Re-analysis of European flight load data

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...

Damage severity of monitored fatigue load spectra

Many military aircraft are used more severely and over a longer periodthan originally intended. Consequently, a careful life management, including service load monitoring has become indispensable. This paper describes the development of a simple method to quantify the severity in terms of "potential crack growth" of recorded load spectra. This...

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...

A literature survey on the fatigue behaviour of hybrid composites

Composite materials with more than one type of fiber in one matrix are known as hybrid composites. In this work the fatigue behaviour of composite materials is discussed and the behaviour of hybrid composites is related to simple (single-fiber) composites. The properties and the behaviour of hybrid composites can mostly be explained...

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.

Useful lifetime prediction software for plane semi-cracks in 3-D solid configurations

Computer programs are described to be used for fracture control purposes. Crack growth lifetimes can be predicted for plane cracks in 3-D structures. Values for stress intensity (K-) distributions at crack fronts are derived from data being available from literature for a restricted number of simple configurations. For arbitrary configurations...

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...

Effect of penetrant on fatigue of aluminium alloy lap joints

The effect of penetrant on the fatigue life of single shear riveted lap joints was investigated by flight simulation fatigue tests using the MINITWIST gust spectrum. The penetrant/material combination investigated was ARDROX 985 P3T and aluminium alloy 202U-T3 sheet material (both bare and clad) respectively. The effect of penetrant on the...

The tail of the test spectrum: The effect of different approximations of the lower end of a gust load spectrum on crack growth and fatigue life in 7075-T6 and 2024-T3 specimens

The influence of the approximation of the lower end of the load spectrum was investigated by comparative tests using the Basic F-27 test programme and an extended version, containing three times more cycles per flight. Crack growth was studied on notched sheet specimens made of Alclad 202U-T3 and Alclad TOT5-T6. Fatigue life tests were done on...

The influence of different types of anodic layers on the fatigue properties of 202U-T3 and 7056-T6 sheet material

Constant amplitude and flight simulation fatigue tests have been carried out on sulphuric acid, chromic acid and phosphoric acid anodized specimens. A comparison was made with the fatigue behaviour of bare sheet material. Before fatigue testing the fracture strain of the anodic layers was determined.

Effects of variations in gust spectrum and ground-load level on fatigue life and crack propagation in 70T5-T6 and 202U-T3 specimens

The effects of systematic variations in mean stress level and in spectrum and ground load severity of a flight simulation test programme have been investigated on riveted specimens (fatigue life) and sheet specimens with central saw cut (crack growth). The fatigue life and crack propagation life in Alclad 202U-T3 compared with Alclad TOT5-T6...

Lasting Friendship: A review of the F-27 fatique evaluation programma carried out by Fokker-VFW

Fokker-VFW is carrying out a completely new fatigue evaluation of the F-2T aircraft, covering lives up to 120000 flights. This evaluation includes; a)A complete inventory of the configuration status of the F-2T fleet, b)An inventory and evaluation of existing test experience, c)Evaluation of service experience, d)Analytical predictions of life...

Influence of corrosion damage on fatigue crack initiation

The influence of previous corrosion on fatigue crack initiation has been determined. Cylindrical specimens and flat specimens with a central hole of the aluminium alloy T075-T6 were corroded in a 3.5 % NaC1 solution. The cylindrical specimens were tested under constant amplitude loading while for the specimens with a central hole a block...