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Technical Paper

Decomposition and Coordination to Support Tradespace Analysis for Ground Vehicle Systems

2022-03-29
2022-01-0370
Tradespace analysis is used to define the characteristics of the solution space for a vehicle design problem enabling decision-makers (DMs) to evaluate the risk-benefit posture of a vehicle design program. The tradespace itself is a defined by a multi-objective solution space (the tradespace) populated by individual design solutions including a set of Pareto design solutions. Designs within the tradespace are defined by a set of input variables whose performance is assessed through a set of functional objectives defined by vehicle simulations. These functional objectives represent individual objectives in a multi-objective optimization problem (MOP). The functional objectives are derived from a combination of simulations to determine vehicle performance metrics and direct calculations using vehicle characteristics. The vehicle characteristics represent vendor specifications of vehicle subsystems representing various technologies.
Technical Paper

Fatigue Endurance Limit of Fasteners in Automotive Application

2022-03-29
2022-01-0260
Fastener commonly used in automotive industry plays an important role in the safety and reliability of the vehicle structural systems. In practical application, bolted joint would never undergo fully reversed loading, there always will be positive mean stress on bolt. The mean stress has little influence on the fatigue life if the maximum stress is lower than a threshold, which is the yield stress of the bolt. However, when the sum of the mean stress and the stress amplitude exceeds the yield stress, the endurance limit stress amplitude decreases fast as the mean stress increases. The purpose of this paper is to research fatigue endurance limit of fastener and establish the threshold for safe design in automotive application. In order to obtain the fatigue endurance limit at different mean stress levels, various mechanical tests were performed on M12x1.75 and M16x1.5 Class 10.9 fasteners using MTS test systems.
Technical Paper

Designing the Design Space: Evaluating Best Practices in Tradespace Exploration, Analysis and Decision-Making

2022-03-29
2022-01-0354
Determining the validity of the design space early in the conceptualization of a project can make the difference between project success and failure. Early assessment of technical feasibility, project risk, technical readiness and realistic performance expectations based on models with different levels of fidelity, uncertainty, and technical robustness is a challenging mission critical task for large procurement projects. Tradespace exploration uses model-based engineering analysis, design exploration methods, and multi-objective optimization techniques to enable project stakeholders to make informed decisions and tradeoffs concerning the scope, schedule, budget, performance and risk profile of a project. As the intersection with a number of project stakeholders, tradespace studies can provide a significant impact upon the direction and decision-making in a project.
Technical Paper

An Investigation of Aerodynamic Characteristics of Three Bluff Bodies in Close Longitudinal Proximity – Part 3: Influence on Lift

2022-03-29
2022-01-0904
The aerodynamic effects of bodies in close proximity continues to be an interest for those involved in aeronautical, automotive and civil engineering together with those involved in sports such as cycling, motor racing and sailing. For passenger cars, research in the USA published in the 1980s had considered travelling in close proximity, termed “platooning”, as a means for reducing congestion. But the aerodynamic drag reduction and fuel-savings found in associated wind tunnel tests and road-trials became the focus of further investigations. Although practical applications were not originally pursued, the recent development of control systems for connected and autonomous vehicles has provided the opportunity for platooning to be considered again within future traffic management systems.
Technical Paper

An Investigation of Aerodynamic Characteristics of Two Bluff Bodies in Close Longitudinal Proximity – Sensitivity to Front-End Geometry

2022-03-29
2022-01-0895
With an increasing focus on the reduction of greenhouse gases by transport industries and the continued development of connected and autonomous vehicle systems, the potential for aerodynamic drag reduction by means of managed systems of vehicles travelling in close-proximity, termed “platooning”, has continued as topic for research. For commercial vehicles the principle variable for drag reduction has been the inter-vehicle spacing since, in effect, the constituents of platoons are of similar geometry. Early-work in passenger car platooning was also conducted with homogeneous platoons, but more recently the use of systematic changes in upper-body geometry has provided a further variable in the assessment of platooning characteristics. The work shown in this paper adds to investigations illustrated in SAE Papers 2019-01-0659 and 2021-01-0952 using the Windsor model with interchangeable backlight angle geometry.
Technical Paper

Standard Approach to Identifying and Defining Functions for Systems Development and Safety Assessments

2022-03-08
2022-01-0008
The Safety Assessment Process, defined by SAE ARP 4761, associated regulatory guidance, and the system development process defined by SAE ARP 4754 are built on an understanding of the functions performed by a system or systems. These recommended practices do not provide, or reference, specific guidance regarding function definition, though they do provide some conventional airplane examples. The function is central to the entire development effort, and it is essential that the functions be identified and described such that the development and safety assessment processes can be applied consistently throughout the development program, and beyond. Without a systematic process for establishing and describing functions, the application of the development and safety assessment processes can be complicated by overly inclusive functions and functions applied at the wrong level of abstraction.
Technical Paper

An On-line path correction method based on 2D laser profile measurement for Gluing Robot

2022-03-08
2022-01-0016
Gluing is an essential fastening step in the field of aircraft assembly except for riveting and bolting. Generally, the robotic programs of gluing are generated in CAM environment. Due to the positioning errors and deformation of the workpiece to be glued in the fixture, the nominal pose and the actual pose of the workpiece are no longer consistent with each other. The Robot trajectory of dispensing glue are adjusted manually according to the actual pose of the workpiece by robot teaching. In this paper, an on-line gluing path correction method is developed by 2D laser profile measurement. A pose calibration method for 2D laser profiler integrated into a gluing robot by measuring a fixed center point of a standard ball is proposed to identify the position and orientation of the laser sensor, which enables the accurate transforming coordinates between the robot frame and the sensor frame. Meanwhile, the pose of the gluing tool mounted on the end of the robot is calibrated.
Technical Paper

Intuitive Robot Programming and Path Planning based on Human-Machine Interaction and Sensory Data for Realization of various Aircraft Application Scenarios

2022-03-08
2022-01-0011
Human-machine interaction (HMI) technologies enable the automation of various manufacturing and assembly applications while maintaining high flexibility. In this context, human-robot collaboration (HRC) capable robots should no longer function as autonomous systems, but much more as assistance systems or as colleagues for workers. In connection with shorter product life cycles, increasing variant diversity and individualization, the challenge arises to set up flexible robot systems, which can be reprogrammed and commissioned with little effort in a short period of time with preservation of the required accuracies. Therefore intelligent path planning is essential for development of flexible robot systems. In this paper different approaches are presented that allow the worker on the shop floor to rapidly and easily program a robot to implement new motion tasks based on a camera system without programming knowledge. Thereby various points are selected manually on an image.
Technical Paper

Simulation Environment for Modeling and Testing of Autonomous Assembly in Space for Multiple Robotic Arms

2022-03-08
2022-01-0012
Multi-arm robotic assembly in space is an increasingly popular research topic as robotic arms can be used to decrease repair costs. We propose a simulation framework to model different scenarios of multi-arm robotic assembly in space with an ever-changing harsh environment. Simulation is a valuable, viable, and low-cost option for testing the developed algorithms without the need to re-create the orbital conditions in an elaborate and expensive laboratory environment. The proposed simulation framework uses the open-source tools: ROS Kinetic and Gazebo 7. We propose a system where robotic arms coordinate and collaborate to drive a screw into a plate autonomously. A move-able robot with a 3D sensing camera maps the environment and, using image recognition and localization, notifies the arms of obstacles and the locations of the screw and plate models. The arms calculate a collision-free path to the model, grasp the object, and return to a shared location.
Technical Paper

Visualization Techniques for Simulation-Based Dependent Failure Analysis

2022-03-08
2022-01-0032
Failure analysis of engineering systems typically emphasises identification and mitigation under an independent failure assumption with dependent failures treated as the exception rather than the rule. Some frameworks for addressing dependent failures through analysis appear in standards including NUREG 0492, ISO 26262, MIL 1629 A, and ARP4761 amongst others. The purpose of identifying these dependencies is to allow system analysts to determine and quantify the factors that influence dependent fault probabilities. Once defined, failure relationships can be incorporated into a Discrete Event Simulation (DES) of the system, providing a mathematically rigorous estimate of system utility (e.g., availability, reliability). Nonetheless, the output of a simulation must not only provide an expected value of performance but also allow the analyst to identify the downstream impact of probabilistic dependencies between system elements.
Technical Paper

Integration of Big Data and Deep Learning for Weapon Combat Effectiveness

2022-03-08
2022-01-0030
This research paper deals with the importance of Weapon Combat Effectiveness (WCE) analytics and the difficulty in measuring this value in tandem with the added complexity of combat environments. This lack of acknowledgment has resulted in utilizing a limited number of scenarios and limiting other factors such as weapon system configurations. Our group has suggested that collecting big data through a federated Live-Virtual-Constructive (LVC) simulation architecture can provide a good assessment. Specifically, the goal is to intersect the areas of weapon combat effectiveness (WCE), defense modeling and simulation (DM&S), and defense with big data (DBD). This intersection will lead to new WCE analytics. However, our hypothesis goes beyond that: It is essential to use the advantages of deep learning to analyze noise, extrapolation, the vast depth of data, and the nonlinearities of data to enhance the analysis of VC simulations.
Technical Paper

Tool Wear Detection in Automated Drilling Operations of Aircraft Structure Components using AI Methods

2022-03-08
2022-01-0040
In fuselage barrels, the mechanical joints are fabricated using a riveting process. With the key feature of rivet bore size and quality of hole, the riveting operation can lead to serious defects with rivet play or fracture due to non-uniform load distribution. Conventional approaches of tool wear inspection lead to delayed diagnosis of tool wear, eventually leading to quality defects in the previous holes generated till the event of tool breakage. To increase the robustness of conventional tool wear inspection, the frequency of inspection is being increased leading to interruptions in productivity. Hence, online tool wear measurement and signaling systems provide efficient solutions with the elimination of direct methods of tool wear inspection. Therefore, this paper presents a feasibility study to detect tool wear in drilling operations using additional sensors combined with the use of AI methods.
Technical Paper

Information Retrieval for Aviation Applications

2022-03-08
2022-01-0044
There is a recurring need for automatic Information Retrieval (IR) from quality documents, price tags, part markings, receipts, purchase orders and technical manuals - which are otherwise non-parsable. IR coupled with search functionalities has a wide range of applications from warehouses, shop floors, marketplaces to even cockpits in the aviation sector. It helps in semi-automating workflows like document reviews, quality checks, collaborative Q&As and contextual extraction of information. These workflows make laborious tasks more intuitive and easier, thereby reducing the workload of the engineers using them. The paper describes an AI based IR platform which caters to the aforesaid scenarios in a scalable manner and integrates seamlessly with similar problems across different domains.
Technical Paper

Avionic Latch Optimization and Production using Additive Manufacturing

2022-03-08
2022-01-0048
Additive Manufacturing (AM) provides significant opportunities in aerospace applications, especially for low-volume, highly customizable parts. Besides the flexibility of part design, the approach offers significant potential of reducing product manufacturing complexity and improving in-service performance. This paper discusses an example which is in serial production at Howmet Fastening Systems. The part is a latch used in a hold-down assembly for avionics. The primary driver for the initiative was the need for increased torsional strength within the geometric constraints of the baseline design. Finite Element Analysis was used to redesign one load limiting component to improve overall torsional capability. Design for AM (DFAM) was used to successfully produce the parts without any defects with limited post-processing. Comprehensive testing included component tensile, fatigue, and microstructure characterization along with assembled part testing.
Technical Paper

Computer Aided Engineering-based Evaluation of a Purpose-built Tooling Concept for the Electroplating of Functional Coatings on Aerospace Components

2022-03-08
2022-01-0045
Industrial hard chrome plating is a rather complex, lengthy and labour-intensive process: typically, the low cathodic current efficiency of Cr plating baths results in limited deposition rates, taking an hour to deposit a thickness of 25 mm on any size of the part. In the majority of cases, the hard Cr plating process requires the use of tooling structures, making the process strongly operator-dependent and therefore, highly prone to errors. According to the Fokker Landing Gear BV team, operator-independence as well as process simplification are expected to be achieved by developing a purpose-built tooling concept. An intelligent support of employees in their increasingly complex work is also sought and thus far addressed by implementation of modern smart technologies. One of them is computer modeling and simulation, which enables to mirror the physical world in a virtual model.
Technical Paper

Super Flush Torque Controlled Screw

2022-03-08
2022-01-0017
Aerodynamic and cosmetic requirements are more and more stringent on new aircraft programs. External aircraft surfaces should ideally be free of any discontinuities and fasteners are usually local points of concern. While pins or lockbolts generally exhibit flush and smooth head surfaces, screws have inherent driving recesses which remain visible after finish paint application. Such screws are typically used in combination with anchor nuts to attach the panels closing thin wing boxes. The AeroDrive™ screw is a global solution to avoid recesses while improving mechanical characteristics of such structural joints. The AeroDrive™ screw features an additional drive head designed to break at a defined torque during installation, leaving a flush and smooth head surface.
Technical Paper

Accuracy Analysis for a Flow Line Process using a Mobile Holding Fixture for Machining CRFP Components

2022-03-08
2022-01-0041
The aerospace sector is challenged to produce airplanes more efficiently and resiliently in the future. This leads to an increasing demand for improving productivity and flexibility as well as providing solutions for sustainable developments. A bottleneck in production is the machining of large-scale components. Apart from the machining tasks, non-productive tasks like fixture adjustment, component handling, referencing and localization are performed within the machining station and can constitute up to 50% of the overall workload. In the UniFix project, Fraunhofer IFAM is participating in the development of a mobile fixture system for large-scale aircraft components, like vertical tail plane and landing flap components of the single aisle aircrafts.
Technical Paper

Towards an intelligent digital cabin twin to support an aircraft’s retrofit and base maintenance

2022-03-08
2022-01-0046
Aircraft are high value-adding and long-living assets, while aircraft cabins are expensive consumer products tailored to each customer. Vastly changing requirements and needs force aircraft holders regularly to instruct modifications to remain attractive on the market. Adaptations, modifications, and development of innovations are handled by multiple organizations, not by a central organization like the aircraft’s manufacturer or owner. Although the Continuing Airworthiness Management Organization manages all aircraft instance-specific documents as required by aviation regulations, their format and types of management differ. Besides, not all information that arises during a parts design phase is included. That means, overall, the consistent model-based maintenance of data within all phases of PLM up to disposal is not guaranteed.
Technical Paper

Skinny Fixture for Use with A Gantry Riveting Machine

2022-03-08
2022-01-0015
Electroimpact provides a solution of a gantry riveting machine which works in cooperation with a wing panel fixture. The fixture features stringer clamps along the length but also needs to reconfigure so that fasteners can be accessed by the heads of the machine. In a recent development we have made the header boards of the fixture both narrow in width and shallow in depth. This has a large operational advantage. Almost all of the fasteners can be installed without disturbing the tooling. And the motions of the tooling are considerably reduced. This was a cooperative effort of the tooling designers and the machine designers, primarily on the stringer side of the panel. How much of a time savings does this provide in comparison with the previous approach? About 20%. This paper will explain how this was done. We have already implemented this solution on ten systems and more are in progress on major aircraft programs.
Technical Paper

Automatic segmentation of aircraft dents in point clouds

2022-03-08
2022-01-0022
Dents on the aircraft skin are frequent and may easily go undetected during airworthiness checks, as their inspection process is tedious and extremely subject to human factors and environmental conditions. Nowadays, 3D scanning technologies are being proposed for more reliable, human-independent measurements, yet the process of inspection and reporting remains laborious and time consuming because data acquisition and validation are still carried out by the engineer. For full automation of dent inspection, the acquired point cloud data must be analysed via a reliable segmentation algorithm, releasing humans from the search and evaluation of damage. This paper reports on two developments towards automated dent detention. The first is a method to generate a synthetic dataset of dented surfaces to train a fully convolutional neural network. Training machine learning algorithms need a substantial volume of dent data, which is not readily available.
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