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Viewing 1 to 30 of 36
2005-05-16
Technical Paper
2005-01-2428
Gang Yin, Federico Lucas, Rolf Balte, John G. Cherng
This paper is to present a systematic study on many critical factors, such as angle of the testing panel, total scanning time of the intensity probe, source room noise level, number of microphones used in the source room, sample size, distance of the microphone in the source room, intensity probe spacer size, measurement time, and receiver room size. Additionally, three noise factors; background noise level, operator and measurement distance were also included. It were discovered that test panel angles and sample sizes were the two most dominant factors. All of above are relevant to experimental SEA or SEA validation process. The complete test results and the experience gained are presented in the paper.
2006-04-03
Technical Paper
2006-01-0366
Nikhil Bhat, Hong Tae Kang, Vivek Bhise
This paper presents a design and development approach for automotive bucket seat frame using a parametric modeling and a finite element analysis methodology. This approach is expected to help build a lightweight seat structure quickly and efficiently. This approach is general, and it can be applied in designing and developing any mechanical structural component. The design process involves, first parametric modeling of the front bucket seat frame using Pro E. This CAD model was then optimized using optimization software called Optistruct, for two cases of load case and boundary condition. The optimized design was then tested for FMVSS seat requirements using LS-DYNA. The dynamic nature of the design approach helps in changing design parameters during different stages of the design process, until the seat structure satisfies the design criteria and the strength requirements. The construction and testing of this design and the design model are still under progress.
2014-05-09
Journal Article
2014-01-9125
Byeong wook Jeon, Sang-Hwan Kim
This study was conducted to develop and validate a multidimensional measure of shift quality as perceived by drivers during kick-down shift events for automatic transmission vehicles. As part of the first study, a survey was conducted among common drivers to identify primary factors used to describe subjective gear-shifting qualities. A factor analysis on the survey data revealed four semantic subdimensions. These subdimensions include responsiveness, smoothness, unperceivable, and strength. Based on the four descriptive terms, a measure with semantic scales on each subdimension was developed and used in an experiment as the second study. Twelve participants drove and evaluated five vehicles with different gear shifting patterns. Participants were asked to make kick-down events with two different driving intentions (mild vs. sporty) across three different speeds on actual roadway (local streets and highway).
2012-04-16
Technical Paper
2012-01-0071
Anjan Vincent, Vivek D. Bhise, Pankaj Mallick
Seat comfort is a highly subjective attribute and depends on a wide range of factors, but the successful prediction of seat comfort from a group of relevant variables can hold the promise of eliminating the need for time-consuming subjective evaluations during the early stages of seat cushion selection and development. This research presents the subjective seat comfort data of a group of 30 participants using a controlled range of seat foam samples, and attempts to correlate this attribute with a) the anthropometric and demographic characteristics of the participants, b) the objective pressure distribution at the body-seat interface and c) properties of the various foam samples that were used for the test.
1998-02-23
Technical Paper
980079
M. Y. Demeri, C. L. Chow, W. H. Tai
Strains in most stamped parts are produced under non-proportional loading. Limit strains induced during forming are, therefore, path dependent. Experimental Forming Limit Diagrams (FLDs) are usually determined under proportional loading and are not applicable to most forming operations. Experimental results have shown that path dependent FLDs are different from those determined under proportional loading. A number of analytical methods have been used to predict FLDs under proportional loading. The authors have recently introduced a new method for predicting FLDs based on the theory of damage mechanics. The damage model was used successfully to predict proportional FLDs for VDIF steel and Al6111-T4. In this paper, the anisotropic damage model was used to predict non-proportional FLDs for VDIF steel. Experiments were conducted to validate model predictions by applying pre-stretch in plane strain followed by uniaxial and balanced biaxial tension.
1996-02-01
Technical Paper
960169
C. L. Chow, Fan Yang, M. Omar Faruque
This paper presents a comprehensive damage model capable of predicting crash behavior of aluminum structures under varying applied loading conditions. The damage model has been implemented in a general purpose explicit nonlinear finite element code and crash analysis has been carried out for aluminum tubes. The response obtained from the finite element analysis shows a close agreement with the experimental data. The finite element program containing the proposed generalized damage model can be used to analyze aluminum structures subjected to complex service loading conditions and identify associated failure modes to assess crashworthiness.
1996-02-01
Technical Paper
960598
C. L. Chow, L. G. Yu, M. Y. Demeri
Abstract Based on the theory of damage mechanics, an orthotropic damage model for the prediction of forming limit diagram (FLD) is developed. The conventional method of FLD used to predict localized necking adopts two fundamentally different approaches. Under biaxial loading, the Hill's plasticity method is often chosen when α (= ε2/ε1) < 0. On the other hand, the M-K method is adopted for the prediction of localized necking when α > 0 or the biaxial stretching of sheet metal is pronounced. The M-K method however suffers from the arbitrary selection of the imperfection size, thus resulting in inconsistent predictions. The orthotropic damage model developed for predicting the FLD is based on the anisotropic damage model recently proposed by Chow et al (1993). The model is extended to take into account, during the sheet forming process, orthotropic plasticity and damage. The orthotropic FLD model consists of the constitutive equations of elasticity and plasticity coupled with damage.
1994-10-01
Technical Paper
941929
Laurine J. Leep, Gary S. Strumolo, Vladimir L. Griaznov, Subrata Sengupta, Andreas M. Brohmer, Juergen Meyer
Computational fluid dynamics simulations of the gas exchange process in a crankcase-scavenged, two-stroke engine were used to study the scavenging characteristics of the engine over the whole operating range and to investigate the effects of various design changes. The simulations used time-dependent velocity and pressure boundary conditions in the transfer and exhaust ports, respectively, which were obtained from a one-dimensional gas exchange code. The bulk flow characteristics, scavenging and trapping efficiencies, computed from these simulations compared well with experimental data. Investigation of the highest load and speed case showed that moderate port angle variations only weakly influenced the scavenging efficiency and velocity field. On the other hand, modifying the exhaust pressure to simulate single cylinder operation had a more significant effect on the scavenging and showed a possible way to control the gas exchange process.
2006-04-03
Technical Paper
2006-01-1277
Chinar Ghike, Taehyun Shim
A vehicle model is an important factor in the development of vehicle control systems. Various vehicle models having different complexities, assumptions, and limitations have been developed and applied to many different vehicle control systems. A 14 DOF vehicle model that includes a roll center as well as non-linear effects due to vehicle roll and pitch angles and unsprung mass inertias, is developed. From this model, the limitations and validity of lower order models which employ different assumptions for simplification of dynamic equations are investigated by analyzing their effect on vehicle roll response through simulation. The possible limitation of the 14 DOF model compared to an actual vehicle is also discussed.
2006-04-03
Technical Paper
2006-01-1284
Jamie Gertsch, Taehyun Shim
Yaw and roll stability limits are derived for three quasi-static roll plane models: rigid vehicle, suspended vehicle, and compliant tire vehicle. A generalized stability equation is identified that fits the stability limits for each model. This generalized stability equation leads to the definition of two new parameters referred to as the generalized superelevation and generalized center of gravity height. These parameters are shown to be physically meaningful. The use of linearizing assumptions is minimized and road superelevation is included, resulting in a more complete equation for each stability limit. Each derived stability limit is then compared and contrasted to the typical representations found in the literature.
2006-04-03
Technical Paper
2006-01-1631
Inchul Kim, Hualei Chen, Roger C. Shulze
The Low Mass Vehicle (LMV) that is a minivan designed to compete with the Toyota Echo but with 30% less mass has been used for the research in the Institute for Advanced Vehicle Systems. To reduce the aerodynamic forces on the LMV, the present authors have developed a rear spoiler of a new type based on the principles of fluid dynamics and through numerical computations. This new spoiler has been developed in such a way that the aerodynamic drag as well as lift on vehicles having a bluff back can be reduced when the new spoiler is attached to them. Numerical simulations show that the aerodynamic drag and lift on the LMV moving at 30 m/s reduce by 5 % and more than 100 %, respectively, when the new spoiler is attached to it.
2006-02-14
Technical Paper
2006-01-1950
Taehyun Shim, Pradheep C. Velusamy
Vehicle roll dynamics is strongly influenced by suspension properties such as roll center height, roll steer and roll camber. In this paper, the effects of suspension properties on vehicle roll response has been investigated using a multi-body vehicle dynamics program. A full vehicle model equipped with front MacPherson and rear multilink suspensions has been used for the study. Roll dynamics of the vehicle were evaluated by performing fixed timing fishhook maneuver in the simulation. Variations of vehicle roll response due to changes in the suspension properties were assessed by quantitatively analyzing the vehicle response through simulation. Critical suspension design parameters for vehicle roll dynamics were identified and adjusted to improve roll stability of the vehicle model with passive suspension. Design of Experiments has been used for identifying critical hardpoints affecting the suspension parameters and optimization techniques were employed for parameter optimization.
2007-04-16
Technical Paper
2007-01-0453
Sonal Onkar, Marc Hayes, Jim Dalpizzol, James Dowd, Vivek D. Bhise
This paper describes a computerized value analysis tool (VAT) developed to aid automotive interior designers, engineers and planners to achieve the high levels of perceived quality of materials used in automotive door trim panels. The model requires a number of inputs related to types of materials, their manufacturing processes and customer perceived quality ratings, costs and importance of materials, features located in different areas of the door trim panel, etc. It allows the user to conduct iterative evaluation of total cost, total weighted customer perceived quality ratings, and estimates of perceived value (perceived quality divided by cost) for different door trim areas as well as the entire door trim panel. The VAT, thus, allows value and cost management related to materials and processing choices for automotive interiors.
2004-03-08
Technical Paper
2004-01-1709
Vivek Bhise, Roger Shulze, Huzefa Mamoola, Jeffrey Bonner
This paper describes a unique interior design and multidisciplinary process implemented by the faculty and students to develop the interior for a Low Mass Vehicle (LMV). The 103 inch LMV was designed with the goal of about 30% reduction in weight than a typical class C segment vehicle and would require low investment in manufacturing. In the early stages of the program, the UM-Dearborn team developed detailed requirements of the vehicle interior based on the vehicle's exterior developed using a similar process. The requirements were given to a senior class of automotive design students from the College of Creative Studies in Detroit to create different interior design themes. Approximately twenty-five interior design themes were judged by a panel of automotive industry experts, and a winning design was selected.
2005-04-11
Technical Paper
2005-01-1027
Mangesh Natu, Vivek Bhise, Roger Shulze
This paper presents results of a research project conducted to develop a methodology and to refine the specifications of a small, low mass, low cost vehicle being developed at the University of Michigan-Dearborn. The challenge was to assure that the design would meet the needs and expectations of customers in three different countries, namely, China, India and the United States. U.S, Chinese and Indian students studying on the university campus represented customers from their respective countries for our surveys and provided us with the necessary data on: 1) Importance of various vehicle level attributes to the entry level small car customer, 2) Preferences to various features, and 3) Direction magnitude estimation on parameters to size the vehicle for each of the three markets.
2008-04-14
Technical Paper
2008-01-0770
Shang-Yeu Chang, Lin Yang, Jinhua Guo
Security is a huge concern in VANETs (Vehicular Ad hoc NETworks) since the information being conveyed may affect life-or-death decisions. One of the security concerns is the Sybil Attack. This attack attempts to create multiple identities to disrupt or control the network. A malicious node utilizing the Sybil Attack in VANETs can disrupt the network in various ways. It can create a large number of Sybil nodes to intervene in message forwarding, potentially causing a massive pileup and great loss of life. A malicious node can also use the Sybil Attack to create illusions of traffic congestions, getting other drivers to take alternate routes and leaving a clear path for the malicious node to its destination. In this paper, we discuss several defense strategies for the Sybil Attack in VANETs.
2008-04-14
Journal Article
2008-01-1446
Sergey F. Golovashchenko, Andrey M. Ilinich
Current die design recommendations attempt to limit the production of burrs through accurate alignment of the upper and lower edges. For common automotive exterior sheet, this translates to a gap less than 0.06mm. Unfortunately, the tolerances required by such standards often exceed the capabilities of many trim dies. The objective of the research described in this paper is to study the mechanisms of burrs generation and their impact on AHSS formability in stretch flanging. Experimental results on influence of trimming conditions on the shape of the sheared surface will be combined with the results of stretching strips after trimming.
2006-04-03
Technical Paper
2006-01-1474
Vivek Bhise, Rhita Boufelliga, Thomas Roney, James Dowd, Marc Hayes
The objective of the paper is to present a unique design approach and its outputs: the design concepts for automotive center consoles for a near term SUV that can be produced in 2-3 years, and the second for, a more futuristic SUV, that could be produced in 10 or more years. In the first phase of this two phase project, we benchmarked center consoles from a number of existing and concept vehicles, analyzed available data (e.g. J.D. Power customer feedback surveys), and conducted studies (e.g. survey of items stored in the vehicles, item location preferences in the console area) to understand customer/user needs in designing the center consoles. In the second phase, we provided the information generated in the first phase to four groups of student teams who competed to create winning designs of the center consoles.
2008-06-23
Technical Paper
2008-01-1828
Yu. S. Usinin, M. A. Grigorjev, K. M. Vinogradov, A. N. Gorozhankin, S. P. Gladyshev
The urban trams with a low floor are more convenient for the passengers, and with a high floor - more cheaply and more technologically during manufacturing and operation. The combined advantages those and others in themselves are trams with average height of a floor, but for this purpose it is necessary to lower height of tram carriages, that is reached by application of electric motors with a small stator external diameter. It is offered in this the perspective electric drive on the base of the synchronous motor with independent excitation. The salient rotor poles of the motor do not contain windings. The motors stator is carried out on the base of the stator body of regular AC electric motor. The multiphase winding is located in the stator. A winding section, which conductors settle down above the between rotor poles, carry out a role of the excitation winding, and others, which conductors lay above poles, - a role of the armature winding.
2016-04-05
Technical Paper
2016-01-1029
Jinsuk Kang, Byungchan Lee, Dohoy Jung
Abstract Charge boosting strategy plays an essential role in improving the power density of diesel engines while meeting stringent emissions regulations. In downsized two-stage turbocharged engines, turbocharger matching is critical to achieve desired boost pressure while maintaining sufficiently fast transient response. A numerical simulation model is developed to evaluate the effect of two-stage turbocharger configurations on the perceived vehicle acceleration. The simulation model developed in GT-SUITE consists of engine, drivetrain, and vehicle dynamics sub-models. A model-based turbocharger control logic is developed in MATLAB using an analytical compressor model and a mean-value engine model. The components of the two-stage turbocharging system evaluated in this study include a variable geometry turbine in the high-pressure stage, a compressor bypass valve in the low-pressure stage and an electrically assisted turbocharger in the low-pressure stage.
2016-04-05
Technical Paper
2016-01-1199
Yao Hong, Cheol W. Lee
Abstract This paper begins with a baseline multi-objective optimization problem for the lithium-ion battery cell. Maximizing the energy per unit separator area and minimizing the mass per unit separator area are considered as the objectives when the thickness and the porosity of the positive electrode are chosen as design variables in the baseline problem. By employing a reaction zone model of a Graphite/Iron Phosphate Lithium-ion Cell and the Genetic Algorithm, it is shown the shape of the Pareto optimal front for the formulated optimization takes a convex form. The identified shape of the Pareto optimal front is expected to guide Design of Experiments (DOE) and product design. Compared with the conventional studies whose optimizations are based on a single objective of maximizing the specific energy, the proposed multi-objective optimization approach offers more flexibility to the product designers when trade-off between conflicting objectives is required.
2004-03-08
Technical Paper
2004-01-0381
Vivek Bhise, Ghassan Kridli, Huzefa Mamoola, Shawn Devaraj, Anitha Pillai, Roger Shulze
This paper describes a research project currently in-progress to develop a parametric model of a vehicle for use in early design stages of a new vehicle program. The model requires key input parameters to define the kind of new vehicle to be designed — in terms of details such as its intended driver/user population, vehicle type (e.g. 2-box, 3-box designs), and some key exterior and interior dimensions related to its size and proportions. The model computes and graphically displays interior package, ergonomics zones for driver controls and displays, and field of views through window openings. It also allows importing or inputting and superimposing and manipulating exterior surfaces created by a designer to assess compatibility between the interior occupant package and the vehicle exterior.
2017-03-28
Technical Paper
2017-01-1606
Sergey P. Gladyshev, Pavel Gladyshev, Irina Okrainskaya
Abstract In this paper, we consider a new design of synchronous motor with salient poles rotor and all coils placed on the stator. This design, uses a laminated silicon steel rotor, which is not so expensive as a rotor with super strong permanent magnets. This design of machine eliminates copper rings on the rotor and brushes which is used in regular synchronous motors, and eliminates disadvantages involved with these arrangements. In an earlier publication, authors considered the opportunity realization of synchronous mode operation in the machine with salient pole rotor and DC stator excitation. Now, we consider the new synchronous mode operation with individual DC excitation of each the alternative current (AC) windings for realization the first, second and third phase synchronous machines. In theoretical basics of analyses and design of synchronous motors we pay more attention to the single-phase motor because it is the basis for design polyphase synchronous machines.
2017-06-05
Technical Paper
2017-01-1900
Leiaixin Yang, Yinong Li, Peiran Ding, Parsa Zamankhan, John G. Cherng
Abstract Brake squeal is an instability issue with many parameters. This study attempts to assess the effect of thermal load on brake squeal behavior through finite element computation. The research can be divided into two parts. The first step is to analyze the thermal conditions of a brake assembly based on ANSYS Fluent. Modeling of transient temperature and thermal-structural analysis are then used in coupled thermal-mechanical analysis using complex eigenvalue methods in ANSYS Mechanical to determine the deformation and the stress established in both the disk and the pad. Thus, the influence of thermal load may be observed when using finite element methods for prediction of brake squeal propensity. A detailed finite element model of a commercial brake disc was developed and verified by experimental modal analysis and structure free-free modal analysis.
2017-03-28
Technical Paper
2017-01-0312
ZiQiang Sheng, Pankaj Mallick
Abstract Based on findings from micromechanical studies, a Ductile Failure Criterion (DFC) was proposed. The proposed DFC treats localized necking as failure and critical damage as a function of strain path and initial sheet thickness. Under linear strain path assumption, a method to predict Forming Limit Curve (FLC) is derived from this DFC. With the help of predetermined effect functions, the method only needs a calibration at uniaxial tension. The approach was validated by predicting FLCs for sixteen different aluminum and steel sheet metal materials. Comparison shows that the prediction matches quite well with experimental observations in most cases.
2017-03-28
Technical Paper
2017-01-0343
Xiao Wu, Zhigang Wei, HongTae Kang, Abolhassan Khosrovaneh
Abstract Over the decades, several attempts have been made to develop new fatigue analysis methods for welded joints since most of the incidents in automotive structures are joints related. Therefore, a reliable and effective fatigue damage parameter is needed to properly predict the failure location and fatigue life of these welded structures to reduce the hardware testing, time, and the associated cost. The nodal force-based structural stress approach is becoming widely used in fatigue life assessment of welded structures. In this paper, a new nodal force-based structural stress recovery procedure is proposed that uses the least squares method to linearly smooth the stresses in elements along the weld line. Weight function is introduced to give flexibility in choosing different weighting schemes between elements. Two typical weighting schemes are discussed and compared.
2000-03-06
Technical Paper
2000-01-0631
C.L. Chow, Y. Wei, Shen Wu, Bala Subbaraman, James Borchelt, Gregory Frederick
The paper presents a method of analysis based on the theory of damage mechanics to quantify the degree of damage in an engineering structure under load. The method is incorporated into a Ford in-house finite element program called FCRASH that is applied to analyze the cumulative damage in a bumper under multiple low speed impacts. The numerical results calculated at the peak value of the contact force are compared with the test results. The FEA results are used to identify the locations of the hotspot in the bumper system and the predicted location where a potential crack would initiate. The microscopic observations showed damage in the area predicted with the finite element program after the specified number of impacts.
2000-03-06
Technical Paper
2000-01-0776
C.L. Chow, W.H. Tai, Sing Tang
In this paper, a predictive method is developed to determine the forming limit strain and fracture limit strain in a stamped automotive component subjected to a complex strain history that would be experienced during an actual forming operation. The method of analysis is based on a damage mechanics model developed recently by the authors and extended to take into account the hysteretic effects of the principal strain and damage planes. The forming limit and fracture limit strains are then predicted using the modified damage model. Satisfactory predictions have been achieved for a practical case where the complex strain history is prescribed based an actual stamping operation.
2001-03-05
Technical Paper
2001-01-1129
C. L. Chow, X. J. Yang, E. Chu
LS-DYNA3D has been widely used to perform computer simulation of sheet metal forming. In the material library of LS-DYNA3D there are a number of user defined material models. In order to take full advantage of the material subroutines, it is important for the users to be able to display user defined history variables in the post processing and to establish user-defined failure criterion. In this report, the development of a damage coupled plastic model is firstly described. The damage model is then programmed in a user defined material subroutine. This is followed by performing finite element simulation of sheet metal forming with the LS-DYNA3D that has incorporated the damage coupled plastic model. The way to display the user defined history variables and how to deal with the failure criterion during the postprocessing of ETA/DYNAFORM are described. History variable distributions at several time steps are displayed and discussed in this paper.
2001-03-05
Technical Paper
2001-01-0335
Dale A. Frank, Shan Shih
Although computer models for vehicle and sub-system performance simulations have been developed and used extensively in the past several decades, there is currently a need to enhance the overall availability of these types of tools. Increasing demands on vehicle performance targets have intensified the need to obtain rapid feedback on the effects of vehicle modifications throughout the entire development cycle. At the same time, evolution of the PC and development of Web-based applications have contributed to the availability, accessibility, and user-friendliness of sophisticated computer analysis. Web engineering is an ideal approach in supporting globalization and is a cost-effective design-analysis integration business strategy. There is little doubt that this new approach will have positive impacts on product cost, quality, and development cycle time. This paper will show how Microsoft Excel and the Web can be powerful and effective tools in the development process.
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