Ricky Curran

Optimization of aircraft fuselage assembly process using digital manufacturing

The work demonstrates the benefits of using digital methods for the development and optimization of large assembly manufacturing networks. Although an aircraft assembly has been used for this work, the methods and advantages of digital manufacturing techniques, which are demonstrated here, are equally applicable to any large assembly process, such as those used in the automotive, railway, and shipbuilding industries. The introduction of manufacturability into the design arena using advanced computer aided methods means that manufacturing engineers can operate more directly in assembly planning and concurrent engineering design. Network analyses carried out on the final assembly operations for a regional jet fuselage section using a methodical, step by step approach, shows that the process efficiency for workers carrying out fitting operations can be more than doubled when compared to existing shop floor performance figures. The more efficient use of operator time results in a simulated 19% improvement in financial efficiency, as the actual working hours required for assembly are reduced to below budgeted levels. The simulation predicts that these results can be achieved with one final assembly station. With two stations currently in use for the fuselage section, this means that a significant financial saving is possible in tooling expenditure.

Integration of friction stir welding into a multi-disciplinary aerospace design framework

Multidisciplinary design and innovative highly automated manufacturing methods are increasingly important to todays aircraft industry: multidisciplinary design because it reduces lead-time and results in a better design, and automated manufacturing methods because they are more capable and reduce manufacturing cost. In this paper a cost estimation model is presented that integrates the manufacturing cost of friction stir welded connections within a multidisciplinary design decision tool. Due to the fact that friction stir welding is a new manufacturing method, the cost estimation model is based on the actual process physics, meaning what the process looks like in terms of processing speeds and characteristics. As an integral part of a multidisciplinary design framework, the developed cost estimation model contributes to a design support tool that assesses not only manufacturing but also structural and aerodynamic issues. It is shown that the cost model developed can be integrated into this more holistic design process support architecture. The predicted costs are accurate to the historical data and allow tradeoff of manufacturing and economic considerations within the context of the multidisciplinary design tool. The tradeoff capability is highlighted through a presented case study that compares the friction stir welding process as an alternative solution to more tradition riveting. Most importantly, this results in a quantitative tradeoff between two processes that shows the manufacturing cycle time of friction stir welding to be reduced by 60% and the recurring assembly cost by 20%.

Intelligent Assembly Time Analysis Using a Digital Knowledge-Based Approach

The implementation of effective time analysis methods fast and accurately in the era of digital manufacturing has become a significant challenge for aerospace manufacturers hoping to build and maintain a competitive advantage. This paper proposes a structure oriented, knowledge-based approach for intelligent time analysis of aircraft assembly processes within a digital manufacturing framework. A knowledge system is developed so that the design knowledge can be intelligently retrieved for implementing assembly time analysis automatically. A time estimation method based on MOST, is reviewed and employed. Knowledge capture, transfer and storage within the digital manufacturing environment are extensively discussed. Configured plantypes, GUIs and functional modules are designed and developed for the automated time analysis. An exemplar study using an aircraft panel assembly from a regional jet is also presented. Although the method currently focuses on aircraft assembly, it can also be well utilized in other industry sectors, such as transportation, automobile and shipbuilding. The main contribution of the work is to present a methodology that facilitates the integration of time analysis with design and manufacturing using a digital manufacturing platform solution.

Value Analysis of Engine Maintenance Scheduling relative to Fuel Burn and Minimal Operating Costs

The paper presents the results from a study in coll aboration with an airline that looked at modeling the relationship of maintenance and fuel burn costs relative to minimizing the life cycle cost relative to schedule. The work has verified that the bucket theory presented in the paper is a correct and has a direct impact on t he scheduling interval. Ultimately, it was found that the maintenance schedule at the collabor ating company was overly long and could be reduced by 15-20%, to reduce total costs i n the longer term. The Genetic-Causal Approach was used in the cost modelling process and incorporated into the Value Operations Methodology. Consequently, the generic relevance of both these theories has been validated through the work presented. I. Introduction HE paper will present a value analysis approach as applied to the scheduling of maintenance for aircra ft engines. The work was carried out in collaboration with a collaborating airline and is of high impact in that it includes the coupling of the cost of fuel-burn as w ell as the cost of maintenance cost in investigatin g how to minimize airline Direct Operating Cost. At a more g eneric level, the paper gives insight in the develo pment and application of the Value Operations Methodology (VOM) that can be used to support a Value Driven Engin eering (VDE) approach.

Agent-Based Modeling and Simulation of Coordination by Airline Operations Control

This paper implements and compares four coordination policies through agent-based modeling and simulation (ABMS), motivated by the need to understand and further optimize coordination processes in the highly complex socio-technical air transportation system. Three policies are based on established practices, whereas a fourth is based on the joint activity coordination theory from the psychology research domain. For each of these four policies, the relation with the literature on coordination is identified. The specific application of the four policies concerns airline operations control (AOC), which cores functionality is one of coordination and taking corrective actions in response to a large variety of airline operational disruptions. In order to evaluate the four policies, an agent-based model of the AOC and crew processes has been developed. Subsequently, this agent-based model is used to assess the effects of the four AOC policies on a challenging airline disruption scenario. For the specific scenario considered, the joint-activity coordination-based AOC policy outperforms the other three policies. More importantly, the simulation results provide novel insight in the operational effects of each of the four AOC policies, which demonstrate that the ABMS allows to analyze the effectiveness of different coordination policies in the complex socio-technical air transportation system.

Use of Digital Manufacturing to Improve Management Learning in Aerospace Assembly

The primary goal of this work is to quantify any benefits that the use of digital manufacturing methods can offer when used upstream from production, for manufacturing process design and tool development. Animated build simulations have been generated and used to develop build procedures and tooling for a panel assembly for the new Bombardier CRJ1000 regional jet. The simulations were used to drive design for manufacture and assembly (DFMA) approaches for both the panel design and the tooling required to assemble and drill individual components prior to riveting. When the jig format was developed, its simulated performance was compared to that of current CRJ700/900 panel builds to identify and quantify any improvements in terms of tooling cost and panel build time. When comparing like for like functions between existing CRJ700/900 and the CRJ1000 tooling, it was predicted that the digitally assisted improvements had brought about a 4.9% reduction in jig cost. This was a direct consequence of the application of DFMA principles resulting in reduced material content. An evaluation of the build process for the CRJ1000 uplock panel, predicted a 5.2% reduction in the assembly time which was a result of improved jig functions as well as the implementation of lean principles to the work cell design around the jig, which reduced non-value added activities. Again, this was on a like for like basis comparing equivalent build procedures on both jigs for location and drilling activities. In addition to the improvement of the tooling functions used for the current apron and uplock assemblies, new jig functionality was added so that both the drilling and riveting functions could be carried out in a single jig for the new RJ1000 panel. This eliminated dis-assembly and re-mounting time for the uplock components between drilling and riveting processes and meant that moving the assembly to another station for riveting, was no longer required.

Benchmarking RAMS driven design best-practices in civil and military aerospace

This paper provides the results of a comparison between Commercial Aircraft and Military Aircraft Development programs, and its best practices towards Reliability, Availability, Maintainability and Supportability (RAMS). This comparison forms part of a research project aimed at the development of a RAMS Driven Design methodology supported by a Strategic Value Based decision model, to allow designers and operators of complex technical systems to make upfront the right decisions - based on a value function - for the most effective implementation of RAMS in the design process, given their type of technical system, operations, and development project.

An Integration Methodology for Automated Recurring Cost Prediction using Digital Manufacturing Technology

The need to account for the effect of design decisions on manufacture and the impact of manufacturing cost on the life cycle cost of any product are well established. In this context, digital design and manufacturing solutions have to be further developed to facilitate and automate the integration of cost as one of the major driver in the product life cycle management. This article is to present an integration methodology for implementing cost estimation capability within a digital manufacturing environment. A digital manufacturing structure of knowledge databases are set out and the ontology of assembly and part costing that is consistent with the structure is provided. Although the methodology is currently used for recurring cost prediction, it can be well applied to other functional developments, such as process planning. A prototype tool is developed to integrate both assembly time cost and parts manufacturing costs within the same digital environment. An industrial example is used to validate this approach.

The KNOMAD Methodology for Integration of Multi-Disciplinary Engineering Knowledge within Aerospace Production

The paper is associated with the integration of multi-disciplinary knowledge within a Knowledge Based Engineering (KBE)-enabled design framework. To support this integration effort, the KNOMAD methodology has been devised. KNOMAD stands for Knowledge Optimized Manufacture And Design and is a methodology for the analytical utilisation of multi-disciplinary engineering knowledge within design. The KNOMAD acronym can also be used to highlight KNOMAD’s formalized process of: (K)nowledge capture; (N)ormalisation; (O)rganizations; (M)odelling; (A)nalysis; and (D)elivery. The main contribution of the paper is to highlight the development of the KNOMAD methodology and to substantiate its individual steps with sufficient detail to support the application of KNOMAD in practice.

A Quantitative Metric for Workstation Design for Aircraft Assembly

This paper is to study an activity-time-based metric, called Non-Value-Added-Ratio (NVAR) which is the ratio between the time consumed by all non-value added activities and the total assembly time, for measuring the goodness of workstation design. With this metric, the manager will have a good sense of shopfloor operation, and the planner will have a target for designing workstations. This metric is specific to an assembly procedure in a workstation. To implement the metric, the shop floor activities are classified into three types, i.e., non-value-added (NVA), value-added (VA) and non-value-added-but-necessary (NVAN) activities. A closed-loop systematic approach is introduced for applying the new metric for continuous productivity improvement. Preliminary results with an industrial case study are presented. Although this metric is currently focusing on the aerospace industry, it can be equally well applied to other industry sectors.