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Ranking of Thick Ice Shapes based on Numerical Simulation for Certification

Airbus Operations Ltd-James Brown
Airbus Operations SAS-Johan DEGRIGNY, Richard LEWIS, Nathalie ALEGRE, Isaac BARRIOS-GARCIA
  • Technical Paper
  • 2019-01-1944
To be published on 2019-06-10 by SAE International in United States
The aim of this paper is to present a numerical method to rank thick ice shapes for aircraft by comparing the ice accretion effects for different icing scenarios in order to determine the more critical ice shape. This ranking allows limiting the demonstration of the aerodynamic characteristics of the aircraft in iced condition during certification to a reduced number of ice shapes. The usage of this numerical method gives more flexibility to the determination of the critical ice shapes, as it is not dependent of the availability of physical test vehicles and/or facilities. The simulation strategy is built on the Lattice Boltzmann Method (LBM) and is validated based on a representative test case, both in terms of aircraft geometry and ice shapes. Validation against existing experimental results shows the method exhibits an adequate level of reliability for the ranking of thick ice shapes.
 

Numerical Modeling of Internal Helmholtz Resonators Created by Punching Small Holes on a Thin-Walled Tube

University of Kentucky-Hao Zhou, T. W. Wu
  • Technical Paper
  • 2019-01-1486
To be published on 2019-06-05 by SAE International in United States
Helmholtz resonators are normally an afterthought in the design of mufflers to target a very specific low frequency, usually the fundamental firing frequency of the engine. Due to space limitations in a complex muffler design, a resonator may have to be built by punching a few small holes on a thin-walled tube to create a neck passage into a small, enclosed volume outside the tube. The short neck passage created by punching a few small holes on a thin-walled tube can pose a great challenge in numerical modeling, especially when the boundary element method (BEM) is used. In this paper, a few different BEM modeling approaches are compared to one another. These include modeling both sides of the thin-walled tube and the details of each small hole, modeling just the mid surface of the thin-walled tube but with the holes and possibly an added neck length, and modeling an equivalent perforated surface patch on the tube without any holes. The BEM results are compared to a detailed simulation using the finite element method (FEM). In…
 

Analyzing Field Environments to Understand Product Failure Causes

Vibration Research-Jade Vande Kamp
  • Technical Paper
  • 2019-01-1477
To be published on 2019-06-05 by SAE International in United States
Product failures often require expensive repairs or replacements. Over-engineering adds to recurring costs and its success is uncertain if the failure’s cause is not understood. Engineers need in-depth knowledge before attempting a re-design. This case study focuses on bus seat failures not predicted by industry standard tests. The goal was to collect comprehensive field vibration data and analyze that data to understand the failure’s cause. The study used accelerometers placed at various points in multiple seating configurations and across multiple field environments. Analysis identified transmissibility issues between axes of motion, as well as higher reliability seat configurations.
 
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Analysis of Passive Low Power Phase Change Heat Dissipation Method for Electric Vehicle Motor

Suizhou-WUT Industry Research Institute-Gangfeng Tan
Wuhan University of Technology-Shiping Huang, Yishi Wang, Jianjie Kuang, Jiakang Quan, Xiaofei Ma
Published 2019-04-02 by SAE International in United States
The electric vehicle motor is developing toward high power density, at the same time brings serious temperature rise problem, which affect the driving motor performance, efficiency, and useful life. Liquid cooling is usually used to solve the problem, but its energy consumption is large and the reliability is poor. In order to solve this problem, this paper proposes a heat dissipation method to improve the reliability and energy efficiency of the driving motor heat dissipation system. The method uses heat pipes heat transfer, and the heat pipes cold end are cooled by vehicle facing the wind. By establishing the motor temperature rise model, heat transfer model and vehicle dynamics model, this paper analyzes the maximum temperature region and reliability of the driving motor heat dissipation system, calculates and analyzes the efficiency of the driving motor under different driving conditions. The results show that with the heat dissipation method of this paper, the reliability of the driving motor cooling system has been improved; the overall efficiency of the driving motor can be increased by 7.4%-27.9% and…
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Research on Dynamic Load of Belgian Event Based on Virtual Proving Ground

CATARC-Jiansen Yang, Xinyu Wang, Xin Li
Published 2019-04-02 by SAE International in United States
The fatigue load spectrum of the physical proving ground is the necessary input for fatigue life analysis of vehicle parts and components. It is usually obtained by Road Load Data Acquisition (RLDA) and loads decomposition using multi-body dynamics tools. Virtual Proving Ground (VPG) methodology is gradually replacing this technical strategy. The belgian road is the typical event in durability test, in this paper, the flexible body and FTire model are applied to the vehicle multi-body dynamics model in order to improve the simulation accuracy. The result shows that all the wheel center force, shock absorber displacement and axial force acquired by VPG simulation have excellent correlation with real vehicle measured data. It is also proved that the virtual proving ground technology is a reliable and effective method to obtain the fatigue load spectrum in the early stage of development.
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Mastering Semiconductor Datasheets for Delivering a Robust ECU Design Meeting Stringent Automotive Application Requirements

Minda Corporation, Ltd.-Vishwas Manohar Vaidya
Published 2019-04-02 by SAE International in United States
As electronics enters every subsystem of a vehicle, ECU (Electronic Control Unit) designers need to judiciously select the semiconductor components to meet automotive application requirements. Choice of semiconductor components is governed by reliability and robustness on one hand and the needs of frugal implementations meeting the stringent automotive requirements. The former calls for adequate design margin to ensure trouble free life outlasting the vehicle life whereas the later demands in depth knowledge of semiconductor behavior so that cost/performance trade-off does not lead to potential filed problems. ECU designers need to critically study semiconductor datasheets, analyze application literature and extensively interact with semiconductor application engineers so as to arrive at the optimum choice of semiconductor components in their ECU Design.This paper stresses on the importance of studying and critically, understanding finer aspects of the semiconductor datasheets in order to make educated design decisions. The paper discusses difficulties generally encountered by the ECU Designers in correctly interpreting finer aspects of the datasheet parameters sometimes leading to field problems. Real life design examples are discussed focusing on datasheet…
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Reliable Processes of Simulating Liner Roughness and Its Lubrication Properties

Massachusetts Institute of Technology-Renze Wang, Chongjie Gu, Tian Tian
Published 2019-04-02 by SAE International in United States
Topology of liner finish is critical to the performance of internal combustion engines. Proper liner finish simulation processes lead to efficient engine design and research. Fourier methods have been well studied to numerically generate liner topology. However, three major issues wait to be addressed to make the generation processes feasible and reliable. First, in order to simulate real plateau honed liners, approaches should be developed to calculate accurate liner geometric parameters. These parameters are served as the input of the generation algorithm. Material ratio curve, the common geometry calculation method, should be modified so that accurate root mean square of plateau height distribution could be obtained. Second, the set of geometric parameters used in generating liner finish (ISO 13565-2) is different from the set of parameters used in manufacturing industry (ISO 13565-3). Quantitative relations between these two sets should be studied. Third, numerically generated liners should be run in deterministic lubrication, dry contact, and engine cycle models. Their outcome behavior should be compared with experimental data. In this article, efforts were made to fill all…
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Non-Destructive Evaluation for High-Pressure Composite Tubes using a Hybrid Approach

Eaton-Zhou Zhou
Lawrence Technological University-Xin Xie, Himanshu Kolambe, Abhijit Bothe
Published 2019-04-02 by SAE International in United States
Recently, composite materials/structures are getting increasingly used in the automotive and aerospace industry. Defects issue is commonly associated with the use of composite materials/structures. Reliable Non-Destructive Evaluation (NDE) of composite structures is still challenging due to the existence of small size defects. In this research, a hybrid approach is used to accurately determine small size internal defects. In this hybrid approach, X-Ray Computed Tomography is used as a reference to accurately determine all defect locations, then a digital shearography method is used to conduct fast NDE for in-line testing. The critical shearographic NDE parameters such as shearing angle, shearing distance and loading amount are determined and optimized based on the X-ray CT scan result. From the comparison of X-ray CT scan results and digital shearography NDE results, the detection rate of digital shearography for defects with a size of larger than 1mm is from 91.91% to 97.30%. The detection rate of digital shearography For defects with a size of 0.4mm - 1mm is from 54.17% to 84.48%. The Shearographic NDE fundamentals, experimental setup, and testing…
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Parameters Analyses and Identification for Rubber Bush Based on Theoretical Dynamic Model with Effects of Temperature and Preload

Tongji University-Rong He, Hong Zhou
Published 2019-04-02 by SAE International in United States
A series connection of the KVBC (Kelvin-Voigt and Bouc-wen) theoretical model of rubber bush in automobile suspension is established. The numerical calculation model is also developed through Matlab/simulation and 9 parameters are identified. Experiments are conducted on the rubber bush on a bench for dynamic and static characteristics and to supply appropriate and reliable data for parameter identification. Based on this, preload and temperature are taken into consideration in an ordinary KVBC model as two important additional factors. As a result, it leads to developing a novel model with new parameter identification, which is validated under different conditions. This new modeling method of rubber bush has three advantages. First, it shows improved accuracy for solving non-linear problems in a multi-body calculation, which is useful for researchers and vehicle engineers. In addition, this new method leads to a very important step for choosing appropriate bush model type before analysis, which depends on the preload value. Furthermore, the model can be used to handle real situations with temperature variation around rubber bushes during simulation, which has been…
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A Methodology of Design for Fatigue Using an Accelerated Life Testing Approach with Saddlepoint Approximation

Oakland University-Zissimos Mourelatos
Oakland University, Beta CAE Systems-Vasiliki Tsianika, Dimitrios Papadimitriou
Published 2019-04-02 by SAE International in United States
We present an Accelerated Life Testing (ALT) methodology along with a design for fatigue approach, using Gaussian or non-Gaussian excitations. The accuracy of fatigue life prediction at nominal loading conditions is affected by model and material uncertainty. This uncertainty is reduced by performing tests at a higher loading level, resulting in a reduction in test duration. Based on the data obtained from experiments, we formulate an optimization problem to calculate the Maximum Likelihood Estimator (MLE) values of the uncertain model parameters. In our proposed ALT method, we lift all the assumptions on the type of life distribution or the stress-life relationship and we use Saddlepoint Approximation (SPA) method to calculate the fatigue life Probability Density Functions (PDFs). Finally, a design for fatigue is performed where a Reliability-Based Design Optimization (RBDO) process is developed to optimize the system’s characteristics (model parameters, fatigue and/or material properties) which are subject to probabilistic constraints. This optimization problem determines optimal values of system parameters to achieve a fatigue reliability target. We will demonstrate all developments using a representative example.
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