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Methods to Find Best Designs Among Infeasible Design Data Sets for Highly Constrained Design Optimization Problems

SAE International Journal of Materials and Manufacturing

Esteco North America Inc.-Adarsh Viji Elango, Zhendan Xue, Apurva Gokhale
Ford Motor Company-Saket Kansara
  • Journal Article
  • 2016-01-0299
Published 2016-04-05 by SAE International in United States
In recent years, the use of engineering design optimization techniques has grown multifold and formal optimization has become very popular among design engineers. However, the real world problems are turning out to be involved and more challenging. It is not uncommon to encounter problems with a large number of design variables, objectives and constraints. The engineers’ expectation, that an optimization algorithm should be able to handle multi-objective, multi-constrained data is leading them to apply optimization techniques to truly large-scale problems with extremely large number of constraints and objectives. Even as newer and better optimization algorithms are being developed to tackle such problems, more often than not, the optimization algorithms are unable to find a single feasible design that satisfies all constraints. It is common to see designers spending large amounts of computational resources in evaluating infeasible designs mainly because either the algorithms take time to get to the feasible regions of the design space, or no feasible designs are obtained after all the allowed optimization iterations.Even with surrogate based or meta-model based optimization, which enables…
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Experimental Determination of Effectiveness of Hydrophilic Coating for Evaporators

SAE International Journal of Materials and Manufacturing

CalsonicKansei North America Inc.-Gursaran D. Mathur
  • Journal Article
  • 2016-01-0191
Published 2016-04-05 by SAE International in United States
Water drainage characteristics of an evaporator changes with the age of the vehicle. This is due to the fact that with time, a part of the hydrophilic coating washes off with the moisture that condenses over the evaporator core from the air-stream. Hence, the effectiveness of the evaporator for water drainage deteriorates with the age of the vehicle. At this condition more water is retained in the evaporator as the contact angle increases. Author has conducted experiments with evaporators from multiple vehicles from different OEMs. These evaporators were analyzed to determine the effectiveness of the hydrophilic coating as a function of time or vehicle age.This is the first paper in the open literature that deals with the vehicle mileage or vehicle age with the evaporator plate contact angle and surface coating of an evaporator.
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A Novel Cooling System Control Strategy for Internal Combustion Engines

SAE International Journal of Materials and Manufacturing

Universita della Calabria-Teresa Castiglione, Francesco Pizzonia, Sergio Bova
  • Journal Article
  • 2016-01-0226
Published 2016-04-05 by SAE International in United States
An innovative control strategy, which is based on the Robust Model Predictive Control (MPC) methodology, was developed with the purpose of optimizing the engine thermal management; the proposed control strategy adjusts the coolant flow rate by means of an electric pump, in order to bring the cooling system to operate around the onset of nucleate boiling. In the present paper, the advantages of the proposed cooling approach are evaluated along the NEDC homologation cycle, which was both simulated and replicated by means of laboratory tests; the latter include coolant, lubricant and wall temperature measurements. Special attention was reserved to the warm-up period. The case considered herein is that of a Spark Ignition engine, about 1.2 dm3 displacement, and a comparison with standard crankshaft driven pump is included. The proposed strategy makes use of a dynamic model of the cooling system of an ICE that is able to predict the heat transfer both under single-phase forced convection and in the presence of nucleate or saturated boiling. The model, which was widely validated by experimental tests, also…
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Multidisciplinary Design Optimization of Vehicle Weight Reduction

SAE International Journal of Materials and Manufacturing

Esteco North America Inc.-Zhendan Xue, Adarsh Elango
Ford Research and Innovation Center-Jian Fang
  • Journal Article
  • 2016-01-0301
Published 2016-04-05 by SAE International in United States
Multidisciplinary Design Optimization (MDO) is often required in aircraft design to address the multidisciplinary feasibility issues due to the disciplines, for example, aerodynamics, propulsion, and structures, are heavily coupled. However, in automobile designs, can we apply different type of MDO decomposition originated from aircraft design, to some MDO problem, for example, a vehicle weight reduction example? Also, to effectively and efficiently accommodate design changes, multi-party collaboration between discipline specialists, and fast decision making, a web-based MDO platform with knowledge-based repository for resource sharing, capability of version control, and enhancing data security, is very much needed. Two types of MDO decomposition: All-at-Once (AAO) and Collaborative Optimization (CO) are formulated for the weight reduction example. A typical six-step MDO process, from building single discipline work flow to comparing optimization results, is illustrated step-by-step.
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A Linkage Based Solution Approach for Determining 6 Axis Serial Robotic Travel Path Feasibility

SAE International Journal of Materials and Manufacturing

CAMufacturing Solutions Inc.-R. Hedrick
University of Windsor-R.J. Urbanic
  • Journal Article
  • 2016-01-0336
Published 2016-04-05 by SAE International in United States
When performing trajectory planning for robotic applications, there are many aspects to consider, such as the reach conditions, joint and end-effector velocities, accelerations and jerk conditions, etc. The reach conditions are dependent on the end-effector orientations and the robot kinematic structure. The reach condition feasibility is the first consideration to be addressed prior to optimizing a solution. The ‘functional’ work space or work window represents a region of feasible reach conditions, and is a sub-set of the work envelope. It is not intuitive to define. Consequently, 2D solution approaches are proposed. The 3D travel paths are decomposed to a 2D representation via radial projections. Forward kinematic representations are employed to define a 2D boundary curve for each desired end effector orientation. The feasible region for all orientations is determined by the use of Boolean intersections of the boundary curves or by overlapping valid regions in which points are placed. Combining the tool path and functional work space regions allow designers to readily visualize regions of concern. A KUKA and Comau robot are used to illustrate…
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Multi-Disciplinary Tolerance Optimization for Internal Combustion Engines Using Gaussian Process and Sequential MDO Method

SAE International Journal of Materials and Manufacturing

Shanghai Jiao Tong University-Jianhua Zhou, Mian LI, Min Xu
  • Journal Article
  • 2016-01-0303
Published 2016-04-05 by SAE International in United States
The internal combustion engine (ICE) is a typical complex multidisciplinary system which requires the support of precision design and manufacturing. To achieve a better performance of ICEs, tolerance assignment, or tolerance design, plays an important role. A novel multi-disciplinary tolerance design optimization problem considering two important disciplines of ICEs, the compression ratio and friction loss, is proposed and solved in this work, which provides a systematic procedure for the optimal determination of tolerances and overcomes the disadvantages of the traditional experience-based tolerance design. A bi-disciplinary analysis model is developed in this work to assist the problem solving, within which a model between the friction loss and tolerance is built based on the Gaussian Process using the corresponding simulation and experimental data. In addition, the formulation of the compression ratio considering those non-critical dimensions which actually affect the friction loss is proposed. Finally the multi-disciplinary tolerance design optimization problem is formulated and solved using a recently developed sequential MDO (S-MDO) method.
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Methods for Evaluating the Functional Work Space for Machine Tools and 6 Axis Serial Robots

SAE International Journal of Materials and Manufacturing

University of Windsor-R.J. Urbanic
Wayne State University-Ana M. Djuric
  • Journal Article
  • 2016-01-0338
Published 2016-04-05 by SAE International in United States
The ‘boundary of space’ model representing all possible positions which may be occupied by a mechanism during its normal range of motion (for all positions and orientations) is called the work envelope. In the robotic domain, it is also known as the robot operating envelope or workspace. Several researchers have investigated workspace boundaries for different degrees of freedom (DOF), joint types and kinematic structures utilizing many approaches. The work envelope provides essential boundary information, which is critical for safety and layout concerns, but the work envelope information does not by itself determine the reach feasibility of a desired configuration. The effect of orientation is not captured as well as the coupling related to operational parameters. Included in this are spatial occupancy concerns due to linking multiple kinematic chains, which is an issue with multi-tasking machine tools, and manufacturing cells. This research presents methodologies to predetermine regions of feasible operation for multiple kinematic chain mechanisms, such as multi-spindle/multiaxis machine tools and industrial serial 6 degree of freedom robots, and manufacturing cells.
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Comparing Various Multi-Disciplinary Optimization Approaches for Performance Enhancement and Weight Reduction of a Vehicle Chassis Frame

SAE International Journal of Materials and Manufacturing

Mahindra & Mahindra, Ltd.-Subhash Hanmant Bhosale, Aditya Malladi, Abhijit Londhe
  • Journal Article
  • 2016-01-0305
Published 2016-04-05 by SAE International in United States
Designing a vehicle chassis involves meeting numerous performance requirements related to various domains such as Durability, Crashworthiness and Noise-Vibration-Harshness (NVH) as well as reducing the overall weight of chassis. In conventional Computer Aided Engineering (CAE) process, experts from each domain work independently to improve the design based on their own domain knowledge which may result in sub-optimal or even non-acceptable designs for other domains. In addition, this may lead to increase in weight of chassis and also result in stretching the overall product development time and cost. Use of Multi-Disciplinary Optimization (MDO) approach to tackle these kind of problems is well documented in industry. However, how to effectively formulate an MDO study and how different MDO formulations affect results has not been touched upon in depth.This study implements various MDO formulations on an established SUV chassis frame for further weight reduction and performance improvement. Results from different MDO formulations are compared and insights are provided into ways of formulating an MDO problem in order to achieve desired results. How the choice of optimization algorithm, number…
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Transient Modelling of Vehicle Exhaust Surface Temperature

SAE International Journal of Materials and Manufacturing

FCA US LLC-Alaa El-Sharkawy, Dipan Arora, Masuma Khandaker
Optumatics LLC-Amr Sami, Abd El-Rahman Hekal
  • Journal Article
  • 2016-01-0280
Published 2016-04-05 by SAE International in United States
In this paper, the development of a transient thermal analysis model for the exhaust system is presented. Given the exhaust gas temperature out of the engine, a software tool has been developed to predict changes in exhaust gas temperature and exhaust surface temperature under various operating conditions. The software is a thermal solver that will predict exhaust gas and wall surface temperatures by modeling all heat transfer paths in the exhaust system which includes multi-dimensional conduction, internal forced/natural convection, external forced/natural convection, and radiation. The analysis approach involves the breaking down of the thermal system into multiple components, which include the exhaust system (manifold, takedown pipe, tailpipe, etc.), catalytic converter, DPF (diesel particulate filter), if they exist, thermal shields, etc. All components are modeled as 1D porous and 1D non-porous flow streams with 3D wall layers (solid and air gaps). The aggregate of all these components is referred to as the thermal network. All relevant modes of heat transfer between the parts, i.e., forced convection, conduction and radiation are considered. Analysis of the thermal network…
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An Empirical Methodology for the Prediction of the Boiling Limits of EGR Coolers

SAE International Journal of Materials and Manufacturing

BorgWarner Emissions Systems-Julio Carrera
  • Journal Article
  • 2016-01-0282
Published 2016-04-05 by SAE International in United States
Recent emissions standards have become more restrictive in terms of CO2 and NOx reduction. This has been translated into higher EGR rates at higher exhaust gas temperatures with lower coolant flow rates for much longer lifetimes. In consequence, thermal load for EGR coolers has been increasing and the interaction of boiling with thermal fatigue is now a critical issue during development.It is almost impossible to avoid localized boiling inside an EGR cooler and, in fact, it would not be strictly necessary when it is below the Critical Heat Flux (CHF). However when CHF is exceeded, film boiling occurs leading to the sudden drop of the heat transfer rate and metal temperature rise. In consequence, thermal stress increases even when film boiling is reached only in a small area inside the part. It is very difficult to accurately predict under which conditions CHF is reached and to establish the margins to avoid it. In this work, a new empirical method has been developed that covers an innovative prototype instrumentation with thermocouples that allows the direct measurement…
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