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Training / Education

Introduction to Rubber Science and Technology

2019-10-15
Rubber – a loosely cross-linked network of polymer chains that when strained to high levels will forcibly return to at or near it original dimensions. This course is designed to provide the participant with a thorough understanding of rubber’s engineering characteristics. This class will introduce the various sources of rubber, both natural and synthetic. The class will contrast the differences between rubber and plastics; including thermoplastic rubber. Detailed discussions on how to select the correct rubber polymer for the application, highlighting the pros and cons of each major rubber type.
Training / Education

Basics of Silicone Rubber Science and Technology

2019-10-14
Silicone rubber is comprised of inorganic-organic polymers. These materials consist of an inorganic backbone with organic side groups attached to silicon atoms. This family of polymers possesses unmatched versatility giving the formulator and user multiple forms and methods to cross link the polymers into rubber materials having the widest service temperature range of any rubber material. This course is designed to provide the participant with a thorough understanding of silicone’s engineering characteristics.
Training / Education

Applying DO-254 for Avionics Hardware Development and Certification

2019-09-26
The avionics hardware industry world-wide is now commonly required to follow DO-254 Design Assurance Guidance for Airborne Electronic Hardware for literally all phases of development: Safety, Requirements, Design, Logic Implementation, V&V, Quality Assurance, etc. The DO-254 standard is a companion to the software DO-178B standard; however, there are many differences between hardware and software which must be understood. This basic course introduces the intent of the DO-254 standard for commercial avionics hardware development.
Technical Paper

Forces vibration assistance for TA6V/CFRP drilling

2019-09-16
2019-01-1874
For aircraft structures, mechanical assembly using fasteners remains the most common technology. The setting of the numerous fasteners requires a large number of drilling operations. In the case of CFRP/TA6V stacks, the drilling still remains a technological challenge. Indeed the high-quality requirements by the aeronautic standards are limited by the fast damaging drilling tool phenomena. For TA6V, the forced assisted drilling provides a breakthrough technology. An axial forced oscillating displacement on the feed direction of the tool allows the creation of segmented chips. Those small chips are then easily evacuated from the cutting area using a vacuum device. This allows the improvement of the hole’s roughness and mastering the burr creation at the exit of the hole. The lubrication process is also enhanced during the exit sequence of the tool. For the CFRP/TA6V configuration, the segmented geometry of the chip avoids the roughness degradation on the composite part of the stack.
Technical Paper

C919 Trailing Edge Assembly Interchangeable Tooling

2019-09-16
2019-01-1880
Traditional Trailing Edge (TE) assembly that utilise fixtures for accurate positioning of aircraft (a/c) parts do not allow for removal of specific tooling from the fixtures to travel with the TE, post assembly. Instead, the tooling that positions all the primary a/c assembly datums generally utilise precision pins of various sizes that index and clamp the a/c ribs. Often it is difficult to remove the pins post assembly before the spar can be taken out of the fixture. Use of hammers is common place to hit pins out of holes which is less than ideal considering the a/c parts can be fragile and the tooling is precision set. Also, the Main Assembly Fixture (MAJ) that will receive the TE will inevitably need to relocate some if not all the primary a/c ribs and therefore will most likely be subject to some amount of persuasion.
Technical Paper

Optimization of automated airframe assembly process on example of A350 S19 splice joint

2019-09-16
2019-01-1882
The paper presents the numerical approach to simulation and optimization of A350 S19 splice assembly process. The main goal is to reduce the number of installed temporary fasteners while preventing the gap between parts from opening during drilling stage. The numerical approach includes computation of residual gaps between parts, optimization of fastener pattern and validation of obtained solution on input data generated on the base of available measurements. The problem is solved with ASRP (Assembly Simulation of Riveting Process) software. The described methodology is applied to the optimization of the robotized assembly process for A350 S19 section.
Technical Paper

Simulation of aircraft assembly via ASRP software

2019-09-16
2019-01-1887
ASRP (Assembly Simulation of Riveting Process) software is a special tool for modelling assembly process for large scale airframe parts. On the base of variation simulation, ASRP provides a convenient way to analyze, verify and optimize the arrangement of temporary fasteners. During the airframe assembly process certain criteria on the residual gap between parts must be fulfilled. The numerical approach realized in ASRP allows one to evaluate the quality of contact on every stage of the assembly process and solve verification and optimization problems for temporary fastener patterns. The paper is devoted to description of several specialized approaches that combine statistical analysis of measured data and numerical simulation using high-performance computing for optimization of fastener patterns, calculation of forces in fasteners needed to close initial gaps and identification of hazardous areas in junction regions.
Technical Paper

The benefits of using Composite Bearings in Aircraft Shock Absorbers

2019-09-16
2019-01-1898
This paper will use actual examples from aircraft recently introduced into service, to describe the main advantages of changing from the currently used metallic bearings, to composite bearings. Abstract: The introduction of composite bearing in a recently introduced twin aisle aircraft has resulted in: • Weight saving, by replacing bronze bearings with plastic bearings • Lowering of the particle count in the shock absorber oil, (Reduced contamination with metal particles) leading to reduced wear on seals and bearings. Qualification testing showed that Composite Bearings are able to provide longer service life than bronze bearings.
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