Practical applications

Abstract

The improvement in fracture mechanics technology occurring in the last time results in the use of fracture mechanics life prediction as part of the engineering design procedure. Previously the principal engineering application of fracture mechanics was to assist in material selection by identifying those materials susceptible to brittle fracture (low fracture toughness). Largely as a result of intensive research, an expertise was developed in linear elastic fracture mechanics (mathematical formulas), material fracture characteristics quantifying crack growth rate, and material inspection procedures quantifying the characteristics of material defects. All three of these developments were necessary before fracture mechanics life prediction could be performed, bringing together for the first time the design life requirements, the possible undetected crack-like defects, the design stresses imposed on the cracked region, and the material fracture characteristics. The incorporation of fracture mechanics life prediction into the engineering design process not only provided an assurance of design success but also allowed necessary adjustment to be made in either the design stress or the inspection procedure before the parts were fabricated and before problems were encountered in service.