Effects of melt flow in casting processes

Flight simulation fatigue crack growth testing of aluminium alloys: Specific issues and guidelines

Flight simulation fatigue crack growth tests are necessary for verification of aircraft damage tolerance analyses and crack growth prediction methods, and also for comparing candidate materials for aircraft structural applications. However, such tests involve complicating issues that have emerged from many investigations on aluminium alloys...

Fatigue and residual strength behaviour of ARALL3 panels with bonded-on doublers

Residual strength tests were performed on ARALL panels consisting of ARALL3 (3/2) laminates with bonded-on doublers. In particular, the effect of the doubler geometry (shape and thickness) on the residual strength was investigated. Prior to residual strength testing all panels were fatigue loaded to create a realistic type of damage, i.e. cracks...

Fatigue Rated Fastener Systems: an AGARD coordinated testing programme

The report contains the description, results and conclusions of a fatigue test programme which assessed the fatigue lives of fastener systems using different joints. High load transfer single shear joints were evaluated in a core programme; secondary bending and load transfer were determined experimentally. About 750 specimens were fatigue...

Constant-amplitude and flight-simulation fatigue tests on adhesive bonded lap joint specimens of 2024-T3 sheet material

Fatigue tests were carried out on Redux and FM 123/5 bonded specimens at various stress levels, temperatures (RT to 65 C) and low and high test frequencies. Observations were made on the type of failure (bond line failure or sheet failure) and the significance of the adhesive squeezeout for crack nucleation. An analysis of the data and a...

Engineering property comparisons for 2324-T39 and 2024-T351 aluminium alloy plate

Engineering property comparisons have been made for plate material of the newly developed aluminium alloy 2324-T39 and the widely used alloy 2024-T351. The properties considered were: tensile strength, fracture toughness, notched fatigue strength, and the resistance to fatigue crack propagation under both constant amplitude and flight simulation...

Some tests to assess the effect of crack stoppers on the fatigue life of centre-notched sheetspecimens

Several simple crack stopping methods were evaluated In fatigue crack propagation tests on 2024-T3 Alclad sheet specimens. After precracklng until a crack of 40 mm was obtained crack stoppers were Installed and the fatigue test was continued. Crack stoppers Installed In stop holes were: a blind rivet, a hard driven rivet, a heavily tightened...

A check of crack propagation prediction models against test results generated under transport aircraft flight simulation loading

The GARTEUR Group of Responsables for Structures and Materials identified the need for an evaluation of fatigue crack propagation models. This resulted in a collaborative GARTEUR activity in which 13 variations of the F-27 transport spectrum were evaluated by 7 institutes and companies using in total 13 crack propagation prediction methods and...

Flight simulation fatigue crack propagation in metal/carbon-epoxy laminates

Flight simulation fatigue crack propagation tests with gust spectrum loading were carried out on laminates of (i) aluminium alloy 2024-T3/carbon-epoxy, (ii) aluminium alloy 7475-T761/carbon-epoxy and (iii) titanium alloy Ti-6Al-4V/carbon-epoxy with nominal weight savings of 30% and 40% as compared to equivalent 2024-T3 Alclad and 7475-T761...

Review of aeronatical fatigue investigations in the Netherlands during the period march 1977 - february 1979

Paper presented at the 16th ICAP Conference, Brussels, 14 and 15 May 1979.

Manoeuvre spectrum fatigue crack propagation in aluminium alloy sheet materials

2024-T3, 2048-T851, 7075-T6 and 7475-T761 aluminium alloy sheets were compared for fatigue crack propagation resistance under manoeuvre spectrum and constant amplitude loading. For manoeuvre spectrum loading 7475-T761 was superior overall, and this superiority is most probably due to superior toughness of this alloy. In more detail, 2024-T3 was...

The effect of sheet thickness on flight simulation fatigue crack propagation in 2024-T3, 7475-T761 and mill annealed Ti-6A1-4V

Flight simulation fatigue crack propagation tests were carried out on 2024-T3, 7475-T761 and mill annealed Ti-6A1-4V sheet in thicknesses up to 3 nim and representative for traJisport aircraft lower wing skin stiffened panels of end load capacities 1.5 and 3 MN/m. There was a significant effect of sheet thickness on crack propagation. Thinner...

The effect of sheet edge working on the fatigue life under flight-simulation loading

Fatigue tests under flight-simulation loading have been performed on unnotched Alclad 2024-T3, anodised 2.0 mm thick sheet specimens, manufactured according to several machine-shop processes applied in the air craft industry. From the results it appears that milling is preferable to stamping. Rounding off the edges is also advantageous. The...

Heat treatment studies of aluminium alloy forgings of the AZ 74.61 type. Interim report no. 3: Fatigue crack propagation performance under manoeuvre spectrum loading

The fatigue crack propagation performance of the alloy AZ 74.61 under manoeuvre spectrum loading was studied. The crack propagation behaviour was also compared with that of the American forging alloy AA 7050, not only for simulated manoeuvre loading but also for simulated gust loading and programme loading. It was found that, at comparable...

Heat treatment studies of aluminium alloy type 7050 forgings. Interim report no. 2: The effect of heat treatment on a variety of engineering properties

The effect of variety of heat treatments on various engineering properties was studied with the aim to derive an optimum heat treatment. The engineering properties comprised Vickers hardness, short-time tensile strength, fatigue crack propagation resistance, fracture toughness and stress corrosion resistance. The test results were compared with...

Fracture toughness and fatigue properties of the new aluminium alloy 7475-T76

Residual strength tests have been performed on 610 mm wide centre cracked panels. During the tests, stable crack growth was filmed and crack opening displacements were measured. Fracture toughness was determined using the method of Feddersen. Flight simulation fatigue tests were carried out to investigate the crack propagation properties. A...

Flight-simulation tests on notched elements

Tests were carried out on open-hole specimens, lugs and riveted strap joints of 2024-T3 and 7075-T6 materials. The effects of design stress level, truncating high-amplitude gust loads and omitting low-amplitude gust cycles were stuaied. Observations of the open-hole specimens include data on crack initiation, crack closure and damage increments....