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Design Analysis for Origami-Based Folded Sheet Metal Parts

SAE International Journal of Materials and Manufacturing

Clemson University ICAR-Ala Qattawi, Mahmoud Abdelhamid, Ahmad Mayyas, Mohammed Omar
  • Journal Article
  • 2014-01-9098
Published 2014-04-20 by SAE International in United States
1The manufacturing of Origami based sheet metal products is a promising technology, mostly in terms of reducing the tooling and process complexity. This procedure can also be called fold forming, as it depends on exclusively shaping the required geometry via sequence of bends. However, the design analysis and modeling of folded sheet metal products are not fully mature, especially in terms of determining the best approach for transferring the analysis from a three-dimensional (3D) to a two-dimensional (2D) context. This manuscript discusses the extension of the Origami technique to the fold forming of sheet metal products represented in modeling approach and design considerations for the topological variations, the geometrical validity, and the variance of stress-based performance. This paper also details the optimization metrics that were developed to reflect the design and manufacturing differences among the possible topological and geometrical options for a single part design. These metrics target five different optimization objectives: material utilization, cost, ease of manufacturability, ease of handling, and mechanical behavior estimation.A boundary representation is first used to embody the 3D geometry…
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S-N Curve Modeling for Finite Life Range under the Assumption of Linearly Changing Scatter

SAE International Journal of Materials and Manufacturing

Schaeffler Holding (China) Co., Ltd.-Zhou Yingjie
Schaeffler Trading (Shanghai) Co., Ltd.-Tang Xuezhi
  • Journal Article
  • 2014-01-0970
Published 2014-04-01 by SAE International in United States
Fatigue test data in finite life region are normally analyzed separately for each stress level because of varying scatters, while another method assuming equal scatters on all levels and thus unifying all data into one model is also welcome for its efficient usage of data. Combining the idea of the two methods, a new method that assumes linear change of scatter according to stress levels is developed in this paper. The algorithm derives from maximum likelihood estimation and general Newton's method. Monte Carlo method is used for theoretical validation and the new method is proved to be correct with the estimations. Finally a set of test data which shows a tendency of trapezoidal data distribution is analyzed and an S-N curve for finite life range is created. The new method has its advantage in certain situations so it's meaningful to add it to the alternatives of fatigue data analysis methods.
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Enhancing Decision Topology Assessment in Engineering Design

SAE International Journal of Materials and Manufacturing

Oakland Univ.-Vijitashwa Pandey, Zissimos Mourelatos
US Army TARDEC-Matthew Castanier
  • Journal Article
  • 2014-01-0719
Published 2014-04-01 by SAE International in United States
Implications of decision analysis (DA) on engineering design are important and well-documented. However, widespread adoption has not occurred. To that end, the authors recently proposed decision topologies (DT) as a visual method for representing decision situations and proved that they are entirely consistent with normative decision analysis. This paper addresses the practical issue of assessing the DTs of a designer using their responses. As in classical DA, this step is critical to encoding the DA's preferences so that further analysis and mathematical optimization can be performed on the correct set of preferences. We show how multi-attribute DTs can be directly assessed from DM responses. Furthermore, we show that preferences under uncertainty can be trivially incorporated and that topologies can be constructed using single attribute topologies similarly to multi-linear functions in utility analysis. This incremental construction simplifies the process of topology construction. The methods are demonstrated using a design decision making problem of a welded beam.
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Fatigue Behavior of Aluminum Alloys under Multiaxial Loading

SAE International Journal of Materials and Manufacturing

General Motors Co.-Qigui Wang, Yucong Wang
Tongji University-Guoqiu He
  • Journal Article
  • 2014-01-0972
Published 2014-04-01 by SAE International in United States
Fatigue behavior of aluminum alloys under multiaxial loading was investigated with both cast aluminum A356-T6 and wrought alloy 6063-T6. The dominant multiaxial fatigue crack preferentially nucleates from flaws like porosity and oxide films located near the free surface of the material. In the absence of the flaws, the cracking/debonding of the second phase particles dominates the crack initiation and propagation. The number of cracked/debonded particles increases with the number of cycles, but the damage rate depends on loading paths. Among various loading paths studied, the circle loading path shows the shortest fatigue life due to the development of complex dislocation substructures and severe stress concentration near grain/cell boundaries and second phase particles.
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Development of an Air Filtration Software

SAE International Journal of Materials and Manufacturing

Röchling Automotive SE & Co. KG-Marco Barbolini
  • Journal Article
  • 2014-01-0758
Published 2014-04-01 by SAE International in United States
The air filters in an air intake system permanently remove foreign particles such as dust, dirt and soot from the intake air, thereby maintaining the performance of the engine and protecting it from damage. The filter performance is typically a trade-off between pressure loss, load capacity and efficiency. Exhaust gas regulations and customer requirements such as filter duration always determine air filter development.For this reason Röchling Automotive has developed a new software tool for estimating air filter lifetime which simplifies and significantly shortens the pre-development of filter elements with regard to filtration and pressure drop. In addition, it is possible to compare the different filter geometries (number of pleats, height, paper etc.) in order to limit the number of different filter elements, for example for a complete series of cars.By correlating the total air consumption with the average dust concentration typical for the environment involved, the air filter lifetime can be precisely predicted. The program utilizes input data such as the maximum flow rate, the condition of the ambient air, filter geometry, filter media and…
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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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Effect of SPS Process Parameters on the Densification Behaviour of Yttria Stabilized Zirconia

SAE International Journal of Materials and Manufacturing

University of British Columbia-Abhinav Karanam, Vishank Kumar, Lukas Bichler
  • Journal Article
  • 2014-01-0835
Published 2014-04-01 by SAE International in United States
Zirconium dioxide (ZrO2) doped with Yttria exhibits superplastic behaviour, corrosion resistance and excellent ion conducting properties [1] at moderate temperatures and thus it can be used as an electroceramic to measure the pH of high temperature water used in fuel cells. Several fabrication processes are available for preparation of zirconia ceramics. This research focused on the study of using Spark Plasma Sintering (SPS) process to prepare Yttria Stabilized Zirconia (YSZ) ceramic.8 mol% YSZ was subjected to varying SPS sintering conditions. Samples were sintered by changing the heating cycle, dwell time, sintering pressure and cooling cycle. Subsequently, these parameters were related to the densification characteristics of the as-sintered YSZ. The results of specific gravity measurements and microstructure evaluation suggest that stepped heating followed by a slow cooling results in YSZ with highest relative density (99.9%).
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A Study on a Visualization of Fatigue Behavior near the Glass Transition Region

SAE International Journal of Materials and Manufacturing

NOK Corp.-Hideto Komurasaki, Kenichi Uchida
  • Journal Article
  • 2014-01-0978
Published 2014-04-01 by SAE International in United States
This study aimed to visualize crack initiation and propagation of rubber at low temperatures. Typical fatigue behavior such as cracking at only the compressed part of rubber products like dustcovers during oscillation tests at ultra-low temperatures have been reported [1]. Rubber products are usually used at temperatures where good rubber elasticity can be obtained. However, in some cases, they are used near glass transition temperatures at which rubber elasticity is poor. Fatigue failures of rubbers generally occur due to existing defects in the rubber material, and rubber tends to fracture easily near glass transition temperatures due to cracking on the surface of the compressed side of the rubber. The observation of the crack initiation process of rubber is difficult at low temperatures because the fracture patterns on rubber disappear when elasticity is recovered at room temperature. For this reason, in this study, we aimed to observe the fatigue behavior of rubber near the glass transition temperature by testing rubber materials whose Tg is above room temperature.
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A Stochastic Bias Corrected Response Surface Method and its Application to Reliability-Based Design Optimization

SAE International Journal of Materials and Manufacturing

Chongqing Univ.-Zhenfei Zhan
Ford Motor Co.-Yan Fu, Ren-Jye Yang
  • Journal Article
  • 2014-01-0731
Published 2014-04-01 by SAE International in United States
In vehicle design, response surface model (RSM) is commonly used as a surrogate of the high fidelity Finite Element (FE) model to reduce the computational time and improve the efficiency of design process. However, RSM introduces additional sources of uncertainty, such as model bias, which largely affect the reliability and robustness of the prediction results. The bias of RSM need to be addressed before the model is ready for extrapolation and design optimization. This paper further investigates the Bayesian inference based model extrapolation method which is previously proposed by the authors, and provides a systematic and integrated stochastic bias corrected model extrapolation and robustness design process under uncertainty. A real world vehicle design example is used to demonstrate the validity of the proposed method.
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Residual Stress Mapping along the Cylinder Bores of Al Alloy Engine Blocks Subjected to Production Solution Heat Treatment Schedule

SAE International Journal of Materials and Manufacturing

National Research Council Canada-Dimitry Sediako
Nemak of Canada-Robert Mackay
  • Journal Article
  • 2014-01-0837
Published 2014-04-01 by SAE International in United States
The development of an optimized heat treatment schedule, with the aim of maximizing strength and relieving tensile residual stress, is important to prevent in-service cylinder distortion in Al alloy engine blocks containing cast-in gray iron liners. However, to effectively optimize the engine block heat treatment schedule, the current solutionizing parameters must be analyzed and compared to the as-cast condition to establish a baseline for residual stress relief. In this study, neutron diffraction was carried out to measure the residual stress along the aluminum cylinder bridge following solution heat treatment. The stresses were measured in the hoop, radial and axial orientations and compared to a previous measured as-cast (TSR) engine block. The results suggest that solution heat treatment using the current production parameters partially relieved tensile residual stress in the Al cylinder bridge, with stress relief being more effective near the bottom of the cylinder.
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