Numerická simulace vlivu obsahu vzduchu v oleji na dynamiku systému

The objective of the paper is a numerical simulation of the influence air content in the oil and bulk modulus of oil on the dynamics of the system. The simulation is realized with Matlab SimHydraulics and verified by experiment. Input values for the mathematical model are detected experimentally.Předmětem příspěvku je numerická simulace vlivu obsahu vzduchu V oleji a modulu pružnosti oleje na dynamiku systému. Simulace je provedena V programu Matlab SimHydraulics a ověřena experimentem. Vstupní hodnoty pro matematický model jsou zjištěny experimentálně

The Optimisation of the Proportional Control System for Removing Moulds

Import 29/09/2010Tato diplomová práce se zabývá dynamikou hydraulického obvodu zdvih odebírání zatěžkávacích desek. Je zde uvedena činnost formovací linky a popis hydraulického obvodu. Dále je popsáno měřící zařízení a vlastní měření. Pomocí výsledku měření je sestaven matematický model v programu Matlab – Simhydraulics. Na závěr je navržena optimalizace hydraulického obvodu.This thesis deals with the dynamics of the hydraulic circuit stroke removing load plates. The actions of forming line a description of the hydraulic circuit are given here. It is described measuring device and the measurement itself. Using the measurement results is constructed a mathematical model in Matlab - Simhydraulics. Finally the optimization of hydraulic circuit is proposed.Prezenční338 - Katedra hydromechaniky a hydraulických zařízenívýborn

Energy and Dynamic Properties of Hydraulic Systems

The aim of the paper is to evaluate hydraulic systems in terms of energy and dynamic properties. There are flow and pressure losses that have influence on total efficiency of hydraulic systems. The systems are compared from lower effective to energy saving. There are described advantages and disadvantages of the systems in this work. Dynamic properties of the investigated energy saving Load-Sensing system were determined based on the system eigenfrequency. Dynamic behaviour of the system was performed by three different methods that were subsequently compared

Režim proudění v axiálním hydrostatickém ložisku s centrální drážkou

This paper deals with the fluid flow in the axial hydrostatic bearing with the central groove. The type of flow in the narrow gap is defined by the dimensionless Reynolds number. The influence of the groove shape on the pressure field in axial hydrostatic bearing is investigated. Numerical modelling and evaluation of the flow field parameters is done using Ansys Fluent software.Režim proudění v axiálním hydrostatickém ložisku s centrální drážko

Experimentální měření dynamického modulu pružnosti oleje

The experimental measurement and evaluation of the dynamic bulk modulus of hydraulic oil is the object of the paper. We take into account the dynamic bulk modulus during the fast processes taking place in the order of several tens milliseconds. The measurement is done using experimental equipment to measure pressure difference depending on time.Předmětem příspěvku je experimentální měření a vyhodnocení dynamického modulu pružnosti hydraulického oleje. Dynamický modul pružnosti uvažujeme při rychlých dějích probíhajících v řádech několika desítek ms. Měření je provedeno pomocí experimentálním zařízení, na kterém měříme tlakovou diferenci v závislosti na čase

Mathematical simulation and measurement of expansion of hydraulic hose with oil

Rad se bavi mjerenjem i matematičkom simulacijom širenja hidrauličnog crijeva, uključujući učinak modula stlačivosti ulja. Youngov modul elastičnosti hidrauličnog crijeva eksperimentalno je određen metodom ekspanzije i metodom kompresije. Modul elastičnosti hidrauličnog crijeva dobiven metodom ekspanzije određen je mjerenjem povećanja volumena ulja, sabijenog u ispitivanom crijevu nakon ekspanzije. Youngov modul elastičnosti hidrauličnog crijeva, dobiven metodom kompresije, određen je mjerenjem protoka ulja i porasta tlaka u hidrauličnom crijevu u odnosu na vrijeme. Modul stlačivosti ulja eksperimentalno je određen metodom ekspanzije i metodom kompresije ulja u čeličnoj cijevi. Hidraulični krug za simulaciju širenja ulja u crijevu i čeličnoj cijevi stvoren je primjenom softvera Matlab SimHydraulics. Povećanje volumena ulja nakon širenja u hidrauličnom crijevu i čeličnoj cijevi numerički je simulirano. Nadalje, vremenske ovisnosti smanjenja tlaka tijekom širenja ulja u hidrauličnom crijevu i čeličnoj cijevi numerički su simulirane. Rezultati matematičkih simulacija uspoređeni su s eksperimentalnim tijekom primjene Youngova modula elastičnosti crijeva i modula stlačivosti ulja određenih metodom ekspanzije i metodom kompresije.The paper deals with measurement and mathematical simulation of expansion of a hydraulic hose including the effect of oil bulk modulus. Young’s modulus of elasticity of the hydraulic hose is experimentally determined by expansion method and by compression method. The modulus of elasticity of the hydraulic hose obtained from the expansion method is determined by measurement of an oil volumetric gain, which is compressed inside the investigated hose after the oil expansion. The Young’s modulus of elasticity of the hydraulic hose obtained from the compression method is determined by measurement of oil flow and pressure increase vs. time in the hydraulic hose. The oil bulk modulus is experimentally determined by means of the expansion method and the method of oil compression in a steel pipe. A hydraulic circuit for simulation of the oil expansion from the hose and the steel pipe was created using Matlab SimHydraulics software. The oil volume increase after the expansion from the hydraulic hose and the steel pipe was numerically simulated. Furthermore, time dependencies of pressure decreases during the oil expansion from the hydraulic hose and the steel pipe were numerically simulated. Results of the mathematical simulations were compared with the experiment while using the Young’s modulus of elasticity of the hose and the oil bulk modulus that were determined by the expansion method and by the compression method

Evaluation of bulk modulus of oil system with hydraulic line

The aim of the paper is to experimentally measure and ealuate bulk modulus of oil/steel pipe system and oil/hose system. The measurement was performed using experimental device on the basis of a measured pressure difference depending on time. Bulk modulus is evaluated from pressure change with known flow and volume of line. Pressure rise is caused by valve closure at the line end. Furthermore, a mathematical model of the experimental device is created using Matlab SimHydraulics software. Time dependencies of pressure for the oil/steel pipe system and the oil/hose system are simulated on this mathematical model. The simulations are verified by experiment. © Owned by the authors, published by EDP Sciences, 2013

Simulation of dynamics of system with hydraulic lines and linear hydraulic motor with mass load

This paper deals with the numerical simulation of dynamic properties of the system consisting of hydraulic lines and linear hydraulic motor with a mass load. The mathematical model is created using Matlab SimHydraulics software. Oil bulk modulus, elasticity and volumes of pipes and hoses play a significant role in this case. Mathematical models are verified on experimental equipment. Pressure and position responses during sudden stop of a moving cylinder are measured on this equipment. © Owned by the authors, published by EDP Sciences, 2013

Experimental analysis of fluidic muscles

Fluidic muscles have been the subject of research since the 1930s to the present day. McKibben's muscle is one of the most common ones. This type is the basis for fluidic muscles already being used commercially. The power-to-weight ratio is one of their main advantages. The disadvantage is difficult handling. The article describes experimental verification of static characteristics of fluidic muscles. During muscle contraction, a tensile force is developed which changes as the length of the muscle changes. This dependence is experimentally verified. A measuring equipment for testing fluidic muscles of various lengths and diameters is designed and assembled. The device consists of a pneumatic circuit, where the output drive is a loaded fluidic muscle. The load of muscle is generated by a hydraulic cylinder. The results will be further applicable to fluidic muscle simulations.Web of Science20225763575

Study of factors influencing vibro- isolating properties of materials for passive elastic bearing of machines

Machinery or instruments are subjected to external forces from a base in many cases. It can have a negative influence on manufacturing accuracy, tightness, wear of machine parts, work safety etc. Therefore, it is necessary to perform suitable passive elastic bearings of machinery to eliminate external vibration from the base. An application of suitable vibro-isolating materials is one way of the vibration elimination. The aim of the paper is to study vibration damping properties of different materials by means of a non-destructive method of forced mechanical oscillations. Different factors influencing transfer damping of mechanical vibration were investigated in this work, e.g., material type and its thickness, excitation frequency of mechanical oscillations, size of mass load and effect of material composition. These factors were subsequently evaluated. Finally, suitable recommendations for passive damping of mechanical vibration were described.Web of Science20225830582