Within the Solid Mechanics Program at the Office of Naval Research (ONR), our primary mission is to establish a basic research program which addresses the funda mental issues in solid mechanics where a clear scientific understanding is lacking. Our approach involves first identifying the various scales at which material and structural response and failure occur. Within each level of behavior we address the basic mechanical phenomena for which a clear physical description is not available. ONR's program emphasizes experimental research to identify and quantify the interacting behavior and response mechanisms. Theoretical and computational approaches are developed to explain the details of the physical processes and to establish the technology necessary to control the thermomechanical behavior of materials and structures. Within the Department of Defense, it is a natural evolution that all new systems must generally operate in more demanding environments than the systems they replace. Thus, structural designers are pushed towards lighter weight, precision structures utilizing new materials. In such an environment, structural design mar gins simultaneously shrink and become more critical. Such trends make it essential that a well founded scientific base for the nondestructive detection and assessment of subcritical flaws in structural materials and structures exist. Within the ONR Solid Mechanics Program we are interested in both the identification of flaws and assessment of their degree of criticality.

This volume (Parts A and B) contains the edited papers presented at the annual Review of Progress in Quantitative Nondestructive Evaluation held at Bowdoin College, Brunswick, ME on July 24-28, 1989. The Review was organized by the Center for Advanced NDE at the Ames Laboratory of the U. S. Department of Energy, in cooperation with the Office of Basic Energy Sciences, USDOE, and the Materials Laboratory at Wright-Patterson Air Force Base. The statistics for the 1989 Review of Progress in QNDE include a total of over 460 participants from the U. S. and nine foreign countries who presented some 325 papers. Over the years this conference has grown into one of the largest, most significant gatherings of NDE researchers and engineers in the world. The meeting was divided into 35 sessions, with as many as four sessions running concurrently, and covering all stages of NDE development from basic research investigations to early engineering applications and all methods of inspection science from ultrasonics to x-ray tomography. The Editors have organized the papers in the Proceedings according to topical subject headings, rather than in the original order of presentation. This rearrangement yields a more user-friendly reference work and follows a pattern now familiar to regular attendees of the Review. Some changes in the headings and their subcategories have been introduced to accommodate dynamic evolution of the field, as we observe it.

Nondestructive evaluation (NDE) procedures are needed for materials processing, as well as for post-process materials testing. They play important roles in product design, analysis of service-life expectancy, manufacturing and quality control of manufactured products. They are also essential to on-line monitoring of the integrity of structural elements and complex systems. Rational accept and reject criteria should be based on NDE tests. Critical safety, efficiency and operational features of large-scale structures depend on adequate NDE capabilities. The lectures presented in this volume are concerned with quantitative ultrasonic NDE. They present fundamental concepts and basic theory, as well as applications to the detection of cracks and the evaluation of material properties. The following topics are discussed: basic wave propagation theory for ultrasonic NDE; piezoelectric transducers, EMATS and ultrasonic spectroscopy; laser-based ultrasonics; acoustoelasticity; ultrasound in solids with porosity, microcracking and polycrystalline structuring; the determination of mechanical properties of composite materials; inverse problems and imaging.

With an emphasis on aircraft materials, this book describes techniques for the material characterization to detect and quantify degradation processes such as corrosion and fatigue. It introduces readers to these techniques based on x-ray, ultrasonic, optical and thermal principles and demonstrates the potential of the techniques for a wide variety of applications concerning aircraft materials, especially aluminum and titanium alloys. The advantages and disadvantages of various techniques are evaluated.

Papers presented at the symposium held in Charlotte, NC, March 1989, examine the phenomenon in which elastic or stress waves are emitted from a rapid, localized change of strain energy in a material. The first section focuses on AE sensors and systems. The second deals with fundamental investigation

The theme of the 15th International Acoustic Emission Symposium (IAES15) was set as 'practicality for life-extension and maintenance of plants and structures'. Special emphasis was placed on the review of acoustic emission (AE) research and applications in the 20th century and its future in the 21st century. The technique for monitoring defects and abnormal vibrations due to machine failures is vitally important for the safety of structures in a modern society. AE, as a passive, rather than an active NDT method, has drawn much attention because of its applicability to on-stream surveillance of structures. One important point is its capability to acquire data very simply but with high sensitivity so that the development of a non-contact sensing technique is particularly important. A quantitative method to evaluate structural integrity and remaining life from the detected AE signals is strongly required. Quantitative analysis, based on inverse procedures, has provided a certain solution, but has not been utilized widely enough in structures due to its complexity. Its applicability is limited partly because the accuracy of solutions depends on noise levels and partly because the phenomenon is usually non-reproducible. AE is expected to be a next-generation technique not only to monitor conditions but also for the repair of damaged structures, combined with an active-adaptive technique using a 'solid state actuator'. 'Smart Materials and Structures' are known in this respect. AE is considered to be a very promising technique, together with such sensing techniques as optical fiber, shape memory alloy and electro-rheological fluid. Thus, AE can play a very important roll in monitoring, evaluating and repairing structures. In this workshop, a limited number of invited papers are presented for technical discussion to review the achievements of AE research and applications in the 20th century. The proceedings are entitled Acoustic Emission - Beyond the Millennium to celebrate the new millennium, and stepping forward to a new era. The authors and topics of these review papers were selected by the editorial board.

This book contains 71 papers presented at the symposium on “Recent Advances in Experimental Mechanics” which was organized in honor of Professor Isaac M. Daniel. The symposium took place at Virginia Polytechnic Institute and State University on th June 23-28, 2002, in conjunction with the 14 US National Congress of Applied Mechanics. The book is a tribute to Isaac Daniel, a pioneer of experimental mechanics and composite materials, in recognition of his continuous, original, diversified and outstanding contributions for half a century. The book consists of invited papers written by leading experts in the field. It contains original contributions concerning the latest developments in experimental mechanics. It covers a wide range of subjects, including optical methods of stress analysis (photoelasticity, moiré, etc.), composite materials, sandwich construction, fracture mechanics, fatigue and damage, nondestructive evaluation, dynamic problems, fiber optic sensors, speckle metrology, digital image processing, nanotechnology, neutron diffraction and synchrotron radiation methods. The papers are arranged in the following nine sections: Mechanical characterization of material behavior, composite materials, fracture and fatigue, optical methods, n- destructive evaluation, neutron diffraction and synchrotron radiation methods, hybrid methods, composite structures, and structural testing and analysis.