ABSTRACT
Engineering components can fail as a result of design deficiencies, poor selection of materials, manufacturing defects, exceeding design limits and overloading, or inadequate maintenance. This chapter discusses mechanical failures, which take place by yielding, buckling, creep, wear, fracture, or stress corrosion. Fracture toughness is shown to be a function of the critical stress intensity factor K IC of the material, and brittle fractures usually take place at sharp corners, surface defects, inclusions, or cracks. Carbon steels are prone to brittle fracture at temperatures below the ductile–brittle transition. Fatigue failures take place under fluctuating loads and the fatigue strength of most steels is about 0.4–0.6 times the tensile strength. Creep occurs at high temperatures and thermal fatigue takes place as a result of repeated changes in temperature. This chapter also discusses experimental and analytical techniques for failure analysis and for preventing failure at the design stage. Failure mode effect analysis (FMEA) is a step-by-step process for identifying all possible scenarios of failures and the consequences of each of them.
