The preceding chapters presented a plethora of equations and formulations, with several examples illustrating the analyses. In this section we bring together all that we have learned into one final example. Reference to the chapters and equations are made to assist in the computation and understanding.
A certain glass is to be used for an aircraft window that is subjected to an unpressurized compartment environment at high altitude with a pressure differential of 0.076 MPa (11 psi) in a moist environment. The window is circular with a 0.3-m (12-in.) diameter and 22-mm (0.875-in.) thickness and is supported through a soft potting compound continuously at its edge. It has a lifetime requirement of 8000 hours under vacuum pressure differential. A literature search shows a flaw growth susceptibility factor N of 20 and a fracture toughness KIc of 0.9 MPa-m1/2. Its Poisson's ratio value is 0.25. Ring-on-ring tests for polished specimens indicate an average inert strength of 172 MPa (25,000 psi) and a Weibull A-basis strength of 86 MPa (12,500 psi).
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