ISSN 2343–7707 ; ISSN-L 1453-7303

Here below we post a list of
Papers already accepted for publication in Issue 1/2018 of HIDRAULICA.
The list displays paper title, author(s) and affiliation,
and also paper abstract.
Full-text paper will be available online only after publication.

  • Analysis of Temperature Resistance of Pressurized Cylindrical Fuel Tanks
    Assoc. Prof. PhD. Eng. Mihai ŢĂLU1, Assoc. Prof. PhD. Eng. Ștefan ŢĂLU2
    1University of Craiova, Romania
    2Technical University of Cluj-Napoca, Romania

    In this study, an approach based on Finite Element Modeling (FEM) was applied to analyze the performances of three different pressurized cylindrical fuel tanks with the same lateral cover, but with various head covers geometries. A specific mechanical and thermal model based on FEM was developed. A particular analysis of temperature resistance was carried out, to define specific key performance indicators and to determine the advantageous form of tank with the minimum stress state and linear deformation.

  • Using the Pressure Intensifiers in Hydraulic Units of Heavy Duty Machine Tools
    Prof. PhD Eng. Dan PRODAN1, Prof. PhD Eng. Anca BUCUREȘTEANU1
    1University POLITEHNICA of Bucharest, Romania

    This paper presents some applications of the pressure intensifiers used in the hydraulic units of the clamping/unclamping systems and unloading systems for the guideways of HBM and GANTRY type heavy duty machine tools. The paper makes a comparison between the systems with and without pressure intensifiers. There are presented mathematical models for the pressure intensifiers and the results obtained after a simulation using specialized programs.

  • Fault Tree Analysis Used in Offshore Industry
    Prof. Dr.Eng. Mariana PANAITESCU1,
    Prof. Dr.Eng. Fanel-Viorel PANAITESCU 1,
    Assist. Dr. Eng. Ionut VOICU1,
    PhD. Student Laurentiu-George DUMITRESCU2
    1Constanta Maritime University, Romania
    2Constanta OIL TERMINAL, Romania

    Fault Tree Analysis is one of the engineering tools that provide a systematic and descriptive approach to the identification of systems under risk. Probabilistic Risk Assessment (PRA) is a method to determine the reliability of a system based on the probability of component(s) and/or system(s) failure. Fault Tree Analysis (FTA), which is a part of PRA, provides a method for determining how failures can occur both quantitatively and qualitatively. In this paper we present the FTA for offshore facility: safety flow chart of offshore production facility, fault tree diagrams for different levels (upper level, intermediate state, overpressure, underpressure, excess temperature, ignition, excess fuel). Also, in this paper is presented FTA for subsea control systems. In conclusions, reliability analysis of the surface facilities shows that mechanical components, pumps and compressors, have higher failure rates compared to other mechanical components.

  • Design and Optimization of Pressurized Toroidal LPG Fuel Tanks with Variable Section
    Assoc. Prof. PhD. Eng. Mihai ŢĂLU1, Assoc. Prof. PhD. Eng. Ștefan ŢĂLU2
    1University of Craiova, Romania
    2Technical University of Cluj-Napoca, Romania

    This study addresses the design and optimization of the pressurized toroidal LPG fuel tanks with variable section used in automotive industry based on the finite element analysis (FEA) approaches, to model both thermal and mechanical processing conditions. To define specific key performance indicators and to determine the optimal form of toroidal LPG fuel tank with the minimum stress state and linear deformation was applied a mathematical and mechanical foundation for the design and optimization. Computer aided investigations are carried out using 3D models done in the AutoCAD Autodesk 2017 software, which were imported to SolidWorks 2017 software for analysis and can offer an important reference for the design of toroidal LPG fuel tanks.

  • Statistical Analysis of the Pollution of a Hydraulic Oil Based on the Evolution of the Filter Clogging on the Pressure Pipe
    Pr. Azzedine BOUZAOUIT1, PhD. Eng. Mounir GAHGAH1
    1Université 20 Aout 1955 de Skikda, Algeria

    We present in this paper the results of an experimental study conducted on the analysis of the influence of clogging of a hydraulic filter, installed on the discharge pipe of a variable displacement pump, the operating pressure is 210 bar. The pump is used to supply hydraulic power to a finisher in the rolling mill at the iron and steel complex in Algeria. In this context, we tested the filter retention efficiency, whose mesh size of the filter element is 15 μm. The influence of the service time and consequently the number of pollutant particles retained per filter on the singular pressure loss ΔP of the filter were characterized. A statistical analysis conducted on the representative sample of ΔP values, followed by adjustment tests has been made. The statistical analysis carried out clearly shows that the evolution of the local pressure losses at the level of the filter follows a Beta law.
    Knowing such a distribution law of a variable is an advantage that will help to establish a predictive maintenance program, with the aim of acting in time, and this to remedy the failures, whose oil pollution is considered the main cause.

  • Improving Roughness Using Toroidal Milling for Complex Surface Processing
    PhD. Student Eng. Andrei OȘAN1
    1Technical University of Cluj-Napoca – North University Center of Baia Mare, Romania

    The paper aims to study the processing of complex and convex surfaces using a cutting tool in a milling radius called toroidal end milling in terms of roughness. Roughness presents important influences on machine parts and not only be in operation contact surfaces are either fixed or mobile. This paper includes a series of 11 experiments in which different regimes are tested with the main purpose of finding the optimum regimen for the work to be subjected to the toroidal milling using the roughness value Ra and Rt as the comparison criterion. For roughness determination, the TR200 is used as a measuring tool and data is loaded into a software called Time Surf. At the end of this paper a point of view will be determined regarding the roughness obtained with the toroidal milling.

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