scholarly journals The Effect of Friction on Actuation Torques of Foldable Rollover Protective Structures

2018 ◽  
Vol 24 (4) ◽  
pp. 227-242 ◽  
Author(s):  
Farzaneh Khorsandi ◽  
Paul D. Ayers
Keyword(s):  
Friction Force ◽  
Dynamic Method ◽  
Protective Structure ◽  
Kinetic Friction ◽  
Safety Standards ◽  
Before And After ◽  
Protective Structures

Abstract. The number of fatal tractor rollover accidents with an inoperative foldable rollover protective structure (FROPS) has increased sharply in recent years. Operators frequently leave the FROPS in the folded-down position after lowering the FROPS to pass a low overhead obstacle. One possible explanation for leaving the FROPS in the folded position is that raising and lowering the FROPS is a time-consuming and strenuous process. The actuation torques required to raise and lower a FROPS are not well known and may be influenced by friction. The actuation torques of ten FROPS from four different models were measured. One model FROPS was tested on seven different vehicles, and three models were tested separately. The dynamic and static (initiation and holding) actuation torques were measured to evaluate the effect of static and kinetic friction on actuation torque. The dynamic actuation torques were measured before and after greasing the FROPS. The proposed instruction to measure the actuation torque based on OECD Code 7 was evaluated. Results showed that friction has a significant effect on the measured actuation torque and can increase the actuation torque by up to 212%. The friction varies between FROPS of the same model, which is due to variations in the manufacturing, maintenance, and age of the FROPS. The friction force could be decreased by greasing the FROPS, and decreasing the friction increased the lowering resisting torques and decreased raising torques of FROPS. The measured actuation torque based on OECD Code 7 instruction (static holding) is not a constant value. The dynamic method is recommended for measuring FROPS actuation torques. Keywords: Actuating torque, Foldable rollover protective structure, FROPS, Safety, Standards, Tractor.

Impact action of a projectiles on special protective structures and ways to increase their protective capacity

2021 ◽  
pp. 95-100
Author(s):  
A. Andrukhiv ◽  
A. Baranov ◽  
N. Huzyk ◽  
B. Sokil ◽  
M. Sokil
Keyword(s):  
Soil Layer ◽  
Strength Characteristics ◽  
Protective Structure ◽  
Impact Action ◽  
Dirac Delta ◽  
Wood Flooring ◽  
Protective Element ◽  
Applied Forces ◽  
Protective Structures ◽  
Elastic Elements

A method for studying the reaction of elastic elements of protective structures to a series of impact actions of shells has been developed. In the work, the elastic elements of the protective structure are modeled by homogeneous beams, and the dynamic action of the shells is simulated by instantaneous point-applied forces. A mathematical model of this dynamic process is constructed, which is a boundary value problem for a hyperbolic equation with an irregular right-hand side. The latter is described using Dirac delta functions. Cases of both fixed and free ends of protective elements are considered. The main ideas of perturbation methods are used for the researches carried out in the work. Analytical dependences for the description of elastic deformations of a protective element which are basic for definition of its strength characteristics are received. They and the graphical dependences built on their basis for specific cases show that the dynamic deformations of the protective element for the fixed ends are greater in the case of the projectile closer to its middle, at the same time for the free ends – closer to the end. With regard to the modernization of protective structures, the dynamic effect on their elements can be reduced by using elastic reinforcement or changing the method of fixing the ends of the protective element: elastic or with a certain angle of inclination of the bearing surfaces. It is proposed to use special plastics, soil layer, flexible wood flooring, etc. as elastic reinforcement. The technique used in the work is the basis for determining the strength characteristics of protective elements, and from so – to check the reliability of the protective structure; study of the dynamics of protective and similar types of structures, taking into account the nonlinear characteristics of the elastic elements of protective structures; study of more complex oscillations of elements of protective structures. In the case of a series of impacts, it is obvious that the amplitude of deflection of the protective element after each impact will increase over time, because the model does not take into account the force of viscoelastic friction. These tasks will be the subject of further research.

Friction Characteristics and Adhesion Force Under Low Normal Load

1995 ◽  
Vol 117 (4) ◽  
pp. 569-574 ◽  
Author(s):  
Yasuhisa Ando ◽  
Yuichi Ishikawa ◽  
Tokio Kitahara
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
Adhesion Force ◽  
Normal Load ◽  
Adhesion Forces ◽  
Test Pieces ◽  
Before And After ◽  
Constant Normal Load ◽  
The Mean ◽  
Steel Balls

The friction coefficient and adhesion force between steel balls and flat test pieces were measured during friction under low normal load in order to examine the tribological characteristics. First, the friction coefficients were measured under a constant normal load of 0.8 to 2350 μN, and the adhesion forces were measured before and after each friction. The result showed that the friction coefficient was highest at low normal loads, while the friction force divided by the sum of the normal load and the mean adhesion force was almost constant over the whole range of loads. Second, when the normal load was reduced gradually during friction, friction still acted when the normal load became negative and a pulling off force was applied to the surface. Thus an adhesion force acts during friction and this adhesion force affects the friction force in the same way as the normal load.

scholarly journals NDT Methods Suitable for Evaluation the Condition of Military Fortification Construction in the Field

2020 ◽  
Vol 10 (22) ◽  
pp. 8161
Author(s):  
Zezulová Eva ◽  
Hasilová Kamila ◽  
Komárková Tereza ◽  
Stoniš Patrik ◽  
Štoller Jiří ◽  
...  
Keyword(s):  
Residual Strength ◽  
Fiber Reinforced Concrete ◽  
Protective Structure ◽  
Steel Fiber Reinforced Concrete ◽  
Degree Of Damage ◽  
Materials Used ◽  
Protective Structures ◽  
The Impact ◽  
Non Destructive

The protective structure is designed to protect the live force against the impact of a shock wave and projectiles, it cannot be diagnosed by the destructive method which devalues the protective structure by sampling. The authors are looking for a combination of suitable non-destructive technology (NDT) methods that would be used in the future to prove the degree of damage to cement-based protective structures after an explosion. This article represents the first part of an experiment designed to verify the applicability of NDT methods, to evaluate the degree of damage of the protective structure in the field. The experiment consists of three parts. The first part is a laboratory verification of the initial material characteristics of the materials used. The first test set of structural elements is made of steel fiber-reinforced concrete. The elements are evaluated using NDT methods and for comparison by destructive laboratory methods. The second part is the impact of structures using explosion and evaluation of the condition of structures using NDT methods in the field. The last part is used to verify the results of the NDT method, which ensures the residual strength of the structure in the laboratory and try to find the relationship between changes in the results of NDT methods and the residual strength. Radiography was included in the introductory and concluding parts of the experiment to verify the results. Although this method is not suitable for using in-situ, it is the only standardized method of the NDT methods used.

The Impact of Seawater Corrosion on Friction Force of Cylindrical Deputy Campaign Latch

2012 ◽  
Vol 531 ◽  
pp. 597-600
Author(s):  
Cheng Zhao ◽  
Kun Luo
Keyword(s):  
Finite Element ◽  
Stress State ◽  
Friction Force ◽  
Similarity Theory ◽  
Research Subject ◽  
Seawater Corrosion ◽  
Load Calculation ◽  
Before And After ◽  
The Impact

According to the stress state and importance of cylindrical deputy campaign latch, NO. 2 cylindrical deputy campaign latch was selected as research subject. The work including design , processing, finite element load calculation, friction force before and after corrosion of similarity samples were carried out according to similarity theory. Friction force calculations of cylindrical deputy campaign latch before and after corrosion were 1206N and 1222N respectively. Compared with the friction force before corrosion, the friction force of cylindrical deputy campaign latch was increased by 19.1% because of seawater corrosion.

scholarly journals Solubility of menthol in pressurized carbon dioxide: Experimental data and thermodynamic modeling

2006 ◽  
Vol 12 (3) ◽  
pp. 152-158 ◽  
Author(s):  
Anatolii Galushko ◽  
Helena Sovová ◽  
Roumiana Stateva
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Thermodynamic Modeling ◽  
Pressure Range ◽  
Dynamic Method ◽  
The Other ◽  
Melting Point Depression ◽  
Before And After ◽  
Modeling Data ◽  
First Time

The paper reports new experimental data and the results of the thermodynamic modeling of menthol solubility in pressurized CO2. The solubility was measured using the dynamic method and modeled with the Soave-Redlich-Kwong equation of state in the temperature range 30-60?C and pressure range 66-144 bar. The results obtained were compared with the solubility data published by Maier and Stephan and by Sovov? and Jez. The agreement with Maier and Stephan was very good: The deviation of the solubilities, published by Sovov? and Jez, from the other data sources was explained and revised accordingly. The paper also presents for the first time experimental and modeling data for the melting point depression of menthol in the presence of carbon dioxide in the pressure range of interest up to 60 bars. The experimental data was obtained comparing the appearance of menthol particles before and after their exposure to pressurized carbon dioxide.

scholarly journals PENUNTUN PRATIKUM FISIKA - MERRY THRESSIA, S.Si, M.Si

2019 ◽  
Author(s):  
Merry Thressia
Keyword(s):  
Friction Force ◽  
Fluid Pressure ◽  
Diffraction Method ◽  
Average Density ◽  
Kinetic Friction ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
Cohesion Force ◽  
Specific Object ◽  
The City

Densistas (density / density) is a measurement of mass per unit volume of matter. The higher the density of an object, the greater the mass of each volume. The average density of each object is the total mass divided by the total volume.Archimedes was the greatest scientist of his time. He was born in the city of Syracuse, Sicily in 287 BC and died in 212 BC. Archimedes is known as a physicist, mathematician, optics and astronomy. He was nicknamed the Father of Experiments, for basing his findings on experiments. He found the law on an event called Archimedes' Law which reads, "if an object is inserted into a liquid, either partially or completely, it will get an upward force equal to the weight of the liquid transferred by the object".X-ray diffraction method is one way to study the regularity of atoms or molecules in a certain structure. If the structure of an atom or molecule is arranged regularly to form a lattice, then electromagnetic radiation in certain experimental conditions will be strengthened.An object moves on a surface, on an object it works a kinetic friction force that opposes the direction of motion of an object. The magnitude of the kinetic force depends on the nature of the two surfaces in contact. For two specific object surfaces, the kinetic friction force is proportional to the normal force. The friction force does not depend on the surface area that is in contact. The rough and slippery nature of the surfaces of two touching fields is expressed by the friction coefficient.Fluid viscosity (liquid) is friction caused by a moving fluid, or solid object that moves in the fluid. The amount of friction is called the degree of viscosity of liquid. So the greater the viscosity of the liquid, the more difficult the solids move within the liquid. Viscosity in liquid, which plays a role is the cohesion force between liquid particles. Viscosity can be expressed as fluid flow resistance which is friction between liquid molecules from one anotherBernoulli principle is fluid pressure in a place where the velocity is smaller than in a place where the speed is lower. So the greater the velocity of fluid in a pipe, the smaller the pressure and vice versa, the smaller the velocity of fluid in a pipe, the greater the pressure.

Research on Protective Performance of Protective Liquid Tank to Shock Wave Generated by Fragment

2020 ◽  
Author(s):  
Yang Hong ◽  
Xiaobin Li ◽  
Yuchen Bao
Keyword(s):  
Shock Wave ◽  
Simulation Method ◽  
Metal Plate ◽  
Protective Effects ◽  
Protective Structure ◽  
Finite Element Software ◽  
Metal Plates ◽  
Basic Parameters ◽  
Protective Structures ◽  
Pressure Changes

Abstract In this paper, the simulation method is used to study the installation of metal plates in the liquid tank as a protective structure. The process of shock wave propagation in the liquid tank is analyzed by finite element software, and the metal plate deformation caused by shock wave is discussed. In addition, the pressure changes of different measuring points are compared when installing aluminum plate, steel plate and no protective structure in the liquid tank, and the effects of different protective structures on weakening shock wave are analyzed. Through the simulation method, the protective effects of the three basic parameters (the layer number, position and angle) of the protective structure are analyzed, and the effects of different forms of protective structures on the ability for weakening shock wave are also discussed. The results of this paper can provide references for the optimal design of liquid tank protection and its application in ship protection.

Evaluation of Palm Olein as Shaft Lubricant

2016 ◽  
Vol 819 ◽  
pp. 479-483
Author(s):  
Norzahir Sapawe ◽  
Samion Syahrullail ◽  
Farizudin Muhammad
Keyword(s):  
Surface Roughness ◽  
Friction Force ◽  
Vegetable Oil ◽  
Palm Olein ◽  
Wear Scar Diameter ◽  
Rbd Palm Olein ◽  
Before And After ◽  
Pin On Disc ◽  
Oil Utilization ◽  
Point Parameter

The demand and usage of vegetable oil utilization in lubricants for many applications increased prompting by continued growing environmental concerns. Today, vegetable oil attracts attention as biodegradable alternates for synthetic esters because they are cheaper and can be obtained from sources that are renewable. The main objectives of this experiment were to measure the friction force at various speeds and to observe the surface roughness before and after experiment. In this experiment, RBD palm olein as represented vegetable oil has been tested by compare the result with fully synthetic oil and mineral-based oil by using modified pin-on-disc machine. Pure RBD palm olein, recorded only 7.4% of increment of maximum friction force compared to results for mineral-based oil. Observation based on surface roughness show that RBD palm olein works as effective as fully synthetic and mineral-based oil since only 14.6% increment of overall surface roughness for the whole shaft. Therefore, the performance of vegetable oil which in this experiment is RBD palm olein, can be improve by adding additive so increase it properties such as can withstand at high load, high flash point parameter, small wear scar diameter, less oxidation rate, and coefficient of friction.

scholarly journals Design and numerical assessment of a rapid-construction corrugated steel-concrete-steel protective structure

2019 ◽  
Vol 10 (4) ◽  
pp. 470-485 ◽  
Author(s):  
Sangwoo Jeon ◽  
Samuel Edward Rigby
Keyword(s):  
Numerical Study ◽  
Near Field ◽  
Steel Structure ◽  
Steel Structures ◽  
Cost Effective ◽  
Protective Structure ◽  
Rapid Construction ◽  
Numerical Assessment ◽  
Protective Structures ◽  
Harmful Effects

A protective structure should be sufficiently resilient to protect its occupants from the harmful effects of an impact or explosion. In many instances, protective structures are also required to be assembled quickly, and be cost-effective. Steel-concrete-steel (SCS) sandwich structures combine the benefits of steel; ductility and anti-scabbing, and concrete; energy absorption and rigidity. Despite these favourable characteristics, the performance of profiled-plate steel-concrete-steel structures under blast and impact loads has yet to be studied in detail. This article presents the results from a numerical study investigating the efficacy of a newly proposed profiled-plate arched steel-concrete-steel structure under the loading from an extremely near-field high explosive detonation. It is observed that as arch thickness (concrete infill depth) increases, a greater proportion of energy is absorbed through concrete crushing and a larger concrete mass is mobilised. It is shown that a 240 mm arch thickness is adequate to resist the blast load from a 5.76 kg TNT charge, therefore proving the suitability of the proposed protective structure.

ESTIMATION OF STABILITY OF LATERAL ROCKS IN A COAL MASSIF WITH INTRODUCE DEFORMATION CHARACTERISTICS OF PROTECTIVE CONSTRUCTIONS

2021 ◽  
pp. 64-74
Author(s):  
Leonid Bachurin ◽  
◽  
Ihor Iordanov ◽  
Olha Kohtieva ◽  
Vitaliy Dovgal ◽  
...  
Keyword(s):  
Uniaxial Compression ◽  
Deformation Modulus ◽  
Bending Stiffness ◽  
Practical Significance ◽  
Relative Deformation ◽  
Deformation Characteristics ◽  
Protective Structure ◽  
The Stability ◽  
Protective Structures ◽  
Supporting Structures

Purpose. Evaluate the stability of lateral rocks in the coal massif containing the workings, with introduce count the deformation characteristics of security structures. Methods. To achieve this goal, laboratory studies of the deformation characteristics of security structures located between the simulated roof and the sole of the coal seam, which were subjected to uniaxial compression. Results. It is proved that the deformation characteristics of protective structures affect the stability of lateral rocks in the coal massif containing the workings. The nature of the deformation of security structures under the action of external forces is determined by their rigidity. All other things being equal, when the roof and sole rocks have a constant bending stiffness, their stability depends on the rigidity of the supporting structures and the direction of the load applied in the tangential (wooden cogs, rolling cogs) or radial (riser bushes) direction. For the simulated security structures with an increase in the compressive load, a simultaneous linear increase in their stiffness and deformation modulus is recorded. Moreover, for wooden pillars, when the load is applied across the fibers, the clamped struts of wooden structures are compacted, as a result of which the convergence of the lateral rocks is limited. There is no such pattern for rigid structures in the form of bushes made of wooden risers. After the loss of stability of the protective structure, the modulus of deformation decreases, which is accompanied by an increase in the convergence of the side rocks to the complete destruction of the structure. It is recommended to abandon the rigid and at the same time fragile protective structures designed to support the side rocks. Scientific novelty. The stability of the roof in the carbonaceous massif containing the workings is estimated by the maximum relative deformation of the supporting structures as a result of uniaxial compression using a coefficient characterizing the ratio of the rigidity of the working protective structure and bending stiffness of the side rocks. Practical significance. To ensure the stability of the side rocks in the coal massif and the operational condition of the workings adjacent to the clearing face at the extraction site of the coal mine, it is necessary to focus on the use of flexible structures.

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