Detailed Transportation Simulation for Improved Logistics Quality

Author(s):  
Harry C. Petersen ◽  
Amy Rummel

Abstract This paper demonstrates the advantages of logistics studies which include detailed transportation simulations based on mechanical engineering principles. Complex transportation system parameters are often averaged, aggregated, or assumed, resulting in models with questionable validity. Detailed simulations of route-specific real-world vehicle performance for analysis systems (such as Transport Probability Analysis) can often provide more accurate predictors of logistics system performance, resulting in valid projections of system transport times, costs, inventory levels, energy usage, standards, and quality control measures. A discussion of logistics is followed by examples of progressively complex logistics transportation simulations and models. Results of a moderately detailed performance-based simulation of high speed trains for the Texas Triangle are used to demonstrate the fallacy of assuming “average” performance measures. Future logistics studies will require detailed vehicle performance simulations using sound mechanical engineering practice, requiring interdisciplinary teams which include mechanical engineers.

Author(s):  
Khaled E. Zaazaa ◽  
Brian Whitten ◽  
Brian Marquis ◽  
Erik Curtis ◽  
Magdy El-Sibaie ◽  
...  

Accurate prediction of railroad vehicle performance requires detailed formulations of wheel-rail contact models. In the past, most dynamic simulation tools used an offline wheel-rail contact element based on look-up tables that are used by the main simulation solver. Nowadays, the use of an online nonlinear three-dimensional wheel-rail contact element is necessary in order to accurately predict the dynamic performance of high speed trains. Recently, the Federal Railroad Administration, Office of Research and Development has sponsored a project to develop a general multibody simulation code that uses an online nonlinear three-dimensional wheel-rail contact element to predict the contact forces between wheel and rail. In this paper, several nonlinear wheel-rail contact formulations are presented, each using the online three-dimensional approach. The methods presented are divided into two contact approaches. In the first Constraint Approach, the wheel is assumed to remain in contact with the rail. In this approach, the normal contact forces are determined by using the technique of Lagrange multipliers. In the second Elastic Approach, wheel/rail separation and penetration are allowed, and the normal contact forces are determined by using Hertz’s Theory. The advantages and disadvantages of each method are presented in this paper. In addition, this paper discusses future developments and improvements for the multibody system code. Some of these improvements are currently being implemented by the University of Illinois at Chicago (UIC). In the accompanying “Part 2” and “Part 3” to this paper, numerical examples are presented in order to demonstrate the results obtained from this research.


2020 ◽  
Vol 140 (5) ◽  
pp. 349-355
Author(s):  
Hirokazu Kato ◽  
Kenji Sato

2016 ◽  
pp. 7-8
Author(s):  
Eric Nyberg ◽  
Jian Peng ◽  
Neale R. Neelameggham

Author(s):  
Deqing Huang ◽  
Wanqiu Yang ◽  
Tengfei Huang ◽  
Na Qin ◽  
Yong Chen ◽  
...  

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402098468
Author(s):  
Xianbin Du ◽  
Youqun Zhao ◽  
Yijiang Ma ◽  
Hongxun Fu

The camber and cornering properties of the tire directly affect the handling stability of vehicles, especially in emergencies such as high-speed cornering and obstacle avoidance. The structural and load-bearing mode of non-pneumatic mechanical elastic (ME) wheel determine that the mechanical properties of ME wheel will change when different combinations of hinge length and distribution number are adopted. The camber and cornering properties of ME wheel with different hinge lengths and distributions were studied by combining finite element method (FEM) with neural network theory. A ME wheel back propagation (BP) neural network model was established, and the additional momentum method and adaptive learning rate method were utilized to improve BP algorithm. The learning ability and generalization ability of the network model were verified by comparing the output values with the actual input values. The camber and cornering properties of ME wheel were analyzed when the hinge length and distribution changed. The results showed the variation of lateral force and aligning torque of different wheel structures under the combined conditions, and also provided guidance for the matching of wheel and vehicle performance.


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