Criteria

Text:
Display:

Results

Viewing 301 to 330 of 112266
2018-04-03
Technical Paper
2018-01-0147
Wang Wenzhu, Liu Gang, Cheng Mianhong
Aiming at the rear disc brake squeal for an SUV, the finite element model (FEM) of contact coupling of disc brake was established by using finite element software. The validity of the FEM is verified by the experimental modal analysis method. The complex modal analysis method was used to analyze the unstable modes of the system under two kinds of friction coefficients. In order to solve the problem of brake squeal, the method of sticking silencing sheet on the brake block backboard was adopted in which the damping of the silencer. In the simulation, the damping of the silencing sheet is described by Rayleigh damping. The simulation results show that the silencing sheet can effectively suppress brake squeal and improve the stability of the system.
2018-04-03
Technical Paper
2018-01-0144
Wenlong Yang, Michael Dinsmore, Alexis Castel, Ricardo Alvarez, Roger Michna
Porous materials have been applied increasingly for absorbing noise energy and improving the acoustic performance. To predict the performance of these materials, different models have been proposed and much progress has been achieved. However, most of the foregoing researches were conducted on single porous material. In real application, porous materials are usually combined with other kinds of materials to compose a multilayered noise control treatment. This paper investigates the acoustic performance of such treatments with a combination of porous and non-porous media. Results from numerical simulation are compared to experimental measurements. Transfer matrix method is adopted to simulate the insertion loss and absorption associated with three samples of a noise control treatment product, which has two porous layers bonded by an impervious screen. The elastic parameters of the foam solid phase are estimated by matching the simulated results to the tested data.
2018-04-03
Technical Paper
2018-01-0145
Urban Rönnqvist, Janos Ribarits
Today’s trend of downsized internal combustion engine development for cars is characterized with; high torque, low engine speed, low weight, high degree of cyclic irregularity, low excitation frequency due to fewer cylinders active e.g. 4-cylinder or less. Torque output 100 Nm at low engine speed 1000 rpm has become normal. This implies in respect of vibrations that it is important to control engine suspension rigid body modes e.g. roll yaw and pith ones. The rigid body modes frequencies should be low so they cannot be reached and induced by the low exciting harmonics of cylinder pressure and mass forces for low engine speeds or idling. Crucial is the rigid body modes in relation to the excitation forces. It is also important to control the overall flexible vibration modes.
2018-04-03
Technical Paper
2018-01-0150
Max Sardou
SARDOU SAS has developed highly stressed composites parts for 36 years. SARDOU SAS and QUALITY INDUSTRIAL PRODUCT jointly invented and patented composite “C” springs in 1993. We have designed and tested ultra-performance “C” springs, giving an incredible energy density of 1350 joules per kilogram (compared to 300 for steel springs). This energy density means a potential 78% weight savings! But in the last century, weight savings was not a must and platform personnel were reluctant to use anything else than coil springs. So in 2002, in order to comply with the wishes of platform personnel, we have invented and developed composite coils springs. Composite coils springs are the best choice for McPherson suspensions. We have identified that the weak point, in composite coils springs, is its epoxy matrix. During heavy loading, the matrix undergoes micro cracking. Then, during repeated loadings, micro cracks propagate and merge, transforming the matrix into a fine powder.
2018-04-03
Technical Paper
2018-01-0148
Ravi (S. T.) Raveendra
A widely-used procedure for the solution of high frequency vibroacoustic problems is statistical energy analysis (SEA). Statistical energy analysis is a lumped parameter approach that treats a buildup system as a collection of subsystems with average properties. While the SEA has found wide acceptance, the approach does not provide any information about the spatial variation of the dynamic response within a subsystem. Integral equations are well suited as a post processing tool to evaluate sound field within a domain using energy density and intensity at the surface of the domain. In the present work, energy flow integral equations are extended to post-process SEA results to predict interior sound field at desired locations.
2018-04-03
Technical Paper
2018-01-0151
Kyoungchun Kweon
In recent years, the emerging technology competitions in automotive industry are improving engine efficiency and electronizing for coping with stringent fuel-economy regulations. However, fuel-economy technologies such as engine down-sizing and numerous electronic parts entrust burden plastic materials acing as mainly electric insulation and housing to have to be higher performance, especially temperature endurance. Engineering plastics(EP) have critical limitations in terms of degradation by heat. Heat-resisting additives in EP are generally used to be anti-degradation as activating non-radical decomposition of peroxide. However, it could not be effective way to impede the degradation in long term heat aging over 1,000 hours at high temperature above 180℃. In this study, we suggested the new solution called ‘shield effect’ that is purposeful oxidation at the surface and local crystallization of EP to stop prevent penetrating oxygen to inside of that.
2018-04-03
Technical Paper
2018-01-0149
Xianjun Sun, Srikar Vallury, Lingxuan Su, Patricia Tibbenham, Hong-Tae Kang, Anthony Yang, Xuming Su, Danielle Zeng
Warpage is the distortion induced by inhomogeneous shrinkage during injection molding of plastic parts. The uncontrolled warpage will result in dimensional instability and bring a lot of challenges to the mold design and part assembly. Current commercial simulation software for injection molding cannot provide consistently accurate warpage prediction, especially for semi-crystalline thermoplastics. In this study, the root cause of the inconsistency in warpage prediction has been investigated by using injection molded polypropylene plaques with a wide range of process conditions. The warpage of injection molded plaques are measured and compared to the numerical predictions from Moldex3D. The study shows that with considering cooling rate effect on crystallization kinetics and using of the improved material model for residual stress calculations, good agreements are obtained between experiment and simulation results.
2018-04-03
Technical Paper
2018-01-0138
Wallace G. Ferreira, Valdir Cardoso, Neil Bishop, Eric FAVRE, Karl Sweitzer
A previous SAE paper (2016-01-0377) did a comparative study of automotive system fatigue models processed in the time and frequency domain. A subsequent paper (2017-01-0339) looked at relative random analysis under base shake loading conditions. This paper proposes to merge these 2 analysis procedures in order to implement a new “Loads Cascading” procedure. The objective of this paper will be to show how loads (accelerations, displacements, forces) can be cascaded (transferred) from input load position (eg RLD body loads) to some internal location, for example a battery pack location. Also note that the response from one “module” could form the input to another. So once the loadings are in the frequency domain the possibility exists to “cascade” the loads through a system. For example, from the Chassis, to the Subframe, to attached Components.
2018-04-03
Technical Paper
2018-01-0139
rong he
Road NVH are becoming one of important performance controlled during passenger vehicle NVH development, especially for these EV vehicles due to lack of traditional gasoline or diesel engines noise sources. Generally speaking, traditional CAE and multi-body dynamic approaches have several drawbacks respectively, such as it is extremely difficult to get precise inputs as excitation to CAE model and non-linear parts in suspensions perform complex high frequency dynamic characteristics that is hard to be dealt with in multi-body software. Therefore, structure-borne road noise prediction has become one of difficult NVH problems in vehicle industry and eagerly, needs a systematic and scientific method. Under this circumstance, a new kind of high frequency road N&V co-simulation method has been introduced here to predict road NVH performance for one brand vehicle. This new approach includes three steps.
2018-04-03
Technical Paper
2018-01-0137
Chris F. Coker
Mechanism simulation of automotive suspension systems has been constantly evolving and improving, to add additional fidelity to results. This improves correlation to physical test data, and allows the tools to be used to study more advanced phenomenon. MacPherson strut suspensions have been popular for decades due to their decreased parts count resulting in lower system costs. The strut in this kind of suspension performs multiple tasks, in addition to supporting the springing and damping loads, it also functions as a kinematic support as part of the overall mechanism. In simplified MacPherson strut simulations, the rod of the MacPherson strut is treated as a rigid body. However, when one compares system level physical test data with simulation data using this rigid body approach, it is apparent that the bending of the strut road influences the system level kinematics and compliances of the suspension.
2018-04-03
Technical Paper
2018-01-0142
Ricardo O. de Alba Alvarez
A model of a tractor cab was built using Statistical Energy Analysis (SEA) best practices. In this paper, it is shown how this model was correlated using data measured using a volume velocity source in the laboratory. After correlation, the model was excited using acoustic loads measured during tractor operation. It was found that the data predicted by the model is in good agreement with the data measured inside the cabin during this test.It was concluded that SEA can be used as an engineering tool to predict the behavior under many different conditions and can be used to guide the development process.
2018-04-03
Technical Paper
2018-01-0143
Ganeswar Sahu, K.S.Gopala Krishnan, Mandar Kulkarni, Vikram Chauhan
With increasing market competition in low cost and mid-range vehicles, it’s important to delight the customer with value for money in terms of better NVH and higher fuel efficiency. Exhaust system plays an important role in noise attenuation and has to be worked upon for the better NVH characteristics without affecting engine performance. This can be achieved using Absorptive/Hybrid mufflers. Glass-wool’s effectiveness is governed by its physical and mechanical properties; this paper focuses on the sensitivity analysis of above properties using CAE for improving the acoustic simulation and its correlation with Testing and subsequently establishing process for acoustical development of mufflers.The study of Porous material in an acoustic field is based on Biot theory.
2018-04-03
Technical Paper
2018-01-0140
Weiguo Zhang, Mark Likich, Brian Butler
The automotive Air Induction System (AIS) is an important part of the engine systems which delivers the clean air to the engine. A well-designed AIS should have minimum flow resistance, minimum thermal gain and radiates a good quality sound at the snorkel. The IDDOV (Identify-Define-Develop-Optimize-Verify) method is a Design For Six Sigma(DFSS) approach which can be used for creating innovative, low cost and robust products on significant short schedules. The CAE simulation method enhanced with DFSS approach has been developed and implemented in AIS development to meet customer expectation in FCA US LLC. The development work included different types of DFSS projects such as IDD project, IOV project and Robust Assessment(RA) project based on the IDDOV method. In this paper, the work of an IOV project is presented on developing a robust AIS parametric model to achieve optimized snorkel noise and flow performance for specified V8 engines.
2018-04-03
Technical Paper
2018-01-0131
xuefeng jiang, zhujun Mao, Wei Chen, Xian Xu, Yuan cao
The powertrain mount design is significance for idle vibration. This paper discusses the effect of powertrain mount parameters for heavy truck idle performance by theory analysis and simulation. Equations of motion for a simply model has been derived which indicated that vertical mount stiffness and lateral coordinate of mounts are the most important factors for roll mode frequency. Meanwhile, based on the same engine excitation, the vibration of powertrain mount upper measure point would reduce while the distance between rear mount and PT center of mass increase in longitudinal direction. According to the flexible analysis model, it is shown that the idle vibration performance would get better with the joint stiffness of mount and frame increase. The validity and accuracy of the study is verified by test result.
2018-04-03
Technical Paper
2018-01-0130
Gang Xu, Rui Zhang
The load act on the component is crucial to assess the durability performance. The boundary conditions of the test specimen under test is another factor to influence the fatigue lives by introducing unrealistic loads on the component of interest. Physical test is widely conducted in the laboratory. The fixture provide additional constraints on the test specimen as well as reaction forces to balance the test system. The characteristics of the fixture involved in the test is important to analysis and assess the test results. The impact of the reaction force of the fixture on the spindle coupled axle road simulation test is presented in this paper. A simplified 7-DoFs (Degrees of Freedom) model is introduced to demonstrate the dynamic behavior of the vehicle. The influence on the internal load by the fixture was analyzed. Followed by a more detailed MBS (Multi-Body System) model to give an in-depth understanding of the phenomenon.
2018-04-03
Technical Paper
2018-01-0135
Xuefeng jiang, Feng Yan, Wei Chen, Huawu wang
Ride comfort is simply defined as the vibration performance of the vehicle which is excited by road surface roughness, generally as the vehicle moves at specific constant velocity over the road profile. Ride comfort was an important index for heavy truck, due to long distance transfer and long time driving. In order to improve the ride comfort of a heavy truck, a detailed model, including flex frame, chassis suspension, cab suspension, powertrain, driveline, etc., was built and assembled by MSC.ADAMS software. Simulation and testing data were consistent very well, which showed the correctness of the model. The optimization of chassis and cab suspension including the stiffness of the leafspring, the damping of the shock absorber, the layout of the cab suspension, etc. was carried out to improve the ride comfort of the vehicle. The ride comfort testing was carried out on the proving ground to verify the effectiveness the optimization results.
2018-04-03
Technical Paper
2018-01-0134
Yunkai Gao, Rui Qian, Gangan Ma
Nowadays, the design and development of the sliding door has been gained great attention for its easy egress and ingress. However, most studies on the kinematic and dynamic characteristics of sliding doors were based on the commercial code ADAMS, while the accuracy of flexibility in modal synthesis method and the ability of complex contact condition may not be guaranteed. Thus, a new dynamic analysis method by using the commercial code LS-Dyna was proposed in this paper to take into account the complex deformation and boundary conditions based on the finite element model. The impact force obtained from the Ls-dyna was compared with that from ADAMS when their monitoring points speed and closing time maintained the same during the sliding process. The impact force between the rollers and the guides was employed as evaluation criterion for different methods because of its effect on the roller wear and the moving smoothness in the sliding process.
2018-04-03
Technical Paper
2018-01-0132
EFE GUNGOR, SALIH KURIS, Baris Aykent
The aim of this paper is to have a realistic simulation to estimate the real test scenario with respect to durability. A bus fatigue analysis results were realized by the Hexagon Studio Vehicle Dynamics Team. The measurements were taken by the test team on the Altoona test ground to provide input for fatigue analysis.The acceleration data were taken from four wheels hub. In addition, the reference acceleration data were taken from the midpoint of the vehicle body to compare the characteristics of the vehicle on the Altoona road with the output of the fatigue analysis. Firstly, the fatigue model must be set up for fatigue analysis. For this analysis,the flexible body given by durability team. The axle components were assembled to flexible body. The Adams durability model was created. This processed data of RLD provides input to the Adams fatigue analysis. Adams fatigue analysis was run to obtain ".dac" files.
2018-04-03
Technical Paper
2018-01-0189
Aimilios Sofianopoulos, Mozhgan Rahimi Boldaji, Benjamin Lawler, Sotirios Mamalis
Paper Title: “Analysis of Thermal Stratification Effects in HCCI engines using Large Eddy Simulations and Detailed Chemical Kinetics” The widespread practical application of Homogeneous Charge Compression Ignition (HCCI) has limited controllability and narrow load range due to high heat release rates. It has been shown that thermal stratification affects ignition and heat release in HCCI and therefore can dictate its upper load limit. Thus, fundamental understanding of thermal stratification in HCCI combustion is necessary, along with the development of appropriate models to simulate it. A 3-D Computational Fluid Dynamics (CFD) model of single cylinder from a 2.0L production engine (LNF type) was developed using CONVERGE CFD, in which large eddy simulations (LES) are combined with combustion modeling using detailed chemical kinetics. The modeling framework is validated against experimental data of HCCI combustion in the modeled engine using negative valve overlap.
2018-04-03
Technical Paper
2018-01-0190
Ahmed Abdul Moiz, Pinaki Pal, Daniel Probst, Yuanjiang Pei, Yu Zhang, Sibendu Som, Janardhan Kodavasal
A Machine Learning - Genetic Algorithm (MLGA) approach was developed to virtually discover optimum designs using training data generated from high-fidelity simulations. Machine learning (ML) presents a pathway to transform complex physical processes that occur in a combustion engine into compact informational processes. In the present work, a total of over 2000 sector-mesh computational fluid dynamics (CFD) simulations of a heavy-duty engine were performed. These were run concurrently on a supercomputer to reduce overall turnaround time. The engine being optimized was run on low-octane (RON70) gasoline fuel using a partially-premixed advanced combustion approach. A total of nine input parameters (or features) were varied, and the CFD simulation cases were generated by randomly sampling points from this nine-dimensional input space.
2018-04-03
Technical Paper
2018-01-0191
Mani Sarathy, Nour Atef, Adamu Alfazazi, Jihad Badra, Yu Zhang, Tom Tzanetakis, Yuanjiang Pei
Toluene primary reference fuel (TPRF) (mixture of toluene, iso-octane and heptane) is a suitable surrogate to represent a wide spectrum of real fuels with varying octane sensitivity. Investigating different surrogates in engine simulations is a prerequisite to identify the best matching mixture. However, running 3D engine simulations using detailed models is currently impossible and reduction of detailed models is essential. This work presents an AramcoMech reduced kinetic model developed at KAUST for simulating complex TPRF surrogate blends. A semi-decoupling approach was used together with species and reaction lumping to obtain a reduced kinetic model. The model was widely validated against experimental data including shock tube and rapid compression machine ignition delay times, premixed laminar flame speeds, and jet stirred reactor speciation measurements.
2018-04-03
Technical Paper
2018-01-0192
David L. Reuss, Ziyang zhong, Xiaofeng Yang, Tang-Wei Kuo, Volker Sick
A large eddy simulation computed 35 consecutive motored cycles for comparison with PIV velocity measurements in the TCC-III engine. As a most basic comparison, this study focuses on the intracycle evolution and cycle to cycle variability, CCV, of the volume average kinetic energy. One purpose is to assess efficacy of comparing the kinetic energy of the two-component two-dimensional velocity in the restricted regions of the PIV measurements, with the three-component three-dimensional data of the LES. A second is to examine how well this simulation captured the kinetic energy production and dissipation through the motored cycles. The volume-averaged kinetic energy from the three-dimensional three-component LES is sampled from the entire cylinder volume and in slabs. These slabs are volumes with areas and thickness equal to the PIV field-of-view and laser sheet thickness. The differences between samples using different slab thickness and cutting planes are assessed.
2018-04-03
Technical Paper
2018-01-0185
Varun Haresh Nichani, Roberto Jaime, Satbir Singh, Xiaofeng Yang, Volker Sick
Large-eddy simulations (LES) of a motoring single-cylinder engine with transparent combustion chamber (TCC-II) are carried out using a commercially available computer code, CONVERGE. Numerical predictions are compared with high-speed particle image velocimetry (PIV) measurements. Predictions of two spatial discretization schemes namely, numerically stabilized central difference scheme (CDS) and fully upwind scheme are compared. Four different sub-grid scale (SGS) models; a non-eddy viscosity dynamic structure turbulence (DST) model of Pomraning and Rutland [AIAA Journal, 40, 2002], one-equation eddy-viscosity (1-Eqn) model of Menon et al. [Computers and Fluids, 1995], a zero-equation eddy-viscosity model of Vreman [Physics of Fluids, 2004] and the zero-equation standard Smagorinsky model [Smagorinsky, 1963] are employed on two different grid configurations. Additionally, simulations are also performed by deactivating the LES SGS models.
2018-04-03
Technical Paper
2018-01-0186
Christian Ibron
This CFD study focuses on the influence of the nozzle diameter on the mixing process and the soot formation and oxidation process in a heavy-duty diesel engine. The CAD simulation is based on the Reynolds Averaged Navier-Stokes approach. The engine set-up is similar to an experimental case that enables smokeless spray combustion. The aim of the paper is to improve the understanding of the physics of the mixing process in a real engine environment with the attention to scrutinize its effect on combustion and soot emission. Two non-reacting cases with different nozzle diameters but constant injection pressure and their corresponding reacting cases are simulated with dynamic mesh motion and fuel spray modeling. The influence of combustion on the mixing process is analysed and the simulation results are compared with the measurement data. The differences in the mixing process between a constant volume vessel and a dynamic combustion chamber with piston motion are evidenced.
2018-04-03
Technical Paper
2018-01-0187
Pinaki Pal, Christopher Kolodziej, Seungmok Choi, Alberto Broatch, Josep Gomez-Soriano, Yunchao Wu, Tianfeng Lu, Yee Chee See, Sibendu Som
Knock is a major bottleneck to achieving higher efficiency in Spark-Ignition (SI) engines. The recent trends of boosting, downsizing and downspeeding have exacerbated this issue by driving engines toward higher power density and higher load duty cycles. Apart from the engine operating conditions, fuel anti-knock quality is a major determinant of the knocking tendency in engines, as quantified by its octane number (ON). The ON of a fuel is based on an octane scale which is defined according to the standard octane rating methods for Research Octane Number (RON) and Motor Octane Number (MON). These tests are performed in a single cylinder Cooperative Fuel Research (CFR) engine. In the present work, a virtual CFR engine model based on 3D computational fluid dynamics (CFD) was developed.
2018-04-03
Technical Paper
2018-01-0188
Guangfei Zhu, Krishna Pattabiraman, Federico Perini, Christopher Rutland
A swept-volume method of calculating the volume swept by the flame during each time step is developed and used to improve the calculation of fuel reaction rates. The improved reaction rates have been applied to the ignition model and coupled with the level set G-equation combustion model. In the ignition model, a single initial kernel is formed after which the kernel is convected by the gas flow and its growth rate is determined by the flame speed and thermal expansion due to the energy transfer from the electrical circuit. The predicted ignition kernel size was compared with the available experimental data and good agreements were achieved. Once the ignition kernel reaches a size when the fully turbulent flame is developed, the G-equation model is switched on to track the mean turbulent flame front propagation.
2018-04-03
Technical Paper
2018-01-0181
Vignesh Pandian Muthuramalingam, Anders Karlsson
This work utilizes previously developed VSB2 (Volvo Stochastic Blob and Bubble) multicomponent fuel spray model to study significance of using non-ideal thermodynamics for droplet evaporation under direct injection engine like operating conditions. Non-ideal thermodynamics is used to account for vapor-liquid equilibrium arising from evaporation of multicomponent fuel droplets. In specific, the evaporation of ethanol/iso-octane blend is studied in this work. Two compositions of the blend are tested, E-10 and E-85 respectively (the number denotes percentage of ethanol in blend). The VSB2 spray model is implemented into OpenFoam CFD code which is used to study evaporation of the blend in constant volume combustion vessel. Liquid and vapor penetration lengths for the E-10 case are calculated and compared with the experiment. The simulation results show good agreement with the experiment. Simulation is performed with two methods- ideal and non-ideal thermodynamics respectively.
2018-04-03
Technical Paper
2018-01-0182
Chaolin Zhang, Bo Hu, Chenguang lai, Hailin Zhang, Ling Qin, Xiaoli Leng, Wenpeng Huang
One-dimensional(1D) simulation tools, the computing speed of which is relatively fast , usually solve simple complexity problems. The solving process of 1D tools is mostly based on one-dimensional dynamic equations and empirical laws and in some cases it cannot obtain a similar accuracy with the three-dimensional(3D) simulation tools, which is usually time-consuming. The 1D-3D co-simulation, which combines the advantages of the two simulation tools while minimizes the disadvantages, is a method that integrates and runs the two simulation tools concurrently. Specially, coupled simulations can offer detailed information where needed 3D domain while offer system level information in the rest of the whole system. The approach not only minimizes the computational cost, but avoids demand for imposing accurate boundary conditions to the 3D simulation.
2018-04-03
Technical Paper
2018-01-0183
Jinlong Liu, James Szybist, Cosmin Dumitrescu
Modern 3D CFD IC engine simulations are extremely complex for the regular user due to the use of complex phenomenological sub-models with solution-adaptive mesh refinement and coarsening, and improved chemistry solvers. This study used ANSYS® Forte, Version 17.2, an IC engine CFD software package, to investigate two tuning constants that influence flame propagation in 3D CFD SI engine simulations: the stretch factor coefficient, C_ms and the flame development coefficient, C_m2. After identifying several C_m2-C_ms pairs that matched experimental data at one operating conditions, simulation results showed that except for HC emissions, the engine models that used different C_m2-C_ms sets predicted similar combustion performance, when the spark timing, engine load, and engine speed were changed from the operating condition used to validate the CFD simulation.
2018-04-03
Technical Paper
2018-01-0179
mohammed jaasim Mubarak ali, Francisco Hernandez Perez, Aliou sow PhD, Hong Im
Super-knock that occurs in spark ignition (SI) engines is investigated using two-dimensional (2D) numerical simulations. The temperature, pressure, velocity, and mixture distributions are obtained and mapped from a top dead center slice of full cycle three-dimensional (3D) engine simulations. Ignition is triggered at one end of the cylinder and a hot spot of known temperature was used to initiate a pre-ignition front to study super-knock. The computational fluid dynamics code CONVERGE was used for the simulations. A minimum grid size of 25 μm was employed to capture the shock wave and detonation inside the domain. The Reynolds averaged Navier-Stokes (RANS) method was employed to represent the turbulent flow and gas phase combustion chemistry was represented using a reduced chemical kinetic mechanism for primary reference fuels. A multi-zone model, based on a well-stirred reactor assumption, was used to solve the reaction terms.
Viewing 301 to 330 of 112266