Stresses in the vicinity of the crack tips are responsible for failure of crack-containing components. The singular stress contribution is characterised by the stress intensity factor K, the first regular stress term is represented by the so-called T-stress. Whereas in the main volume, IKM 50, predominantly one-dimensional cracks were considered in homogeneous materials, this supplement volume compiles new results on one-dimensional and two-dimensional cracks.

In this book the authors describe methods for the calculation of weight functions. In the first part they discuss the accuracy and convergence behaviour of methods for one- and two-dimensional cracks, while in the second part they provide solutions for cracks subjected to mode-I and mode-II loading.

Fracture mechanics is an indispensible tool in the design and safe operation of damage tolerant structures. One of the essential elements in fracture mechanics based analysis is the stress intensity factor. This book provides a powerful theoretical background to the weight function method in fracture mechanics and numerous stress intensity factors. Part I gives a theoretical background and overview of the weight function method. Part II provides further details of the weight functions for various geometries and a large number of stress intensity factor solutions. Part II deals with the determination of crack opening displacements, Dugdale model solutions and crack opening areas.

On Fracture Mechanics A major objective of engineering design is the determination of the geometry and dimensions of machine or structural elements and the selection of material in such a way that the elements perform their operating function in an efficient, safe and economic manner. For this reason the results of stress analysis are coupled with an appropriate failure criterion. Traditional failure criteria based on maximum stress, strain or energy density cannot adequately explain many structural failures that occurred at stress levels considerably lower than the ultimate strength of the material. On the other hand, experiments performed by Griffith in 1921 on glass fibers led to the conclusion that the strength of real materials is much smaller, typically by two orders of magnitude, than the theoretical strength. The discipline of fracture mechanics has been created in an effort to explain these phenomena. It is based on the realistic assumption that all materials contain crack-like defects from which failure initiates. Defects can exist in a material due to its composition, as second-phase particles, debonds in composites, etc. , they can be introduced into a structure during fabrication, as welds, or can be created during the service life of a component like fatigue, environment-assisted or creep cracks. Fracture mechanics studies the loading-bearing capacity of structures in the presence of initial defects. A dominant crack is usually assumed to exist.

An improved method of boundary collocation was developed and applied to the two-dimensional stress analysis of cracks emanating from, or in the vicinity of, holes or boundaries of various shapes. The solutions, presented in terms of the stress-intensity factor, were based on the complex variable method of Muskhelishvili and a modified boundary-collocation method. The complex-series stress functions developed for simply and multiply connected regions containing cracks were constructed so that the boundary conditions on the crack surfaces are satisfied exactly. The conditions on the other boundaries were satisfied approximately by the modified collocation method. This improved method gave more rapid numerical convergence than other collocation techniques investigated.