In order to obtain an appraisal of the state of the art of fail-safe design, the author made an investory of fail-safe design methods applied by various aerospace companies and of research work relevant to the engineering approach of fatigue-crack propagation and residual strength. This memorandum is based on information from discussions with personnel of several companies and research laboratories, with the main emphasis on plane stress and transitional fracture behavior. The memorandum presents a brief description of the general approach to the fail-safe problem, an analysis of several of the existing methods that use this approach, including their shortcomings, and a summary of the data required for a good fail-safe design. A specific approach proposed for the presentation in MIL-HDBK-5 of data pertinent to the fail-safe design concept is evaluated in terms of its applicability to that concept. (Author).

This legendary, still-relevant reference text on aircraft stress analysis discusses basic structural theory and the application of the elementary principles of mechanics to the analysis of aircraft structures. 1950 edition.

Aerospace structural design, especially for large aircraft, is an empirical pursuit dominated by rules of thumb and often-painful service experiences. Expertise on traditional materials is not transferable to "new materials, processes and structural concepts. This is because it is not based on or derived from well-defined measures of safety. This book addresses the need for safe innovation based on practical, explicit structural safety constraints for use in innovative structures of the future where guiding service experience is non-existent. The book covers new ground by the demonstration of ways to satisfy levels of safety by focusing on structural integrity; and complementing the lack of service experience with risk management, based on flexible inspection methods recognizing that safety is a function of time. Fundamentally the book shoes demonstrates how safety methods can be made available to the engineering community without requiring huge statistical databases to establish internal and external loads distributions for use in reliability analysis.An essential title for anyone working on structural integrity, or composite structures. It will be of equal interest to aerospace engineers and materials scientists working in academia, industry and government. - Demonstrates a practically manageable way to produce safe innovation using composites in environments with no service experience - New approach to a subject that has not previously been treated in a holistic manner - This book could not have come at a more topical time, Boeing are currently launching the first commercial plane made entirely of composite materials - The focus of this book is Composite Materials but other fields of innovation could be treated in the same manner

Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.

In this report, an approach to damage-tolerant aircraft structural design is proposed based on the concept of an equivalent "Level of Safety" that incorporates past service experience in the design of new structures. The discrete "Level of Safety" for a single inspection event is defined as the compliment of the probability that a single flaw size larger than the critical flaw size for residual strength of the structure exists, and that the flaw will not be detected. The cumulative "Level of Safety" for the entire structure is the product of the discrete "Level of Safety" values for each flaw of each damage type present at each location in the structure. Based on the definition of "Level of Safety", a design procedure was identified and demonstrated on a composite sandwich panel for various damage types, with results showing the sensitivity of the structural sizing parameters to the relative safety of the design. The "Level of Safety" approach has broad potential application to damage-tolerant aircraft structural design with uncertainty. Lin, K. Y. and Du, Jiaji and Rusk, David Langley Research Center NAG1-2055; RTOP 522-31-71-02