Bøger i Engineering Applications of Fracture Mechanics serien

The majority of the work dealt with energy release rate or critical stress intensity factor and is applicable only to fracture toughness testing. The main reason for this restriction is that the energy release concept cannot easily be extended to mixed mode fracture that occurs in practice as the rule rather than the exception.

Following Volumes III and IV that dealt with the fracture mechanics of concrete emphasizing both material testing and structural application in general, it was felt that specimen size and loading rate effects for concrete require further attention.

''It is true that "Nothing is more practical than a theory" Provided - however - That the assumptions on which the theory is founded Are well understood.

''It is true that "Nothing is more practical than a theory" Provided - however - That the assumptions on which the theory is founded Are well understood.

In this volume on the mechanics of fracture of Portland cement concrete, the general theme is the connection between microstructural phenomena and macroscopic models.

Par ticular emphases are given to predicting crack initiation, subcritical growth and the onset of rapid fracture from a single criterion. The differences in the global and energy states before and after crack extension were associated with the energy required to create a unit area of crack surface.

The material presented falls within the areas of: Fundamentals of Strain Energy Density, Damage Analysis on Strain Energy Density, Strain Energy Density as Failure Criterion, Applications, and Composites.

Concrete has traditionally been known as a material used widely in the construction of roads, bridges and buildings. Because of the demand for concrete to operate under different loading and environmen tal conditions, increasing attention has been paid to study concrete specimens and structure behavior.

With the advent of the 80's there has been an increasing need for analytic and numerical techniques, based on a thorough understanding of microstructural processes, that express in a manner suitable for practicing engineers the reliability of components and structures that are being subjected to degradation situations.

The assessment of crack initiation and/or propagation has been the subject of many past discussions on fracture mechanics. Barring changes in the local temperature,* the energy released to create a unit surface area of an existing crack can be obtained by considering the change in elastic energy of the system before and after crack extension.

The three-dintensional character of rail and its stress fields make it essential to apply both experimental and analytical methods in order to twderstand the effects of pro duction and service variables on residual stress and the effects of the stress on fatigue crack propagation and fracture.

The assessment of crack initiation and/or propagation has been the subject of many past discussions on fracture mechanics. Barring changes in the local temperature,* the energy released to create a unit surface area of an existing crack can be obtained by considering the change in elastic energy of the system before and after crack extension.

The conventional approach to through-life-support for aircraft structures can be divided into the following phases: (i) detection of defects, (ii) diagnosis of their nature and significance, (iii) forecasting future behaviour-prognosis, and (iv) pre scription and implementation of remedial measures including repairs.

The three-dintensional character of rail and its stress fields make it essential to apply both experimental and analytical methods in order to twderstand the effects of pro duction and service variables on residual stress and the effects of the stress on fatigue crack propagation and fracture.

In this volume on the mechanics of fracture of Portland cement concrete, the general theme is the connection between microstructural phenomena and macroscopic models.

With the advent of the 80's there has been an increasing need for analytic and numerical techniques, based on a thorough understanding of microstructural processes, that express in a manner suitable for practicing engineers the reliability of components and structures that are being subjected to degradation situations.

Concrete has traditionally been known as a material used widely in the construction of roads, bridges and buildings. Because of the demand for concrete to operate under different loading and environmen tal conditions, increasing attention has been paid to study concrete specimens and structure behavior.

Par ticular emphases are given to predicting crack initiation, subcritical growth and the onset of rapid fracture from a single criterion. The differences in the global and energy states before and after crack extension were associated with the energy required to create a unit area of crack surface.

Starting with technologies concerned with assessing the change in material microstructure in terms of the processing parameters, this work offers methodologies to account for tradeoffs between the fundamental variables such as temperature and pressure that control the product quality.

This book consists of a collection of lectures prepared for a short course on "Fracture Mechanics Methodology" sponsored by the Advisory Group for Aerospace Research and Development (AGARD), part of the North Atlantic Treaty Organization (NATO). The course was organized jointly by Professor George C. Sih of the Institute of Fracture and Solid Mechanics at Lehigh University in the United States and Professor Luciano Faria from Centro de Mecanica e de Materiais das Universidade de Lisboa in Portugal. It was held in Lisbon from June 1 to 4, 1981. Dr. Robert Badaliance from the McDonnell Aircraft Company in St. Louis and Dr. Oscar Orringer from the Depart­ ment of Transportation in Cambridge are the other US lecturers while Professor Carlos Moura Branco from Portugal also lectured. The audience consisted of engineers from the Portuguese industry with a large portion from the aeronautical sector and others who are particularly interested to apply the fracture mechanics discipline for analyzing the integrity of structural components and fracture control methods. Particular. emphases were given to the fundamentals of fracture mechanics as applied to aircraft structures.

The material presented falls within the areas of: Fundamentals of Strain Energy Density, Damage Analysis on Strain Energy Density, Strain Energy Density as Failure Criterion, Applications, and Composites.