Application of the Sc-theory to structural design

Fracture mechanics is a powerful tool in the hands of a knowledgeable engineer. It offers the designer and structural analyst quantitative guidelines to the design, evaluation and maintenance of high-performance fracture-resistant structures in terms of material selection, safe operating stress levels, and quality assurance standards. However, it must be applied properly and integrated with the other design requirements early in the design phase to reap the desired benefits. In this connection, the strain-energy-density factor theory, or the Sc-theory, is applied in this paper to illustrate the principles of fracture mechanics methodology towards the design of a cylindrical shell structure under complex loading conditions. The versatility of this theory in selecting competing structural materials and in determining safe operating stress levels, allowable loads, factors of safety, damage tolerance and safe crack propagation life are highlighted.