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Technical Paper

Development of a Climate and Altitude Simulation Test Bench for Handheld Power Tools

2018-10-30
2018-32-0033
For evaluating the overall suitability of using innovative biofuels in handheld power tools such as chainsaws, trimmers and blowers, under any typical operating condition worldwide, a climate and altitude conditioning test bench was developed at the Institute of Energy Efficient Mobility (IEEM) of Karlsruhe University of Applied Sciences. The 6 m³ hermetically sealed and thermally insulated test chamber is large enough to fit the entire power tool. A two-stage refrigeration system with intake air drying and resistance heating allows for realistic temperature conditions to be set in the test chamber, ranging from arctic cold to tropical heat (-20 to 45 °C). Altitudes up to 3,000 m above sea level can be simulated using a throttle valve at the inlet of the chamber and a pressure-controlled rotary piston blower positioned downstream the test chamber outlet.
Technical Paper

Environmental and Sustainability Aspects of an Aviation Auxiliary Power Unit Analyzed with the Aid of Exergy

2018-10-30
2018-32-0071
During the past decade environmental and sustainability issues have become major problems to overcome since they have caused regional and global consequences. This paper discusses the environmental and sustainability aspects of Gas Turbine (GT) based aviation Auxillary Power Unit (APU) with the aid of exergy. Exergy is a potential tool to determine exergy destructions and losses and their true magnitudes and exact locations. In this study some exergy based parameters such as: exergetic efficiency, waste exergy ratio, exergy recoverability ratio, exergy destruction ratio, environmental impact factor, and exergetic sustainability index are proposed and investigated. Cycle operating parameters of the gas turbine cycle based APU such as compressor-pressure-ratio (rp,c), Turbine Inlet Temperature (TIT) have been chosen for analysis. Mathematical modeling of the cycle has been done and the same has been coded in MATLAB.
Technical Paper

Power Dissipation Optimization for Solid State Power Control Modules in Aircraft Secondary Power Distribution System

2018-10-30
2018-01-1930
In the last two decades, an aerospace industry trend in secondary power distribution concept has been dominated with power electronics technology which includes power converters and Power Control Modules based on Solid State Power Control (SSPC) switching elements. Those Power Control Modules, grouped around microprocessor based controllers and combined in a single electronic chassis have become a backbone of electrical power distribution systems on all major commercial and military transport aircraft. Due to the resistive properties of the semiconductor based SSPC devices, which behaviors can be described as nonlinear functions of ambient operating temperature, power distribution system integration with SSPCs is challenged and heavily affected with operating temperatures and power dissipation limits. Although, aircraft compartments where Power Control Modules are located are considered temperature and pressure controlled, high ambient operating temperatures are possible and expected.
Technical Paper

Challenges of Digital Twin in High Value Manufacturing

2018-10-30
2018-01-1928
Digital Twin is a dynamic digital representation of a real-world asset, process or system. Industry 4.0 has recognised Digital Twin as the game changers for manufacturing industries in their digital transformation journey. Digital Twin will play a significant role in improving consistency, seamless process development, and the possibility of reuse in subsequent stages across the complete lifecycle of the product. As the concept of Digital Twin is novel, there are several challenges that exist related to its phase of development and implementation, especially in high value manufacturing sector. The paper presents a thematic analysis of current academic literature and industrial knowledge. Based on this, eleven key challenges of digital twin were identified and further discussed. This work is intended to provide an understanding of the current state of knowledge around Digital Twin and formulate the future research directions.
Technical Paper

Improving Manufacturing Efficiencies Through Industry 4.0 Technologies in Aerospace

2018-10-30
2018-01-1929
In the age of 4th industrial revolution, Operational and Information Technologies are increasingly getting converged to help organizations to improve their topline through new innovative products and services. Organizations are able to improve bottom line by improving efficiencies through this transformation which is driven by convergence of many advanced technologies such as Advanced Sensors, Communication Technologies, Big Data, Advanced Analytics, Artificial Intelligence, Robotics, Additive Manufacturing, Virtual and Augmented Reality. New age Enterprises Digitization strategy journey continues to adopt technology lead multi-pronged approach to achieve their near-term and long-term goals. Aerospace and defense industry is dynamic and continuously evolving. It has stringent quality and production requirements to ensure consistency, reliability, and performance of products.
Technical Paper

Transient Stability Analysis of DC Solid State Power Controller (SSPC) for More Electric Aircraft

2018-10-30
2018-01-1927
The solid state power controller (SSPC) is one of the most important power electronic component of the aircraft’s electrical power distribution (EPS) system. This paper presents the architecture of the DC SSPC and provides the mitigation techniques for transient voltage overshoot during turn-off. The high source side inductance carries breaking current (9xnominal current) just before turn-off and induces large voltage transient across the semiconductor devices. Therefore, the stored inductive energy needs to be dissipated in order to prevent semiconductor switches from over-voltage/thermal breakdown. Three different transient voltage suppression (TVS) devices to reduce voltage stress across switches are included in the paper for detail study. The comprehensive comparison of the TVS devices is presented. In addition, the thermal impact of the TVS devices on the semiconductor switches is also analyzed.
Technical Paper

Energetic, Environmental and Range Estimation of Hybrid and All-Electric Transformation of an Existing Light Utility Commuter Aircraft

2018-10-30
2018-01-1933
Today it is necessary to face the energetic, environmental, and safety-related issues of a significant industrial sector such as aeronautic one. Even if it is a marginal contributor to today global GHG emissions (less than 3%), the increasing mobility of people is determining a continuous increase of air traffic with an annual rate of growth around 5%. Consequently, aviation will need to face four fundamental problems for the future: 1. the overall impact of aviation is expected to grow up to 10÷15% of global GHG emissions by 2050; 2. the emissions of pollutants by commercial aviation affects the fragile atmospheric layers in the low stratosphere; 3. the increasing age of the flying fleet also deals with increasing maintenance and safety issues; 4. the dependence on fossil fuels which deals strictly with areas which are characterized by significant problems of geopolitical instability and oscillations of prices.
Technical Paper

Power Quality Test Data Analysis for Aircraft Sub-System

2018-10-30
2018-01-1932
Aircraft sub-system development involves various combinations of testing and qualification activities to realize a flight worthy system. The sub-system needs to be verified for massive number of customer requirements. Power quality (PQ) testing is also an important testing activity carried out as a part of environmental qualification test. It is intended to verify the functionality of sub-system with various power disturbances, to determine the ability of a sub-system to withstand power quality disturbances. The sub-system being designed should be reliable enough to handle power quality anomalies. Power quality test generates enormous amount of test result data for analysis with millions of data samples depending on the test, and can be identified as Big Data. The engineer needs to analyze each set of test data as a part of post processing to ensure the power disturbances during testing are as per the standard requirements and functional performance of the sub-system is met.
Technical Paper

Definition of Test Conditions for High Voltage Aerospace Systems Using the IAGOS Atmospheric Dataset

2018-10-30
2018-01-1931
Aerospace electrical systems are continuing to increase their voltage levels to meet the on-board power demands of more-electric aircrafts (MEAs) where hydraulic and pneumatic systems are replaced with electrical equivalents. Higher power demands are leading to the use of higher voltages and as such it is essential to explore the behaviour of the insulation system in the aerospace environment. This degradation takes place in situations where equipment can be exposed to an aerospace environment consisting of operating temperatures up to 250 °C or as low as - 50 °C, varying air pressure, humidity and ozone. Understanding the impact of these variables on the ageing of high voltage insulation systems is crucial in predicting lifetime over the service life of an aircraft. This paper describes the results derived from an analysis of data within the In-service Aircraft for a Global Observing System (IAGOS) database. This database includes 47,000 flight profiles.
Technical Paper

A Structured Assurance Case for Commercial Off-The-Shelf (COTS) Airborne Electronic Hardware (AEH)

2018-10-30
2018-01-1939
One particular issue with Commercial Off-The-Shelf (COTS) components is that they are not developed to avionics industry standards and that their design and development data remain proprietary, hence are not available for review to the levels expected by those standards. The purpose of this research was to assess feasibility and to provide recommendations in how COTS components could be “assured” at system level, i.e. possibly going beyond ED-80/DO-254 for AEH or ED-79A/ARP-4754A standard for systems.
Technical Paper

Dynamic Stability Analysis of High-Speed Traction Drive CVT for Aircraft Power Generation

2018-10-30
2018-01-1936
The traction drive - integrated drive generator (T-IDG®) has been developed since 1999 to replace current hydrostatic transmission drive generators mounted on Japanese military aircrafts. The T-IDG® consists of a generator and a half-toroidal traction-drive continuously variable transmission (CVT), which maintains a constant output speed of 24,000 rpm, that is, 400Hz AC power supply. In terms of coping with recent trends of high-power electric drive aircraft (MEA) and the need for weight reduction, a high-speed traction-drive CVT is advantageous over current hydro-static drive transmissions. The torque on the half-toroidal CVT is transmitted through multiple power rollers. The equal load sharing among power rollers are typically controlled by mechanical-hydraulic feedback system, whose stability is one of the biggest issues for the high-speed traction-drive CVT.
Technical Paper

Modulation Index Limit Based Control Strategy for the More Electric Aircraft Generator System

2018-10-30
2018-01-1937
Vector based control strategies have been extensively employed for drive systems, and in recent times to the More Electric Aircraft (MEA) generator based systems. The core functionalities of the control scheme are usually to sustain the bus voltage and field weakening to maintain drive system controllability throughout a wide speed range. Typically, the control schemes for high speed generator systems uses a dedicated controller for field weakening that ensures AC voltage regulation within the modulation index limit. A drawback to these types of control is that the modulation index limit can be exceeded due to change in operating conditions or disturbance factors. This may lead to generator system instability. In this paper, an alternative control strategy has been investigated to address this drawback. The control scheme includes a dynamic limit for the generator reference voltages such that the modulation index limit is adhered.
Technical Paper

Multi-Organization Model Integration with AADL

2018-10-30
2018-01-1944
The Architecture Analysis and Description Language (AADL) is a modeling language for predictive analysis of real-time software reliant, safety critical systems that provides both the precision of formal modeling and the vendor-agnostic freedom of a text-based representation. These traits make AADL ideal for virtual integration, a process that enables early detection of integration defects through model integration of software, computer hardware, and interacting physical devices. AADL supports multiple domains of architectural analysis such as timing, latency, safety, scheduling, and security. Adventium Labs conducted an exercise to determine the applicability of agile software development tools and practices (e.g., continuous integration (CI) programming interface (API) sharing, test driven development (TDD)) to the AADL-based process of Architecture Centric Virtual Integration. Our exercise consisted of three teams: vendor, integrator, and customer.
Technical Paper

An Integrated Approach to Model Based Engineering with SysML, AADL and FACE

2018-10-30
2018-01-1942
Multiple model-based engineering (MBE) frameworks have emerged to cover the many requirements for the engineering of avionics systems: from early requirement capture to the final system and embedded software generation, through refinement and V&V activities. In this paper, we consider the SysML, AADL and FACE standards. They are promoted by different standardization bodies, with different objectives. We note they are often seen as competitive, while we argue it is the opposite: there is a potential for a synergistic coupling. To date, no complete open evaluation on the feasibility of such capability has been done. SysML covers early systems engineering activities: stakeholder needs elicitation, system requirements analysis, functional breakdown and architecture definition. AADL can then be leveraged to refine a more precise architecture of the embedded system under consideration, meeting specific architectural styles such as ARINC653 and perform detailed timing analysis.
Technical Paper

Model-Based System Engineering Methodology for Implementing Networked Aircraft Control System on Integrated Modular Avionics - Environmental Control System Case Study

2018-10-30
2018-01-1943
Integrated Modular Avionics (IMA) architecture host multiple federated avionics applications into a single platform and provides benefits in terms of size, weight and power. But, IMA brings a high level of complexity to aircraft control systems. In this context, a structured Model-Based Systems Engineering (MBSE) development method is promising to deal efficiently and effectively with the complex aircraft control system design. This paper presents a MBSE approach for the use case of the Environmental Control System (ECS) integration into the aircraft control architecture. The proposed methodology adapts the open source ARCADIA methodology and the Capella tool to evaluate a complete design cycle: starting with requirements capture from the aircraft level to streamlining the development, integration of avionics application in an ARINC 653 platform.
Technical Paper

A Methodology for Formal Requirements Validation and Automatic Test Generation and Application to Aerospace Systems

2018-10-30
2018-01-1948
Automation of Validation and Verification (V&V) leveraging Formal Methods, and in particular Model Checking, is seeing an increasing use in the aerospace domain. In recent years, Formal Methods have been used to verify systems and software and its correctness as a way to augment traditional methods relying on simulation and testing. Recent updates to the relevant aerospace regulations (e.g. DO-178C, DO-331 and DO-333) now have explicit provisions for utilization of models and formal methods in the software development process. In a previous paper a compositional methodology for the validation of aerospace systems has been described with application to Electrical Power Generation and Distribution Systems. In this paper we present an expansion of the previous work in two directions. First, we describe the application of the methodology to the validation of aerospace proximity sensing systems (PSS) showing the effectiveness of the method to a new aerospace domain.
Technical Paper

ED-247 (VISTAS) Gateway for Hybrid Test Systems

2018-10-30
2018-01-1949
Testing a full Aircraft System involving several on-board computers, physical I/O and communication buses require connecting them to adequate test benches to stimulate or monitor the I/O in a suitable way. These benches are under control of models that reproduce the flight situations that occur in a real Aircraft. In many situations, it makes sense to replace one or several real computers by a virtualized equivalent device. Basically, a software representation of the equipment running on a PC helps achieving V&V tasks, even when the real systems are not yet all available. Such a setup, combining real and virtualized systems is called "Hybrid Test System". But then, how can we handle I/O and buses on a virtual equipment? One answer to this is the ED-247 EUROCAE standard, also called "VISTAS", which recently has been brought to a mature state. The main idea behind is to encapsulate I/O or busses information in UDP multicast datagrams on an Ethernet network.
Technical Paper

Numerical and Experimental Analysis and Energy Model of a High Camber Wing

2018-10-30
2018-01-1955
This paper presents a coupled numerical and experimental study of an unconventional wing profile such as cp-180-050-gn (Cambered plate C=18% T=5% R=0.78). This wing profile deals with low speeds and is not currently used on any aircraft model. Otherwise it presents interesting performances that can be exploited for design of low speed STOL or VTOL aircraft by mean of the very high lift that it can generate and it simplicity which can fit with VAWT, drones specifically designed for low speed operations and cyclorotors. After a preliminary CFD assessment of the wing a complete experimental characterization also at high angles of attack has been performed. The excellent agreement between CFD and experiments has allowed producing a complete analysis of the behavior of the wing profile both before and after stall conditions. This study has the key objective of analyzing the viability of such an unconventional wing in traditional or over-stalling conditions.
Technical Paper

Wireless Sensor Networks – Design Methodology, Challenges and Guidelines for Avionic Systems

2018-10-30
2018-01-1951
Avionics industry is moving towards more electric & lightweight aircrafts. Wireless sensor networks help in achieving the same. There are numerous challenges in implementing the wireless sensor networks in safety critical as well as non-safety critical systems on board aircraft. Traditional design methods of wireless sensors network will not be sufficient in an Aircraft environment. In general this increases the complexity of in-flight wireless sensor hardware elements and network. This paper discusses the safety critical and non-safety critical sensor networks in an Aircraft. Security aspects of wireless sensor network at physical layer as well as higher layers. Also presents the outcome of the study with respect to isolation of the Wireless Sensor Network from external networks and neighboring network of other aircraft.
Technical Paper

Investigations on Microstructural, Mechanical Properties of Friction Stir Processed Aluminium -Graphene Nanoplatelets Composites

2018-10-30
2018-01-1957
The present exploration deals with the study of microstructural and mechanical properties of Friction stir processed (FSP) Pure Aluminium Graphene Nano platelets (GNPs) composites. The proportion of GNPs varied from 0.5 to 2.0 wt. % in pure aluminium matrix. Ultrasonic Assisted Stir Casting Technique (UASCT) was used for composites fabrication. Friction stir processing (FSP) has been employed for enhancement of mechanical properties through grain refinement. Mechanical test such as Tensile strength, Micro hardness, Fracture Toughness and Impact Strength are conducted. FESEM, Fractography and XRD analysis were used for characterization of prepared composites and inspection of reactions occurred during the synthesis of composites and after Friction stir processing. The analysis revealed that there was a uniform Plastic deformation of GNPs in the pure aluminium matrix with less porosity due to which there is enhancement progress in mechanical properties.
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