Search Results for commercial transport aircrafts

Damage tolerance is a philosophy used for maintaining the structural safety of commercial transport aircrafts. This article describes the structural evaluations necessary to comply with the regulations contained in the Federal Air worthiness Requirements 25.571 whose guidance is given in Advisory Circular 25.571-1A from the Federal Aviation Administration. It provides an overview of the historical evolution of damage tolerance philosophy and presents a discussion of the design philosophies and a summary of the evaluation tasks for damage tolerance certification.

The high-strength plate alloy 2324 is a modification of 2024 alloy composition and process conditions to increase strength in both plate and extrusions without a loss in fracture toughness and other characteristics. This datasheet provides information on key alloy metallurgy, as well as the effects of processing on mechanical properties of this 2xxx series alloy. A comparison of fracture toughness of 2324-T39 to 2024-T351 is presented.

This article provides non-proprietary and non-competition-sensitive information related to aircraft applications. It presents an overview of reliability and commonly used measurements. Failure modes that cause the negative performance are reviewed based on many types of sources. These include manufacturer service bulletins, reliability and customer service departments, literature reviews, demonstration programs, in-service evaluations, design guides, and surveys of commercial and military aircraft maintenance organizations. The article also describes lessons learned while attempting to avoid overlapping maintainability, reparability, and materials choice.

This article provides a summary of the concepts discussed in the Section “Corrosion in Specific Industries” in the ASM Handbook, Volume 13C:Corrosion: Environments and Industries. This Section applies the fundamental understanding of corrosion and knowledge of materials of construction to practical applications. The industries addressed are nuclear power, fossil and alternative fuel, land transportation, air transportation, microelectronics, chemical processing, pulp and paper, food and beverage, pharmaceutical and medical technology, petroleum and petrochemical, building, and mining and metal processing.

This article describes the commonly observed forms of airplane corrosion, namely: general corrosion, exfoliation corrosion, pitting corrosion, microbiologically induced corrosion, galvanic corrosion, filiform corrosion, crevice corrosion, stress-corrosion cracking, and fretting. It discusses the factors influencing airplane corrosion from the manufacturing perspective: design, manufacturing, and service-related factors. The article explains the collection of corrosion data and provides an overview of the implementation and evolution of airline corrosion prevention and control programs and directions being considered in the design for corrosion prevention of airplanes.

This article presents the importance of progressing from post-manufacturing inspection/verification to in-process inspection/verification methods. It lists the various quality assurance factors considered for typical composite laminate lay-up process. The article provides information on composite cure tooling that is fabricated from steel, aluminum, or high-temperature composite materials. The quality assurance for commercial applications is reviewed. The article concludes with a discussion on data fusion systems designed to provide nondestructive analysis data from fabrication and assembly processes for each individual composite part.

This article begins with a brief history of composite materials and discusses its characteristics. It presents an introduction to the constituents, product forms, and fabrication processes of composite materials. The article concludes with a discussion on the applications of organic-matrix, metal-matrix, and ceramic-matrix composites.

This datasheet provides information on composition limits for aluminum alloys 7150 and 7050, and processing effects on mechanical properties of alloy 7150-T7751 plate and 7150-T77511 extrusions.

This article describes the various environments affecting corrosion performance, corrosion protection, and corrosion control. These include freshwater environments, marine environments, and underground environments. The article provides information on corrosion in military environments and specialized environments, representing less-well-known environments with more limited applications.

This article describes the types of repair and presents reasons for avoiding damage to a structure or component during repair. It discusses the major standardization issues with emphasis on design, repair materials, repair techniques, and inspection.

This article describes two analysis methods that are used to determine the life of aircrafts: fatigue life and fracture mechanics methods. The life limiting factors that control the durability of the aircraft are also discussed. The article provides an overview of the various approaches to corrosion identification and prevention. These include safe-life, fail-safe, and damage tolerance approaches. The article discusses their application to the process of extending the life of aircraft structural components.

Reinforcing fibers are a key component of polymer-matrix composites (PMCs), ceramic-matrix composites (CMCs), and metal-matrix composites (MMCs). This article discusses the mechanical and nonmechanical properties of these composites. It presents an overview of PMC, CMC, and MMC reinforcing fibers. The article describes cost-considered value-in-use of the ultimate-use temperature of selected fibers in three fiber categories: metal fibers or wires, oxide ceramic fibers, and non-oxide ceramic fibers.

Automated tape laying is a mature process used in both commercial and military aircraft applications. This article provides a brief history of the process and describes the use of commercially available flat and contour tape-laying equipment. It discusses the advantages and disadvantages of the tape laying. The article describes the various components of a ten-axis gantry-type tape laying machine and the tape laying process. It provides a discussion on typical material types and forms for tape laying and provides information on design guidelines for tape laying.

This article reviews corrosion problems in the U.S. Department of Defense (DoD) and discusses management and maintenance aspects of the practices that address the cost and readiness. It describes the plans to institute corrosion prevention and control strategies under DoD directives in engineering design, material selection, and fabrication processes for new acquisitions. The article also suggests a long-term strategy to reduce the cost of corrosion control.

Nonferrous metals and alloys are widely used to resist corrosion. This article describes the corrosion behavior of the most widely used nonferrous metals, such as aluminum, copper, nickel, and titanium. It also provides information on several specialty nonferrous products that cannot easily be categorized by elemental base.

The development of aluminum alloys has progressed along two tracks: heat treatable and non-heat treatable. The Aluminum Association alloy composition limits and product temper are defined for major alloying elements. This article summarizes the historical evolution of the different series of wrought aluminum alloys (1xxx to 8xxx) and discusses their applications based on the alloying system introduced by the Aluminum Association.

The chemical composition of Kevlar aramid fiber is poly para-phenyleneterephthalamide. Para-aramid fibers belong to a class of materials known as liquid crystalline polymers. This article discusses the manufacture of aramid fibers and the major fiber forms, such as continuous filament yarns, rovings, woven fabrics, discontinuous staple and spun yarns, fabrics, and pulp. Key representative properties of para-aramid fibers are listed in a table. The article reviews the properties of aramid fibers, including tensile modulus, tensile strength, creep and fatigue, compressive properties, toughness, thermal properties, as well as electrical and optical properties. It concludes with a discussion on the environmental behavior of para-aramid fibers.

This article first describes the two methods used in the 1998 U.S. corrosion cost study. In the first method, the cost was determined by summing the costs for corrosion control methods and contract services. In the second, the cost of corrosion was first determined for specific industry sectors and then extrapolated to calculate a national total corrosion cost. The article then reports the results and conclusions of the study. It concludes with information on corrosion prevention strategies.

This article discusses the types, properties, and uses of continuous-fiber-reinforced composites, including glass, carbon, aramid, boron, continuous silicon carbide, and aluminum oxide fiber composites. While polyester and vinyl ester resins are the most used matrix materials for commercial applications, epoxy resins, bismaleimide resins, polyimide resins, and thermoplastic resins are used for aerospace applications. The article addresses design considerations as well as product forms and fabrication processes.

Titanium has been recognized as an element with good mechanical and physical properties, alloying characteristics, and corrosion resistance. Providing an outline of general characteristics and types of titanium alloys, this article discusses the contemporary technology of titanium along with its market developments. It also discusses the application of titanium and titanium alloys in corrosive environments and in aerospace and automotive industries. The article describes the developments in titanium processing and materials technologies, which include the development of sponge production and melting processes, oxide dispersion-strengthened alloys by powder metallurgy techniques, titanium-base intermetallic compounds, and titanium-matrix composites.