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Viewing 1 to 30 of 5193
2017-10-08
Technical Paper
2017-01-2186
Lukas Urban, Michael Grill, Sebastian Hann, Michael Bargende
The development of IC engines is a complex process where 0D/1D-simulation tools became more important in the past few years. Different designs can be investigated in very early stages of the development process without the expensive buildup of prototypes and it is possible to get reliable results with passable effort. The quality of the overall simulation results depends on the quality of the sub-models. Simulation of the combustion process in natural-gas SI engines relies on predictive models for burn rates and knock. Existing knock models for gasoline fuels are based on a time-integrated ignition delay, using a fitted Arrhenius equation. Within a research project an enhanced knock-model approach for methane based fuels was developed. Chemical kinetics models were used to calculate the auto-ignition times for various temperatures, pressures and air-fuel-ratios (AFR).
2017-10-08
Technical Paper
2017-01-2202
Shiyou Yang
This work presents an application of two sub-models relative to chemical-kinetics-based turbulent pre-mixed combustion modeling approach on the simulation of burn rate and emissions of spark ignition engines. In present paper, the justification of turbulent pre-mixed combustion modeling directly based on chemical kinetics plus a turbulence model is given briefly. Two sub-models relative to this kind of pre-mixed combustion modeling approach are described generally, including a practical PRF (primary reference fuel) chemical kinetics mechanism which can correctly capture the laminar flame speed under a wide range of Ford SI (spark ignition) engines/operating conditions, and an advanced spark plug ignition model which has been developed by Ford recently.
2017-09-26
Event
The future of Aerospace Operations modeling and simulation requires the development of new technologies and concepts, and the capability to integrate complex systems to satisfy the needs of future aerospace operations. Presentations are solicited in Aerospace Modeling and Simulation. These sessions will provide a forum for international discussion and information on leading-edge research and development associated with insights of future concept elements and technologies in aerospace operations.
2017-09-26
Event
The future of Aerospace Operations modeling and simulation requires the development of new technologies and concepts, and the capability to integrate complex systems to satisfy the needs of future aerospace operations. Presentations are solicited in Aerospace Modeling and Simulation. These sessions will provide a forum for international discussion and information on leading-edge research and development associated with insights of future concept elements and technologies in aerospace operations.
2017-09-23
Technical Paper
2017-01-1952
ChengJun Ma, Fang Li, Chenglin Liao, Lifang Wang
With the increasing number of vehicles, the load of urban traffic system becomes more serious, and the Automatic Parking System (APS) plays an important role in alleviating the burden of drivers and improving vehicle safety. Therefore, it is essential to study high performance automatic Parking technology. The APS is consisted of environmental perception, path planning and path following.The path following controls the lateral movement of vehicle during the parking process, and requires the trajectory tracking error to be as small as possible. At present, some control algorithms are used including PID control, pure pursuit control, etc. However, these algorithms relying heavily on parameters and environment, have some problems under large curvature conditions, such as slow response and low precision. To solve this problem, a path following control method based on Model Predictive Control (MPC) algorithm is proposed in this paper.
2017-09-19
Technical Paper
2017-01-2018
Won Il Jung, Larry Lowe, Luis Rabelo, Gene Lee, Ojeong Kwon
Operator training using a real weapon in a real-world environment is risky, expensive, time-consuming, and restricted to the given environment. The simulator, or a virtual simulation, is usually employed to solve these limitations. As the operator is trained to maximize weapon effectiveness, the effectiveness-focused training can be completed. However, the training was completed in limited scenarios without guidelines to optimize the weapon effectiveness for an individual operator, thus the training will not be effective with a bias. For overcoming this problem, we suggest a methodology on guiding effectiveness-focused training of the weapon operator using big data and Virtual and Constructive (VC) simulations. Big data, which includes structured, unstructured, and semi-structured types, are generated by VC simulations under a variety of scenarios.
2017-09-19
Technical Paper
2017-01-2022
Katherine Loundy, Louis Schaefer, Andrew Foran, Catherine Ninah, Khristopher Bandong, Robert Brown, Hunter Heston, John-Paul Steed, William Young, Mark Heinrich, Luis Rabelo
The future of human exploration in the solar system is contingent on the ability to exploit resources in-situ to produce mission consumables. Specifically, it has become clear that the success of a manned mission to Mars will likely depend on fuel components created on the Martian surface. While several architectures for an un-manned fuel production surface facility on Mars exist in theory, a simulation of the performance and operation of these architectures has not been created. In this paper, the framework describing a simulation of one such architecture is defined. Within this architecture, each component of the base is implemented as a state machine, with the ability to communicate with other base elements as well as a supervisor. An environment supervisor is also created which governs low level aspects of the simulation such as movement and resource distribution, in addition to higher-level aspects such as location selection with respect to operations specific behavior.
2017-09-19
Technical Paper
2017-01-2025
Eugenio Rodriguez
One of the most important activities associated with the Aerospace and Defense industry is maintenance. Maintainability procedures have a direct impact of safety and operational availability of the system. The processes or procedures used during maintenance activities, whether removing and replacing a component of a system, or even conducting troubleshooting, are generally discrete by design, and in most cases, a maintainer, or a field service representative (FSR), will follow a sequence of steps as part of a maintenance work package or work instruction. Depending on the system, those maintenance activities could be complex, requiring many steps to complete. In order to successfully accomplish complex tasks, generally, one of two possibilities need to exist, either the maintainer is well trained and experienced, or the maintenance work instructions are extremely detailed and precise; both of options can be time consuming and expensive to achieve.
2017-09-19
Technical Paper
2017-01-2024
Natasha L. Schatzman, Narayanan Komerath, Ethan A. Romander
The crossing event of the blades of a coaxial counter-rotating rotor is a potential source of noise and severe blade loads. Blade crossings occur several times each rotor revolution. Most of the radial variation in the flow field can be efficiently captured by stacking the results of a 2-D analysis using two airfoils approaching each other at the appropriate relative Mach number and separation distance. Previously, this phenomenon was analyzed by simulating two airfoils passing each other at specified speeds and vertical separation distances, using the compressible Navier-Stokes solver OVERFLOW. The simulations explored thickness, circulation, and compressible effects. Results revealed the complex nature of the aerodynamic and fluid dynamic impulses generated by blade-blade interactions, with implications for aeroelastic loads and aeroacoustic sources.
2017-09-04
Technical Paper
2017-24-0139
Francesco Barba, Alberto Vassallo, Vincenzo Greco
The aim of the present study is to improve the effectiveness of the engine and aftertreatment calibration process through the critical evaluation of several methodologies available to estimate the soot mass flow produced by diesel engines and filtered by Diesel Particulate Filters (DPF). In particular, the focus of the present study has been the development of a reliable simulation method for the accurate prediction of the engine-out soot mass flow starting from Filter Smoke Number (FSN) measurements executed in steady state conditions, in order to predict the DPF loading considering different engine working conditions corresponding to NEDC and WLTP cycles. In order to achieve this goal, the study was split into two parts: - Correlation between ‘wet soot’ (measured by soot filter weighing) and the ‘dry soot’ (measured by the Micro Soot Sensor MSS).
CURRENT
2017-07-06
Standard
AIR6297
This document describes a method to calculate noise level adjustments at locations behind an airplane (described by an angular offset or directivity) at the start of takeoff roll (SOTR). This method is derived from empirical data from jet aircraft (circa 2004), most of which are configured with wing-mounted engines with high by-pass ratios (Lau, et al., 2012). Methods are also described which apply to modern turboprop aricraft.
2017-06-05
Technical Paper
2017-01-1802
Dong chul Lee, Insoo Jung, Jaemin Jin, Stephan Brandl, Mehdi Mehrgou
Abstract In the automotive industry, various simulation-based analysis methods have been suggested and applied to reduce the time and cost required to develop the engine structure to improve the NVH performance of powertrain. This simulation is helpful to set the engine design concept in the initial phase of the powertrain development schedules. However, when using the conventional simulation method with a uniformed force, the simulation results sometimes show different results than the test results. Therefore, in this paper, we propose a method for predicting the radiated noise level of a diesel engine using actual combustion excitation force. Based on the analytical radiated noise development target, we identify the major components of the engine that are beyond this development target by in the frequency range. The components of the problem found in this way are reflected in the engine design of the early development stage to shorten the development time.
2017-06-05
Technical Paper
2017-01-1892
Yosuke Tanabe, Masanori Watanabe, Takafumi Hara, Katsuhiro Hoshino, Akira Inoue, Masaru Yamasaki
Abstract Predicting the vibration of a motor gearbox assembly driven by a PWM inverter in the early stages of development is demanding because the assembly is one of the dominant noise sources of electric vehicles (EVs). In this paper, we propose a simulation model that can predict the transient vibration excited by gear meshing, reaction force from the mount, and electromagnetic forces including the carrier frequency component of the inverter up to 10 kHz. By utilizing the techniques of structural model reduction and state space modeling, the proposed model can predict the vibration of assembly in the operating condition with a system level EV simulator. A verification test was conducted to compare the simulation results with the running test results of the EV.
2017-06-05
Technical Paper
2017-01-1788
Kishore Chand Ulli, Upender Rao Gade
Abstract Automotive window buffeting is a source of vehicle occupant’s discomfort and annoyance. Original equipment manufacturers (OEM) are using both experimental and numerical methods to address this issue. With major advances in computational power and numerical modelling, it is now possible to model complex aero acoustic problems using numerical tools like CFD. Although the direct turbulence model LES is preferred to simulate aero-acoustic problems, it is computationally expensive for many industrial applications. Hybrid turbulence models can be used to model aero acoustic problems for industrial applications. In this paper, the numerical modelling of side window buffeting in a generic passenger car is presented. The numerical modelling is performed with the hybrid turbulence model Scale Adaptive Simulation (SAS) using a commercial CFD code.
2017-06-05
Journal Article
2017-01-1902
Guan Qiao, Geng Liu, Zhenghong Shi, Yawen Wang, Shangjun Ma, Teik Lim
Abstract Actuator and roller screw mechanism are key components of electromechanical brake (EMB) system in automotive and aerospace industry. The inverted planetary roller screw mechanism (IPRSM) is particularly competitive due to its high load-carrying capacity and small assembly size. For such systems, friction characteristic and friction torque generated from rolling/sliding contacts can be an important factor that affects the dynamic performance as well as vibration behavior. This paper investigates the modeling and simulation of the EMB system in early design stage with special attention to friction torque modelling of IPRSM. Firstly, a step-by-step system model development is established, which includes the controller, servo motor, planetary gear train and roller screw mechanism to describe the dynamic behavior of the EMB system.
2017-05-05
Magazine
Alternative fuels and challenges Automotive powertrain development: virtually-connected hardware co-simulation Functional Safety-progressing towards safer mobility Electric rockets and the future of satellite propulsion Achates powers toward production A potential ICE game-changer, the Achates OP engine is being tooled up for production at one OEM while a new 2.7-L triple for light-truck demonstrations enters the build phase. Engineering with simulation and data Companies are discovering new simulation techniques, especially optimization; the next step is to combine simulation with sensor data and predictive analytics to create even more robust off-highway equipment.
CURRENT
2017-04-27
Standard
ARP1420C
The turbine-engine inlet flow distortion methodology addressed in this document applies only to the effects of inlet total-pressure distortion. Practices employed to quantify these effects continue to develop and, therefore, periodic updates are anticipated. The effects of other forms of distortion on flow stability and performance, and of any distortion on aeroelastic stability are not addressed. The guidelines can be used as necessary to create a development method to minimize the risk of inlet/engine compatibility problems. The degree to which guidelines for descriptor use, assessment techniques, and testing outlined in this document are applied to a specific program should be consistent with the expected severity of the compatibility problem.
2017-04-27
Magazine
Interoperability Standards Pave the Way for Modular Robotic Manipulators Solar Powering UAVs Deploying COTS Subsystems in UUVs Developing a Multi-Modal UGV Robot Control Interface Fast-Tracking Autonomous Vehicles with Simulation Gesture-Based Controls for Robots: Overview and Implications for Use by Soldiers Identifying the Flow Physics and Modeling Transient Forces on Two-Dimensional Wings Experimental Confirmation of an Aquatic Swimming Motion Theoretically of Very Low Drag and High Efficiency The Scaling of Loss Pathways and Heat Transfer in Small Scale Internal Combustion Engines A Guide for Developing Human-Robot Interaction Experiments in the Robotic Interactive Visualization and Experimentation Technology (RIVET) Simulation
2017-04-10
WIP Standard
ARP6538
The aerospace industry is facing some of its biggest challenges to date. Chief among these are range and endurance limitations, restricted flight envelopes caused by thermal constraints, increasing power demands, and power compatibility issues. Unlike past challenges, these are too complex to solve at just the component level, and a subsystem and/or air vehicle level analysis is necessary. An important tool utilized by aerospace community for this is modeling, simulation, analysis, and testing (MSAT). Unfortunately, there are as many modeling methods as there are model users. Thus, a set of modeling standards and guidelines is necessary in order to facilitate the interconnection and compatibility of electric power system models across industry. This document, the Dynamic Modeling and Simulation (DyMAS) Aerospace Recommended Practice, provides this.
2017-04-06
Magazine
Connectivity continues its advance More OEMs and Tier 1 suppliers are focusing on embedded telematic systems, hoping to displace aftermarket hardware. Tailoring fuel injection to control NOx The next big step to help heavy-duty diesel engines meet stricter emissions regulations involves adapting the fuel-injection system to the combustion needs. Active on safety Crash-avoidance technologies are vital "building blocks" to automate commercial vehicles, implement truck platooning and ultimately achieve zero accidents. Engineering with simulation and data Companies are discovering new simulation techniques, especially optimization; the next step is to combine simulation with sensor data and predictive analytics to create even more robust off-highway equipment.
2017-03-28
Technical Paper
2017-01-0250
Jizhou Zhang, Jianhua Zhou, Mian LI, Min Xu
Abstract Manufacturing of the internal combustion engines (ICEs) has very critical requirements on the precision and tolerance of engine parts in order to guarantee the engine performance. As a typical complex nonlinear system, small changes in dimensions of ICE components may have great impact on the performance and cost of the manufacturing of ICES. In this regard, it is still necessary to discuss the optimization of the tolerance and manufacturing precision of the critical components of ICEs even though the tolerance optimization in general has been reported in the literature. A systematic process for determining optimal tolerances will overcome the disadvantages of the traditional experience-based tolerance design and therefore improve the system performance.
2017-03-28
Technical Paper
2017-01-0260
Yuanying Wang, Heath Hofmann, Denise Rizzo, Scott Shurin
Abstract This paper presents a computationally-efficient model of heat convection due to air circulation produced by rotor motion in the air gap of an electric machine. The model calculates heat flux at the boundaries of the rotor and stator as a function of the rotor and stator temperatures and rotor speed. It is shown that, under certain assumptions, this mapping has the homogeneity property. This property, among others, is used to pose a structure for the proposed model. The coefficients of the model are then determined by fitting the model to the results of a commercial Computational Fluid Dynamics (CFD) simulation program. The accuracy of the new model is compared to the CFD results, shown an error of less than 0.3% over the studied operating range.
2017-03-28
Technical Paper
2017-01-0264
Venkatesh Babu, Ravi Thyagarajan, Jaisankar Ramalingam
Abstract In this paper, the capability of three methods of modelling detonation of high explosives (HE) buried in soil viz., (1) coupled discrete element & particle gas methods (DEM-PGM) (2) Structured - Arbitrary Lagrangian-Eulerian (S-ALE), and (3) Arbitrary Lagrangian-Eulerian (ALE), are investigated. The ALE method of modeling the effects of buried charges in soil is well known and widely used in blast simulations today [1]. Due to high computational costs, inconsistent robustness and long run times, alternate modeling methods such as Smoothed Particle Hydrodynamics (SPH) [2, 9] and DEM are gaining more traction. In all these methods, accuracy of the analysis relies not only on the fidelity of the soil and high explosive models but also on the robustness of fluid-structure interaction. These high-fidelity models are also useful in generating fast running models (FRM) useful for rapid generation of blast simulation results of acceptable accuracy.
2017-03-28
Technical Paper
2017-01-0261
Randolph Jones, Robert Marinier III, Frank Koss, Robert Bechtel, John A. Sauter
Abstract When evaluating new vehicle designs, modeling and simulation offer techniques to predict parameters such as maximum speed, fuel efficiency, turning radius, and the like. However, the measure of greatest interest is the likelihood of mission success. One approach to assessing the likelihood of mission success in simulation is to build behavior models, operating at the human decision-making level, that can execute realistic missions in simulation. This approach makes it possible to not only measure changes in mission success rates, but also to analyze the causes of mission failures. Layering behavior modeling and simulation on underlying models of equipment and components enables measurement of more conventional parameters such as time, fuel efficiency under realistic conditions, distance traveled, equipment used, and survivability.
2017-03-28
Technical Paper
2017-01-0182
Gautam Peri, Saravanan Sambandan, S. Sathish Kumar
Abstract Cool down of a passenger vehicle cabin is a preferred method to test the efficiency of the vehicle HVAC (Heating, Ventilation and Air Conditioning) system. The intended primary objective of a passenger vehicle air conditioning system is to ensure thermal comfort to the passengers seated inside at all prevailing conditions. Presently 1-D analysis plays a major role in determining the conformation of the selected system to achieve the desired results. Virtual analysis thus saves a lot of time and effort in predicting the system performance in the initial development phase of the vehicle HVAC systems. A variety of parameters play an important role in achieving the above thermal comfort. Thermal comfort is measured using the Human comfort sensor for all the passengers seated inside.
2017-03-28
Technical Paper
2017-01-1141
Bashar Alzuwayer, Robert Prucka, Imtiaz Haque, Paul Venhovens
Abstract Fuel economy regulations have forced the automotive industry to implement transmissions with an increased number of gears and reduced parasitic losses. The objective of this research is to develop a high fidelity and a computationally efficient model of an automatic transmission, this model should be suitable for controller development purposes. The transmission under investigation features a combination of positive clutches (interlocking dog clutches) and conventional wet clutches. Simulation models for the torque converter, lock-up clutch, transmission gear train, interlocking dog clutches, wet clutches, hydraulic control valves and circuits were developed and integrated with a 1-D vehicle road load model. The integrated powertrain system model was calibrated using measurements from real-world driving conditions. Unknown model parameters, such as clutch pack clearances, compliances, hydraulic orifice diameters and clutch preloads were estimated and calibrated.
2017-03-28
Technical Paper
2017-01-0903
Sarp Mamikoglu, Jelena Andric, Petter Dahlander
Abstract Many technological developments in automobile powertrains have been implemented in order to increase efficiency and comply with emission regulations. Although most of these technologies show promising results in official fuel economy tests, their benefits in real driving conditions and real driving emissions can vary significantly, since driving profiles of many drivers are different than the official driving cycles. Therefore, it is important to assess these technologies under different driving conditions and this paper aims to offer an overall perspective, with a numerical study in simulations. The simulations are carried out on a compact passenger car model with eight powertrain configurations including: a naturally aspirated spark ignition engine, a start-stop system, a downsized engine with a turbocharger, a Miller cycle engine, cylinder deactivation, turbocharged downsized Miller engine, a parallel hybrid electric vehicle powertrain and an electric vehicle powertrain.
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