2D Analytical Model for Evaluation of the Forces in the Three-point Hitch Mechanism

ABSTRACT Large investments, research efforts and time have been allocated till nowadays for innovation of agricultural tractors and machinery, with the primary aim to increase their productivity, reliability, durability, as well as the environmentally friendly, safe and easy usage. Following this general trend, present work is focused on theoretical analysis of the forces acting on the links of the three-point hitch mechanism. The simulation algorithm and computer code have been developed for calculation of draft forces by two methods (following ASAE D497.4 standard and Goryachkin approach), depending on the three point linkage geometry and mouldboard technical characteristics, and calculation of forces acting on lower and upper links of three-point hitch mechanism. Calculated forces values, based on ASAE draft, exposes smaller differences compared to experimental values, while for the Goryachkin method improvement is possible by entering experimental values for soil resistance coefficient k and coefficient of dynamic resistance ε, as we did in this study performing measurements on the aggregate comprehending tractor IMT 539 (IMT Belgrade, Serbia) and two furrow moldboard plough PTO 2.25 (OLT, Osijek, Croatia)

2D Analytical Model for Evaluation of the Forces in the Three-point Hitch Mechanism

Large investments, research efforts and time have been allocated till nowadays for innovation of agricultural tractors and machinery, with the primary aim to increase their productivity, reliability, durability, as well as the environmentally friendly, safe and easy usage. Following this general trend, present work is focused on theoretical analysis of the forces acting on the links of the three-point hitch mechanism. The simulation algorithm and computer code have been developed for calculation of draft forces by two methods (following ASAE D497.4 standard and Goryachkin approach), depending on the three point linkage geometry and mouldboard technical characteristics, and calculation of forces acting on lower and upper links of three-point hitch mechanism. Calculated forces values, based on ASAE draft, exposes smaller differences compared to experimental values, while for the Goryachkin method improvement is possible by entering experimental values for soil resistance coefficient k and coefficient of dynamic resistance s, as we did in this study performing measurements on the aggregate comprehending tractor IMT 539 (IMT Belgrade, Serbia) and two furrow moldboard plough PTO 2.25 (OLT, Osijek, Croatia)

Experimental measurements of the stresses in the lower link of the three-point hitch mechanism

Agricultural machines and their implements are subjected to dynamic loads during farm operations. Depending on the type of operation (e.g. lifting or plowing), lower links of the three-point hitch mechanism are exposed to stresses caused by combination of bending moments and axial forces. In this paper we analysed influence of the soil resistance during plowing on the lower link and the possibility of its failure. The stresses were measured using strain gauges at locations with uniform stress distribution in order to enable more reliable comparison with finite element analysis (FEA). Recorded stresses vs. time were used for identifying mean stresses and amplitudes for different plowing depth and different tractor speeds. Due to the geometry of the lower links and their joints in the three-point hitch mechanism, during plowing and transferring soil resistance, links are loaded not only by axial forces but also by bending moment in the horizontal plane. Under some assumptions, FEA provided us to make relations between the measured stresses and the loads that caused them. Measured stresses show that links have significant safety margin relative to tractor installed power and soil resistance, which enables the possibility of their design optimization. Obtained results may also serve for further analyses of fatigue life prediction, measurement of the draft forces etc

Interdisciplinary crossover for rapid advancements - collaboration between medical and engineering scientists with the focus on Serbia

Over the past decades, development of engineering sciences has vastly contributed to advancements in medicine by production of numerous devices for diagnostics and treatment. In the middle of the 20th century, a new scientific field, biomedical engineering (BE), was established, which has developed into an extremely complex scientific discipline requiring a distinctive educational profile. Various study programs in BE have been established at universities around the world but also at several universities in Serbia. Also, intensive research in this field is performed at several scientific institutions in Serbia. In the present paper, short summaries of the research results of several groups of engineers and medical doctors are presented as an illustration of the wide field of BE research and possibilities of its application in diagnosis and therapy of various diseases

Interdisciplinary crossover for rapid advancements: Collaboration between medical and engineering scientists with the focus on Serbia

Napretku medicine su poslednjih decenija veoma mnogo doprineli pronalasci iz različitih oblasti inženjerstva. Polovinom dvadesetog veka uspostavlja se nova naučna oblast, biomedicinsko inženjerstvo (BI), koje se do sada razvilo u veoma složenu naučnu disciplinu koja je zahtevala i poseban obrazovni profil. Na univerzitetima širom sveta, kao i na nekoliko univerziteta u Srbiji ustanovljeni su različiti programi iz oblasti biomedicinskog inženjerstva. Takođe, u nekoliko naučnih institucija u Srbiji sprovode se intenzivna istraživanja u ovoj oblasti. U ovom radu prikazani su rezultati istraživanja nekoliko grupa naučnika iz oblasti inženjerstva i medicine sa ciljem da se ilustruje koliko je široko polje istraživanja u oblasti biomedicinskog inženjerstva i kakve su mogućnosti njihove primene u dijagnostici i lečenju različitih bolesti.Over the past decades, development of engineering sciences has vastly contributed to advancements in medicine by production of numerous devices for diagnostics and treatment. In the middle of the 20th century, a new scientific field, biomedical engineering (BE), was established, which has developed into an extremely complex scientific discipline requiring a distinctive educational profile. Various study programs in BE have been established at universities around the world but also at several universities in Serbia. Also, intensive research in this field is performed at several scientific institutions in Serbia. In the present paper, short summaries of the research results of several groups of engineers and medical doctors are presented as an illustration of the wide field of BE research and possibilities of its application in diagnosis and therapy of various diseases

The Effect of Water Concentration in Ethyl Alcohol on the Environmentally Assisted Embrittlement of Austempered Ductile Irons

Austempered ductile iron (ADI) is an advanced cast iron material that has a broad field of application and, among others, it is used in contact and for conveyance of fluids. However, it is noticed that in contact with some fluids, especially water, ADI material becomes brittle. The most significant decrease is established for the elongation. However, the influence of water and the cause of this phenomenon is still not fully understood. For that reason, in this paper, the influence of different water concentrations in ethyl alcohol on the mechanical properties of ADI materials was studied. The test was performed on two different types of ADI materials in 0.2, 4, 10, and 100 vol.% water concentration environments, and in dry condition. It was found that even the smallest concentration of water (0.2 vol.%) causes formation of the embrittled zone at fracture surface. However, not all mechanical properties were affected equally and not all water concentrations have been critical. The highest deterioration was established in the elongation, followed by the ultimate tensile strength, while the proof strength was affected least

The Catalytic Effect of Vanadium on Sorption Properties of MgH2-Based Nanocomposites Obtained Using Low Milling Time

The effects of catalysis using vanadium as an additive (2 and 5 wt.%) in a high-energy ball mill on composite desorption properties were examined. The influence of microstructure on the dehydration temperature and hydrogen desorption kinetics was monitored. Morphological and microstructural studies of the synthesized sample were performed by X-ray diffraction (XRD), laser particle size distribution (PSD), and scanning electron microscopy (SEM) methods, while differential scanning calorimetry (DSC) determined thermal properties. To further access amorph species in the milling blend, the absorption spectra were obtained by FTIR-ATR analysis (Fourier transform infrared spectroscopy attenuated total reflection). The results show lower apparent activation energy (Eapp) and H2 desorption temperature are obtained for milling bland with 5 wt.% added vanadium. The best explanation of hydrogen desorption reaction shows the Avrami-Erofeev model for parameter n = 4. Since the obtained value of apparent activation energy is close to the Mg-H bond-breaking energy, one can conclude that breaking this bond would be the rate-limiting step of the process

2D Analytical Model for Evaluation of the Forces in the Three-point Hitch Mechanism

Large investments, research efforts and time have been allocated till nowadays for innovation of agricultural tractors and machinery, with the primary aim to increase their productivity, reliability, durability, as well as the environmentally friendly, safe and easy usage. Following this general trend, present work is focused on theoretical analysis of the forces acting on the links of the three-point hitch mechanism. The simulation algorithm and computer code have been developed for calculation of draft forces by two methods (following ASAE D497.4 standard and Goryachkin approach), depending on the three point linkage geometry and mouldboard technical characteristics, and calculation of forces acting on lower and upper links of three-point hitch mechanism. Calculated forces values, based on ASAE draft, exposes smaller differences compared to experimental values, while for the Goryachkin method improvement is possible by entering experimental values for soil resistance coefficient k and coefficient of dynamic resistance s, as we did in this study performing measurements on the aggregate comprehending tractor IMT 539 (IMT Belgrade, Serbia) and two furrow moldboard plough PTO 2.25 (OLT, Osijek, Croatia)

Coupled axial-bending vibration of axially functionally graded Timoshenko cantilever beams of non-uniform cross-section with an attached rigid body

The coupled axial-bending vibration of an axially functionally graded Timoshenko cantilever beam of non-uniform cross-section is considered. The coupling phenomenon appears due to the presence of the transverse eccentricity of the mass centre of a rigid body attached to the beam free end. To study the coupled phenomenon, an approach based on the symbolic-numeric method of initial parameters is proposed. The influence of the transverse eccentricity on the cantilever beam natural frequencies and mode shapes is examined. The approach has the potential to be also applied to vibration problems of the systems composed of rigid bodies interconnected by non-uniform non-homogeneous beams

Coupled axial-bending vibration of axially functionally graded Timoshenko cantilever beams of non-uniform cross-section with an attached rigid body

The coupled axial-bending vibration of an axially functionally graded Timoshenko cantilever beam of non-uniform cross-section is considered. The coupling phenomenon appears due to the presence of the transverse eccentricity of the mass centre of a rigid body attached to the beam free end. To study the coupled phenomenon, an approach based on the symbolic-numeric method of initial parameters is proposed. The influence of the transverse eccentricity on the cantilever beam natural frequencies and mode shapes is examined. The approach has the potential to be also applied to vibration problems of the systems composed of rigid bodies interconnected by non-uniform non-homogeneous beams