Report of NRL Progress


Book Description




Engineering Fracture Design


Book Description

Fracture: An Advanced Treatise, Volume IV: Engineering Fracture Design presents the development and status of knowledge on sudden, catastrophic failure of structures due to unexpected brittle fracture of component materials. This book provides information pertinent to the engineering fracture design as well as the microscopic and macroscopic fundamentals of fracture. Organized into eight chapters, this volume begins with an overview of the evaluation of fracture tests. This text then presents an analysis of temperature effects on fracture. Other chapters consider the fracture and carrying capacity of long, slender columns and related topics. This book discusses as well the problems in connection with columns, beams, and plates, and experimental evidence to support theories proposed for describing the strength and stiffness of these elements. The final chapter presents an analysis of the problem of brittle fracture in weldments. This book is a valuable resource for engineers, students, and research workers in industrial organizations, education and research institutions, and various government agencies.




Welding High-strength Steels


Book Description

Recent studies of the developments in welding steels with yield strengths greater than 150 ksi have included low-alloy martensitic steels, medium-alloy martensitic steels, nickel maraging steels, and bainitic steels. Only weldments from medium-alloy martensitic steels and nickel maraging steels have mechanical properties approaching those of the base plate without a complete postweld heat treatment. The most serious problem with the other steel is low toughness in the weld fusion zone. Adequate weld metal toughness under conditions of elastic strain can be obtarined over the entire 150 to 225 ksi yield-strength range only if the tungsten-arc welding process is used. Processes with higher deposition rates can produce comparable weld deposits only in the lower portion of the range. Above a yield strength of 200 ksi, 18Ni maraging steel weldments have the best combination of strength and toughness. Below 200 ksi, the HP 9-4-25 medium-alloy martensitic steel and 12Ni maraging steel weldments have nearly equal properties.




Impact Testing of Metals


Book Description




Fracture Toughness Characteristics of the New Weldable Steels of 180- to 210-Ksi Yield Strengths


Book Description

The yield strength range for steels from 180 to 210 ksi is currently covered by four weldable alloys of the following nominal chemical analysis: 18%Ni-8%Co-3%Mo maraging steel, 12%Ni-5%Cr-3%Mo maraging steel, 9%Ni-4%Co-0.20%C quenched and tempered (Q and T) steel, and 10%Ni-8%Co-2%Cr-1%Mo-0.10%C Q and T steel. Broad ranges of fracture resistance have been reported for these materials based on various fracture tests, and this report presents information for material selection and design guidance by providing an analysis of the interactions between the metallurgical and mechanical parameters that contribute to the fracture resistance of plate products. Definitions of the interaction between the metallurgical and the mechanical aspects are developed with the use of the Dynamic Tear (DT) test and the Ratio Analysis Diagram (RAD). (Author).







Optimum Structural Design Concepts for Aerospace Vehicles


Book Description

Minimum weight design of aerospace structres has evolved during the past two decades into a rather rigorous scientific discipline that permits the rational selection of structural configurations and materials for various design requirements. Because of the pertinence of this body of literature to the structural design of advanced aerospace vehicles, a comprehensive bibliography of published literature on optimim structural design has been compiled and reviewed herein. In Part 1, a critical historical review highlights the significant advances in the literature concerned with analytical optimum design techniques for various structural elements, materials and thermal protection systems. The annotated bibliography is contained in Part 2. In Part 3, the current state of the art of the theory of optimum structural and thermostructural design is assessed. Included are the derivation of design indices resulting from various design requirements, a generalized presentation of optimum design theory and preferred methods of presenting optimum design results. (Author).