Testing Design Optimization for Uncertainty Reduction in Generating Off-Road Mobility Map Using a Bayesian Approach

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Zhen Hu ◽  
Zissimos P. Mourelatos ◽  
David Gorsich ◽  
Paramsothy Jayakumar ◽  
Monica Majcher

Abstract The Next Generation NATO Reference Mobility Model (NG-NRMM) plays a vital role in vehicle mobility prediction and mission planning. The complicated vehicle–terrain interactions and the presence of heterogeneous uncertainty sources in the modeling and simulation (M&S) result in epistemic uncertainty/errors in the vehicle mobility prediction for given terrain and soil conditions. In this paper, the uncertainty sources that cause the uncertainty in mobility prediction are first partitioned into two levels, namely uncertainty in the M&S and uncertainty in terrain and soil maps. With a focus on the epistemic uncertainty in the M&S, this paper presents a testing design optimization framework to effectively reduce the uncertainty in the M&S and thus increase the confidence in generating off-road mobility maps. A Bayesian updating approach is developed to reduce the epistemic uncertainty/errors in the M&S using mobility testing data collected under controllable terrain and soil conditions. The updated models are then employed to generate the off-road mobility maps for any given terrain and soil maps. Two types of design strategies, namely testing design for model selection and testing design for uncertainty reduction, are investigated in the testing design framework to maximize the information gain subject to limited resources. Results of a numerical example demonstrate the effectiveness of the proposed mobility testing design optimization framework.

Author(s):  
Zhen Hu ◽  
Zissimos P. Mourelatos ◽  
David Gorsich ◽  
Paramsothy Jayakumar ◽  
Monica Majcher

Abstract The Next Generation NATO Reference Mobility Model (NG-NRMM) plays a vital role in vehicle mobility prediction and mission planning. The complicated vehicle-terrain interactions and the presence of heterogeneous uncertainty sources in the modeling and simulation (M&S) result in epistemic uncertainty/errors in the vehicle mobility prediction for given terrain and soil conditions. In this paper, the uncertainty sources that cause the uncertainty in mobility prediction are first partitioned into two levels, namely uncertainty in the M&S and uncertainty in terrain and soil maps. With a focus on the epistemic uncertainty in the M&S, this paper presents a testing design optimization framework to effectively reduce the uncertainty in the M&S and thus increase the confidence in generating off-road mobility maps. A Bayesian updating approach is developed to reduce the epistemic uncertainty/errors in the M&S using mobility testing data collected under controllable terrain and soil conditions. The updated models are then employed to generate off-road mobility maps for any given terrain and soil maps. Two types of design strategies, namely testing design for model selection and testing design for uncertainty reduction, are investigated in the testing design framework to maximize the information gain subject to limited resources. Results of a numerical example demonstrate the effectiveness of the proposed mobility testing design optimization framework.


2020 ◽  
Vol 57 (4) ◽  
pp. 715-729 ◽  
Author(s):  
Alessandro Sgueglia ◽  
Peter Schmollgruber ◽  
Nathalie Bartoli ◽  
Emmanuel Benard ◽  
Joseph Morlier ◽  
...  

Author(s):  
Reza Pejman ◽  
Ahmad Raeisi Najafi

Abstract Microvascular composite offers a variety of multi-functionality based on the choice of fluid flowing through the embedded microchannels. The design of the microchannel network in microvascular composites is quite challenging. Indeed, the design is often expected to have high cooling efficiency, satisfy the manufacturing and operating constraints, and also have redundancy to increase the temperature uniformity and alleviate the destructive effects of potential microchannel blockage. In this study, we present a design optimization framework to satisfy these requirements. We use the Hybrid Topology/Shape (HyTopS) optimization scheme to design a redundant blockage-tolerant cooling network. In this method, the optimizer can change the topology of the design during the shape optimization process. Being able to modify the topology of the network enables the optimizer to provide network redundancy to effectively optimize the design for blockage tolerance. We also solve several numerical examples to show the unique features of the proposed method.


2020 ◽  
Vol 2020 ◽  
pp. 1-19
Author(s):  
Hong Zhang ◽  
Guangchen Bai ◽  
Lukai Song

To improve the accuracy and efficiency of multiobjective design optimization for a multicomponent system with complex nonuniform loads, an efficient surrogate model (the decomposed collaborative optimized Kriging model, DCOKM) and an accurate optimal algorithm (the dynamic multiobjective genetic algorithm, DMOGA) are presented in this study. Furthermore, by combining DCOKM and DMOGA, the corresponding multiobjective design optimization framework for the multicomponent system is developed. The multiobjective optimization design of the carrier roller system is considered as a study case to verify the developed approach with respect to multidirectional nonuniform loads. We find that the total standard deviation of three carrier rollers is reduced by 92%, where the loading distribution is more uniform after optimization. This study then compares surrogate models (response surface model, Kriging model, OKM, and DCOKM) and optimal algorithms (neighbourhood cultivation genetic algorithm, nondominated sorting genetic algorithm, archive microgenetic algorithm, and DMOGA). The comparison results demonstrate that the proposed multiobjective design optimization framework is demonstrated to hold advantages in efficiency and accuracy for multiobjective optimization.


2019 ◽  
Vol 91 (7) ◽  
pp. 1067-1076
Author(s):  
Maxim Tyan ◽  
Jungwon Yoon ◽  
Nhu Van Nguyen ◽  
Jae-Woo Lee ◽  
Sangho Kim

Purpose Major changes of an aircraft configuration are conducted during the early design stage. It is important to include the airworthiness regulations at this stage while there is extensive freedom for designing. The purpose of this paper is to introduce an efficient design framework that integrates airworthiness guidelines and documentation at the early design stage. Design/methodology/approach A new design and optimization process is proposed that logically includes the airworthiness regulations as design parameters and constraints by constructing a certification database. The design framework comprises requirements analysis, preliminary sizing, conceptual design synthesis and loads analysis. A design certification relation table (DCRT) describes the legal regulations in terms of parameters and values suitable for use in design optimization. Findings The developed framework has been validated and demonstrated for the design of a Federal Aviation Regulations (FAR) 23 four-seater small aircraft. The validation results show an acceptable level of accuracy to be applied during the early design stage. The total mass minimization problem has been successfully solved while satisfying all the design requirements and certification constraints specified in the DCRT. Moreover, successful compliance with FAR 23 subpart C is demonstrated. The proposed method is a useful tool for design optimization and compliance verifications during the early stages of aircraft development. Practical implications The new certification database proposed in this research makes it simpler for engineers to access a large amount of legal documentation related to airworthiness regulations and provides a link between the regulation text and actual design parameters and their bounds. Originality/value The proposed design optimization framework integrates the certification database that is built of several types of legal documents such as regulations, advisory circulars and standards. The Engineering Requirements and Guide summarizes all the documents and design requirements into a single document. The DCRT is created as a summary table that indicates the design parameters affected by a given regulation(s), the design stage at which the parameter can be evaluated and its value bounds. The introduction of the certification database into the design optimization framework significantly reduces the engineer’s load related for airworthiness regulations.


2015 ◽  
Vol 2 (1) ◽  
pp. 17-44 ◽  
Author(s):  
Darcy L. Allison ◽  
Craig C. Morris ◽  
Joseph A. Schetz ◽  
Rakesh K. Kapania ◽  
Layne T. Watson ◽  
...  

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