The hoop stress at the outer surface of a pipe of internal diameter 2R 1 and external
Question:
The hoop stress at the outer surface of a pipe of internal diameter 2R1 and external diameter 2R2 under internal pressure P is given by:
When a/W < 0.05, Y = 1.12. A toughened rigid PVC water pipe has R1 = 147.5 mm and R2 = 167.5 mm. Tests show KIC = 3.1 MPa m0.5 and σY = 40 MPa. The largest defects are equivalent to 100 um cracks in the outer surface. (A) Determine whether the pipe will fail by yield or fracture in a pressurization test, and find the pressure to cause failure. (B) Find the maximum value of yield stress σY (max) that will permit ductile failure in the pipe as strain rate increases, assuming that KIC remains constant. (C) Calculate σY (max) for poorly processed PVC pipe, for which KIC = 1.5 MPa m0.5, assuming that a remains unchanged at 100 um.
Fundamentals of Thermal-Fluid Sciences
ISBN: 978-0078027680
5th edition
Authors: Yunus A. Cengel, Robert H. Turner, John M. Cimbala