The tube shown in Figure 9.8 is subjected to an internal pressure, p = 5 MPa, instead of a torque. Neglecting the stress along the longitudinal axis of the tube, and assuming that the mode I fracture...

The tube shown in Figure 9.8 is subjected to an internal pressure, p = 5 MPa, instead of a torque. Neglecting the stress along the longitudinal axis of the tube, and assuming that the mode I fracture toughness is K_Ic
= 10 MPa m^1/2, determine the critical crack size.

The sandwich beam described in Example 9.3 is subjected to a total applied load P = 500 N. Assuming that a shear crack is located at the middle surface of the beam in the region of maximum shear force, determine the critical crack size for mode II core shear fracture.

EXAMPLE 9.3

A foam core sandwich beam in 4-point flexural loading is described in Example 7.19 and Figure 7.68. Core shear fracture is observed to occur in the regions of maximum shear force V. If the critical stress intensity factor for mode II shear fracture in the foam core is K_IIc
= 0.0654 MPa m^1/2
and a shear crack of size 2a_II
= 1.566 mm is located at the point of maximum core shear stress, determine the critical value of the total applied load, P_c