scholarly journals Alternative Models for Calculation of Static Overturning Angle and Lateral Stability Analysis of Subcompact and Universal Tractors

Agriculture ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 861
Author(s):  
Radoslav Majdan ◽  
Rudolf Abrahám ◽  
Katarína Kollárová ◽  
Zdenko Tkáč ◽  
Eva Matejková ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Calculation Method ◽  
Rear Axle ◽  
Rear Wheel ◽  
Center Of Gravity ◽  
Lateral Stability ◽  
Regression Effect ◽  
Minimal Difference ◽  
Significant Regression ◽  
The Stability

Vehicle lateral stability is evaluated using the static overturning angle. The correct value of this parameter depends on the calculation method. The aim of this study was to compare the latest standard with previously published methodology, to propose two alternative methodologies (Models 1 and 2) and to analyze the influence of various levels of rear wheel ballast weights and overall tire widths on the stability of universal and subcompact tractors. The results showed a significant regression effect of the rear wheel ballast weight on static overturning angle. The influence of the rear wheel ballast weight was higher in the subcompact tractor than in the universal tractor due to a larger distance between the height of the center of gravity and the center of the rear axle. Comparing the latest standard with the previously published methodology, the highest difference values were 13.82% and 7.30%. Both models are based on the previously published methodology and differ from each other in rolling and slope lines. The methodology proposed in Model 2 differed from the standard similarly to the previously published methodology; therefore, it is irrelevant. Model 1 reached differences of only −1.81% and −1.63%, representing a minimal difference from the standard.

A Study of the Lateral Stability of Railroad Vehicles Using a Nonlinear Constrained Multibody Formulation

2001 ◽  
Author(s):  
Davide Valtorta ◽  
Khaled E. Zaazaa ◽  
Ahmed A. Shabana ◽  
Jalil R. Sany
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Theory ◽  
Linear Stability Analysis ◽  
Numerical Study ◽  
Operating Conditions ◽  
Lateral Stability ◽  
Railroad Vehicles ◽  
Contact Formulation ◽  
The Stability

Abstract The lateral stability of railroad vehicles travelling on tangent tracks is one of the important problems that has been the subject of extensive research since the nineteenth century. Early detailed studies of this problem in the twentieth century are the work of Carter and Rocard on the stability of locomotives. The linear theory for the lateral stability analysis has been extensively used in the past and can give good results under certain operating conditions. In this paper, the results obtained using a linear stability analysis are compared with the results obtained using a general nonlinear multibody methodology. In the linear stability analysis, the sources of the instability are investigated using Liapunov’s linear theory and the eigenvalue analysis for a simple wheelset model on a tangent track. The effects of the stiffness of the primary and secondary suspensions on the stability results are investigated. The results obtained for the simple model using the linear approach are compared with the results obtained using a new nonlinear multibody based constrained wheel/rail contact formulation. This comparative numerical study can be used to validate the use of the constrained wheel/rail contact formulation in the study of lateral stability. Similar studies can be used in the future to define the limitations of the linear theory under general operating conditions.

Numerical Analysis on the Influence of Joints Inclination on the Characteristics of Deformation and Stability of Tunnel

2013 ◽  
Vol 790 ◽  
pp. 299-305
Author(s):  
Xiao Song Tang ◽  
Yong Fu Wang ◽  
Ying Ren Zheng
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Calculation Method ◽  
Research Result ◽  
Bending Moment ◽  
Surrounding Rock ◽  
Interface Element ◽  
Tunnel Stability ◽  
Stability Of Surrounding Rock ◽  
The Stability

The paper adopts the interface element to simulate the joints so as to systematically and quantitatively study the deformation around tunnel, the mechanic state of lining and the stability under different inclining angles of joints. The result shows that the deformation around tunnel deteriorates mainly along the joint during the inner convergence effects of surrounding rock. When the inclining angle α=45°, the deformation around the tunnel is most serious, followed by that when α=90°, α=60°, α=30° and α=0°. At the same time, the influence of inclining angle on the distribution of the axial force of lining is comparatively small. But the distribution of bending moment and shear change obviously where the joints penetrate the tunnel. The tunnel stability of surrounding rock is the poorest when α=90° and the tunnel is most stable when α=0°. The stability of surrounding rock changes little when α is between 30° and 60°. The research result provides an effective calculation method for the forecast of deformation, the design of structure and the stability analysis of jointed tunnel. It is also helpful for the monitoring of construction and calculation of jointed tunnel in the future.

scholarly journals Preliminary calculation of the landing gear of a military training aircraft

2020 ◽  
Vol 12 (4) ◽  
pp. 241-247
Author(s):  
Ilie NICOLIN ◽  
Bogdan Adrian NICOLIN
Keyword(s):  
Calculation Method ◽  
Military Training ◽  
Landing Gear ◽  
Lateral Stability ◽  
Preliminary Calculation ◽  
The Stability

The paper presents a preliminary calculation method, which is easy to apply for pre-dimensioning the landing gear. Preliminary calculation of the landing gear includes estimating the loads on landing and determining the position of the nose landing gear and the main landing gear of a military training aircraft. Another purpose of the preliminary calculation is to ensure the stability of a military training aircraft on landing and take-off, as well as to ensure the lateral stability of the aircraft during ground operations such as taxiing, landing or take-off.

A study on an anti-lock braking system controller and rear-wheel controller to enhance vehicle lateral stability

2007 ◽  
Vol 221 (7) ◽  
pp. 777-787 ◽  
Author(s):  
Jeonghoon Song ◽  
Heungseob Kim ◽  
Kwangsuck Boo
Keyword(s):  
Sliding Mode ◽  
Dynamic Performance ◽  
Rear Wheel ◽  
Slip Angle ◽  
Lateral Stability ◽  
Motion Controller ◽  
Wheel Slip ◽  
Stopping Distance ◽  
Braking System ◽  
The Stability

This paper presents a mathematical vehicle model that is designed to analyse and improve the dynamic performance of a vehicle. A wheel slip controller for anti-lock braking system (ABS) brakes is formulated using a sliding mode controller and a proportional-integral-derivative (PID) controller for rear wheel steering is also designed to enhance the stability, steerability, and driveability of the vehicle during transient manoeuvres. The braking and steering performances of controllers are evaluated for various driving conditions, such as straight and J-turn manoeuvres. The simulation results show that the proposed full car model is sufficient to predict vehicle responses accurately. The developed ABS reduces the stopping distance and increases the longitudinal and lateral stability of both two-and four-wheel steering vehicles. The results also demonstrate that the use of a rear wheel controller as a yaw motion controller can increase its lateral stability and reduce the slip angle at high speeds.

scholarly journals IMPROVING THE STABILITY TWO-LEVEL CAR HAULER

2017 ◽  
Vol 1 (48) ◽  
pp. 8-18
Author(s):  
N. N. Shpilka
Keyword(s):  
Mathematical Model ◽  
Elastic Properties ◽  
Correct Choice ◽  
Center Of Gravity ◽  
Dynamic Processes ◽  
Lateral Stability ◽  
Location Parameters ◽  
Simulation Results ◽  
The Stability

To improve the lateral stability of car hauler way you value optimal cargo location parameters, elastically mounted on a platform, developed a mathematical model of its motion. At the same time take into account fluctuations in cargo and car hauler. According to the simulation results revealed that the system for car «hauler – cargo» accounting for elastic properties leads to a significant decrease in the frequency and amplitude of the system vertical oscillations. Therefore, the presence of the cargo can be regarded as a dynamic passive damping (in the case of a correct choice and design of layout parameters). There is proposed to reduce the distance between the cargo and the upper platform by determination of maximum values of the cargo oscillations amplitudes. In turn, the reduction of the height of the platform reduces the height of the center of gravity of the system, improves the stability of car hauler. Keywords: car hauler, dynamic processes, fluctuations, platform, stability.  

scholarly journals STABILITY ANALYSIS OF OCEAN PIPELINES : A PROBABILISTIC APPROACH

1986 ◽  
Vol 1 (20) ◽  
pp. 139
Author(s):  
Leon C. Geustyn ◽  
Gideon De F. Retief
Keyword(s):  
Monte Carlo Simulation ◽  
Stability Analysis ◽  
Probabilistic Approach ◽  
Statistical Error ◽  
Lateral Stability ◽  
Deterministic Approach ◽  
Stochastic Nature ◽  
Simulation Techniques ◽  
Sea Bed ◽  
The Stability

A probabilistic approach to the lateral stability of a pipeline on the sea-bed is considered. The uncertainties involved in the deterministic approach, due to the stochastic nature of variables, inaccuracy of models and statistical error are discussed. Variables representing these uncertainties are identified and their statistical properties investigated. Procedures for computing the probability of stability failure are developed using both analytical and Monte Carlo simulation techniques. Example calculations are presented indicating typical applications. It is concluded that the probabilistic procedure, as presented here, can serve as a valuable tool in the stability analysis of ocean pipelines.

scholarly journals Effect of Twin Vertical Stabilizers on Lateral Directional Static Stability of an Aircraft – A Computational Study

2022 ◽  
pp. 89-95
Author(s):  
K Ajay Kumar Goud ◽  
Y D Dwivedi
Keyword(s):  
Stability Analysis ◽  
Dynamic Model ◽  
Computational Study ◽  
Static Stability ◽  
Lateral Stability ◽  
Control Parameters ◽  
Stability And Control ◽  
The Stability ◽  
And Control ◽  
The Relationship

The advantages of twin vertical Stabilizers over a single vertical Stabilizer of an aero plane are the rationale for this study. For conventional aero planes, the use of double vertical Stabilizers is being considered. The contribution to lateral stability has been examined for this application. XFLR5 software was used to conduct the overall analysis. The analysis was conducted for a single vertical Stabilizer as well as twin vertical Stabilizers, and the findings were compiled and correlated. It is critical to be able to fully explain and evaluate the stability and control parameters. It is crucial to understand the relationship between the aerodynamics of the airframe and its stability characteristics in order to increase flight endurance and deployment effectiveness. The stability analysis based on the dynamic model of the twin boom vertical Stabilizer is presented in this paper. The lateral-directional stability of an aero plane with a single vertical tail is determined to be 20% more efficient than that with twin boom vertical Stabilizers. The trim condition is moderately satisfied by an aircraft with twin vertical Stabilizers.

Stability Analysis of the Nanjung Water Diversion Twin Tunnels based on Convergence Measurement

2019 ◽  
Vol 1 (1) ◽  
pp. 49-60
Author(s):  
Simon Heru Prassetyo ◽  
Ganda Marihot Simangunsong ◽  
Ridho Kresna Wattimena ◽  
Made Astawa Rai ◽  
Irwandy Arif ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Convergence Rate ◽  
Critical Strain ◽  
Convergence Rates ◽  
Strain Analysis ◽  
Water Diversion ◽  
Tunnel Face ◽  
Tunnel Stability ◽  
The Stability ◽  
Twin Tunnels

This paper focuses on the stability analysis of the Nanjung Water Diversion Twin Tunnels using convergence measurement. The Nanjung Tunnel is horseshoe-shaped in cross-section, 10.2 m x 9.2 m in dimension, and 230 m in length. The location of the tunnel is in Curug Jompong, Margaasih Subdistrict, Bandung. Convergence monitoring was done for 144 days between February 18 and July 11, 2019. The results of the convergence measurement were recorded and plotted into the curves of convergence vs. day and convergence vs. distance from tunnel face. From these plots, the continuity of the convergence and the convergence rate in the tunnel roof and wall were then analyzed. The convergence rates from each tunnel were also compared to empirical values to determine the level of tunnel stability. In general, the trend of convergence rate shows that the Nanjung Tunnel is stable without any indication of instability. Although there was a spike in the convergence rate at several STA in the measured span, that spike was not replicated by the convergence rate in the other measured spans and it was not continuous. The stability of the Nanjung Tunnel is also confirmed from the critical strain analysis, in which most of the STA measured have strain magnitudes located below the critical strain line and are less than 1%.

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