An Experimental Study of Longitudinal Tire Relaxation Constants for Vehicle Traction Dynamics Modeling

2019 ◽  
Author(s):  
Vladimir V. Vantsevich ◽  
Lyubomyr I. Demkiv ◽  
Sviatoslav R. Klos ◽  
Samuel R. Misko ◽  
Lee Moradi
Keyword(s):  
Experimental Study ◽  
Dynamic Models ◽  
Testing Machine ◽  
Transient Dynamics ◽  
Dynamics Modeling ◽  
Test Procedures ◽  
Advantages And Disadvantages ◽  
Frequency Domains ◽  
Tire Testing ◽  
Relaxation Characteristics

Abstract Existing literature on vehicle traction dynamics were reviewed for a variety of vehicle and tire dynamic models, some of which consider the pneumatic tires’ relaxation as a property of vehicle transient dynamics. In general, unlike the lateral relaxation counterpart, the longitudinal tire relaxation characteristics were mostly overlooked in tire transient dynamics modeling. As a continuation of the analytical study published in the 2018 DSCC Proceedings, the co-authors of this paper present an experimental study of the longitudinal tire relaxation characteristics of a Continental MPT 81 tire. Experimental results were obtained by conducting tests on an MTS Flat-Trac LTR tire testing machine. The experimental data is analyzed to investigate longitudinal tire relaxation characteristics as they relate to changes of tire conditions. The goal is to verify and refine the existing models suggested in the literature; as well as, discuss advantages and disadvantages of different test procedures and tire testing equipment. In particular, the paper investigates the longitudinal tire relaxation constant variation due to changes of wheel velocity, tire inflation pressure, and sine oscillations of tire slippage in the time and frequency domains. The paper concludes on the influence of the longitudinal tire relaxation constants on the tire/vehicle traction dynamics modeling.

Dynamical Modeling of Gear Transmission Considering Gearbox Casing

2018 ◽  
Author(s):  
Yang Luo ◽  
Natalie Baddour ◽  
Ming Liang
Keyword(s):  
Dynamic Models ◽  
Signal Propagation ◽  
Gear Transmission ◽  
Gear System ◽  
Dynamical Model ◽  
Contact Friction ◽  
Dynamical Response ◽  
Dynamic Simulations ◽  
Friction Forces ◽  
Frequency Domains

Much research has been carried out to investigate the dynamical response of a gear system because of its importance on vibration feature analysis. It is well known that the gearbox casing is one of the most important components of the gear system and plays an important role in signal propagation. However, its effects have widely been neglected within the dynamic simulations and few dynamic models have considered the gearbox casing when modeling a gear transmission. This paper proposes a gear transmission dynamical model with the consideration of the effects of gearbox casing. The proposed dynamical model incorporates TVMS, a time-varying load sharing ratio, as well as dynamic tooth contact friction forces, friction moments and dynamic mesh damping coefficients. The proposed gear dynamical model is validated by comparison with responses obtained from experimental test rigs under different speed conditions. Comparisons indicate that the responses of the proposed dynamical model are consistent with experimental results, in both time and frequency domains under different rotation speeds.

Employing Dynamic Models to Enhance Corporate IT Security Policy

2012 ◽  
Vol 4 (2) ◽  
pp. 42-59
Author(s):  
Nathan A. Minami
Keyword(s):  
Security Policy ◽  
Dynamic Models ◽  
Insider Threat ◽  
Dynamics Modeling ◽  
Patriot Act ◽  
Individual Agent ◽  
Agent Behavior ◽  
System A ◽  
The Government ◽  
Government Surveillance

Since 9/11 and the creation of the U.S. Patriot Act, the intrusion of government surveillance into the lives of ordinary Americans has become a topic of great concern to many citizens. While many Americans view surveillance as a necessity in the name of national security, the government is not the only organization conducting surveillance. As technological capacity increases, an increasing number of employers are implementing technologies that allow them to maintain vigilance over the actions of their employees in the workplace. Despite many attempts to implement surveillance technologies, there is little evidence that companies are any safer now than they were ten years ago. This paper demonstrates how System Dynamics modeling can be utilized to help model the insider threat as a system. It provides analysis of the non-linear affect of decision making, assessing the 2nd, 3rd, and 4th order impacts of decisions, and demonstrates the important impact of delays in the system. A mathematical model is presented and simulations are conducted to determine the likely affect of company decisions and individual agent behavior.

scholarly journals Comparison of Usability between Gear Shifters with Varied Visual and Haptic Patterns and Complexities

2020 ◽  
Vol 4 (2) ◽  
pp. 24
Author(s):  
Sanna Lohilahti Bladfält ◽  
Camilla Grane ◽  
Peter Bengtsson
Keyword(s):  
Experimental Study ◽  
Ease Of Use ◽  
Manual Transmission ◽  
The Other ◽  
Complexity Level ◽  
The Road ◽  
Advantages And Disadvantages ◽  
Driver Performance ◽  
Different Types ◽  
Haptic Patterns

Shift-by-wire technology enables more options concerning the design, placement and functions of gear shifters compared to traditional gear shifters with manual transmission. These variations can impact usability and driver performance. There is a lack of research regarding the potential advantages and disadvantages of different types of gear shifters. The purpose of this study was to investigate the efficiency and subjective ease-of-use of mono- and polystable joystick gear shifter types at different complexity levels and with full or limited visibility. An experimental study with 36 participants was conducted. The results showed that monostable joysticks, especially those with an I/J-shape, were overall less efficient and easy to use than polystable joysticks. The highest complexity level clearly affected the efficiency for the monostable joystick with an I/J-shape (mono I/J) compared with the other gear shifter types. The monostable joystick with an I/J-shape (mono I/J) was also most affected by reduced visibility at the highest level of complexity, indicating that it was more prone to causing users to take their eyes off the road.

Test of Physical Mechanical Properties of Gingko，Hickory Nut and their Stalks

2012 ◽  
Vol 479-481 ◽  
pp. 1145-1150
Author(s):  
Xiao Feng Xu ◽  
Wen Bin Yao ◽  
Jiu Hua Xu ◽  
Wei Zhang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Testing Machine ◽  
Physical Characteristics ◽  
Harvest Time ◽  
Cutting Resistance ◽  
Moisture Contents ◽  
Universal Testing ◽  
The Impact ◽  
Physical Mechanics

In order to get the physical mechanics of gingko，hickory nut and their stalks, microprocessor controlled electronic universal testing machine (WDW-5E) was used to study the basic physical characteristics，pulling resistance and cutting resistance of their stalk in different harvest time and moisture contents. The impact of physical mechanics of cones and stalks on the picking process were analyzed and some concrete suggestions were put forward in the paper. This experimental study provides an important theory basis on designing and manufacturing different cones picking machine.

Experimental Study on Pressure Fluctuations in the Boundary Layer of an Axisymmetric Body

2011 ◽  
Vol 66-68 ◽  
pp. 1488-1493
Author(s):  
Hong Xiao ◽  
Chao Gao ◽  
Zhen Kun Ma
Keyword(s):  
Boundary Layer ◽  
Experimental Study ◽  
Mach Number ◽  
Dynamic Pressure ◽  
Pressure Fluctuations ◽  
Axisymmetric Body ◽  
Pressure Measurements ◽  
Fluctuating Pressure ◽  
Frequency Domains ◽  
Dynamic Pressure Measurements

The characteristics of the fluctuating pressure in the boundary layer of an axisymmetric body have been investigated experimentally using dynamic pressure measurements and Schlieren photograghs. Data were acquired at subsonic and super-sonic Mach numbers. The angles of attack ranged from 0° to 5°. Pressure signals were measured simultaneously in several positions along the model and were analyzed both in the time and frequency domains. The Mach number shows the relevant influence on . Furthermore, the pressure fluctuations’ level decreases with the increasing of Mach number except M=1.15. And it is shown that, the location along the axis of the model and the angles of attack have small effect on pressure fluctuations.

scholarly journals Washing Machine Dynamic Model to Prevent Tub Collision during Transient State

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6636
Author(s):  
Beatriz Sánchez-Tabuenca ◽  
Carmen Galé ◽  
Juan Lladó ◽  
Cristian Albero ◽  
Roberto Latre
Keyword(s):  
Experimental Study ◽  
Steady State ◽  
Dynamic Models ◽  
Transient State ◽  
Design Phase ◽  
Washing Machine ◽  
Transient Motion ◽  
Multibody Model ◽  
Transient Period ◽  
Displacement Measurements

In horizontal-axis washing machines, the front gasket as well as the damping system are crucial owing to the possible collision of the tub with the housing during the transient period. However, most dynamic models for predicting tub motion focus on the steady state and consider only the suspension system without including the gasket. We conducted an experimental study to analyze the effect of the gasket on the transient motion of the tub. The results obtained indicate the necessity of implementing the gasket in the multibody model of a washing machine to accurately predict the tub behavior during this period. The gasket model is formed by a combination of Voigt elements. Stiffness parameters are determined using a load cell, and damping factors are estimated using a process that integrates Adams/View, Matlab optimization algorithms, and displacement measurements that are taken using accelerometers. A D-optimal design used to predict the effect of the gasket parameters reveals that the tub displacement is most sensitive to the changes in linear stiffness in the transversal direction. Finally, the model of the gasket provides a better approach for predicting the tub movement during resonance that can be used in the design phase to avoid tub collision.

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