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Automotive Vehicle Body Temperature Prediction in a Paint Oven

Chrysler Group LLC-Yu Hsien Wu, Sreekanth Surapaneni, Kumar Srinivasan, Paul Stibich
Published 2014-04-01 by SAE International in United States
Automotive vehicle body electrophoretic (e-coat) and paint application has a high degree of complexity and expense in vehicle assembly. These steps involve coating and painting the vehicle body. Each step has multiple coatings and a curing process of the body in an oven. Two types of heating methods, radiation and convection, are used in the ovens to cure coatings and paints during the process. During heating stage in the oven, the vehicle body has large thermal stresses due to thermal expansion. These stresses may cause permanent deformation and weld/joint failure. Body panel deformation and joint failure can be predicted by using structural analysis with component surface temperature distribution. The prediction will avoid late and costly changes to the vehicle design. The temperature profiles on the vehicle components are the key boundary conditions used to perform structure analysis. This paper presents an efficient method to predict vehicle body temperature profiles as the vehicle pass through the radiant section of an e-coat and/or paint oven. Transient analysis coupled with geometry movement is used to predict the vehicle…
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A Mesoscopic-Stress Based Fatigue Limit Theory - A Revised Dang Van's Model

Chrysler Group LLC-Yung-Li Lee
Oakland University-Virgiliu-Adrian Savu, Anthony Han, Azadeh Narimissa, Amir Kazemi
Published 2014-04-01 by SAE International in United States
Dang Van (Dang Van et al., 1982 and Dang Van, 1993) states that for an infinite lifetime (near fatigue limit), crack nucleation in slip bands may occur at the most unfavorable oriented grains, which are subject to plastic deformation even if the macroscopic stress is elastic. Since the residual stresses in these plastically deformed grains are induced by the restraining effect of the adjacent grains, it is assumed that the residual stresses are stabilized at a mesoscopic level. These stresses are currently approximated by the macroscopic hydrostatic stress defined by the normal stresses to the faces of an octahedral element oriented with the faces symmetric to the principal axis; mathematically they are equal to each other and they are the average of the principal stresses. This paper proposes and supports the novel hypothesis of normal stress to the maximum shear stress plane being an alternative to the octahedral normal stress, and better aligning with the restraining effect of the adjacent grains defined by Dang Van Multi Scale Approach.
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Energy Efficient Routing for Electric Vehicles using Particle Swarm Optimization

Chrysler Group LLC-Rami Abousleiman
Oakland Univ.-Osamah Rawashdeh
Published 2014-04-01 by SAE International in United States
Growing concerns about the environment, energy dependency, and unstable fuel prices have increased the market share of electric vehicles. This has led to an increased demand for energy efficient routing algorithms that are optimized for electric vehicles. Traditional routing algorithms are focused on finding the shortest distance or the least time route between two points. These approaches have been working well for fossil fueled vehicles. Electric vehicles, on the other hand, require different route optimization techniques. Negative edge costs, battery power and capacity limits, as well as vehicle parameters that are only available at query time, make the task of electric vehicle routing a challenging problem. In this paper, we present a simulated solution to the energy efficient routing for electric vehicles using Particle Swarm Optimization. Simulation results show improvements in the energy consumption of the electric vehicle when applied to a start-to-destination routing problem.
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Design for Six Sigma (DFSS) for Optimization of Automotive Heat Exchanger and Underhood Air Temperature

SAE International Journal of Materials and Manufacturing

Chrysler Group LLC-Alaa El-Sharkawy, Asif Salahuddin, Brian Komarisky
  • Journal Article
  • 2014-01-0729
Published 2014-04-01 by SAE International in United States
In this paper a design methodology for automotive heat exchangers has been applied which brings robustness into the design process and helps to optimize the design goals: as to maintain an optimal coolant temperature and to limit the vehicle underhood air temperature within a tolerable limit. The most influential design factors for the heat exchangers which affect the goals have been identified with that process. The paper summarizes the optimization steps necessary to meet the optimal functional goals for the vehicle as mentioned above. Taguchi's [1] Design for Six Sigma (DFSS) methods have been employed to conduct this analysis in a robust way.
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A Technique to Predict Thermal Buckling in Automotive Body Panels by Coupling Heat Transfer and Structural Analysis

Chrysler Group LLC-Paul R. Stibich, Yu Hsien Wu, Weidong Zhang, Michao Guo, Kumar Srinivasan, Sreekanth Surapaneni
Published 2014-04-01 by SAE International in United States
This paper describes a comprehensive methodology for the simulation of vehicle body panel buckling in an electrophoretic coat (electro-coat or e-coat) and/or paint oven environment. The simulation couples computational heat transfer analysis and structural analysis. Heat transfer analysis is used to predict temperature distribution throughout a vehicle body in curing ovens. The vehicle body temperature profile from the heat transfer analysis is applied as an input for a structural analysis to predict buckling. This study is focused on the radiant section of the curing ovens. The radiant section of the oven has the largest temperature gradients within the body structure. This methodology couples a fully transient thermal analysis to simulate the structure through the electro-coat and paint curing environments with a structural, buckling analysis. The ability to predict the buckling phenomenon using a virtual simulation will reduce the risk of late production changes to the vehicle class “A” surfaces.
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A Scenario-Based Approach to Assess Exposure for ASIL Determination

Chrysler Group LLC-Barbara J. Czerny, Robert Suchala
Chrysler Powertrain Engrg-Michael Runyon
Published 2014-04-01 by SAE International in United States
Exposure in ISO 26262 is defined as the state of being in an operational situation that can be hazardous if coincident with the failure mode under analysis. An operational situation is defined as a scenario that can occur during a vehicle's life with examples given such as driving, parking, or maintenance. Accurately predicting exposure is one of the more difficult tasks in the ASIL determination. ISO 26262 Part 3 attempts to provide guidance in Annex B through tables of potential operational situations and associated exposure levels. However, the contents of these tables may not allow for an accurate prediction of exposure and may lead to an exposure value that is too high or too low.In this paper, we describe a potential method for determining exposure that considers a potential mishap scenario as a composition of multiple coincident operational situations rather than considering a single operational situation as indicated in the tables in Annex B of Part 3. We purport that for a potentially hazardous situation to occur if the failure mode under analysis occurs, it…
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Sensitivity and Uncertainty Analysis in Computational Thermal Models

Chrysler Group LLC-Alaa El-Sharkawy
Published 2014-04-01 by SAE International in United States
Computational tools have been extensively applied to predict component temperatures before an actual vehicle is built for testing [1, 2, 3, 4, and 5]. This approach provides an estimate of component temperatures during a specific driving condition. The predicted component temperature is compared against acceptable temperature limits. If violations of the temperature limits are predicted, corrective actions will be applied. These corrective actions may include adding heat shields to the heat source or to the receiving components. Therefore, design changes are implemented based on the simulation results.Sensitivity analysis is the formal technique of determining most influential parameters in a system that affects its performance. Uncertainty analysis is the process of evaluating the deviation of the design from its intended design target. In the case of thermal protection, uncertainty analysis is applied in order to determine the variation of the calculated component temperature around its nominal value. It has been a common understanding that no engineering analysis is complete without conducting uncertainty analysis. Though sensitivity and uncertainty analysis topics have been widely discussed in engineering applications,…
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A Study on Body Panel Stress Analysis under Distributed Loads

Chrysler Group LLC-Bhaskar Kusuma, Kaizhi Quan, Mingchao Guo, Ram Bhandarkar
Published 2014-04-01 by SAE International in United States
In this paper, four possible CAE analysis methods for calculating critical buckling load and post-buckling permanent deformation after unloading for geometry imperfection sensitive thin shell structures under uniformly distributed loads have been investigated. The typical application is a vehicle roof panel under snow load. The methods include 1) nonlinear static stress analysis, 2) linear Eigen value buckling analysis 3) nonlinear static stress analysis using Riks method with consideration of imperfections, and 4) implicit quasi-static nonlinear stress analysis with consideration of imperfections. Advantage and disadvantage of each method have been discussed. Correlations between each of the method to a physical test are also conducted. Finally, the implicit quasi-static nonlinear stress analysis with consideration of geometry imperfections that are scaled mode shapes from linear Eigen value buckling analysis is preferred.
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Application of the Glinka's ESED Criterion in Optimization Design

Chrysler Group LLC-Wenxin Qin, Sandip Datta
Chrysler LLC-Fred Zweng
Published 2014-04-01 by SAE International in United States
In order to take into account the local material non-linear elastic-plastic effects generated by notches, Glinka proposed the equivalent strain energy density (ESED) Criterion which has been widely accepted and used in fatigue theory and calculation for the last few decades. In this paper, Glinka's criterion is applied to structural optimization design for elastic-plastic correction to consider material non-linear elastic-plastic effects. The equivalent (fictitious) stress was derived from Glinka's Criterion equation for the commonly used Ramberg-Osgood and bi-linear stress and strain relationships. This equivalent stress can be used as the stress boundary constraint threshold in structural optimization design to control the elastic-plastic stress or strain in nonlinear optimization. Examples demonstrated this application was an efficient and effective practice within the material non-linear elastic-plastic range when using the equivalent elastic stress as constraints in automotive engineering structural optimization designs.
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Non-Linear Modeling of Bushings and Cab Mounts for Calculation of Durability Loads

Chrysler Group LLC-Nantu Roy, Orlando Silva Parez
Munich University of Applied Sciences-Christian Scheiblegger, Peter Pfeffer
Published 2014-04-01 by SAE International in United States
Cab mounts and suspension bushings are crucial for ride and handling characteristics and must be durable under highly variable loading. Such elastomeric bushings exhibit non-linear behavior, depending on excitation frequency, amplitude and the level of preload. To calculate realistic loads for durability analysis of cars and trucks multi-body simulation (MBS) software is used, but standard bushing models for MBS neglect the amplitude dependent characteristics of elastomers and therefore lead to a trade-off in simulation accuracy. On the other hand, some non-linear model approaches lack an easy to use parameter identification process or need too much input data from experiments. Others exhibit severe drawbacks in computing time, accuracy or even numerical stability under realistic transient or superimposed sinusoidal excitation.To improve bushing modeling of cab/box mounts for heavy duty/light duty trucks, a practical approach to model non-linear bushing dynamic characteristics has been tested and validated against standard bushing models. For model parameterization, several elastomeric cab mounts have been tested for their static and dynamic properties. The paper discusses the parameter identification process and validates the new non-linear…
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