Search Results

iOS devices, including iPhones and iPads, are being used increasingly for professional and scientific applications. Using an iOS device for noise and vibration measurements is an application with many advantages, given its small size, availability, cost, and ease of operation. A system for measuring noise level, logging noise over time, doing FFT frequency analysis of sound, and measuring speech intelligibility has been created. This platform has been developed to use either an iPhone or iPad as a host device. This provides a portable, cost-effective and easy to deploy test and measurement system. The main area of system performance concern is the transducer. The typical transducer in an iOS device is designed with speech analysis in mind, rather than wide-band acoustical analysis. Additionally, the iOS device gyroscope has been optimized to recognize gross movement, rather than detailed fine movement. The strategy for addressing these set of issues has been two-fold.

Comparison studies have been conducted on a 1:16th scale model and a full scale tractor trailer of a variety of sealed aft cavity devices as a means to develop or enhance commercial drag reduction technology for class 8 vehicles. Various base cavity geometries with pressure taps were created for the scale model. The studies confirmed that length has an important effect on performance. The interaction of the boat-tailed aft cavity with other drag reduction devices, specifically side skirts, was investigated with results showing no discernable drag performance interaction between them. Overall, the experiments show that a boat-tailed aft cavity can reduce the drag up to 13%. Full-scale tests of a commercially derived product based on these scale tests were also completed using SAE Type II testing procedures. Full-scale tests indicated a fuel savings of over 6.5%.

This paper reports the correlation of truck interior noise, near the driver's right ear, between driving on road and while operating on a dynamometer. It was a critical benchmark in the commissioning process of a heavy-duty truck anechoic chassis dynamometer. It required road load data to be gathered on a Proving Ground, using the Coast Down procedure detailed in SAE J2263 OCT96, and then simulated, while operating the same test vehicle on the dynamometer, using SAE J2264 APR95. The criteria for interior noise comparisons were typical Class 8 driving scenarios: constant high gear cruising, full power single gear acceleration runs, and engine braking. The analyses using these SAE standards, together with the final correlation results, are presented and discussed. A footnote is the unique challenge of Class 8 testing versus SAE coast down procedure, since truck transmissions must not be tested in Neutral, per SAE protocol, to avoid damage.

A new Low-Voltage Electromagnetic Riveting (LVER) machine has entered service at the Airbus UK wing factory in Broughton, Wales, in an assembly workcell for A320 family wing panels. The machine is based on existing Electroimpact technology but incorporates numerous design modifications to process tools, fastener feed hardware, machine structure and the control system. In the first months of production these modifications have demonstrated clear improvements in fastener installation cycle times and machine reliability.

It is well known that the spacing of planets in an epicyclic gear set is an important “macro” design feature that is used to balance planet load sharing, increase gear life and reduce gear whine. What is less understood is how the manufacturing tolerance of the position of the planet pins within the carrier, a “micro” phenomenon, affects the gear whine. This paper describes an analysis technique that can predict system level behaviour and shows that the inherent variability in the manufacturing processes has a very significant effect on the TE and thus generated gear whine. The manufacturing variability causes radial, circumferential and tilt displacements of planet gears - these phenomenon are all investigated.

Generally within engineering design, the current emphasis is on biasing the development process towards increased virtual prototyping and reduced “real” prototyping. Therefore there is a requirement for more CAE based automated optimisation, Design of Experiments and Design for Six Sigma. The main requirements for these processes are that the model being analysed is parametric and that the solution time is short. Prediction of gear whine behaviour in automatic transmissions is a particularly complex problem where the conventional FEA approach precludes the rapid assessment of “what if?” scenarios due to the slow model building and solution times. This paper will present an alternative approach, which is a fully parametric functionality-based model, including the effects of and interactions between all components in the transmission. In particular the time-varying load sharing and misalignment in the planetary gears will be analysed in detail.

The A380 aircraft is the largest passenger aircraft ever built and an appropriate machine was required to accomplish the fastening of the wing plank to stringer and buttstrap joints. The lower wing panels are curved along the length and move 1.42m out of plane. All previous E4000 machines had clampup heads that would extend and retract whatever distance was required to contact the wing panel. To improve toolpoint alignment, Electroimpact added a Z-axis that moves the yoke in order to reduce the necessary travel envelope of the clamp table axes and to cause them to clamp in the same plane regardless of panel position along the Z-axis.

Most new aircraft programs encounter the challenge of balancing the time required for design optimization with product delivery constraints. The high cost and long lead times of traditional tooling makes it difficult for aircraft manufactures to efficiently meet ever-changing market demands. The large size, low relative stiffness and high positional tolerances required for aircraft components drive the requirement for rigid fixed tooling to maintain the precision part relationships over time. Use of today’s advance 3-Dimensional CAD systems coupled with the high accuracy of CNC machines enables the success of the determinate assembly approach for aircraft tooling. This approach provides the aircraft manufacturer significant lead-time reductions while at the same time it supports enhanced system flexibility. Determinate assembly for aircraft tooling has been proven to be high successful for tooling manufacture on large-scale system such as the A380 and A340–600 wing assembly projects.

Vehicle diagnostics and information systems have followed separate, parallel evolutionary paths. In addition, advances in hardware technology and software architecture are making possible new, integrated systems that provide a wide range of capabilities. These new capabilities require a significant software investment just to create the telematics infrastructure to support wireless access to the vehicle, new displays, or a different vehicle bus interface. This paper discusses the benefits of software architecture for the on-vehicle portion of such a telematics infrastructure, the key drivers for such architecture, and the benefits being realized as the architecture evolves.

The Airbus A340-600 wing panel manufacturing system, which entered production in 1999, represents a major milestone for automated aircraft assembly. The new A340-600 system builds upon the success of the E4000 based A320 wing panel assembly system, which was introduced into production three years ago. The new A340-600 system consists of two 440 ft. assembly lines. One produces upper wing skin panels and the second produces lower skin panels. Each line consists of three fully automated CNC controlled flexible fixtures placed end to end serviced by two E4100 CNC assemble machines. Each fixture accepts multiple wing panels and can be automatically changed between the different configurations. Stringers are located and held using clamps mounted to “popping posts”. These posts automatically drop out of the machine path into the floor to provide clearance for complete stringer to skin fastening.

Robotic gripper technology has been integrated into CNC riveting machines. Handling fasteners efficiently is critical in automated wing panel riveting. Computer controlled rivet gripper and collar gripper technology has been developed that demonstrates high reliability and decreased fastener cycle times

British Aerospace needed an automated wing riveting system for fastening the A320 wing sections. The E4000 Wing Riveting System was designed and installed at their Airbus factory in Chester, UK and is now in production. It uses a five axis solid yoke with workheads on each end of the yoke. It accurately installs both rivets and lockbolts over the entire wing panel, including offset areas.