From the symposium (on title) held in Sparks, Nevada, April 1988. Twenty-two peer-reviewed papers are divided into sections on models and experiments (monotonic loading), and fatigue crack growth. Areas addressed include the differences in constraint for 2-D through-thickness cracks and 3-D surface

The Irwin stress intensity factor for surface cracks with crack depths less than half the plate thickness is extended to cases of relatively deep cracks by including the effect of the free surface opposite the crack. The stress intensity magnification factor is given as a function of applied load, crack length, crack depth, sheet thickness, yield strength, and Poisson's ratio. The combinations of these variables for which the plastic zone extends completely through the thickness a r e also predicted. The range of applicability of the analysis to surface-crack specimen data was investigated in terms of crack-depth-to-specimen-thickness ratio and crack depth-to-length ratio.

Cracks can develop in rotating shafts and can propagate to relevant depths without affecting consistently the normal operating conditions of the shaft. In order to avoid catastrophic failures, accurate vibration analyses have to be performed for crack detection. The identification of the crack location and depth is possible by means of a model based diagnostic approach, provided that the model of the crack and the model of the cracked shaft dynamical behavior are accurate and reliable. This monograph shows the typical dynamical behavior of cracked shafts and presents tests for detecting cracks. The book describes how to model cracks, how to simulate the dynamical behavior of cracked shaft, and compares the corresponding numerical with experimental results. All effects of cracks on the vibrations of rotating shafts are analyzed, and some results of a numerical sensitivity analysis of the vibrations to the presence and severity of the crack are shown. Finally the book describes some crack identification procedures and shows some results in model based crack identification in position and depth. The book is useful for higher university courses in mechanical and energetic engineering, but also for skilled technical people employed in power generation industries.

- Executive Summary - Introduction - Literature review update - Methodology - Trial sites - Results obtained from initial monitioring - Dicussion - Conclusions and recommendations - Acknowledgements - References - Abbreviations - Appendix A: Draft specification for the induced cracking of cement bound materials roadboase pavements - Astract - Related publications

Comprises ten papers discussing topics including methods for the measurement of surface crack size, multiple site cracking, and cracking under nonisothermal conditions using AC potential difference procedures; influences of crack deflection and crack splitting on DC potential calibrations; complianc

Crack Control: Using Fracture Theory to Create Tough New Materials goes beyond just trying to understand the origin of cracks and fracture in materials by also providing readers with the knowledge and techniques required to stop cracks at the nano- and micro-levels, covering the fundamentals of crack propagation, prevention, and healing. The book starts by providing a concise foundational overview of cracks and fracture mechanics, then looks at real-life ways that new tougher materials have been developed via crack inhibition. Topics such as crack equilibrium, stress criterion, and stress equations are then outlined, as are methods for inventing new crack-resistant materials. The importance of crack healing is emphasized and cracks that grow under tension, bending, compression, crazing, and adhesion are discussed at length as well - Provides a better understanding of crack formation in various materials allowing for more efficient investigations of crack-based material or structural failure - Demonstrates how to prevent cracks by arresting them at the nano- and micro-levels - Looks at methods for developing new tougher and stronger materials through crack inhibition - Emphasizes the importance of crack healing and explains crack stopping through changing the peel shape in various ways