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Despite the increasing use of carbon fibre reinforced plastic (CFRP) composites, titanium and aluminium alloys still constitute a significant proportion of modern civil aircraft structures, which are primarily assembled via mechanical joining techniques. Drilling of fastening holes is therefore a critical operation, which has to meet stringent geometric tolerance and integrity criteria. The paper details the development of a three-dimensional (3D) finite element (FE) model for drilling aerospace grade aluminium (AA7010-T7451 and AA2024-T351) and titanium (Ti-6Al-4V) alloys. The FE simulation employed a Coupled Eulerian Lagrangian (CEL) technique. The cutting tool was modelled according to a Lagrangian formulation in which the mesh follows the material displacement while the workpiece was represented by a non-translating and material deformation independent Eulerian mesh.

The effect of the upstream wake of a Formula 1 car on a following vehicle has been investigated using experimental and computational methods. Multiple vehicle studies in conventional length wind tunnels pose challenges in achieving a realistic vehicle separation and the use of a short axial length wake generator provides an advantage here. Aerodynamic downforce and drag were seen to reduce, with greater force reductions experienced at shorter axial spacings. With lateral offsets, downforce recovers at a greater rate than drag, returning to the level for a vehicle in isolation for offsets greater than half a car width. The effect of the wake was investigated in CFD using multiple vehicle simulations and non-uniform inlet boundary conditions to recreate the wake. Results closely matched those for a full two-vehicle simulation provided the inlet condition included unsteady components of the onset wake.

A review of critical technologies and manufacturing advances that have enabled the evolution of the composite fuselage is described. The author’s perspective on several development, military, and production programs that have influenced and affected the current state of commercial fuselage production is presented. The enabling technologies and current approaches being used for wide body aircraft fuselage fabrication and the potential reasons why are addressed. Some questions about the future of composite fuselage are posed based on the lessons learned from today and yesterday.

Since, ice accretion can significantly degrade the performance and the stability of an airborne vehicle, it is imperative to be able to model it accurately. While ice accretion studies have been performed on airplane wings and helicopter blades in abundance, there are few that attempt to model the process on more complex geometries such as fuselages. This paper proposes a methodology that extends an existing in-house Extended Messinger solver to complex geometries by introducing the capability to work with unstructured grids and carry out spatial surface streamwise marching. For the work presented here commercial solvers such as STAR-CCM+ and ANSYS Fluent are used for the flow field and droplet dispersed phase computations. The ice accretion is carried out using an in-house icing solver called GT-ICE. The predictions by GT-ICE are compared to available experimental data, or to predictions by other solvers such as LEWICE and STAR-CCM+.

Based on the first sedan of the LYNK&CO brand from Geely, the high-performance configuration equipped with an additional aerodynamic package was developed. The aerodynamic package including front wheel deflectors, front lip, side skirts, rear spoiler, and rear diffuser, was required to be upgraded to generate enough aerodynamic downforce for better handling stability, without compromising the aerodynamic drag of the vehicle too much to keep a low fuel consumption. Starting from the baseline configuration of the aerodynamics package provided by the design studio, the components were optimized for aerodynamic drag and lift using the simulation approach with PowerFLOW in combination with a design space exploration method. As a result, the targets for the aerodynamic coefficients of the vehicle and in particular a good trade-off between lift and drag were achieved.

The lightning represents a fundamental threat to the proper operation of aircraft systems. For aircraft protection, Electromagnetic Compatibility requires conductive structure that will provide among all, electromagnetic shielding and protection from HIRF and atmospheric electricity threat. The interaction of lightning with aircraft structure, and the coupling of induced energy with harnesses and systems inside the airframe, is a complex subject mainly for composite aircraft. The immunity of systems is governed by their susceptibility to radiated or conducted electromagnetic energy. The driving mechanism of such susceptibility to lightning energy is the exposure to the changing magnetic field inside the aircraft and IR voltage produced by the flow of current through the structural resistance of the aircraft. The amplitude of such magnetic field and IR voltage is related to the shielding effectiveness of the aircraft skin (wiremesh, composite conductivity).

The paper is devoted to further development of numerical methods for simulation of riveting process during aircraft assembly (see [3, 4]). Algorithm modifications that increase computation accuracy, speed and complexity are given. These modifications involve the dual problem solving, incorporation of multiple calculation nets and special two stage procedure for calculation of deformations and stresses arising during assembly.

The Boeing Company is striving to improve quality and reduce defects and injuries through the implementation of lightweight “Right Sized” automated drill and fasten equipment. This has lead to the factory adopting Boeing developed and supplier built flex track drill and countersink machines for drilling fuselage circumferential joins, wing panel to spar and wing splice stringers. The natural evolution of this technology is the addition of fastener installation to enable One Up Assembly. The critical component of One Up Assembly is keeping the joint squeezed tightly together to prevent burrs and debris at the interface. Traditionally this is done by two-sided machines providing concentric clamp up around the hole while it is being drilled. It was proposed that for stiff structure, the joint could be held together by beginning adjacent to a tack fastener, and assemble the joint sequentially using the adjacent hole clamp up from the previous hole to keep the joint clamped up.

Radical new electrically propelled aircraft are being considered to meet strict future performance goals. One concept design proposed is a Turboelectric Distributed Propulsion (TeDP) aircraft that utilises a number of electrically driven propulsors. Such concepts place a new and significant reliance on an aircraft's electrical system for safe and efficient flight. Accordingly, in addition to providing certainty that supply reliability targets are being met, a contingency analysis, evaluating the probability of component failure within the electrical network and the impact of that failure upon the available thrust must also be undertaken for architecture designs. Solutions that meet specified thrust requirements at a minimum associated weight are desired as these will likely achieve the greatest performance against the proposed emissions targets.

Interiors of past vehicles were created to satisfy specific functions with appearance being a secondary consideration, but in the present & future market with ever increasing vehicle luxury, decoration of vehicle has become a prime focus in automobile industry along with the safety & economy. Automotive interiors have evolved over the years from a collection of trims covering bare sheet metal panels to add quality & richness of interior cabin, ultimately delivering greater value to customers. One such area in interiors is Side door trims serving the dual purpose of functionality and creating a pleasing environment too. The aesthetic appeal to the Side door trim is added usually through a Door trim insert having a decorative skin pasted on to the plastic base. And the selection of pasting technique for pasting decorative film on to the plastic base insert is a challenge for an automotive interior designer.

A mobile robotic system is presented as a new approach for machining applications of large aircraft components. Huge and heavy workshop machines are commonly used for components with large dimensions. The system presented in this paper consists of a standard serial robot kinematics and a mobile platform as well as a stereo camera system for optical measurements. Investigations of the entire system show that the mechanical design of the mobile platform has no significant influence on the machining accuracy. With mobile machines referencing becomes an important issue. This paper introduces an optical method for determining the position of the mobile platform in relation to the component and shows its accuracy limits. Furthermore, a method for increasing the absolute accuracy of the robots end-effector with help of stereo camera vision is presented.

Ground Vibration Testing (GVT) of aircraft is typically performed very late in the development process. Main purpose of the test is to obtain experimental vibration data of the whole aircraft structure for validating and improving its structural dynamic models. Among other things, these models are used to predict the flutter behaviour and carefully plan the safety-critical in-flight tests. Due to the limited availability of the aircraft for a GVT and the fact that multiple configurations need to be tested, an extreme time pressure exists to get the test results. The aim of the paper is to discuss recent hardware and software technology advancements for performing a GVT that are able to realize an important testing and analysis time reduction without compromising the accuracy of the results.

The demand of fulfilling the increasing requirements to shorten development lead times force suppliers to enhance modularity and flexible applicability of their machinery component portfolio. The presented examples show how basically similar machinery components, i.e. traveling column systems, can be applied for significantly different types of applications in the aircraft industry. Application examples are shown for drilling and installation of two-piece and blind rivet fasteners on box-type and barrel-type aircraft structures at Airbus Deutschland. It is shown how the basic drilling/riveting system is integrated into assembly stations and assembly lines and how it adapts to the varying operational requirements of A380 and A400M.

The rear end geometry of road vehicles has a significant impact on aerodynamic drag and hence on energy consumption. Notchback (sedan) geometries can produce a particularly complex flow structure which can include substantial flow asymmetry. However, the interrelation between rear end geometry, flow asymmetry and aerodynamic drag has lacked previous published systematic investigation. This work examines notchback flows using a family of 16 parametric idealized models. A range of techniques are employed including surface flow visualization, force measurement, multi-hole probe measurements in the wake, PIV over the backlight and trunk deck and CFD. It is shown that, for the range of notchback geometries investigated here, a simple offset applied to the effective backlight angle can collapse the drag coefficient onto the drag vs backlight angle curve of fastback geometries.

In this paper the design, fabrication and analysis of behavior by full-scale verification testing for the tail rotor blade of composite laminated materials for a heavy transport helicopter is given. The verification test program for the tail rotor blade encompassed static and dynamic testing. The static tests of the blade involved experimental evaluation of torsional and flexional blade stiffness and its elastic axis position. Dynamic tests involved testing of vibratory characteristics and testing of blade fatigue characteristic. In structural vibration tests natural frequency, vibration modes and damping ratio for the structure were measured. The fatigue analysis of the structure of blade root section was performed after fatigue test cycles for detection of laminate separation, tolerance and distortion of crossections of structure.

A unique perspective of system integration is presented in terms of statistical design and analysis. Advanced statistical concepts are employed to quantify the variance of the statistical models as well as to specify model truncation error. Three models are developed for this study: 1) a supersonic wing section; 2) a supersonic turbojet system and; 3) an integrated supersonic wing section and supersonic turbojet. The three models are analyzed and separately and surrogate models are developed for each model independently using Design of Experiments and advanced statistical analyses. The individual surrogate models are statistically validated compared to their respective models. The individual wing and turbojet surrogate models are then used to estimate the performance of the combined wing and turbojet system surrogate model performance.

A drill/ream cycle is necessary to produce high quality, large diameter holes in carbon-titanium stacks. Manual tool changes and traditional automatic tool changers limit hole-to-hole cycle times and hole quality. An in-process tool changer, mounted directly on the machine head, replaces a cutting tool with a reaming tool while clamp-up is maintained on the aircraft panel. By reducing or eliminating operator intervention, machine-axis moves, and optical resynchronization, an in-process automatic tool changer shortens cycle time, improves hole quality, and increases positional accuracy of holes. Automating this process also reduces risk of harm to the operator and aircraft structure.

Manufacturing C cross-sectional components with high aspect ratios out of carbon fiber reinforced composites is desirable by the aircraft industry. Modular AFP heads with short, fixed tow path have the fundamental performance characteristics required to successfully and productively automate the production of these part families. Aircraft parts in this family include wing spars, stringers, and fuselage frames.

Magneto-rhelological(MR) dampers are devices that use rheological fluids to modify the mechanical properties of fluid absorber. The mechanical simplicity, high dynamic range, large force capacity, lower power requirements, robustness and safe manner of operation have made MR dampers attractive devices for semi-active real-time control in civil, aerospace and automotive applications. Landing gear is one of the most essential components of the aircraft, which plays an extreme important role in preventing the airframe from vibration and excessive impact forces, improving passenger comfortable characteristics and increasing aircraft flight safety. In this paper, the semi-active system used in landing gear damping controller design, simulation, and the vibration test-bed are discussed and researched. The MR dampers employed in landing gear system were designed, manufactured and characterized as available semi-active actuators.

Currently the wing box rib assembly process requires the manual location and temporary fixing of components within product specific jig or fixtures for drilling. After drilling and reaming, parts are separated, cleaned, deburred prior to adding sealant, reclaiming and final bolting, but this may significantly increase cost, manufacturing lead-time, reduces flexibility and cannot usually be economically modified for use on other aircraft types. Due to potential increase in demand for the next generation single isle aircraft, existing tooling solutions have to be improved and new technologies have to be developed. This paper describes the development and testing of flexible tooling to provide clamping and support for drilling wing box ribs to mating rib posts within a restricted environment. Results are presented along with a discussion of the problems that may be encountered during clamping trials.