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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

Flight Optimization Model on Global and Interval Ranges for Conceptual Studies of MEA Systems

2019-09-16
2019-01-1906
In development of more electric aircraft applications, it is important to discuss aircraft energy management on various level of aircraft operation. This paper presents a computationally efficient optimization model for evaluating flight efficiency on global and interval flight ranges. The model is described as an optimal control problem with an objective functional subjected to state condition and control input constraints along a flight path range. A flight model consists of aircraft point-mass equations of motion including engine and aerodynamic models. The engine model generates the engine thrust and fuel consumption rate for operation condition and the aerodynamic model generates the drag force and lift force of an aircraft for flight conditions. These models is identified by data taken from a published literature as an example. First, approximate optimization process is performed for climb, cruise, decent and approach as each interval range path.
Technical Paper

Analytical Model for Calibration Results performances enhancement, resulting in automated prescription for equipments

2019-09-16
2019-01-1878
The current aeronautical manufacturing sector is characterized by the high level of competence and the required requirement in its production processes, based on the objectives of profitability and safety (airworthiness). In recent years, there is a real revolution in the sector, where the most advanced tools for the organization and optimization of production are given priority, supported by the latest massively used techniques of automatic data collection. , their organized storage and their analytical classification. Metrology plays a key role in ensuring the quality and reliability of the information generated in these productive cycles. The provision of an analytical model of flexible measurement systems, capable and easily adaptable to the dynamics of the company, is presented as one of the pillars in which this new conception of production is based.
Technical Paper

Impact of Oil cooler on performance of Engine thermal management system

2019-08-15
2019-24-0178
Currently automotive design is facing multi facet challenges such as reduction in greenhouse gases, better thermal management, low cost solution to market, etc. Considering these challenges, effort has been taken to improve thermal management of engine while optimizing the cost of engine. This paper evaluate the impact of Oil cooler on Engine thermal behavior. To achieve this goal, Engine prototypes made with and without Oil cooler configuration. Further, engine performance and engine temperature behavior investigated with respect to with and without oil cooler configuration. Finally both configuration were validated at engine test bed and Vehicle level to understand real world behaviour of the system. Test results were compared for further optimization proposed in lubrication system.
Technical Paper

Balancing Hydraulic Flow and Fuel Injection Parameters for Low Emission and High-Efficiency Automotive Diesel Engines

2019-08-15
2019-24-0111
The introduction of new light-duty vehicle emission limits to comply under real driving conditions (RDE) is pushing the diesel engine manufacturers to identify and improve the technologies and strategies for further emission reduction. The latest technology advancements on the after-treatment systems have permitted to achieve very low emission conformity factors over the RDE, and therefore, the biggest challenge of the diesel engine development is maintaining its competitiveness in the trade-off “CO2-system cost” in comparison to other propulsion systems. In this regard, diesel engines can continue to play an important role, in the short-medium term, to enable cost-effective compliance of CO2-fleet emission targets, either in conventional or hybrid propulsion systems configuration. This is especially true for large-size cars, SUVs and light commercial vehicles.
Technical Paper

Quantification of Linear Approximation Error for Model Predictive Control of Spark Ignited Turbocharged Engines

2019-08-15
2019-24-0014
Modern turbocharged spark-ignition engines are being equipped with an increasing number of control actuators to simultaneously meet fuel economy, emissions and performance targets. The response time variations between a given set of engine control actuators tends to be significant during transients and necessitate highly complex actuator scheduling routines. Model Predictive Control (MPC) algorithms have the potential to significantly reduce calibration and control tuning efforts as compared to current methodologies that are designed around integration of multiple single-input single-output sub-system controllers. MPC systems simultaneously generate all actuator responses by using a combination of current engine conditions and optimization of a control-oriented plant model. To achieve real-time control the engine model and optimization processes must be computationally efficient without sacrificing effectiveness.
Technical Paper

Model based hybrid vehicle ideal control for eco-driving

2019-08-15
2019-24-0065
The predictive optimization of energy consumption and carbon dioxide emissions is currently heavily investigated and implemented for extended horizon driving control of hybrid vehicles for both light and heavy duty purposes. The complex architecture of hybrid vehicle can be used to optimize additional criteria, which reflect various and fluctuating constraints (like traffic density, maximum time of travel, load mass, external charging, weather – external temperature etc.). The driving strategy should assess the possibilities of re-charging an accumulator for the optimum combination of prime mover power (today, an internal combustion engine), electric motor power booster, considering recharging during stops (if possible), taking the rest of the trip and the need for electric boosting into account. Battery state of charge is kept in its best range. Energy recuperation including transformation efficiency is foreseen.
Technical Paper

Study of Friction Optimization Potential for Lubrication Circuits of Light-duty Diesel Engines

2019-08-15
2019-24-0056
Over the last two decades, engine research has been mainly focused on reducing fuel consumption in view of compliance with stringent homologation targets and customer expectations. As it is well known, the objective of overall engine efficiency optimization can be achieved only through the improvement of each element of the efficiency chain, of which mechanical constitutes one of the two key pillars (together with thermodynamics). In this framework, the friction reduction for each mechanical subsystems has been one of the most important topics of modern diesel engine development. In particular, the present paper analyzes the lubrication circuit potential as contributor to the mechanical efficiency improvement, by investigating the synergistic impact of oil circuit design, oil viscosity characteristics (including new ultra-low formulations) and thermal management. For this purpose, a combination of theoretical and experimental tools were used.
Technical Paper

Development of a hybrid power unit for Formula SAE application: ICE CFD-1D optimization and vehicle lap simulation

2019-08-15
2019-24-0200
The paper reviews the CFD optimization of a motorcycle engine, modified for the installation in a hybrid powertrain of a Formula SAE car. In a parallel paper [Development of a hybrid power unit for Formula SAE application: packaging optimization and thermo-mechanical design of the electric motor case], the choice of the donor engine (Ducati 959 “Panigale”) is thoroughly discussed, along with all the hardware modifications oriented to minimize the new powertrain dimensions, weight and cost, and guarantee the mechanical reliability. In the current paper, the attention is focused on two main topics: 1) CFD-1D tuning of the modified Internal Combustion Engine (ICE), in order to comply with the Formula SAE regulations, as well as to maximize the power output; 2) Simulation of the vehicle in racing conditions, comparison between a conventional and a hybrid powertrain
Technical Paper

Fuel-optimal Power Split and Gear Selection Strategies for a Hybrid Electric Vehicle

2019-08-15
2019-24-0205
In order to operate state-of-the-art hybrid electric vehicles (HEVs) at the lowest possible cost and with the least impact on the environment, the degrees of freedom available to their energy management, namely the power split, the internal combustion engine (ICE) on/off signal and the gear selection, need to be carefully controlled. In this paper, we propose an equivalent consumption minimization strategy (ECMS) that simultaneously optimizes the continuous power split and the discrete ICE on/off signal and gear selection of HEVs in a fuel-optimal way. First, we formulate the minimum-fuel optimization problem by identifying a mixed-integer convex model of the vehicle’s powertrain. Second, we derive the fuel-optimal control policy with Pontryagin’s Minimum Principle and non-smooth convex analysis. Third, we compute the charge sustaining optimal strategies combining single shooting and a bisection algorithm.
Technical Paper

Fuel Consumption and Pollutant Emission Optimization at Part and Full Load of a High-Performance V12 SI Engine by a 1D Model

2019-08-15
2019-24-0080
Modern internal combustion engines show complex architectures in order to improve their performance in terms of brake torque and fuel consumption. Concerning naturally-aspirated engines, the arrangement of intake and exhaust systems is crucial to get the prescribed target. An optimization of the intake port geometry, together with the selection of a proper valve timing, allow to improve the cylinder filling and hence the performance. This possibility is enhanced by a variable valve timing, even more with unphased intake and exhaust controls. The identification of an optimal calibration strategy at test bench usually requires long and expensive experimental activities. Focusing on these aspects, numerical tools can help to support engine calibration, especially in the early design phases. In the present work, a 12-cylinder naturally aspirated spark ignition engine is investigated. In a preliminary stage, the engine is experimentally tested under full load operation.
Technical Paper

Aero-Engine Inlet Vane Structure Optimization for Anti-Icing with Hot Air Film Using Neural Network and Genetic Algorithm

2019-06-10
2019-01-2021
An improved anti-icing design with film heating ejection slot and cover for the inlet part of aero-engine was brought out, which combines the interior jet impingement with the exterior hot air film heating and shows promising application for those parts manufactured with composite materials. A hybrid method based on the combination of the Back Propagation Neural Network (BPNN) and Genetic Algorithm (GA) is developed to optimize the anti-icing design for a typical aero-engine inlet vane in two dimensions. The optimization aims to maximize the heating performance of the hot air film, which is assessed by the heating effectiveness. The film-heating ejection angle and the cover opening angle are the two geometric variables to be optimized. Numerical model was established and validated to generate training and testing samples for BPNN, which was used to predict the objective function and find the optimal design variables in conjunction with the GA.
Journal Article

Process Regulations and Mechanism of WEDM of Combustor Material

2019-06-07
Abstract This study discusses the experimental investigation on WEDM of combustor material (i.e., nimonic 263). Experimentation has been executed by varying pulse-on time (Ton), pulse-off time (Toff), peak current (Ip), and spark gap voltage (Sv). Material removal rate (MRR), surface roughness (SR), and wire wear rate (WWR) are employed as process performance characteristics. Experiments are designed as per the box-Behnken design technique. Parametric optimization has also been performed using response surface methodology. Besides this, field-emission scanning electron microscope (FE-SEM) and an optical microscope are utilized to characterize WEDMed and worn-out wire surfaces. It is observed that both surfaces contain micro-cracks, craters, spherical droplets, and a lump of debris. Furthermore, the mechanism of recast layer formation has been critically evaluated to apprehend a better understanding of the technique. The key features of the experimental procedure are also highlighted.
Technical Paper

Multiphysics Multi-Objective Optimization for Electric Motor NVH

2019-06-05
2019-01-1461
Prediction and reduction of noise/vibration at the early design stage is important for motor design. Rapid design iterations require a platform where electromagnetic, structural and acoustic solvers can communicate with each other without user scripting or interventions. Based on the platform, multiple designs in a given design space need to be analyzed by distributed high performance computers automatically. To demonstrate such a multiphysics multi-objective optimization workflow, four geometrical variables for an interior permanent magnet motor are selected for optimizing the electric and acoustic performance (Figure 1). Average torque and equivalent radiated power level (ERP) are calculated for multiple design points and response surfaces are then created for the sensitivity study and optimization.
Technical Paper

Engine Exhaust Noise Optimization Using Sobol DoE Sequence and NSGA-II Algorithms

2019-06-05
2019-01-1483
Exhaust muffler is one of the most important component for overall vehicle noise signature. Optimized design of exhaust system plays a vital role in engine performance as well as auditory comfort. Exhaust orifice noise reduction is often contradicted by increased back pressure and packaging space. The process of arriving at exhaust design, which meets packaging space, back pressure and orifice noise requirements, is often manual and time consuming. Therefore, an automated numerical technique is needed for this multi-objective optimization. In current case study, a tractor exhaust system has been subjected to Design of Experiments (DoE) using Sobol sequencing algorithm and optimized using NSGA-II algorithm. Target design space of the exhaust muffler is identified and modeled considering available packaging constrain. Various exhaust design parameters like; length of internal pipes, location of baffles and perforation etc. are defined as input variables.
Technical Paper

Structural-Acoustic Modeling and Optimization of a Submarine Pressure Hull

2019-06-05
2019-01-1498
The Energy Finite Element Analysis (EFEA) has been validated in the past through comparison with test data for computing the structural vibration and the radiated noise for Naval systems in the mid to high frequency range. A main benefit of the method is that it enables fast computations for full scale models. This capability is exploited by using the EFEA for a submarine pressure hull design optimization study. A generic but representative pressure hull is considered. Design variables associated with the dimensions of the king frames, the thickness of the pressure hull in the vicinity of the excitation (the latter is considered to be applied on the king frames of the machinery room), the dimensions of the frames, and the damping applied on the hull are adjusted during the optimization process in order to minimize the radiated noise in the frequency range from 1,000Hz to 16,000Hz.
Technical Paper

Optimization of Hypoid Gear Tooth Profile Modifications on Vehicle Axle System Dynamics

2019-06-05
2019-01-1527
The vehicle axle gear whine noise and vibration are key issues for the automotive industry to design a quiet, reliable driveline system. The main source of excitation for this vibration energy comes from hypoid gear transmission error (TE). The vibration transmits through the flexible axle components, then radiates off from the surface of the housing structure. Thus, the design of hypoid gear pair with minimization of TE is one way to control the dynamic behavior of the vehicle axle system. In this paper, an approach to obtain minimum TE and improved dynamic response with optimal tooth profile modification parameters is discussed. A neural network algorithm, named Back Propagation (BP) algorithm, with improved Particle Swarm Optimization (PSO) is used to predict the TE if some tooth profile modification parameters are given to train the model.
Technical Paper

A Comparison of Near-Field Acoustical Holography Methods Applied to Noise Source Identification

2019-06-05
2019-01-1533
Near-Field Acoustical Holography (NAH) is an inverse process in which sound pressure measurements made in the near-field of an unknown sound source are used to reconstruct the sound field so that source distributions can be clearly identified. NAH was originally based on performing spatial transforms of arrays of measured pressures and then processing the data in the wavenumber domain, a procedure that entailed the use of very large microphone arrays to avoid spatial truncation effects. Over the last twenty years, a number of different NAH methods have been proposed that can reduce or avoid spatial truncation issues: for example, Statistically Optimized Near-Field Acoustical Holography (SONAH), various Equivalent Source Methods (ESM), etc.
Technical Paper

Optimal Pressure Relief Groove Geometry for Improved NVH Performance of Variable Displacement Oil Pumps

2019-06-05
2019-01-1548
Variable Displacement Oil Pump (VDOP) is becoming the design of choice for engine friction reduction and fuel economy improvement. Unfortunately, this pump creates excessive pressure ripples, at the outlet port during oil pump shaft rotation, causing oscillating forces within the lubrication system and leading to the generation of objectionable tonal noises and vibrations. In order to minimize the level of noise, different vanes spacing and porting geometries are used. Moreover, an oil pressure relief groove can be added, at the onset of the high pressure port, to achieve this goal. This paper presents an optimization method to identify the best geometry of the oil pressure relief groove. This method integrates adaptive meshing, 3D CFD simulation, Matlab routine and Genetic Algorithm based optimization. The genetic algorithm is used to create the required design space in order to perform a multi-objective optimization using a large number of parameterized groove geometries.
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