scholarly journals Reliability and Efficiency of Tractive Force Generation by the Interlock Drive System

2020 ◽  
Author(s):  
Volker Nannen ◽  
Damian Bover ◽  
David Reiser ◽  
Dieter Zöbel
Keyword(s):  
Weight Ratio ◽  
Drive System ◽  
Limiting Factors ◽  
Mechanical Field ◽  
System P ◽  
Draft Force ◽  
Series Of Experiments ◽  
Dry Soil ◽  
Tractive Efficiency ◽  
Wheeled Vehicles

Tractors and other wheeled vehicles need considerable ballast to gain traction and have low tractive efficiency due to slip and tire flexing. The resulting soil degradation and energy cost are limiting factors that hinder the intensification of mechanical field management. The interlock drive system overcomes these limitations through the use of articulated spikes which temporarily interlock with the soil to generate traction. Once inserted into the soil, relatively thin and short spikes provide sufficient motion resistance to pull implements through the soil, with no need for additional ballast. To better understand the interaction of a spike with the soil, we conducted a series of experiments where we controlled the draft force and measured the resulting motion of the spike as it penetrates the soil and interlocks with it. Results show that the interlock drive system can generate pull reliably even on wet soil, and that a pull/weight ratio of 2 and higher is possible. The tractive efficiency for a vehicle using the interlock drive system can reach a ratio as high as 0.96 for wet and 0.975 for dry soil, as calculated from the experimental results. Precise soil applications would benefit from further improvement in the horizontal precision of soil penetration.

scholarly journals A Novel Traction Mechanism Based on Retractable Crampons to Minimize Soil Compaction and Reduce Energy Consumption

2020 ◽  
Author(s):  
Volker Nannen ◽  
Damian Bover ◽  
Dieter Zöbel
Keyword(s):  
Soil Compaction ◽  
Agricultural Soil ◽  
Weight Ratio ◽  
Rake Angle ◽  
Inherent Limitation ◽  
Soil P ◽  
Mechanical Field ◽  
Motion Resistance ◽  
Reduce Energy Consumption ◽  
Tractive Efficiency

Tired and tracked tractors on agricultural soil have the inherent limitation of needing considerable ballast to gain traction and have low tractive efficiency due to slip and tire flexing. These limitations contribute to soil degradation and reduce the possibility to intensify mechanical field management. To address these disadvantages, we introduce a novel traction mechanism which combines inching or push-pull locomotion with retractable tines or crampons which penetrate the soil every few meters. Once inserted into the soil, relatively thin and short crampons provide sufficient motion resistance to pull tillage implements through the soil, with no need for additional ballast. Optimal crampon design depends on the width, depth in the soil, rake angle, and inter-crampon spacing. A hinged design allows for reliable crampon insertion and extraction. The pull/weight ratio of the vehicle can be controlled by placing the hinge low and by separating the crampon from the hinge by an arm. Travel reduction and tractive efficiency can be controlled through the actuation length of the push-pull mechanism. Experimental results show that crampons can achieve a high pull/weight ratio, travel reduction of less than 10%, and a tractive efficiency of over 90% on agricultural soil.

scholarly journals Germination of Ocotea pulchella (Nees) Mez (Lauraceae) seeds in laboratory and natural restinga environment conditions

2009 ◽  
Vol 69 (3) ◽  
pp. 935-942 ◽  
Author(s):  
LA. Pires ◽  
VJM. Cardoso ◽  
CA. Joly ◽  
RR. Rodrigues
Keyword(s):  
Soil Moisture ◽  
Soil Moisture Content ◽  
Weibull Model ◽  
Limiting Factors ◽  
Base Temperature ◽  
Temperature Range ◽  
Optimal Temperature Range ◽  
Dry Soil ◽  
Moisture Conditions ◽  
Temperature Water

The germination response of Ocotea pulchella (Nees) Mez seeds to light, temperature, water level and pulp presence is introduced. The laboratory assays were carried out in germination chambers and thermal-gradient apparatus, whereas the field assays were performed in environments with distinct light, temperature and soil moisture conditions within a permanent parcel of Restinga forest of the Parque Estadual da Ilha do Cardoso, Cananéia, São Paulo. The seeds do not exhibit dormancy, they are non photoblastic, and a loss of viability in dry stored seeds can be related to a decrease in water content of the seed. The presence of the pulp and the flooded substratum influenced negatively the germination of O. pulchella seeds tested in the laboratory. Otherwise, light and temperature probably are not limiting factors of the germination of O. pulchella seeds in the natural environment of Restinga. The optimum temperature range for germination of Ocotea pulchella seeds was 20 to 32 ºC, the minimum or base temperature estimated was 11 ºC and the maximum ranged between 33 and 42 ºC. The isotherms exhibited a sigmoidal pattern well described by the Weibull model in the sub-optimal temperature range. The germinability of O. pulchella seeds in the understorey, both in wet and dry soil, was higher than in gaps. Germination was not affected by fluctuations in soil moisture content in the understorey environment, whereas in gaps, germination was higher in wet soils. Thus, the germination of this species involves the interaction of two or more factors and it cannot be explained by a single factor.

scholarly journals Interlocking Spikes for Extreme Mobility

2020 ◽  
Author(s):  
Volker Nannen ◽  
Damian Bover
Keyword(s):  
Fundamental Problem ◽  
Weight Ratio ◽  
Penetration Resistance ◽  
Rake Angle ◽  
Vehicle Stability ◽  
Engineering Science ◽  
Critical Depth ◽  
Low Thrust ◽  
Penetration Force ◽  
Draft Force

The interlock drive system generates traction by penetrating articulated spikes into the ground and by using the natural strength of the ground for traction. A fundamental problem of traction by interlocking spikes is how to penetrate the ground such that the spike will withstand the draft force. The theory of critical depth suggests that a high rake angle reduces soil fragmentation, while vehicle stability and demand for a high pull/weight ratio require a low thrust angle. To satisfy both requirements, we connect an interlocking spike with a high rake angle via a lever arm to a hinge close to the ground for a low thrust angle. The resulting friction of the spike with the soil increases the vertical penetration force during penetration. Experimental data shows that such a spike penetrates soil of a much higher penetration resistance than predicted from an analysis of the forces involved, possibly because the spike follows the path of least resistance. To better understand and improve the potential of interlocking spikes for mobility in extreme terrain, we need a comprehensive experimental analysis. Accepted Paper in Proc. Earth & Space 2020: 17th Biennial ASCE International Conference on Engineering, Science, Construction and Operations in Challenging Environments, ASCE, Seattle WA.

Incremental Damage Development in a 3D Woven Carbon Fibre Composite

2007 ◽  
Vol 15 (7) ◽  
pp. 521-533
Author(s):  
S. King ◽  
G. Stewart ◽  
A.T. McIlhagger ◽  
J.P. Quinn
Keyword(s):  
Carbon Fibre ◽  
Fibre Composite ◽  
Weight Ratio ◽  
Matrix Cracking ◽  
Limiting Factors ◽  
Damage Development ◽  
Carbon Fibre Composite ◽  
Damage Initiation ◽  
Fibre Composites ◽  
Carbon Fibre Composites

Interest in 3D woven carbon fibre composites has increased within industries such as aerospace, automotive and marine, due to their high strength to weight ratio, their increased tailorability and their capacity to be manufactured into near net shape preforms, thereby reducing parts count, assembly time, labour intensity and costs. It is vital that critical areas of concern such as damage (and in particular damage initiation and development) are studied and understood, thereby reducing the limiting factors to their acceptance. The damage initiation and subsequent intervals of development for ILSS (Interlaminar Shear Strength) were determined experimentally. Particular focus is paid to the significance of binder edge and binder middle testing and the influence of through-the-thickness (T-T-T) reinforcement in relation to damage types and development. Control samples for binder edge and binder middle loading locations were tested to failure as a means of determining an average point of failure, allowing the generation of testing intervals. The performance and architecture of samples from each incremental interval were characterised using a combination of graphical analysis and optical microscopy with the aid of dye-penetrant to highlight fibre damage and matrix cracking. Samples displayed specific damage initiation points, thus allowing the generation of a damage guide relating to applied force. In addition, the results imply that a relationship exists between the location of applied load and subsequent damage, thus showing the significant influence played by the T-T-T binder loading location on damage development within 3D woven carbon fibre composites. Some of the preliminary data shown in this paper was presented at IMC23 at the University of Ulster, UK in August 2006 and at Texcomp 8 in Nottingham, UK October 2006.

scholarly journals Research on the Mechanical Efficiency of High-Speed 2D Piston Pumps

Processes ◽  
2020 ◽  
Vol 8 (7) ◽  
pp. 853 ◽  
Author(s):  
Yu Huang ◽  
Jian Ruan ◽  
Chenchen Zhang ◽  
Chuan Ding ◽  
Sheng Li
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
High Pressures ◽  
Weight Ratio ◽  
Rolling Friction ◽  
Mechanical Efficiency ◽  
Load Pressure ◽  
Axial Piston Pumps ◽  
Series Of Experiments ◽  
Rolling Friction Coefficient

Since many studies on axial piston pumps aim at enhancing their high power-weight ratio, many researchers have focused on the generated mechanical losses by the three friction pairs in such pumps and attempted to diminish them through abundant and new structural designs of the pump’s components. In this paper, a high-speed 2D piston pump is introduced and its architecture is specifically described. Afterward, a mathematical model is established to study the pump’s mechanical efficiency, including the mechanical losses caused by the viscosity and stirring oil. Additionally, in this study the influences of the rotational speed, the different load pressures, and the rolling friction coefficient between the cone roller and the guiding rail are considered and discussed. By building a test rig, a series of experiments were carried out to prove that the mechanical efficiency was accurately predicted by this model at low load pressures. However, there was an increasing difference between the test results and the analytical outcomes at high pressures. Nevertheless, it is still reasonable to conclude that the rolling friction coefficient changes as the load pressure increases, which leads to a major decrease in the mechanical efficiency in experiments.

THE STUDY ON LUBRICITY PROPERTIES OF ARTERIAL VENOUS FISTULA NEEDLES

2002 ◽  
Vol 14 (03) ◽  
pp. 127-130 ◽  
Author(s):  
MING-CHUNG LEE ◽  
CHING-LUNG LIN ◽  
CHIU-LIN HUANG
Keyword(s):  
Medical Device ◽  
Weight Ratio ◽  
Experimental Results ◽  
Friction Reduction ◽  
Coating Solution ◽  
Silicone Fluid ◽  
Series Of Experiments ◽  
Venous Fistula

Silicone fluid is applied to reduce the friction of medical device in this study. Several factors, which might affect the friction of Arterial-Venous Fistula (A. V.F.) Needles, were investigated by a series of experiments. The experimental results showed that a better condition for the coating is using 10/90-weight ratio of MDX4/n-hexane silicone solution and dipping for 1.5 seconds. Two-step coating with an interval of 20 minutes also was examined to give an improvement in the lubricity of needles. It was observed that increased DC 360 concentration in coating solution displays more excellent friction reduction properties. Experimental consequences also showed that the lubricity of needles coated with DC 360 (350cst) is superior to that of coated with DC 360 (12,500cst).

Space vector modulation with reduced common mode voltage for six-phase drives

2020 ◽  
Vol 39 (2) ◽  
pp. 395-411
Author(s):  
Mohammad Jafar Zandzadeh ◽  
Mohsen Saniei ◽  
Reza Kianinezhad
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Torque Ripple ◽  
Drive System ◽  
Limiting Factors ◽  
Space Vector ◽  
Common Mode ◽  
Content Type ◽  
Common Mode Voltage ◽  
Space Vectors

Purpose This paper aims to present a modified space vector pulse width modulation (SVPWM) technique for six-phase induction motor drive based on common-mode voltage (CMV) and current losses which are two important issues affecting drive system behavior and quality. Design/methodology/approach It is shown that the presence of z-component currents and the presence of CMV in six-phase drive system are two major limiting factors in space vector selection. The behavior of several space vector selections in a two-level inverter considering minimum CMV and z-components is investigated. Then, the space vectors in a three-level inverter is analyzed and tried to explore an SVM technique with better behavior. Findings The analyses show that all the problems cannot be solved in a six-phase drive system with two-level inverter despite having 64 space vectors; this study tried to overcome the limitations by exploring space vectors in a three-level inverter. Originality/value The proposed pulse width modulation (PWM) strategy leads to minimum current distortion and undesired current components with zero CMV and modest torque ripple.

Malawi Drive System

2017 ◽  
Author(s):  
Matthew Harris
Keyword(s):  
Drive System ◽  
System P ◽  
Wheel Drive

A Pelton wheel drive system for a hydroelectric turbine

scholarly journals Soil moisture influence in the soil tillage operations

2020 ◽  
Vol 180 ◽  
pp. 03002
Author(s):  
Petru Cardei ◽  
Raluca Sfiru ◽  
Sebastian Muraru ◽  
Paula Condruz
Keyword(s):  
Mathematical Model ◽  
Soil Moisture ◽  
Soil Tillage ◽  
Physical Parameters ◽  
Water Mixture ◽  
Working Process ◽  
Draft Force ◽  
Moisture Influence ◽  
Dry Soil ◽  
Design Calculations

This article presents results obtained by the author in an attempt to introduce new parameters that influence the working process of agricultural soil working machines, in the classical formulas that mathematically model the tillage draft force. This article naturally introduces soil moisture. To introduce soil moisture into the calculation formulas of the tillage draft force, other physical parameters affected by soil moisture were used: density, cohesion, adhesion, etc. In this article, is explicitly describes, only the variation of soil density with its moisture. Considering some phenomena such as soil swelling or shrinkage, required the development of an adequate mathematical model of the expression of the density of soil-water mixture, concerning the concentration of water and the densities of dry soil and water. The final formulas obtained are tested to experimental results from the literature. Finally, the author sets out his opinion regarding the use of the results in design calculations and regarding the elevation to the rank of physical law of a mathematical model represented by a formula with a large number of parameters, which in turn are still dependent on many others parameters.

Sign in / Sign up

Export Citation Format

Share Document