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Viewing 1 to 30 of 2891
2011-04-12
Journal Article
2011-01-0344
Gilsu Choi, Zhuxian Xu, Ming Li, Shiv Gupta, Thomas Jahns, Fred Wang, Neil A. Duffie, Laura Marlino
This paper introduces a promising approach for developing an integrated traction motor drive based on the Integrated Modular Motor Drive (IMMD) concept. The IMMD concept strives to meet aggressive power density and performance targets by modularizing both the machine and power electronics and then integrating them into a single combined machine-plus-drive structure. Physical integration of the power electronics inside the machine makes it highly desirable to increase the power electronics operating temperature including higher power semiconductor junction temperatures and improved device packaging. Recent progress towards implementing the IMMD concept in an integrated traction motor drive is summarized in this paper. Several candidate permanent magnet (PM) machine configurations with different numbers of phases between 3 and 6 are analyzed to compare their performance characteristics and key application features.
2011-04-12
Technical Paper
2011-01-0421
V. A. Muruganandam, Maruthi Dhulipudi, Uday Korde
Coolant pipes are a prime connection units present in any engines that facilitates the flow of coolant and thereby keeping the engine under its optimum operating condition. Among the several influencing factors that deteriorate engines performance, the coolant leak is also one of the contributors. This could be caused primly due to leakage issues that arises from the pipe press fit zones. Henceforth it is very important to understand the root cause of this press-fit connection failure. The present study deals with press-fit between the pipe and housing in an engine which is subjected to extreme thermal loads (min of -40°C to a max temperature of +150°C) thereby causing the press-fit loosening effect.
2011-04-12
Technical Paper
2011-01-0667
Ramesh Rebba, Jeong Hun Seo, Ann Marie Sastry, Mary Fortier
Rechargeable energy storage systems with Lithium-ion pouch cells are subject to various ambient temperature conditions and go through thousands of charge-discharge cycles during the life time of operation. The cells may change their thickness with internal heat generation, cycling and any other mechanisms. The stacked prismatic cells thus experience face pressure and this could impact the pack electrical performance. The pack consists of stiff end plates keeping the pack in tact using bolts, cooling fins to maintain cell temperature and foam padding in between cells. The pack level thermal requirements limit the amount of temperature increase during normal operating conditions. Similarly, the structural requirements state that the stresses and the deflection in the end plates should be minimal. Uncertainties in cell, foam mechanical and thermal properties might add variation to the pack performance.
2011-04-12
Technical Paper
2011-01-0658
Juan Carlos Martinez Laurent
With the constant need to meet new environmental regulations, the improvement of automotive exhaust systems technologies to be cleaner and more effective is a necessity. To achieve these regulations the automakers have been focused on the development of better particle filters and more effective cleaning processes. Catalyst Oxidation and Diesel Particle Filter Regeneration are good and effective techniques to accomplish these objectives but the amount of heat generated by these processes is a concern in the thermal management of the vehicle. To gain a better understanding of these effects Finite Element Thermal Analysis has proved to be a useful tool to predict and observe the increment of temperature during these processes. This work is focus on a simulation process using several 1-D and 3-D techniques to predict the skin exhaust temperature during the regeneration process moment in which the system achieve the maximum temperature.
2011-04-12
Journal Article
2011-01-0019
Kyoo Sil Choi, Ayoub Soulami, Wenning Liu, Xin Sun, Moe Khaleel
In this paper, the microstructure-based finite element modeling method is used in investigating the loading path dependence of formability of transformation induced plasticity (TRIP) steels. For this purpose, the effects of different loading path on the forming limit diagrams (FLD) of TRIP steels are qualitatively examined using the representative volume element (RVE) of a commercial TRIP800 steel. First, the modeling method was introduced, where a combined isotropic/kinematic hardening rule is adopted for the constituent phases in order to correctly describe the cyclic deformation behaviors of TRIP steels during the forming process with combined loading paths which may include the unloading between the two consecutive loadings. Material parameters for the constituent phases remained the same as those in the authors' previous study [ 1 ] except for some adjustments for the martensite phase due to the introduction of the new combined hardening rule.
2011-04-12
Journal Article
2011-01-0218
Johnson Joseph, S Raja, Y Charles Lu
Piezoelectric materials are smart materials that can undergo mechanical deformation when electrically or thermally activated. An electric voltage is generated on the surfaces when a piezoelectric material is subjected to a mechanical stress. This is referred to as the ‘direct effect’ and finds application as sensors. The external geometric form of this material changes when it is subjected to an applied voltage, known as ‘converse effect’ and has been employed in the actuator technology. Such piezoelectric actuators generate enormous forces and make highly precise movements that are extremely rapid, usually in the micrometer range. The current work is focused towards the realization and hence application of the actuator technology based on piezoelectric actuation. Finite element simulations are performed on different types of piezoelectric actuations to understand the working principle of various actuators.
2011-04-12
Technical Paper
2011-01-0199
Thomas Christiner, Wilfried Eichlseder, Istvan Gódor, Johannes Reiser, Franz Trieb, René Stuehlinger
Recent trends in mechanical engineering are focusing on optimization of components with respect both to weight and lifetime by using numerical simulation even in the early design stages. For a reliable prediction of in service performance by simulation, both loading as well as different damage and failure mechanisms that may be activated during operation have to be known. In mechanical engineering applications, cyclic loadings are most common. In many assemblies of moving components, contact problems under various lubrication conditions are lifetime-limiting. There, relative motion of contacting bodies combined with high loads transmitted via the contact surface lead to fretting fatigue failure. In this contribution a few selected results of a currently conducted research project are presented. The aim of this study was to examine the material behavior of a surface stressed steel. The influence of the Fretting regime on fatigue properties has been investigated.
2011-04-12
Technical Paper
2011-01-0186
Manfred Baecker, Axel Gallrein, Michael Hack, Alessandro Toso
During the last ten years, there is a significant tendency in automotive design to use lower aspect ratio tires and meanwhile also more and more run-flat tires. In appropriate publications, the influences of these tire types on the dynamic loads - transferred from the road passing wheel center into the car - have been investigated pretty well, including comparative wheel force transducer measurements as well as simulation results. It could be shown that the fatigue input into the vehicle tends to increase when using low aspect ratio tires and particularly when using run-flat tires. But which influences do we get for the loading and fatigue behavior of the respective rims? While the influences on the vehicle are relatively easy to detect by using wheel force transducers, the local forces acting on the rim flange (when for example passing a high obstacle) are much more difficult to detect (in measurement as well as in simulation).
2011-04-12
Technical Paper
2011-01-0184
Jianfeng Ma, Joshua Summers, Paul Joseph
In this paper, the Finite Element Method (FEM) is used to model and simulate the dynamic interaction between non-pneumatic tire and sand with obstacle to investigate the influence of obstacle on performance of the non-pneumatic tire. The non-pneumatic tire consists of three major components: two inextensible circumferential membranes, a critical shear beam, and a group of deformable spokes. The non-pneumatic tire fabricated of segmented cylinders is illustrated and the FEM model for the tire is given in detail. The tire is treated as an elastic deformable body with the inertia effect included. Lebanon sand found in New Hampshire is used in this simulation because of the availability of a complete set of material properties in the literature. Modified Drucker-Prager/Cap plasticity constitutive law with hardening is utilized to model the sand. The obstacle is represented as an elastic body.
2011-04-12
Technical Paper
2011-01-0099
Kwangwon Kim, Doo Man Kim
A Non-Pneumatic Tire (NPT) appears to have advantages over the conventional pneumatic tire in terms of flat proof and maintenance free. In this study, the static contact pressure of NPTs with hexagonal honeycomb spokes is investigated as a function of vertical loading and is compared with that of a pneumatic tire. Finite element based numerical simulation of the 2D contact pressure of a NPT is carried out with ABAQUS for varying vertical forces and lattice spoke geometries. A lower contact pressure is obtained with NPTs than with the pneumatic tire due to a high lateral spoke stiffness of NPTs when they are designed to be the same load carrying capability. The NPT with the spoke of a low cell angle, Type A spoke in this study, shows a low contact pressure; Type A in this study. On the other hand, the NPT with Type C spoke shows a lower local stress in the spoke cell struts, associated with the flexible cellular structural property in the uni-axial compression.
2011-04-12
Journal Article
2011-01-0058
Giles Bryer, Christopher Eccles
As mass reduction becomes an increasingly important enabler for fuel economy improvement, having a robust structural development process that can comprehend Vehicle Dynamics-specific requirements is correspondingly important. There is a correlation between the stiffness of the body structure and the performance of the vehicle when evaluated for ride and handling. However, an unconstrained approach to body stiffening will result in an overly-massive body structure. In this paper, the authors employ loads generated from simulation of quasi-static and dynamic vehicle events in ADAMS, and exercise structural finite element models to recover displacements and deflected shapes. In doing so, a quantitative basis for considering structural vehicle dynamics requirements can be established early in the design/development process.
2011-04-12
Technical Paper
2011-01-0507
Shuming Chen, Dengfeng Wang, Wei Li, Jianming Zan
For the purpose of predicting the interior noise of a passenger automobile at middle and high frequency, an energy finite element analysis (EFEA) model of the automobile was created using EFEA method. The excitations including engine mount excitation and road excitation were measured by road experiment at a speed of 120 km/h. The sound excitation was measured in a semi-anechoic chamber. And the wind excitation was calculated utilizing numeric computation method of computational fluid dynamics (CFD). The sound pressure level (SPL) and energy density contours of the interior acoustic cavity of the automobile were presented at 2000 Hz. Meanwhile, the flexural energy density and flexural velocity of body plates were calculated. The SPL of interior noise was predicted and compared with the corresponding value of experiment.
2011-04-12
Journal Article
2011-01-0506
Sangyun Lee, Kwangseo Park, Shung H. Sung, Donald J. Nefske
Three different acoustic finite element models of an automobile passenger compartment are developed and experimentally assessed. The three different models are a traditional model, an improved model, and an optimized model. The traditional model represents the passenger and trunk compartment cavities and the coupling between them through the rear seat cavity. The improved model includes traditional acoustic models of the passenger and trunk compartments, as well as equivalent-acoustic finite element models of the front and rear seats, parcel shelf, door volumes, instrument panel, and trunk wheel well volume. An optimized version of the improved acoustic model is developed by modifying the equivalent-acoustic properties. Modal analysis tests of a vehicle were conducted using loudspeaker excitation to identify the compartment cavity modes and sound pressure response to 500 Hz to assess the accuracy of the acoustic models.
2011-04-12
Journal Article
2011-01-0529
Sujit Chalipat, Ganesh Radha, Adwait Kulkarni, Rahul Mahajan
Passive safety regulations specify minimum safety performance requirements of vehicle in terms of protecting its occupants and other road users in accident scenarios. Currently for majority cases, the compliance of vehicle design to passive safety regulations is assessed through physical testing. With increased number of products and more comprehensive passive safety requirements, the complexity of certification is getting challenged due to high cost involved in prototype parts and the market pressures for early product introduction through reduced product development timelines. One of the ways for addressing this challenge is to promote CAE based certification of vehicle designs for regulatory compliance. Since accuracy of CAE predictions have improved over a period of time, such an approach is accepted for few regulations like ECE-R 66/01, AIS069 etc which involves only loadings of the structures.
2011-04-12
Technical Paper
2011-01-0476
Philip J. Bates, Gene Zak, Xiaochao Cao
In Laser Transmission Welding (LTW), a laser beam passes through a transparent part and is dissipated as heat in an absorbent material through the use of laser-absorbing pigments such as carbon black (CB). This energy is then conducted further into both parts. Melting and subsequent solidification occur at the interface causing a weld to form between the two parts. Gluing or welding structures to the back of automotive Class-A panels often results in the appearance of undesirable surface deformations on the Class-A side. Through control of the laser welding and material parameters, it may be possible to use contour LTW as a means of joining structures to the back of absorbent Class-A panels without creating these unwanted surface defects. A series of lap welds was made using a range of CB levels and laser powers. A profilometer was used to measure the size and shape of the defects generated on the surface of the black part. Two types of defects were observed: ribs and sink marks.
2011-04-12
Technical Paper
2011-01-0496
Shung Sung, Sung Chao, Hari Lingala, Lee Mundy
A structural-acoustic finite element model of an automotive vehicle is developed and applied to evaluate the effect of structural and acoustic modifications to reduce low-frequency ‘boom’ noise in the passenger compartment. The structural-acoustic model is developed from a trimmed body structural model that is coupled with an acoustic model of the passenger compartment and trunk cavities. The interior noise response is computed for shaker excitation loads at the powertrain mount attachment locations on the body. The body panel and modal participation diagrams at the peak response frequencies are evaluated. A polar diagram identifies the dominant body panel contributions to the ‘boom’ noise. A modal participation diagram determines the body modes that contribute to the ‘boom’ noise. Finally, structural and acoustic modifications are evaluated to determine their effect on reducing the ‘boom’ noise and on the overall lower-frequency sound pressure level response.
2013-05-13
Technical Paper
2013-01-1998
Nickolas Vlahopoulos, Geng Zhang, Walter Brophy, Madhan Ramaswami
The Energy Finite Element Analysis (EFEA) has been developed for computing the structural vibration and the interior noise level of complex structural-acoustic systems by solving numerically governing differential equations with energy densities as primary variables. In this paper a complete simulation process for evaluating airborne noise in an automotive vehicle is presented and validated through extensive comparison to test data. The theoretical elements associated with the important paths of the noise transfer from the exterior of the vehicle to the interior acoustic space are discussed. The steps required for developing an EFEA model for a vehicle are presented. The model is developed based on the physical construction of the vehicle system and no test measurements are utilized for adjusting the numerical model.
2013-05-13
Journal Article
2013-01-1990
Esmaeil Bahmyari
This article has investigated dynamic response of simply supported beams carrying moving distributed mass or force. A one dimensional finite element based on the both the first shear deformation (FSDT) and the Classical Laminate beam (CLT) theories is assumed for beam model. A ten degree of freedom beam element for FSDT theory and six degree of freedom element for CLT theory is considered for the beam and the moving distributed mass. Combination of the element property matrices for the moving distributed mass or force and the associated overall property matrices for the beam itself determines the overall effective property matrices of the entire vibrating system. After deriving the governing equations of motion of the beam and the moving distributed mass, the corresponding equations of motion are integrated by applying the Newmark's time integration scheme to obtain the system responses in each time step.
2013-05-13
Journal Article
2013-01-1993
Terence Connelly
SEA models are used to predict the performance of acoustic packages when assessing the performance of vehicle level or body noise reduction targets. One of the challenges faced by CAE engineers is the ability to estimate the performance of different materials used in the sound package at the design stage. Analysts can use measured data in the form of insertion loss and random incidence absorption if available or can predict the performance of materials using a Biot type description. The use of the full poro-elastic Biot model for materials requires knowledge of the fluid and elastic properties, however a limp or rigid model can be used to describe the material based only on the fluid properties and this is often sufficient to describe fibrous materials. In this paper a method will be outlined which will allow the material properties of fibrous materials to be estimated from basic normal incidence data that is provided by material suppliers.
2013-05-13
Technical Paper
2013-01-1994
Chadwyck Musser, Melzak Marques da Silva, Paulo Sérgio Lima Alves
For purposes of reducing development time, cost and risk, the majority of new vehicles are derived strongly or at least generally from a surrogate vehicle, often of the same general size or body style. Previous test data and lessons learned can be applied as a starting point for design of the new vehicle, especially at early phases of the design before definite design decisions have been finalized and before prototype of production test hardware is available. This is true as well of vehicle NVH development where most new vehicles being developed are variants of existing vehicles for which the main noise transfer paths from sources of interest are already understood via test results and existing targets. The NVH targets for new vehicles are defined via benchmarking, market considerations, and other higher-level decisions. The objective is then to bridge the gap between test data from surrogate vehicles to direct support of the NVH development of new vehicle programs.
2013-05-13
Technical Paper
2013-01-2000
Ronald Gerdes, Jonathon Alexander, Thomas Herdtle
In recent years, interest in microperforated panels (MPPs) has been growing in the automotive industry and elsewhere. Acoustic performance prediction is an important step toward understanding and designing MPPs. This paper outlines a start-to-finish procedure to predict the transfer impedance of a particular MPP based on its hole geometry and to further use this information in a simple plane wave application. A computational fluid dynamics (CFD) approach was used to calculate the impedance of the MPP and the results compared to impedance tube and flow resistance measurements. The transfer impedance results were then used to create a computationally efficient acoustic finite element (FE) model. The results of the acoustic FE model were also compared to impedance tube measurements.
2013-05-13
Technical Paper
2013-01-1988
Lingyun Yao, Jianwen Zhou, Zhou Zhou
Nowadays, the finite element method (FEM) is used to predict the performance of vehicle compartment cavity, i.e. the acoustic modal, the acoustic frequency response, etc. The accuracy of conventional FEM for acoustic problem strongly depends on the size of the mesh, element quality, etc. As element size gets greater and distortion gets severer, the deviation of high wave number problem also gets larger. In order to improve the accuracy of acoustic problem, this paper introduces a novel cell-based smoothed radial point interpolation method (CS-RPIM) to solve the vehicle compartment cavity model. In present method, the cavity is discretized using tetrahedron background cells, the each cell is further divided into four smoothing cells and then the cell-based gradient smoothing operation is implemented through the smoothing cells.
2013-04-08
Technical Paper
2013-01-1398
Peter Qiu, Yuan Qu, Shen Wu, Min Sun
The door closing effort is one of the first impressions to customer's mind about the engineering and quality of the vehicle. The door closing force and the minimum door closing speed are two important characteristics for evaluation. But we can obtain these two indices only by experiments and/or subjective assessments. To predict the door closing effort by the simulation method during the design phase, a finite element analysis model is established. The compression load deflection behavior of seals is converted to the parameters of constitutive model of seals by the parameters identification method. Then, the seal resistance force and the minimum door closing speed are calculated. The later correlates very well with the experiment data.
2013-04-08
Technical Paper
2013-01-1242
Yasuhiro Dokko, Toshiyuki Yanaoka, Kazuki Ohashi
Corresponding to the increasing need for the protection of elderly people from traffic accidents, the authors have been developing age-specific human FE models capable of predicting body kinematics and skeletal injuries for younger adult (35y.o.) and the elderly (75y.o.). The models have been developed and validated part by part referring to the literature and then integrated into whole bodies. Validation had been conducted in order of single bones, components and whole body. Whole body kinematics in frontal impact had been validated against the PMHS frontal belt restrained sled tests series, resulting in good biofidelity scores. In this study, the models were validated for lateral impact. The models were validated against several impact tests of body regions from ISO-TR9790 and against recently published full scale lateral sled tests for whole body kinematics. In most cases, the results showed good biofidelity of the models.
2013-09-08
Technical Paper
2013-24-0140
Francesco Vivio, Vincenzo Vullo, Gino Bella, Michele Ferracci, Luigi Arnone
An engine head of a common rail direct injection engine with three in line cylinders for Light Transportation Vehicle (LTV) applications has been analyzed and optimized by means of uncoupled CFD and FEM simulations in order to assess the strength of the components. This paper deals with a structural stress analysis of the cylinder head considering the thermal loads computed through an CFD simulation and a detailed FV heat-transfer analysis. The FE model of the cylinder head includes the contact interaction between the main parts of the cylinder head assembly and it is subjected to the gas pressure, thermal loads and the effects of bolts tightening and valve springs. The results, in term of temperature field, are validated by comparing with those obtained by means of experimental analyses. Then a fatigue assessment of the cylinder head has been performed using a multi-axial fatigue criterion.
2013-04-08
Technical Paper
2013-01-0456
Binhui Jiang, Haojie Mao, Libo Cao, King H. Yang
Previously, a 10-year-old (YO) pediatric thorax finite element model (FEM) was developed and verified against child chest stiffness data measured from clinical cardiopulmonary resuscitation (CPR). However, the CPR experiments were performed at relatively low speeds, with a maximum loading rate of 250 mm/s. Studies showed that the biomechanical responses of human thorax exhibited rate sensitive characteristics. As such, the studies of dynamic responses of the pediatric thorax FEM are needed. Experimental pediatric cadaver data in frontal pendulum impacts and diagonal belt dynamic loading tests were used for dynamic validation. Thoracic force-deflection curves between test and simulation were compared. Strains predicted by the FEM and the injuries observed in the cadaver tests were also compared for injury assessment and analysis. This study helped to further improve the 10 YO pediatric thorax FEM.
2004-03-08
Technical Paper
2004-01-0164
R. Mohan Iyengar, T. Chang, S. Laxman, S. Thirupathi, S. Perumalswami
A finite element methodology, based on implicit numerical integration procedure, for simulating oil-canning tests on Door assemblies is presented. The method takes into account nonlinearities due to geometry, material and contact between parts during deformation. The simulation results are compared with experimental observations. Excellent correlation between experimental observations and analytical predictions are obtained in these tests. Armed with the confidence in the methodology, simulations on a door assembly are conducted to study the gage and grade sensitivities of the outer panel. The sensitivity studies are conducted on three different grades of steel for the outer panel. Further studies are conducted to understand the effects of manufacturing (forming operation) on the oil canning behavior of door assembly. Results demonstrate the utility of the method in material selection during pre-program design of automotive structures.
2004-03-08
Technical Paper
2004-01-0163
S. Sriram, O. Lanzi
Prediction of dent resistance of automotive closure panels using Finite Element Analysis (FEA) has increased in popularity as an effective screening tool to determine the optimum combination of material properties and thickness for a given exposed panel application. The analysis process typically includes formability analysis, the results of which are mapped onto a structural model for analysis of dent resistance. Although this method is general, allowing for consideration of the entire panel assembly and boundary conditions, the approach can be very time consuming especially when evaluating several combinations of material grade and thicknesses. This paper presents an alternative approach for the prediction of dent resistance. Using a number of screening simulations the most influential variables affecting dent resistance were determined. A rectangular bi-curved plate was used to approximate the panel assembly.
2004-03-08
Technical Paper
2004-01-0182
G. Gottstein, M. Crumbach, M. Goerdeler, L. Neumann, R. Kopp
We report on a novel approach for through-process modeling of anisotropy development during AA5182 sheet production from hot rolling through terminal annealing. For this a thermomechanical process model was coupled to physics based microstructure models for deformation texture (GIA), work hardening (3IVM), and recrystallization texture (StaRT). The model overpredicts the Cube texture during hot rolling but properly predicts the terminal texture after multiple cold rolling with intermediate annealing. This approach can be extended to forming of automative sheet or integrated in crash simulations.
2004-03-08
Technical Paper
2004-01-0188
Christoph Knotz, Bernd Mlekusch
Many safety regulations in the automotive engineering use impactor testing (e.g. FMVSS201 in the US; Pedestrian Protection, ECE-R21, proposal for EEVC WG13 in Europe) in the certification process. Through the increasing demand for very short development times virtual engineering has become an inevitable tool. We show a complete virtual development process for the Free-Motion-Headform (FMH) regulation (FMVSS201u), where we use a combination of self-developed and standard software. The process starts with the definition of the target-points, the possible and allowed positioning of the FMH, the detection of worst case angles, the automated generation of section cuts, the Finite-Elements (FE) analysis and the web based documentation of the results. Our self-developed tools play an important role in the FMH-positioning/worst case detection area as well as in the result analysis and documentation.
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