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Fatigue life Prediction of HVAC pipe assembly for measured powertrain load by virtual simulation

FCA Engineering India Pvt., Ltd.-Sathish Kumar Pandi, C Elango, Kameswara Rao Appana, Roshan N. Mahadule, DivaKaruni Murali Krishna
  • Technical Paper
  • 2020-01-0188
To be published on 2020-04-14 by SAE International in United States
Structural durability of automotive components is one of the key requirements in design and development of today’s automobiles. Virtual simulations are used to estimate component durability to save the cost and time required to build the components and testing. The objective of this work is to find the service life of automotive HVAC pipe assembly by calculating cumulative fatigue life for operation under actual powertrain load conditions. Modal transient response analysis is performed using MSC-Nastran with the measured powertrain load time history. Strain based fatigue life analysis is carried out in n-code using modal superposition method (MSM). The estimated fatigue life was compared with the physical test results. This paper also explains the root cause of low fatigue life on pipe assembly and provide the solution. Keywords: Durability, HVAC Pipe, Powertrain, Modal Transient, Fatigue Life
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Application of Multivariate Control Chart Techniques to Identifying Nonconforming Pallets in Automotive Assembly Plants

FCA US LLC-Michael Huang, Yuqin Wang
University of Texas at San Antonio-Adel Alaeddini
  • Technical Paper
  • 2020-01-0477
To be published on 2020-04-14 by SAE International in United States
The Hotelling multivariate control chart and the sample generalized variance |S| are used to monitor the mean and dispersion of underbody data including the pallet information to identify the non-conforming pallets. An iterative procedure and the Gaussian mixture model (GMM) are used to rank the non-conforming pallets in the order of severity. The multivariate Hotelling T^2 test statistic with Mason-Tracy-Young (MYT) signal decomposition method are used to identify the features that are affected by the non-conforming pallets. These algorithms were implemented in Advanced Pallet Analysis module of FCA Body Shop Analysis Tool (BSAT). The identified non-conforming pallets are displayed in a scatter plot with different color for each pallet. The run chart of an affected feature confirms the nonconforming pallets by highlighting data points from the nonconforming pallet. The analysis module has been successfully used in the body shops of FCA plants. One example is presented to demonstrate the application.
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Coupled Weld-Rupture Analysis of Automotive Assemblies

ESI North America-Yogendra Gooroochurn, Ramesh Dwarampudi, Vijay Tunga
ESI US R&D-Megha Seshadri, Ravi Raveendra
  • Technical Paper
  • 2020-01-1076
To be published on 2020-04-14 by SAE International in United States
Lightweight driven design in the automotive industry and the push for Electric Vehicles mandate the use of innovative materials such as Steel (HSS, UHSS, AHSS) and Aluminum alloys. For steel suppliers to meet the strength requirements of high strength steels, they often alloy the steel chemistry (depending on mill capability, rolling capacity, quenching capacity, etc.). When used in welded assembly constructions, these steels, as compared to traditional steels, behave differently. Depending on the welding heat input, the material chemistry and thickness, they either harden or soften in the heat affected zone. Similar behavior is observed with the most commonly used aluminum alloys (5000 and 6000 series) in the automotive sector. For both alloy types, different strengthening mechanism are used to meet their initial strength requirements (by work hardening and by heat treating respectively) but they both undergo softening in the heat affected zone during welding. Regardless of the alloys, the material in the heat affected zone is affected and so is the performance of the weldment during service. FE analyzes of Welding and Performance have…
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FAULT IDENTIFICATION OF ASSEMBLY PROCESSES USING FUZZY SET THEORY

University Of Detroit Mercy-Mostafa Mehrabi
University Of Detroit Mercy-Jonathan Weaver
  • Technical Paper
  • 2020-01-0487
To be published on 2020-04-14 by SAE International in United States
performance and productivity. Tracking faults in a typical manufacturing system is inherently an inverse problem which makes it more challenging and difficult to solve. Presented in this article is the development of a new methodology for fault identification and root-cause analysis of complex assembly systems. A combination of a knowledge-based system and fuzzy set theory is used to develop this new technique, which is an intelligent system that mimics the behavior of an expert in the field, and can trace back the source(s) of the fault to the relevant station. Examples from real assembly operations are provided to show the effectiveness of this approach.
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Vibration and Dynamic Analysis of Right-angle Geared Drives Considering the Influence of Gear-Shaft-Bearing Assembly Design

Marshall University-Xia Hua
  • Technical Paper
  • 2020-01-0415
To be published on 2020-04-14 by SAE International in United States
Dynamics of hypoid or spiral bevel gears like most high-speed precision gears employed in the powertrains of automobiles, commercial trucks, and off highway vehicles are significantly influenced by the design of the shafts and bearings. The finite element modeling approach is one of the useful methodologies applied to perform gear dynamic analysis. One of the major advantages of the finite element modeling approach is that it is able to account for the gear-shaft-bearing assembly design more accurately than other modeling approaches, for example, the lumped parameter modeling approach. In this paper, the finite element formulation, which can generally represent more complete characteristics of the gear-shaft-bearing assembly design, is employed to investigate how the key design changes of gear-shaft-bearing assembly influence the dynamics of spiral bevel gears. Accordingly, the underlying physics controlling these effects is also uncovered.
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A Method Using FEA for the Evaluation of Tooling and Process Requirements to Meet Dimensional Objectives

FCA US LLC-Amandeep Singh Jhajj, Steven Ford, Gregory Dwyer, William Stewart
  • Technical Paper
  • 2020-01-0497
To be published on 2020-04-14 by SAE International in United States
Dimensional Engineering concentrates effort in the early design phases to meet the dimensional build objectives in automotive production. Design optimization tools include tolerance stack up, datum optimization, datum coordination, dimensional control plans, and measurement plans. These tools are typically based on the assumption that parts are rigid and tooling dimensions are perfect. These assumptions are not necessarily true in automotive assemblies of compliant sheet metal parts on high volume assembly lines. To address this issue, FEA has been increasingly used to predict the behavior of imperfect and deformable parts in non-nominal tooling. This paper demonstrates an application of this approach. The complete analysis is divided into three phases. The first phase is a nominal design gravity analysis to validate the nominal design and tooling. In the second phase, the worst case scenarios are considered based on the previous programs to see their effects on assembly. Lastly, dimensional deviations and tooling loads are estimated to determine if they meet the constraints of both the part design and the tooling design. The novelty of this approach lies…
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Experimentation for design improvements for coil spring in the independent suspension

Automann Inc.-Viraj Dave
Kettering University-Yaomin Dong
  • Technical Paper
  • 2020-01-0503
To be published on 2020-04-14 by SAE International in United States
The objective of this project is to analyze potential design changes that can improve the performance of helical spring in an independent suspension. The performance of the helical spring was based upon the result measure of maximum value of stress acting on it and the amount displacement caused when the spring undergoes loading. The design changes in the spring were limited to coil cross section, spring diameter (constant & variable), pitch and length of the spring. Using all the possible combinations of these design parameters linear stress analysis was performed on different spring designs and their Stress and displacement results were evaluated. Based on the results, the spring designs were classified as over designed or under designed springs. Next in this process, it was checked if the under designed springs can be optimized and classified according to a relevant application of the vehicles (racing cars or luxurious cars) and can they satisfy the requirements of fatigue life and vibration that helical spring suspension should under normal working conditions. The driving factor for this project was…
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Establishing Flex Plate optimization using hybrid technique for SUV Automatic transmission

Mahindra & Mahindra Ltd.-Vadivazhagan Gandhi, Vivek Yadav, Karthikeyan K, Anand Bidre
  • Technical Paper
  • 2020-01-0916
To be published on 2020-04-14 by SAE International in United States
For Automatic transmission application, crankshaft torque is transferred to torque converter through flex plate. As the flex plate design has no functionality of storing energy as in case of MT flywheel, flex plate design can be optimized to great extent. Flex plate structure must have compliance to allow the axial deformation of torque convertor due to ballooning pressure generated inside the converter. Flex plate experiences dynamic torque and centrifugal forces due to high rotational speed. It should have compliance to accommodate the assembly misalignments with torque convertor in both axial and radial directions. In this paper, hybrid optimization technique is described used to optimize the flex plate design with stress, stiffness and mass as design criteria. The load path, corrugation length and axial stiffness of flex plate captured accurately using this hybrid optimization. The variation of shape, size, orientation and number of holes are based on the load path and axial stiffness of flex plate. The results show that 35 % of weight reduction is achieved with original design and it meets all design requirements…
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Automotive Dimensional Quality Control with Geometry Tree Process

FCA US LLC-James Cole, Yuqin Wang, Robert Bertucci
  • Technical Paper
  • 2020-01-0480
To be published on 2020-04-14 by SAE International in United States
Geometry Tree is a term describing the product assembly structure and the manufacturing process for the product. The concept refers to the assembly structure of the final vehicle (the Part Tree) and the assembly process and tools for the final product (the Process Tree). In the past few years, the Geometry Tree-based quality process was piloted in the FCA NAFTA region and has since evolved into a standardized quality control process. In the Part Tree process, the coordinated measurements and naming convention are enforced throughout the different levels of product sub-assemblies and measurement processes. The Process Tree, on the other hand, includes both prominently identified assembly tools and the mapping of key product characteristics to key assembly tools. The benefits of directly tying critical customer characteristics to actual machine components that have a high propensity to influence them is both preventive and reactive. This article describes the integrated Geometry Tree quality process and how it has been implemented at the FCA vehicle assembly plants and in the dimensional data management system.
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State-of-the-Art and Development Trends of Assembly Technologies for Proton Exchange Membrane Fuel Cell Stack: A Review

Tongji University-Yimin Wang, Ke Song
  • Technical Paper
  • 2020-01-1175
To be published on 2020-04-14 by SAE International in United States
Proton Exchange Membrane Fuel Cell (PEMFC) uses hydrogen and oxygen for fuel, the whole energy conversion process almost has no negative impact on the environment. The PEM fuel cell stack with the advantages of low-operating temperature, high current density and fast start-up ability is considered to be the next generation of new electric vehicle power. However, due to the limited current output, it is difficult for a single cell to meet the practical application requirements. The actual fuel cell stack is formed by many single cells assembled together. The assembly process is often related to load transfer, material transfer, energy exchange, multi-phase flow, electrochemical reaction and other factors. The performance of MEA (Membrane Electrode Assembly), sealing gaskets and other components will change during the assembly process, which makes the fuel cell stack assembly process more complex. The assembly load of large stack and the inside interface pressure homogeneity significantly affect the efficiency, stability and durability of the stack. Assembly technology of low efficiency and accuracy increases manufacturing costs of stack. Therefore, there is an urgent…