scholarly journals Dynamic Behavior of the Full-Car Model in the J-Turn Maneuver by Considering the Engine Gyroscopic Effects

2021 ◽  
Vol 23 (3) ◽  
pp. B237-B249
Author(s):  
Ali Shahabi ◽  
Amir Hossein Kazemian ◽  
Said Farahat ◽  
Faramarz Sarhaddi
Keyword(s):  
Numerical Simulation ◽  
Coordinate System ◽  
Dynamic Behavior ◽  
Equations Of Motion ◽  
Simulation Method ◽  
Governing Equations ◽  
Car Model ◽  
Roll Rate ◽  
Gyroscopic Effects ◽  
Engine Crankshaft

This study presents a new dynamic modeling of a vehicle by considering the engine dynamics. By selecting the vehicle coordinate system as the reference frame, all the force-torque equations of the sprung mass and unsprung masses are derived in this coordinate system by using the Newton’s equations of motion. Unlike the previous researches, in this work the sprung mass of the vehicle is not considered as a rigid body. The dynamics of the sprung mass components, such as gyroscopic effects of the engine crankshaft, is considered. In order to study the vehicle's dynamic behavior, in the J-turn maneuver, the governing equations of the full-car model are evaluated and validated by the numerical simulation method and ADAMS/Car software. Based on the results, the maximum roll angle and roll rate of a vehicle reach about 8 degrees and 40 degrees per second, respectively.

The influence of engine gyroscopic moments on vehicle transient handling

2021 ◽  
pp. 095440702199689
Author(s):  
Ali Shahabi ◽  
Amir Hossein Kazemian ◽  
Saeid Farahat ◽  
Faramarz Sarhaddi
Keyword(s):  
Coordinate System ◽  
Dynamic Behavior ◽  
Opposite Direction ◽  
Rotation Speed ◽  
Equations Of Motion ◽  
Vehicle Handling ◽  
Torque Vector ◽  
Crankshaft Rotation ◽  
External Forces ◽  
Engine Crankshaft

This study presents the dynamics of a 15-DOF model of the vehicle by performing simulations to investigate the vehicle handling dynamics in J-turn maneuver. Using Newton’s equations of motion, the equations of motion for the sprung and unsprung masses are all written in the vehicle coordinate system and the tire is modeled with the Pacejka 89 model. Since the engine crankshaft has a rotation relative to the vehicle coordinate system, in order to investigate the effect of the engine gyroscopic moments on the vehicle handling dynamics, the effect of the crankshaft rotation on the torque vector of external forces is considered. The direction of crankshaft rotation can change the direction of engine rotation in the direction of the wheels rotation or in the opposite direction of their rotation, which causes some changes in the gyroscopic torque vector of the engine. Due to the rotation speed of the crankshaft and its moment of inertia, the gyroscopic moments which resulted from the angular momentum of the engine crankshaft are considerable. These gyroscopic moments are added to the torque equation of external forces in the vehicle coordinate system and affect the vehicle handling dynamics. By using the numerical method of Newmark, vehicle’s dynamic behavior is investigated and the validation of its dynamic behavior is done by ADAMS/Car software. This study shows that in transverse engine, if the direction of engine rotation is in the opposite direction of the wheels, the vehicle handling dynamics is improved.

Numerical Simulation of Interior Flow Field of Reactor Coolant Pump under Station Blackout Accident

2012 ◽  
Vol 455-456 ◽  
pp. 1002-1008 ◽  
Author(s):  
Yi Ming Xu ◽  
Shi Ming Xu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Internal Flow ◽  
Simulation Method ◽  
Governing Equations ◽  
Coolant Pump ◽  
Reactor Coolant ◽  
Internal Characteristic ◽  
Station Blackout ◽  
Interior Flow

Numerical simulation is used for researching the transient characteristic and internal characteristic of the reactor coolant pump under station blackout accident. The simulation method has been presented by analyzing difference scheme for governing equations. The analytical model of reactor coolant pump flow field has been established by analyzing adequately the influence of varying rotation speed to the pump external characteristic. Finally, the pump internal flow characteristic is exposed.

scholarly journals An Approach to Determine Optimal Bow Configuration of Polar Ships under Combined Ice and Calm-Water Conditions

2021 ◽  
Vol 9 (6) ◽  
pp. 680
Author(s):  
Hui Li ◽  
Yan Feng ◽  
Muk Chen Ong ◽  
Xin Zhao ◽  
Li Zhou
Keyword(s):  
Numerical Simulation ◽  
Water Resistance ◽  
Numerical Technique ◽  
Experimental Studies ◽  
Resistance Index ◽  
Simulation Method ◽  
Present Approach ◽  
Calm Water ◽  
Level Ice ◽  
Ice Resistance

Selecting an optimal bow configuration is critical to the preliminary design of polar ships. This paper proposes an approach to determine the optimal bow of polar ships based on present numerical simulation and available published experimental studies. Unlike conventional methods, the present approach integrates both ice resistance and calm-water resistance with the navigating time. A numerical simulation method of an icebreaking vessel going straight ahead in level ice is developed using SPH (smoothed particle hydrodynamics) numerical technique of LS-DYNA. The present numerical results for the ice resistance in level ice are in satisfactory agreement with the available published experimental data. The bow configurations with superior icebreaking capability are obtained by analyzing the sensitivities due to the buttock angle γ, the frame angle β and the waterline angle α. The calm-water resistance is calculated using FVM (finite volume method). Finally, an overall resistance index devised from the ship resistance in ice/water weighted by their corresponding weighted navigation time is proposed. The present approach can be used for evaluating the integrated resistance performance of the polar ships operating in both a water route and ice route.

A numerical simulation method for molten material behavior in nuclear reactors

2017 ◽  
Vol 322 ◽  
pp. 301-312 ◽  
Author(s):  
Susumu Yamashita ◽  
Takuya Ina ◽  
Yasuhiro Idomura ◽  
Hiroyuki Yoshida
Keyword(s):  
Numerical Simulation ◽  
Nuclear Reactors ◽  
Simulation Method ◽  
Material Behavior ◽  
Molten Material ◽  
Numerical Simulation Method

scholarly journals Strata behavior and control strategy of backfilling collaborate with caving fully-mechanized mining

2020 ◽  
Vol 12 (1) ◽  
pp. 703-717
Author(s):  
Yin Wei ◽  
Wang Jiaqi ◽  
Bai Xiaomin ◽  
Sun Wenjie ◽  
Zhou Zheyuan
Keyword(s):  
Numerical Simulation ◽  
Control Strategy ◽  
Three Dimensional ◽  
Simulation Method ◽  
Mine Pressure ◽  
Hydraulic Support ◽  
Transition Area ◽  
Pressure Concentration ◽  
Strata Behavior ◽  
And Control

AbstractThis article analyzes the technical difficulties in full-section backfill mining and briefly introduces the technical principle and advantages of backfilling combined with caving fully mechanized mining (BCCFM). To reveal the strata behavior law of the BCCFM workface, this work establishes a three-dimensional numerical model and designs a simulation method by dynamically updating the modulus parameter of the filling body. By the analysis of numerical simulation, the following conclusions about strata behavior of the BCCFM workface were drawn. (1) The strata behavior of the BCCFM workface shows significant nonsymmetrical characteristics, and the pressure in the caving section is higher than that in the backfilling section. φ has the greatest influence on the backfilling section and the least influence on the caving section. C has a significant influence on the range of abutment pressure in the backfilling section. (2) There exits the transition area with strong mine pressure of the BCCFM workface. φ and C have significant effect on the degree of pressure concentration but little effect on the influence range of strong mine pressure in the transition area. (3) Under different conditions, the influence range of strong mine pressure is all less than 6 m. This article puts forward a control strategy of mine pressure in the transition area, which is appropriately improving the strength of the transition hydraulic support within the influence range (6 m) in the transition area according to the pressure concentration coefficient. The field measurement value of Ji15-31010 workface was consistent with numerical simulation, which verifies the reliability of control strategy of the BCCFM workface.

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