Variation in load experience: A re-analysis of Fokker F27 and Foker F28 operational acceleration data

Fatigue meter data obtained during operational flights of Fokker F27 and Fokker F28 aircraft were re-processed and analyzed to study the variation in load experience between different aircraft of the same type. The Data covered about 470000 flights, made by 101 aircraft of 51 different operators. A simple algorithm was developed to quantify the...

Variability of fatigue crack growth properties for 2024-T3 aluminium alloy

Discussions between D-BAA and the NLR have shown that significant variability in fatigue crack growth properties is possible for the industry standard damage tolerant aluminium alloy, 2024-T3 sheet. This is important for two reasons: (1) design assumptions and (2) comparisons of different candidate materials, such as 6013-T6, with 2024-T3....

Damage assessment and preservation of an Egyptian silver vase (300 - 200 B.C.)

An Egyptian metal vase from the Ptolemaic period was investigated metallurgically and fractographically. The metal is nearly pure silver, and chemical analysis indicates it was obtained from the cupellation of lead. Despite its high purity (in archaeological terms) the metal is severely cracked and embrittled, with fractures mainly along grain...

Aircraft corrosion and fatigue damage assessment (USAF ASIP Publication)

This paper reviews currently available information on corrosion and fatigue in aircraft as a background to discussing the assessment of corrosion and fatigue damage. The main topics are: - aircraft operating environments and loads - corrosion - fatigue - corrosion and fatigue - corrosion and fatigue damage assessment. Aircraft structures are...

Aircraft corrosion and fatigue damage assessment

This report reviews currently available information on corrosion and fatigue in aircraft as a background to discussing the assessment of corrosion and fatigue damage. The main topics are: * aircraft operating environments and loads * corrosion * fatigue * corrosion and fatigue * corrosion and fatigue damage assessment. Aircraft structures are...

A damage tolerance study conducted with structure relevant specimens

A preliminary investigation is reported of the development of a Structure Relevant (SR-) specimen, which maintains the essential features of a stiffened panel configuration, in order to study damage growth behavior at limited cost. Several SR-specimens were fabricated, damage was applied, either through impacts or by the insertion of artificial...

Ageing aircraft research in The Netherlands

The problems of Ageing Aircraft are worldwide. Hence, actions to overcome or prevent these problems should be taken in international collaboration. The Federal Aviation Administration FAA and the Netherlands Civil Aviation Department RLD have signed a Memorandum of Cooperation in the area of structural integrity, with specific reference to...

Potential applications of laser anemometry for in-flight measurements

This report concerns the application of laser anemometry for flight testing and other aircraft-related measurements. The laser anemometry technique and previous work in this field are reviewed and applications are described. A comparison of possibilities of laser anemometry with conventional techniques shows some unique advantages of laser...

Toepassing van kennissystemen voor diagnose van vliegtuigsystemen

Maintenance organisations experience an increasing pressure to optimize the availability of company assets. Meanwhile the complexity of systems increases. As a consequence, there is a need for tools with which maintenance can be performed more effectively and efficiently. NLR is engaged in applied research into knowledge-based systems for...

Monitoring load experience of individual aircraft

Paper presented at the 17th ICAS Congress, Stockholm, September 1990. The actual service load experience of aircraft may differ appreciably from design assumptions. The necessity to monitor service loads is generally recognized now for military aircraft. This paper starts with a general review of the overall life management procedure commonly...

Delamination growth in improved carbon composites under constant amplitude fatigue loading

Constant amplitude tension-compression fatigue tests were performed on notched (± 45, 02, 90, 02)s coupon specimens of the composite systems T300/F593, T400H/6376, T800H//5245C and IM6/APC-2. Delamination damage growth as a function of the number of fatigue cycles was determined using the ultrasonic C-scan technique. Considering the resistance...

Fatigue damage in composites under different loading conditions

The damage development In notched (± 45, 0„, 90, 0-) carbon-epoxy coupon specimens tested under different loading conditions was determined. Constant amplitude tests at R = -1 and R = 0.1 as well as flight simulation tests were performed to establish those stress values for which no damage growth occurs.

Prediction of fatigue crack growth

As an introduction the practical significance of fatigue crack growth life prediction is related to the service life, the inspection period and the fracture control requirements. Then different aspects of fatigue crack growth in metallic materials are discussed in more detail. Important effects such as chemical environment, short cracks, crack...

Damage tolerance of stiffened-skin structures: prediction and experimental verification

Some consequences of application of the current damage tolerance airworthiness requirements for transport aircraft in designing stiffened-skin structures to be safe under all operational load conditions are discussed. Compliance with these requirements may be shown by analysis supported by test evidence. To provide the designer with analytical...

Loads and damage tolerance for helicopters

This report reviews the applicability of damage tolerance concepts to helicopter structures. After a general discussion of the damage tolerance concept, attention is paid to the specific aspects of the helicopter loading environment. Examples are presented of damage tolerant design, both in metal and in composite structures. However, it is felt...

Technical evaluation report on the AGARD Fluid Dynamics Panel symposium on improvement of aerodynamic performance through boundary layer control and high lift systems

The symposium demonstrated the importance of research in the area of mechanical high-lift systems for transport aircraft to improve the total performance of current transports. Computational techniques are shown to provide new tools for high-lift design. With regard to drag reduction by laminar flow control it is concluded that the information...

Het gebruik van glasvezels in de vliegtuiginstrumentatie

Fiber optics, a rapidly advancing new technology, seems very well suited for use as data transmission medium in aircraft. The advantages are substantial: galvanic isolation, electromagnetic compatibility, savings in volume and weight, and superior transmission qualities. In this report possibilities and limitations are discussed for using...

Trends in airline avionics

Modern avionics are an integral part of the aircraft. They provide the functions of communication, navigation, energy management, identification, weather, terrain, and collision avoidance, the presentation of flight and warning data as well as aircraft guidance and stabilization. New developments in micro-electronics and display technology...