Some numerical studies of crack propagation are based on using constitutive models that account for damage evolution in the material. When a critical damage value has been reached in a material point, it is natural to assume that this point has no more carrying capacity, as is done numerically in the element vanish technique. In the present review this procedure is illustrated for micromechanically based material models, such as a ductile failure model that accounts for the nucleation and growth of voids to coalescence, and a model for intergranular creep failure with diffusive growth of grain boundary cavities leading to micro-crack formation. The procedure is also illustrated for low cycle fatigue, based on continuum damage mechanics. In addition, the possibility of crack growth predictions for elastic-plastic solids using cohesive zone models to represent the fracture process is discussed.

It is well known that many engineering structures and components, as well as consumer items, contain cracks or crack-like flaws. It is widely recognised that crack growth must be considered both in design and in the analysis of failures. The complete solution of a crack growth problem includes determination of the crack path. Macroscopic aspects of crack paths have been of industrial interest for a very long time. At the present state of the art the factors controlling the path taken by a crack are not completely understood. Eight brief case studies are presented. These are taken from the author’s professional and personal experience of macroscopic crack paths over many years. They have been chosen to illustrate various aspects of crack paths. One example is in a component from a major structure, three examples are in laboratory specimens, and four are in nuisance failures. Such nuisance failures cause, in total, a great deal of inconvenience and expensive, but do not normally receive much publicity.

History of studies of fracture is inherently intermingled with the history of technology developments. In the beginning very little was written about. We must credit Leonardo and Galileo as the first ones that wrote about the problem and on how to measure and foresee rupture loads. Later, nineteenth century italian scientists distinguished themselves in attempting to establish material laws and multiple stresses rupture criteria. A review of the works of past centuries italian scientists is presented, along with a critical compari-son with the work of other past european scientists.

The knowlegde of dynamic mechanical properties is useful in all cases where the strain rate sensitivity of metallic materials is an issue, and whenever the actual loading conditions for a structure (either in normal operation or under accidental circumstances) are different from static. Furthermore, in some investigations increasing the loading rate is used to simulate other embrittling mechanisms such as thermal aging or neutron exposure. This paper provides an overview of SCK•CEN experience on measuring fracture toughness of steels at ele-vated loading rates, with specific emphasis on instrumented impact tests on precracked Charpy (PCVN) specimens. After briefly dwelling on the basic mechanisms which explain loading rate effects on cleavage and ductile fracture toughness, the experimental and analytical procedures for measuring fracture toughness at elevated loading rates are addressed, both in terms of official ASTM and ISO test standards and considering stand-ardization efforts currently in progress under SCK•CEN coordination: revision of ASTM E1921 (Master Curve methodology for measuring fracture toughness in the ductile-to-brittle transition region) and a future ISO standard on instrumented PCVN testing. This latter document is examined in more detail, focussing the attention on the dynamic evaluation of brittle fracture toughness (Impact Response Curve) and the determi-nation of crack resistance curves using multiple and single-specimen techniques. Finally, selected examples from SCK•CEN database of dynamic toughness measurements will be illustrated, mainly relevant to reactor pressure vessel (RPV) steels.