scholarly journals Levels of vibration transmitted to the operator of the tractor equipped with front axle suspension

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Daniele Pochi ◽  
Roberto Fanigliulo ◽  
Laura Fornaciari ◽  
Gennaro Vassalini ◽  
Marco Fedrizzi ◽  
...  
Keyword(s):  
High Speed ◽  
Travel Speed ◽  
Front Axle ◽  
Operating Conditions ◽  
Road Surface ◽  
Air Conditioner ◽  
Test Results ◽  
The Road ◽  
Seat Suspension ◽  
Agricultural Tractors

In recent years the comfort and the preservation of the health of the operators became central issues in the evolution of agricultural machinery and led to the introduction of devices aimed at improving working conditions. Thereby, for instance, the presence of air conditioner, soundproof cab and driver seat suspension became normal on agricultural tractors. The vibrations are one of the most complex issues to deal with, being determined by the characteristics and interaction of elements such as tyres, axles, mainframe, cab and seat suspension. In this respect, manufacturers are trying to improve their products, even integrating these elements with new devices such as the suspension on the front axle of the tractor, aimed at reducing the level of vibrations during the transfers at high speed. One of these underwent tests at CRA-ING. Since its purpose is to reduce the level of vibration transmitted to the driver, their measurements in different points of the tractor and in different operating conditions, were compared in order to evaluate the effectiveness of the device, expressed as time of exposure. The suspension system of the front axle is designed to absorb the oscillations (especially pitching) determined by irregularities in the road surface, allowing an increased control of the vehicle at high speed, as demonstrated by the test results and confirmed by the driving impressions outlined by the operator. The action of the device under these conditions results in an increase of the exposure time, important fact because of the relevance of the road transfer operations of tractors with mounted implements or trailers to tow and of the tendency to increase the speed limit for the road tractors (in Germany were brought to 50 km h–1 for several years). The action just described is less evident with increasing irregularity of the road surface and with the decrease of the travel speed. Nevertheless, in such conditions, the device appears to positively work along the other directions, in particular in the Z-axis, improving the action of the suspension of the driver seat.

Hysteresis loss of ultra-large off-the-road tire rubber compounds based on operating conditions at mine sites

2021 ◽  
pp. 095440702110155
Author(s):  
Shaosen Ma ◽  
Guangping Huang ◽  
Khaled Obaia ◽  
Soon Won Moon ◽  
Wei Victor Liu
Keyword(s):  
Large Strain ◽  
Tensile Tests ◽  
Operating Conditions ◽  
Hysteresis Loss ◽  
Strain Rates ◽  
Test Results ◽  
Tire Rubber ◽  
The Road ◽  
Rubber Compounds ◽  
Mine Sites

The objective of this study is to investigate the hysteresis loss of ultra-large off-the-road (OTR) tire rubber compounds based on typical operating conditions at mine sites. Cyclic tensile tests were conducted on tread and sidewall compounds at six strain levels ranging from 10% to 100%, eight strain rates from 10% to 500% s−1 and 14 rubber temperatures from −30°C to 100°C. The test results showed that a large strain level (e.g. 100%) increased the hysteresis loss of tire rubber compounds considerably. Hysteresis loss of tire rubber compounds increased with a rise of strain rates, and the increasing rates became greater at large strain levels (e.g. 100%). Moreover, a rise of rubber temperatures caused a decrease in hysteresis loss; however, the decrease became less significant when the rubber temperatures were above 10°C. Compared with tread compounds, sidewall compounds showed greater hysteresis loss values and more rapid increases in hysteresis loss with the rising strain rate.

scholarly journals Pavement State Recognition Method Considering Slope

2021 ◽  
Vol 2113 (1) ◽  
pp. 012080
Author(s):  
Xiuhao Xi ◽  
Jun Xiao ◽  
Qiang Zhang ◽  
Yanchao Wang
Keyword(s):  
Surface Condition ◽  
Lateral Force ◽  
Longitudinal Force ◽  
Operating Conditions ◽  
Road Surface ◽  
Tire Model ◽  
State Recognition ◽  
Adhesion Coefficient ◽  
The Road ◽  
Real Time Tracking

Abstract For the problem of road surface condition recognition, this paper proposes a real-time tracking method to estimate road surface slope and adhesion coefficient. Based on the fusion of dynamics and kinematics, the current road slope of the vehicle which correct vertical load is estimated. The effect of the noise from dynamic and kinematic methods on the estimation results is removed by designing a filter. The normalized longitudinal force and lateral force are calculated by Dugoff tire model, and the Jacobian matrix of the vector function of the process equation is obtained by combining the relevant theory of EKF algorithm. The road adhesion coefficient is estimated finally. The effectiveness of the algorithm is demonstrated by analyzing the results under different operating conditions, such as docking road and bisectional road, using a joint simulation of Matlab/Simulink and Carsim.

Integrated Dynamic Thermo-Mechanical Modeling of High Speed Spindles, Part 2: Solution Procedure and Validations

2004 ◽  
Vol 126 (1) ◽  
pp. 159-168 ◽  
Author(s):  
Hongqi Li ◽  
Yung C. Shin
Keyword(s):  
High Speed ◽  
Solution Procedure ◽  
Operating Conditions ◽  
Test Results ◽  
Mechanical Modeling ◽  
Spindle Bearing ◽  
Wide Range ◽  
Bearing Stiffness ◽  
Models Validation ◽  
Validation Tests

This paper presents a new solution procedure for an integrated thermo-dynamic spindle model and validation results. Based on the model presented in Part 1 of this paper, a computer program has been developed to generate comprehensive solutions for high speed spindle-bearing systems, such as bearing stiffness, contact load and temperature, spindle dynamic characteristics and response, temperature distributions, and thermal expansions. The model and the solution procedure are modular such that solutions for different spindle set-ups can be easily generated by combining a given spindle model with different toolholder models. Validation test results for thermal and dynamic predictions are presented for four different spindle systems, including the thermal and dynamic validation tests on a specially constructed spindle testbed. The validation results show the model has accurate predictive capabilities for a wide range of operating conditions and various spindle designs.

Tread Groove Void and Developed Tread Width (Aspect Ratio): Their Joint Influence on Wet Traction

1999 ◽  
Vol 72 (4) ◽  
pp. 684-700 ◽  
Author(s):  
Alan G. Veith
Keyword(s):  
Aspect Ratio ◽  
Discharge Capacity ◽  
Deep Water ◽  
High Speed ◽  
Operating Conditions ◽  
Performance Parameter ◽  
Testing Program ◽  
The Road ◽  
Joint Influence ◽  
Specific Discharge

Abstract Other than treadwear testing, tires are normally evaluated for important performance features in the virgin or new state. One performance feature that changes, as the tire wears in service, is wet traction. For any given tread compound the wet traction performance is jointly influenced by the groove void level (it changes with wear) and a factor that is a function of the aspect ratio, the “developed tread width,” i.e., the actual width that contacts the road surface. Based on a comprehensive testing program, a wet traction performance parameter called the “specific discharge capacity” has been developed. This accounts for the interactive or joint influence of both of these factors and how this influence changes across a range of operating conditions (speed, pavement texture). The specific discharge capacity is especially important at high levels of “criticality”, i.e., deep water, slippery pavement, high speed.

scholarly journals Investigation of the wear of asphalt concrete pavement taking into account the influence of temperature, moisture of the pavement and the presence of an aggressive environment

2021 ◽  
Vol 2 (92) ◽  
pp. 68
Author(s):  
Andrii Siedov ◽  
Olena Fomenko
Keyword(s):  
Asphalt Concrete ◽  
High Speed ◽  
Climatic Factors ◽  
Load Capacity ◽  
Weather Conditions ◽  
Road Surface ◽  
Winter Period ◽  
Influence Of Temperature ◽  
The Road ◽  
Industrial Enterprises

Abstract. The emergence of a large number of modern high-speed cars with improved dynamic characteristics and an increase in the share of cars, especially large load capacity, have significantly accelerated the destruction of asphalt roads. Plastic deformations, tracks and cracks are more and more often observed on asphalt concrete pavements of roads, their wear is accelerated. As a result, the transport and operational condition of roads deteriorates, the speed of traffic decreases, the cost of road transport increases, and increasing costs are required for road repairs. Thus, the conditions of traction of the wheels of the car with the road surface are influenced by the service life of the coating, traffic intensity, the amount of harmful emissions of industrial enterprises and climatic factors. At the same time uneven change of conditions of coupling in cross and longitudinal profiles of the highway comes to light. Analyzing the natural and climatic factors, we can establish that different weather conditions have different effects on the condition of the road surface. In summer, the condition of the surface is dry and clean, so the driving conditions are safe. Taking into account all the factors that lead to the destruction of the coating with the formation of residual deformations and irreversible changes, requires the study of wear of the coating surface. he wear of the coating largely depends on the friction force in the area of contact of the tire with the surface of the coating, the type of tires and the pressure in the tires. But the random nature of changes in the intensity and composition of traffic, seasons, temperature, humidity, rainfall affects the amount of wear over a period of operation of the road surface. The presence of water or solutions in the pores of the coating leads to the separation of mineral particles from the layer under the action of impact force from the wheels of vehicles. It is experimentally established that the wear of asphalt concrete in the dry and wet state increases with increasing temperature. One of the main types of damage to road surfaces is their premature wear under the influence of vehicle wheels, in combination with changing weather conditions. Analyzing the natural and climatic factors, we can establish that different weather conditions have different effects on the condition of the road surface. The article considers the influence of temperature, humidity and the presence of solutions of chloride anti-icing materials on the process of abrasion of asphalt pavement in the autumn-winter period. Occurrence of big differences of temperature and humidity accelerates processes of aging of materials from which layers are made, influencing their durability and wear resistance.

scholarly journals Vibration modeling of a vehicle equipped with MR damper and aerodynamic elements

2019 ◽  
Vol 20 (1-2) ◽  
pp. 57-61
Author(s):  
Wiesław Grzesikiewicz ◽  
Michał Makowski
Keyword(s):  
High Speed ◽  
Mr Damper ◽  
Road Surface ◽  
Vehicle Model ◽  
Numerical Investigations ◽  
The Road ◽  
Mr Dampers ◽  
On The Road ◽  
Magneto Rheological ◽  
Vibration Modeling

We considered of a vehicle model equipped with controlled magneto-rheological (MR) dampers and controlled aerodynamic elements. The vibrations of the vehicle moving at high speed during acceleration and braking are analysed. The purpose of this analysis is to determine the effect of forces generated on aerodynamic elements on vehicle vibrations and changes in wheel pressure on the road surface during acceleration and braking. The presented work presents the results of numerical investigations obtained on the basis of the developed vehicle model.

Study on Construction Machinery Speed Measurement Based on Road Surface Texture Image

2011 ◽  
Vol 135-136 ◽  
pp. 950-953
Author(s):  
Shou Feng Jin ◽  
Yong Biao Hu
Keyword(s):  
Surface Texture ◽  
High Speed ◽  
Road Surface ◽  
Continuous Image ◽  
Construction Machinery ◽  
The Road ◽  
Essential Variable ◽  
Image Pixels ◽  
Set Up ◽  
Moving Speed

The construction machinery moving speed is an essential variable to identify its attractive performance. To realize construction machinery real-time and adaptive control, it is necessary to measure the machinery actual speed. But the traditional measurement method is not precise enough and costly too much. To search a new method, the high-speed linear CCDcamera is used to collect the road surface gray image. A machinery vision model is set up for the random road surface texture. Using cross-correlation algorithm two frame continuous image pixels are figured out. The construction machinery moving speed can be counted out by analyzing the vision model projection relationship and the two frame continuous image time.The feasibleness and precision of this method are proved by experiments.

Noise Influence of High-Speed Train Based on Air Dynamics

2014 ◽  
Vol 687-691 ◽  
pp. 265-269
Author(s):  
Xiao Qin Wang
Keyword(s):  
High Speed ◽  
Pressure Ratio ◽  
Flow Distribution ◽  
Large Change ◽  
Aerodynamic Noise ◽  
Maximum Pressure ◽  
Air Conditioner ◽  
Test Results ◽  
Train Speed ◽  
Stable Flow

How to control aerodynamic noise of high speed motor train, this paper starts from the basic theory of hydrodynamics and acoustics, it adopts method of numerical simulation and applies Fluent and VirtuaUab Acousticsand software to make study on characteristics of aerodynamic noise for high speed motor train, the test results indicates that in the stable flow distribution, the baric gradient is relatively larger when its surface pressure is in area with large change in curve curvature, when it is in the area with even curve change, the baric gradient is relatively smaller. In different gradient, the train head, the maximum pressure and the maximum negative pressure ratio of air-conditioner air deflector predicate are in proportion to the square of train speed.

scholarly journals Analisis terjadinya hentakan dan suara keras pada suspensi belakang unit dump truck HD 785-7

2020 ◽  
Vol 8 (2) ◽  
Author(s):  
Hendro Purwono ◽  
Rasma Rasma ◽  
Riki Effendi
Keyword(s):  
High Speed ◽  
Vertical Vibration ◽  
The Body ◽  
Road Surface ◽  
Unit Weight ◽  
Dump Truck ◽  
Nitrogen Gas ◽  
The Road ◽  
Library Research ◽  
Using Data

The suspension system on the machine unit is very important to support the unit weight against the road surface and also protect the transmission from the vertical vibration of the wheels to the body of the unit. When the unit passes a damaged or bumpy road at high speed, shock loads from the road surface will be felt, so the role of the suspension is crucial in protecting components from damage, maintaining operator comfort and undamaged loads. HD 785-7 unit is one type of dump truck that uses cylindrical pneumatic hydro suspension that contains nitrogen and oil gases to absorb loads or vibrations from the road surface. In its operation which functions as a material carrier in the mine area, there are often problems with the suspension especially at the rear because it is holding a heavier load. Therefore, research needs to be carried out aimed at finding the main causes and solutions to these problems using data collection methods, namely: field surveys, interviews, and library research. The results show that damage to the valve core causes the valve to leak and cause the chamber at the top of the cylinder suspension to be occupied by nitrogen gas to be reduced so that the suspension suffers harsh strokes when operated especially on damaged roads. Damage to the valve core is caused by the use of non-standard and too tight tools in its installation. Keywords: hard suspension, valve core, feed valve, nitrogen gas, oil.

scholarly journals The roads of Pskov borderlands of the XVII centuries: from Pskov to Narva

2021 ◽  
pp. 58-77
Author(s):  
Maksim Yur'evich Kolpakov
Keyword(s):  
Road Network ◽  
Travel Speed ◽  
Road Surface ◽  
Average Speed ◽  
The Road ◽  
Everyday Activities ◽  
Road Signs ◽  
Trunk Road ◽  
History Of

This article traces the history of the development and operation of trunk road from Pskov through Gdov, to Ivangorod and Narva, which was actively used during the pre-Petrine era. This route can be viewed as one of the typical examples of the Pskov border road. Written and visual sources of the XVII century allow reconstructing the isolated sections of the road, estimating the quality of road surface and infrastructure, and characterizing everyday activities of the travelers. The texts of the report compiled by the Dutch envoy Albert Joachim (1616), schedule of routs from Pskov of 1656, “Notes about Russia” of Erich Palmquist (1674), and “Diary Notes” of the General von Allart (1700) served as the sources for this research. The travel from Pskov to Narva took traditional (long) route and two short roads. Travelers faced multiple difficulties common to the borderland roads – poor condition of road surface, lack of accommodation, absence of road signs, rough weather, threat to health and property. The maximum average travel speed on the known road was 61 verst (65.07 km) per day. The typical average speed of a summer trip was 30 verst (32 km) per day. From December to March, most commodities were transported between the cities by sledge. The road network of the Pskov borderlands was more adapted for winter trips.

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