Mechanical properties and fracture of materials

Ensuring the integrity of structural components is paramount for the safe and reliable operation of engineering plant across a wide range of industries, including process and power, aerospace, and transport. Safety cases for structural components are often made using a multilegged approach (Bullough, R.; Burdekin, F. M.; Chapman, O. J. V.; Green, V. R.; Lidbury, D. P. G.; Swingler, J. N.; Wilson, R. Int. J. Press. Vess. Piping,. 2001,. 78, 539-552), in which a number of separate and distinct safety arguments are combined to build a robust case. These arguments include, but are not limited to, design basis, quality of construction, nondestructive examination (NDE), and defect assessment. The development of the defect assessment argument or 'leg' of the safety case is thus critically dependent on the engineer's ability to assess the severity of defects that are either present from the start of life or which may form during service. Start-of-life defects may include welding defects such as porosity, slag inclusions, lack of fusion, cold-cracking, and (or) undercuts (. Welding Handbook, Fundamentals of Welding, 7th ed.; Charlotte Weisman, Ed.; American Welding Society, 1976; pp 209-215). The mechanisms by which defects can form during service include stress corrosion cracking (SCC), fatigue, corrosion-fatigue, and creep. This chapter provides an overview of the mechanical properties of materials and describes fracture mechanics principles, which are used widely to assess the severity of such defects in engineering structures. . © 2010