglect the effect of shear and the effect of stress discontinuity) b- An elliptical surface crack of 10 mm length and 2 mm depth is detected at location A. If the fracture toughness of the pipe material is 15 MPa m¹, determine the margin of safety against brittle fracture. 1/2 c- Estimate the safe life cycle of the pipe. (Consider Paris law and assume that the crack aspect (a/2C) ratio remains constant) The pipe and weld material data is steel of the following properties: 12 m 600 Nim 14 m Crack- Weld Yield stress σ = 350 MPa, Ultimate strength σ = 500 MPa, Endurance limit σ = 200 MPa, v = 0.3, da/dN = 11 × 10" (AK) 35 (MPa - m-cycle units). The average configuration correction factor for bending loading is 1.12 while for tension is 1.12/0. pipe thickness 10 mm 0/201 2C 0.4 0.3- 0.2- 0.1- 1.0 1.5 2.0 2 K mm Elliptical crack at location A For elliptical crack: f(a/W) = 1.12/0 a