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Fuselage structures are subjected to combinations of axial, bending, shear and differential pressure loads. The validation of advanced metallic and composite fuselage designs against such loads is based on the full-scale testing of the fuselage barrel, which, however, is highly demanding from a time and cost viewpoint. This paper aims to assist in scaling-down the experimentation to the stiffened panel level which presents the opportunity to validate state-of-the-art designs at higher rates than previously attainable.

Development of a methodology to successfully design tests at the stiffened panel level and realize them using advanced, complex and adaptable test-rigs that are capable of introducing independently a set of distinct load types (e.g. internal overpressure, tension, shear) while applying appropriate boundary conditions at the edges of the stiffened panel.

A baseline test-rig configuration was developed after extensive parametric modelling studies at the stiffened panel level. The realization of the loading and boundary conditions on the test-rig was facilitated through innovative supporting and loading system set-ups.

The proposed test bench is novel and compared to the conventional counterparts more viable from an economic and manufacturing point of view. It leads to panel responses, which are as close as possible to those of the fuselage barrel in-flight and can be used for the execution of static or fatigue tests on metallic and thermoplastic curved integrally stiffened full-scale panels, representative of a business jet fuselage.

When smelting Al-Li alloy, the material inevitably comes into contact with various oxide-refractories. These refractories are subjected to varying degrees of melt-corrosion at high temperatures. The purpose of this study is to find stable oxide refractories at casting temperature.

Four materials were selected for evaluation, and their corrosion by the Al-Li alloy at casting temperature and different holding times was measured. Subsequently, scanning electron microscopy and energy-dispersive spectroscopy were used to study the interfaces. Stable refractory materials were selected by comparing the thicknesses of the reaction layers.

The thickness of the Al-Li/ZrO₂ reaction layer varies linearly with the square root of the holding duration. Therefore, the growth of the reaction layer is controlled by diffusion. The reaction layer of Al-Li/Al₂O₃ is thinner, and its growth is also controlled by diffusion. However, there were no obvious reaction layers between the Al-Li alloy and MgO or Y₂O₃. By comparing these reaction-layer thicknesses, the order of stability was found to be ZrO₂ < Al₂O₃ < MgO and Y₂O₃.

These results provide a scientific basis for the optimal selection of refractory materials for Al-Li alloy smelting.

This paper aims to investigate the fretting wear mechanism of an Al-Li alloy at room temperature, the tangential fretting wear tests were carried out.

The effects of displacement amplitude and fretting frequency on the tangential fretting wear characteristics were mainly investigated. The experimental data obtained are analyzed and compared.

The results indicated that the fretting friction coefficient increased with the increase of displacement amplitude. As the displacement amplitude increased, the wear scar morphology changed significantly, mainly in terms of delamination debris and furrow scratches. The wear mechanism changed from initial mild wear to more severe oxidative wear, adhesive wear and abrasive wear.

This paper extends the knowledge into mechanical tight connections. The conclusions can provide theoretical guidance for the fretting of mechanical tight connections in the field of automotive lightweight and aerospace.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2019-0490/

Composite materials and metallic structures already compete for the next generation of single-aisle aircraft. Despite the good mechanical properties of composite materials metallic structures offer challenging properties and high cost effectiveness via the automation in manufacturing, especially when metallic structures will be welded. In this domain, metallic aircraft structures will require weight savings of approximately 20 per cent to increase the efficiency and reduce the CO₂ emission by the same amount. Laser beam welding of high-strength Al-Li alloy AA2198 represents a promising method of providing a breakthrough response to the challenges of lightweight design in aircraft applications. The key factor for the application of laser-welded AA2198 structures is the availability of reliable data for the assessment of their damage tolerance behaviour. The paper aims to discuss these issues.

In the presented research, the mechanical properties concerning the quasi-static tensile and fracture toughness (R-curve) of laser beam-welded AA2198 butt joints are investigated. In the next step, a systematic analysis to clarify the deformation and fracture behaviour of the laser beam-welded AA2198 four-stringer panels is conducted.

AA2198 offers better resistance against fracture than the well-known AA2024 alloy. It is possible to weld AA2198 with good results, and the welds also exhibit a higher fracture resistance than AA2024 base material (BM). Welded AA2198 four-stringer panels exhibit a residual strength behaviour superior to that of the flat BM panel.

The present study is undertaken on the third-generation airframe-quality Al-Li alloy AA2198 with the main emphasis to investigate the mechanical fracture behaviour of AA2198 BMs, laser beam-welded joints and laser beam-welded integral structures. Studies investigating the damage tolerance of welded integral structures of Al-Li alloys are scarce.

This paper aims to accomplish friction stir welding (FSW) of Al–Li alloy AA8090 to determine optimal settings of the process parameters for higher tensile strength and higher micro-hardness (MH) to achieve the objective of adequate butt-joint strength.

An empirical relation is implemented to govern the utmost influence parameters, i.e. tool rotation speed (TRS), tool transverse speed (TTS) and dwell time (DT). Taguchi grey relational analysis (GRA) was applied for multi-response optimization of response parameters. The grey relational grades (GRs) have been calculated for both the responses MH and ultimate tensile strength to get optimal parametric settings. The variance test has been performed to check the adequacy of the model.

The Taguchi L9 orthogonal array design was used in establishing the relation between input parameter and output parameter (tensile and MH). TTS and DT have been predicted to be the two most important parameters that influence the extreme quality features of joints by using friction stir welding. Scanning electron microscopy fractography shows the ductile failure of the welded joints.

The experimental trials provided the followings results, maximum ultimate tensile strength (UTS) of 219 MPa and MH 107.1 HV under 1,400 rpm of TRS, 40 mm/min of TTS and 8 s of DT founded the optimum value through GRA.

This paper aims to predict the performance of friction stir welded AA8090 joint.

In the present study, Al-Li AA8090 plates are butt joined using friction stir welding (FSW). The experiments are designed and optimized using a Taguchi-orthogonal array. The experiments are conducted at three different process parameters, i.e. tool rotational speed (TRS), tool transverse speed (TTS) and dwell time (DT). The ultimate tensile strength (UTS) and microhardness (MH) are considered as response parameters. In addition, a statistical tool (ANOVA) is used to check the adequacy of experiment results.

The maximum UTS of 220 MPa is obtained at a TRS of 1,400 rpm, tool TTS of 40 mm/min and DT of 15 s. The maximum microhardness is obtained for 1,400 rpm, 25 mm/min and 8 s, i.e. 108.6 HV. The microstructural showed that the minimum grain is observed at the nugget zone. Fractography analysis revealed the ductile behaviour of fractured surfaces.

From the reported literature, it has been observed that very limited work is reported on the FSW of AA8090 alloy. Further, the thermal behaviour of welded joint is also observed in this experimental work.

AA8090 aluminum alloy is used in industrial applications for weight reduction purposes. However, its usage is limited due to shortcomings such as low wear resistance. Hence, the purpose of this study is to improve the wear properties of the material. A particle strengthening mechanism was tried to improve the wear properties of materials.

AA8090 aluminum alloy composites were prepared by stir casting methods using AA8090, boron carbide (B₄C) and aluminum oxide (Al₂O₃) materials. Totally, four different types of composites were prepared, namely, AA/3Al, AA/1BC-2Al, AA/2BC-1Al and AA/3BC. Wear behavior and mechanical properties of the composites were analyzed by conducting wear test, microhardness test, tensile test and morphological analysis.

Results showed that the composite materials showed superior properties compared with AA8090 alloy due to the reinforcing effect of B₄C and Al₂O₃ particles. Further, the AA/3BC composite showed 12.9% and 10.8% enhancement in microhardness and tensile strength, respectively. Further, a minimum wear rate of 0.009 × 10^–3 mm³/m was observed for AA/3BC composite.

This study is original and would add new information to the literature. Further, it solves the problem of low wear resistance issues in AA8090 aluminum alloy materials.

EFA, the European Fighter Aircraft developed jointly by British Aerospace, MBB, Aeritalia and CASA, will be the world's first production aircraft to use the new super‐lightweight, aluminium‐lithium alloys for its primary structure.

A development with a great deal of potential, at least in the military field, is the production of so‐called ‘intelligent skins’. The technology for these will form part of that required for smart structures, that is those that contain sensors and actuators embedded within the laminate with built‐in signal processing and adaptive control. The intelligent skin is a step towards this technology since it contains fibre optic sensors that can be used to sense strain, temperature, deformation, pressure and other conditions. If the sensor does not need to be embedded or is to be used on metallic structures, the fibre optics can be adhered to the surface.