scholarly journals Multi-objective optimization of single-lane roundabout geometric design: safety, mobility, and environmental sustainability

2021 ◽  
Author(s):  
Hend Ahmed ◽  
Said M. Easa
Keyword(s):  
Environmental Sustainability ◽  
Vehicle Emissions ◽  
Geometric Design ◽  
Geometric Parameters ◽  
Specific Power ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Highway Safety Manual ◽  
Optimization Methodology ◽  
The Uk

Mobility, safety performance and environmental sustainability are priorities in the geometric design of roundabouts. This thesis presents a multi-objective optimization methodology for the geometric design of single-lane roundabouts. Mobility is defined in terms of roundabout delay and modeled using the (UK) empirical model. The collision frequency represents the safety objective, and modeled using the methodology outlined in the Highway Safety Manual. Environmental sustainability is represented by NOX, HC, CO2, and CO vehicle emissions and is modeled using the vehicle specific power (VSP) methodology. The presented model directly identifies the optimal geometric parameters of roundabouts. Traffic data, site conditions, and guidelines limitations were used as input data while the output decision values that minimize delay, collisions, and vehicle emissions are the optimal geometric parameters. The practical application of the proposed model is illustrated using an application example. The model was validated using an actual location, and a sensitivity analysis was conducted.

scholarly journals Multi-objective optimization of single-lane roundabout geometric design: safety, mobility, and environmental sustainability

2021 ◽  
Author(s):  
Hend Ahmed ◽  
Said M. Easa
Keyword(s):  
Environmental Sustainability ◽  
Vehicle Emissions ◽  
Geometric Design ◽  
Geometric Parameters ◽  
Specific Power ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Highway Safety Manual ◽  
Optimization Methodology ◽  
The Uk

Mobility, safety performance and environmental sustainability are priorities in the geometric design of roundabouts. This thesis presents a multi-objective optimization methodology for the geometric design of single-lane roundabouts. Mobility is defined in terms of roundabout delay and modeled using the (UK) empirical model. The collision frequency represents the safety objective, and modeled using the methodology outlined in the Highway Safety Manual. Environmental sustainability is represented by NOX, HC, CO2, and CO vehicle emissions and is modeled using the vehicle specific power (VSP) methodology. The presented model directly identifies the optimal geometric parameters of roundabouts. Traffic data, site conditions, and guidelines limitations were used as input data while the output decision values that minimize delay, collisions, and vehicle emissions are the optimal geometric parameters. The practical application of the proposed model is illustrated using an application example. The model was validated using an actual location, and a sensitivity analysis was conducted.

scholarly journals Multi-Objective Evaluation Model of Single-Lane Roundabouts

2021 ◽  
pp. 036119812110114
Author(s):  
Hend Ahmed ◽  
Said M. Easa
Keyword(s):  
Environmental Sustainability ◽  
Evaluation Model ◽  
Objective Evaluation ◽  
Design Guidelines ◽  
Geometric Design ◽  
Specific Power ◽  
Design Elements ◽  
Multi Objective ◽  
Proposed Model ◽  
Comparison Results

Mobility, safety, and environmental sustainability are priorities in the geometric design of roundabouts. This paper presents a multi-objective optimization model that determines the geometric design elements of single-lane roundabouts using all three objectives. The user can specify weights for the objectives, or the model can determine the optimal weights. Mobility is defined in terms of roundabout delay and modeled using the United Kingdom empirical model. Safety is modeled in terms of collision frequency based on the methodology of the Highway Safety Manual. Environmental sustainability is represented by vehicle emissions (nitrogen oxides, hydrocarbons, carbon dioxide, and carbon monoxide) and is modeled using the vehicle-specific power methodology. The proposed model directly identifies the optimal geometric dimensions (decision variables) of the roundabout, including entry width, exit width, approach half-width, circulatory width, effective flare length, entry radius, entry angle, and inscribed circle diameter. The input data to the model include traffic data, site conditions, and limitations based on design guidelines. Application of the proposed model is illustrated using two actual roundabouts. The comparison results show that the proposed model provides substantial improvements in safety, mobility, and environmental sustainability compared with existing conditions. In addition, the model requires much less effort to apply compared with the traditional iterative method, and as such should be of interest to highway designers.

Optimization of Process Parameters in Laser Engineered Net Shaping (LENS) Deposition of Multi-Materials

2015 ◽  
Author(s):  
Jingyuan Yan ◽  
Nafiseh Masoudi ◽  
Ilenia Battiato ◽  
Georges Fadel
Keyword(s):  
Fabrication Process ◽  
Optimal Solutions ◽  
Multi Objective Optimization ◽  
Feeding Rates ◽  
Multi Objective ◽  
Heterogeneous Objects ◽  
Multiple Materials ◽  
Optimization Methodology ◽  
Manufacturing Technologies ◽  
Net Shaping

During the past few years, metal based additive manufacturing technologies have evolved and may enable the direct fabrication of heterogeneous objects with full spatial material variations. A heterogeneous object has potentially many advantages and in many cases can realize appearance and/or functionality that homogeneous objects cannot achieve. In this work we employ a preprocess computing combined with a multi-objective optimization algorithm based on the modeling of the LENS deposition of multiple materials to optimize the fabrication process. The optimization methodology is applied to the fabrication of cermet composite (using Inconel 718 and ceramic powders) with prescribed material feeding rates. The multi-objective optimization considers that the energy consumption and the material waste during the fabrication process should be minimized, while the probability of the melting of the powders should be maximized. The optimization software modeFRONTIER® is used to drive the computation procedure with a MATLAB code. The results show the design and objective spaces of the Pareto optimal solutions, and enable the users to select preferred setting configurations from the set of optimal solutions.

scholarly journals Multi-objective Optimization of Turning Tool Geometric Parameters Based on Kriging Model

2021 ◽  
Vol 2137 (1) ◽  
pp. 012046
Author(s):  
Jianxiang Sun ◽  
Huan Xie ◽  
Wei Zeng ◽  
Yaoyao Tong ◽  
Zhenyu Cai
Keyword(s):  
Rake Angle ◽  
Geometric Parameters ◽  
Cutting Edge ◽  
Cutting Performance ◽  
Performance Parameters ◽  
Multi Objective Optimization ◽  
Cutting Edge Radius ◽  
Multi Objective ◽  
Edge Radius ◽  
Relief Angle

Abstract Cutting performance parameters of turning tool in different geometric parameters are obtained using finite element model, and the Kriging models of cutting stress and temperature are constructed, taking the cutting performance parameters as training samples. The multi-objective optimization model of turning tool geometric parameters is established based on the constructed cutting performance Kriging models, in which the design variables are rake angle, relief angle and cutting-edge radius, the objective parameters are cutting stress and temperature. The multi-island genetic algorithm is used to obtain the optimum turning tool geometric parameters: rake angle γo is 10.59°, relief angle λs is 6.15°and cutting-edge radius γE is 0.73mm. The simulation results after optimization demonstrate that the corresponding cutting temperature reduces 263.1°C, cutting stress drops by 550.8MPa.

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