bluuebunny/crossref_metadata_2025 huggingface dataset:
The Graph of Operations Planning Sequence of a Production Order for Scheduling with Mixed Planning Strategies and Alternatives
Authors: Kalinowski Krzysztof , Grabowik Cezary , Ćwikła Grzegorz , Janik Witold
Published: November 2015

The paper presents the most important issues related to the scheduling of production orders in real manufacturing systems. In the elaborated method an and/or type graph of operations planning sequence of a production order is proposed for modelling the production system load. In a single structure the graph takes into account alternative routes of a production order realisation and the precedence constraints in presence of complex, hierarchical structures of processes. Two modelling ways of that process using the "operation on the edge" or "operation on the node" notation are also presented. In the developed method scheduling strategies, which have a major impact on the order of placing operations in the schedule and handling of production lots are also considered. By a state space graph representation of scheduling problem, using graph theory, it can be possible to analyze the structure and complexity of both the modelling problem and the graph search techniques.
Results of an Experimental Research Concerning the Evaluation of Machinability by Drilling under Constant Feed Force
Authors: Manole Vasile , Slătineanu Laurenţiu , Olaru Sergiu Constantin , Beşliu Irina , Iurea Pavel , Gonçalves-Coelho António
Published: November 2015

The knowledge about machinability indices for distinct machining processes allows finding the most appropriate values of the relevant factors for definite machining operations. Several criteria can be used to characterize machinability, such as the tool wear, the magnitude of the cutting forces, the roughness of the machined surfaces, or the shape of the chips that are formed during the machining process. One of the methods for studying the machinability is based on the analysis of drilling operations that are made under constant feed force. A drill press is probably the most readily available device to implement an experimental setup for drilling machinability tests. In normal operation, however, the chip accumulation at the dead end of the machined hole has a detrimental impact on the results of machinability tests, so that an improved setup was designed. A two-level, full factorial experiment with three independent factors (the drilling tool diameter, the rotational speed of the spindle and the feed force) has proven the suitability of the new experimental setup. Using it, we could find a power-type empirical model that explains the impact of the input factors in the depth of a hole that is machined in a pre-defined time interval.
Modeling and Analysis of Processing Flow in a Flexible Manufacturing System Using Synchronized Petri Nets
Authors: Culea George , Cristea Ion , Puiu Petru Gabriel
Published: November 2015

This paper presents the modeling and analysis of processing flow in a flexible manufacturing system. We considered the case of a flexible manufacturing system consists of three machining centers MC1, MC2, MC3 and two material handling system which assure parts loading and discharge, respectively. The parts incorporate an Arduino system with XBee wireless module. These embedded systems connected through a network wireless can allow easy identification of parts, easy identification of their position, of performed operations, ensuring optimal guiding pallets. In order to be able to model all the requirements imposed were used synchronized Petri nets with inhibiting arcs and with threshold test. Developed model aims to optimize parts flow, under the conditions in which MC1 and MC3 have a buffer for 3 parts and MC2 have a buffer for 4 parts, respectively. By implementing a wireless ZigBee network for the control of parts movement it provides a modern solution by which central control system will know the position of every intelligent parts and will be able change the flow of processing according to unpredictable circumstances. FMS modeling is useful both in the design to implementation of the program which controls material movements and machine flow, as well as part of exploitation, providing a clear view of FMS functioning. By that model verified through simulation it was able to optimize the flow of parts, so as that there are no blockage in the flow of manufacturing. The study allows software implementation of control systems for the FMS.
Solution Improvement for Existing Concrete Formwork Equipment by Using Creative Methods and PLM Concept
Authors: Diaconu Raluca , Brindasu Dan Paul
Published: November 2015

The construction domain is an important part of everybody's life consisting of one of the major needs in the Maslow's pyramid: safety. The now-a-days complex, spectacular designed constructions imply new technologies with high efficiency and precise equipment.The paper analyses the optimum solution for the desired product by using the PLM (Product Lifecycle Management) approach, starting by using previous primary and secondary information and pursuing with the solution determination. The conceptual solutions are obtained through creative methods from the specifications-the functions-of the improved product.Hence, having the proper solution that responds to the client's needs we can make the next step in designing the model of the improved formwork equipment.
Integrating Advanced Engineering Solutions for Enhancing Product Development Sustainability
Authors: Merticaru Vasile , Ripanu Marius Ionuţ , Mihalache Marius Andrei , Cucos Marius Marian
Published: November 2015

The research approach presented in the paper targets the integration of some advanced engineering principles, methods and instruments for enhancing the effectiveness and efficiency of Product Design activities. In order to reduce the product development resources consumption, to improve the product functionality, reliability and flexibility and to reduce the product lifecycle environmental impact, all of these being considered as instruments for improving Product Sustainability, some conceptual models for integrating advanced Product Design theories and principles such as Holistic Design and Axiomatic Design, together with the use of some advanced CAD/CAE tools are discussed in the paper. As case study, the paper submits to discussion the problem of enhancing the design activities for the development of a technical solution of a device adaptable on an electrical discharge machine-tool and being able to generate cycloid profiles based on a double-planetary mechanism driving. The research approach on integrating the principles of axiomatic design within activities of the design model structuring, the decomposition rules have been mainly targeted to be applied. The presented case study refers also to the performance of using advanced capabilities of Solid Edge as CAD solution which provides dynamic generation of the product model structure and to those of its embedded module entitled Engineering Reference, as valuable CAE instrument. Some adequate conclusions are finally presented and some directions of further research development are identified, such as integrating also an economic efficiency analysis and a Life Cycle Impact Assessment approach as Concurrent Engineering activities, to enhance the new product development sustainability.
The Effect of EP/AW Additives in Emulsion Mist on the Geometric Structure of the Machined Surface during Carbon Steel C45 Turning
Authors: Maruda Radoslaw W. , Legutko Stanislaw , Krolczyk Grzegorz M. , Adamczuk Krzysztof
Published: November 2015

One of the problems of metal alloys machining in view of the environment protection is the use of cooling lubricants. From this viewpoint, it is preferred to limit the use or completely eliminate them from the cutting process. The solution may be the method of Minimum Quantity Cooling Lubrication (MQCL). The results of the machined surface roughness measurements of carbon steel C45 after turning when: machining for dry cutting, using cooling method MQCL and using MQCL with additives EP/AW have been presented. One used two anti-wear and antiseizure additives based on phosphate ester. Experimental studies have been planned according to the Parameter Space Investigation method. The application of EP/AW additives entered in the emulsion determined the ranges of cutting parameters at which lower values of selected roughness parameters were obtained in comparison with dry cutting. The lowest values of Ra and Rz parameter for variables of cutting parameters and creating emulsion mist within their whole range were obtained for cooling with pure emulsion mist based on boric acid and amine compound.
Maintenance Strategy Optimization for Computer Numerical Control Machine Tools
Authors: Ungureanu Ana Lacramioara , Stan Gheorghe , Butunoi Paul Alin
Published: November 2015

In this paper are proposed two new approaches to maintenance strategies for Computer Numerical Control (CNC) machine tools. The analysis is done for different families of CNC machine tools from S.C. Elmet Bacau, a company specialized in aviation. In maintenance actions applied to CNC machine tools is very important to know the evolution of defects and critical state of electrical and mechanical components. The results of this analysis concludes that maintenance actions can be judged by the developing time period diagram, between failure appearance and interruptions in operation. It is also analyzed the financial impact, revealed from known maintenance strategies adopted on CNC machine tools, resulting in a positive approach of condition based maintenance.
Security Information and Risk Management Assessment
Authors: Anton Nicolae , Nedelcu Anișor
Published: November 2015

This work approaches the assessment of the security and information risks in order to find the optimal values of the risks by applying and comparing different methods to measure and assess the security risks. By describing structural characteristics of standards and methods implemented in the information security management system (ISMS), this paper underlines the necessity, means and effectiveness of information security modeling. The conclusions of this paper highlights the importance of standards and methods of risk management assessment.
Value Analysis and TRIZ - A Methodology for Innovative Economics and Technical Solutions
Authors: Ionescu Gabriela Mariana
Published: November 2015

This paper presents a new methodology entitled AVTRIZ by its author, which allows technical, economic and managerial innovation based on the forecasting approach, while operating inside various systems. As the foundation of the new methodology, a classical method was chosen, well-known and widely applied that is the Method of Value Analysis and Engineering, a domain where the author has previous concerns. Starting from the fact that this method is deficient in terms of generating improvement solutions, the author searched and identified a method of current interest and global opportunity that is the TRIZ method [1], which is a method of wide debate, very controversial in terms of its adaptability from the technical to the business and management domains. On the other hand, TRIZ is deficient in terms of checking the solutions, a fact which can be successfully compensated by the Value Analysis Engineering method. Based on the above-mentioned approach, the research activities carried out by the author have brought in a new methodology, which is structured on 3 steps, 8 stages and 30 phases, based on the method of Value Analysis and Engineering, while also applying the TRIZ method.
Influence of Inserts Number on Surface Quality in Milling
Authors: Tâmpu Nicolae Cătălin , Brabie Gheorghe , Chiriţă Bogdan Alexandru
Published: November 2015

Surface quality is very important for the finished components. One of the most important parameters that define surface quality in milling is surface roughness . Depending on the cutting conditions chosen, different milling strategies can be applied. One of the ways to reduce the production costs is to optimize the number of inserts that are involved in machining. The aim of present paper is to investigate the behavior of surface roughness under the influence of the number of inserts used in an operation.
Taguchi Design of Experiment in the Optimization of Tool Life in Turning Process of Duplex Stainless Steel DSS
Authors: Krolczyk Grzegorz , Metelski Andrzej , Maruda Radoslaw , Legutko Stanislaw
Published: November 2015

The paper presents the contribution in methodology of production processes of difficulty to cut materials particularly in optimization method of Duplex Stainless Steels (DSS). In this work, Design of Experiment (DOE) is used to examine turning experimental data. The DOE, based on the Taguchi method with orthogonal array L9 and signal-to-noise ratio are used. The optimal values of the technological cutting parameters with coated carbide tool point are searched. ANOVA analysis was performed to determine the signification of machining parameters. The significance of various cutting parameters on tool life have been proven. The results at optimum cutting condition are predicted using estimated values. The study was performed within a production facility during the machining of electric motor parts and deep-well pumps.
Aspects of Machining Parameter Effect on Cut Quality in Abrasive Water Jet Cutting
Authors: Janković Predrag , Radovanović Miroslav , Dodun Oana , Madić Miloš , Petković Dušan
Published: November 2015

Abrasive water jet machining is frequently used in industry. It is one of the most versatile processes in the world. The basic advantages of abrasive water jet machining is that no heat affected zones or mechanical stresses are left on an abrasive water jet cut surface, high flexibility and small cutting forces. Although this cutting technology includes many advantages, there are some drawbacks. For instance, abrasive water jet cutting can produce tapered edges on the kerf of workpiece being cut. This can limit the potential applications of abrasive water jet cutting, if further machining of the edges is needed to achieve the engineering tolerance required for the part. The machining parameters have a great influence on these phenomena. The aim of this paper is to investigate the cut quality of EN AW-6060 aluminium alloy sheets under abrasive water jets. The experimental results indicate that the feed rate (nozzle traverse speed) of the jet is a significant parameter on the surface morphology.
Analysis of Postimpact Plastic Indentation Profiles
Authors: Alaci Stelian , Ciornei Florina Carmen , Filote Constantin , Românu Ionuţ Cristian
Published: November 2015

The paper presents the analysis of plastic indentations resulting after the impact between a steel ball and a disc made of mild steel, rotating about a vertical axis. The imprints are analysed using a laser scanner, the profiles of the mark, in normal and tangent section about the impact point radius, being relevant. It is shown that the use of parabolas is sufficient to approximate the profiles of the imprint. The profiles from the two sections are interpolated and then brought for comparison into the same coordinate system. Finally, the curvature radii of the profiles from the two sections are found and the remark that increasing the angular speed of the disc presents opposite effects to the curvature radius in the two sections.
The Influence of the Blank Holder Force during Forming Process of a U-Shaped Part Made from AZ31 Magnesium Alloy
Authors: Albut Aurelian , Zichil Valentin , Judele Adrian
Published: November 2015

In case of sheet metal forming the main dimensional errors are caused by the springback phenomena. The present work deals with numerical simulation related to draw bending and springback of U - shaped part made from magnesium alloy. The current paper is trying to prove out the important role of the blank holder force with respect to the forming process. Though novel approaches relating to the formality of magnesium alloy sheets, the change of springback due to the characteristic of each process should be verified by finite element method. Springback refers to the elastic recovery of deformed parts. Springback occurs because of the elastic relief from the bending moment imparted to the sheet metal during forming. Springback is mainly influenced by the sheet thickness, the punch and die profile radii, initial clearance between punch and die, friction conditions, rolling direction of the materials, blankholder force and by material properties. In this study, the magnesium alloy strips with two types of material having the thickness of 1mm, are used to investigate springback characteristics in U-shape bending. The Dynaform 5.6 software was used to simulate the forming process, in which the blank holder force takes values between 15 and 35 kN. In this study, the springback was analyzed by U-forming at room temperature conditions with different blank holder forces. Springback decreased with the increase of the blank holding force. Excessive holding force cause irregular thinning of the material, especially in the radius area.
A Study on Using Cover Blank in Single Point Incremental Forming Process by Finite Element Analysis
Authors: Abass Khalil Ibrahim
Published: November 2015

The Single Point Incremental Forming Process (SPIF) is a forming technique of sheet material based on layered manufacturing principles. The forming tool is moved along the tool path while the edges of sheet material are clamped. The finished part is manufactured by the CNC machine. SPIF involves extensive plastic deformation and the description of the process is more complicated by highly nonlinear boundary conditions, namely contact and frictional effects have been accomplished. However, due to the complex nature of these models, numerical approaches dominated by the FEA are now in widespread use. The paper presents the data and main results of a study on effect of using cover blank in SPIF through FEA. The considered SPIF has been studied under certain process conditions referring to the test work piece, tool, etc., applying ANSYS 11.0. The results show that the simulation model can predict an ideal profile of processing track, spring back error of SPIF, the behavior of contact tool-work piece, the product accuracy by evaluation its thickness and strain distributions, the contact status and chattering among surface interface tool-work piece.
Investigation of the Rolling Direction Influence on Springback Effect of a U-Shaped Made from AZ31 Magnesium Alloy
Authors: Albut Aurelian
Published: November 2015

Magnesium alloys were being increasingly considered for sheet forming applications because of their low density and high strength. Therefore, the main areas of research focused on the deformation mechanisms, improving ductility, and possible forming applications [1]. Published results on deformability and springback prediction of magnesium alloy stripes are minimal. The rolling direction of the materials with respect to the deformation direction can greatly influence on springback as well as formability. Though novel approaches relating to the formality of magnesium alloy stripes are available, the change of springback due to the characteristic of each process should be verified by finite element method [2]. In this study, the magnesium alloy strips having the thickness of 1mm, are used to investigate springback characteristics in U-shape bending. The Dynaform 5.8 software was used to simulate the forming process, in which the rolling directions of the material vary with respect to the main deformation axis. There are three different cases: RD0o, RD45o and RD90o. The springback phenomenon is simulated using the same software, but a different module. The following aspects stand out from the simulation tests of the influence of rolling direction on springback parameters: the material rolling direction perpendicular to the deformation direction (0o) leads to reduction of springback intensity; the thickness of the material in case of RD0o is reduced in comparison with the one of RD90o. It can be considered that the results generated by the analysis of springback phenomenon using finite element method are sufficiently accurate and can be considered valid.
Effects of Different Types of Grinding Fluids on Grinding Force with a Semi-Empirical Based Model
Authors: Yin Guo Xu , Marinescu Ioan D. , Weismiller Michael
Published: November 2015

In present paper, a semi-empirical grinding force model is developed combined with the achievements of previous researchers by composing effects of normal and tangential grinding forces in two main parts respectively: cutting force and sliding force. Final equations for the total normal and tangential force components is established. This model is used to predict the total normal and tangential force in the surface grinding. These force components were expressed in terms of the grinding process parameters. There are four unknown coefficients in each equation which can be determined by experiment results at specific conditions with the variations of grinding process parameters. An equation for sliding force is established with the effect of specific sliding energy in terms of the experimental parameters. The average contact pressure and friction coefficient are taken into account. Four different water-based grinding fluids were tested for different specific grinding conditions. Low viscosity grinding fluid can have better performance than the high viscosity one due to the higher useful flow in the grinding contact area. The calculated normal and tangential grinding results are compared with the experimental ones. The verifications show that deviations can be affected by the performance of the fluid at heavy grinding conditions due to the sliding friction inside of rolling friction. To have a better agreement with experiment data. Shallow grinding condition is chosen to obtain the modified model.
Researches Regarding Optimizing the Accuracy of CNC Laser Cutting Machines
Authors: Biris Cristina Maria , Girjob Claudia Emilia , Bologa Octavian
Published: November 2015

The experimental researches presented in this paper are aimed to improve the manufacturing accuracy of a contouring machine together with an approach to eliminate the errors which lead to a less precise part after machining.In order to eliminate the errors, the machine's feed drives were tuned leading to a more precise part. In order to validate the proposed approach, the accuracy of the machine was tested before and after the tuning process.
Researches upon Thin Layers Deposition on Cutting Inserts
Authors: Lupescu Octavian , Bădănac Ana , Popa Mădălina , Ulianov Cristian
Published: November 2015

It is known that during the cutting process the tool wears out. This is due to the high temperatures, the relative velocities and shocks between the contact surfaces of the tool-part and the mechanical and thermal stresses which appear on the active surfaces of the tool. The result is loss of cutting and reduced processing quality. This involves taking measures to increase the values of the cutting tools and/or the durability of their cutting inserts. Tool durability can be increased by various coating methods by the depositing in a vacuum of some different materials which achieve the necessary effect. These methods are being researched globally. So far there are several methods of applying these layers. They are classified as: vacuum thermal evaporation, pulverization, ion plating and chemical vapor depositing. In order to increase the durability of the cutting tools, and to increase the wear resistance of the metal carbide insert, the authors propose in this paper the depositing of a titanium thin layer on these cutting inserts by the ionic plating method. This method has produced increased durability of the coated cutting insert and increased resistance to wear, higher than in the uncoated case. The values slightly vary depending on the complexity of the cutting insert profile and the dimensions of the work pieces dimensions being processed.
Kinetics of Titanium Alloy Nitriding by Diode Laser
Authors: Lisiecki Aleksander
Published: November 2015

Based on the wide range study of laser gas nitriding (LGN) of commercially pure titanium and the titanium alloy Ti6Al4V by means of high power direct diode laser (HPDDL), the kinetics of nitrogen absorption by the melt pool and related titanium nitrides growth was analyzed. Also a schematic model of nitrogen absorption by the melt pool was proposed. According to the hypothetical model three cases of nitrogen absorption by the melt pool were be distinguished and discussed. It was found that in a case of HPDDL nitriding of the Ti6Al4V alloy the presence of a thin homogenous layer of TiNx on the top surface of melt pool affects the nitrogen absorption kinetics. The process of nitrogen desorption at the cooling stage of melt pool is inhibited by the layer of TiNx as well as by the phase transformation and titanium nitrides formation.
Mechanism of Titanium Matrix Composite Ti/TiN Formation during Diode Laser Gas Nitriding of Ti6Al4V
Authors: Lisiecki Aleksander
Published: November 2015

Three mechanisms of titanium matrix composite Ti/TiN formation during diode laser nitriding of Ti6Al4V alloy in liquid stage were identified and discussed. When the titanium alloy surface is melted by a laser beam the first mechanism of nucleation and growth of d-TiN was identified in the temperature range of melt pool from 1650 up to 2320 °C, when the nitrogen concentration in the Tia solution reaches at least to the concentration limit in a range 20,5 to 22 at. %. Next different mechanism of nucleation of d-TiN was identified in the temperature range of melt pool from 2320 up to 2950 °C. In turn, the third mechanism of d-TiN formation was identified above the melting point of titanium nitrides, i.e. 2950 °C.
Improvement of Wear Resistance of Stainless Steel AISI 304L by Diode Laser Surface Alloying with Chromium Carbide
Authors: Janicki Damian
Published: November 2015

Metal matrix composite layers were fabricated on AISI 304L substrate by diode laser surface alloying with direct injection of chromium carbide Cr3C2 powder into the molten-pool. The influence of laser alloying parameters on the quality of the alloyed layers were investigated. The alloyed layers were examined by optical metallography and scanning electron microscopy. Comparative erosion tests between the AISI 304L substrate and the alloyed layers have been performed following the ASTM G 76 standard test method. The uniform laser beam intensity profile of the laser used ensures to produce fully dense alloying layers with homogenous distribution of Cr3C2 particle throughout the matrix alloy. Distribution and dissolution of Cr3C2 particles are strongly dependent on the laser power level. The alloyed layers exhited noticeable increased erosion resistance in comparison to AISI 304L substrate for both 30° and 90° impact angles.
Influence of Layer Thickness on Internal Structure of Parts Manufactured from 316-L Steel Using SLM Technology
Authors: Buican George Răzvan , Oancea Gheorghe , Lancea Camil , Pop Mihai Alin
Published: November 2015

Nowadays Additive Manufacturing, and in particular Selective Laser Melting (SLM ), is being used more and more. The SLM manufacturing process has been subjects to a lot of studies in order to improve the manufacturing parameters. In this paper are presented some researches on the internal structure of the manufactured parts with two layer thickness: 30[μm] and 50[μm]. The internal structure of parts manufactured on SLM machine is obtained as images with a microscope. On the images each grain of the internal structures is painted in a different color and grouped according to its shape. All data about grains are analyzed by the means of statistical methods. The two manufacturing strategies, 30[μm] and 50[μm] layer thickness, generate parts that have slightly different internal structures. Thus, from the point of views of internal structure and manufacturing time, the strategy with 50[μm] layer thickness can be used because it generates a lowering in manufacturing costs and increases the overall productivity.
Premises for Experimental Research of the Electrochemical Machining
Authors: Caracaş Geo , Slătineanu Laurenţiu , Mourão António , Coteaţă Margareta , Beşliu Irina
Published: November 2015

The electrochemical machining method ensures conditions for machining workpieces made of electroconductive materials, when the classical machining methods could not be applied or when their use is not able to offer a high efficiency of the machining process. The large diversity of the electrochemical machining procedures needs information about the specific work conditions and adequate establishing of the parameters which characterize the machining process and the factors able to exert influence on the parameters of technological interest. In order to design and materialize some electrochemical machining procedures, an analysis of the conditions specific to the work zone and of distinct subsystems specific to electrochemical equipment was developed. Taking into consideration the results of analysis, equipment for electrochemical machining was designed and materialized. One considered also some possibilities to develop subsequently scientific researches concerning aspects specific to the electrochemical machining process. Preliminary tests proved the possibilities of using the equipment and of its improving in the future.
Application of the Ideas Diagram Method for Device Design in Wire Electrical Discharge Machining
Authors: Bosoancă Gheorghe , Slătineanu Laurenţiu , Coteaţă Margareta , Badanac Ana
Published: November 2015

Wire electrical discharge machining is nowadays applied by using adequate specialized machine tools. A research problem could refer to a device for wire electrical discharge machining, adaptable on the current computer numerical controlled ram electrical discharge machines. The device could be able to be used in order to develop cutting processes in plate type workpieces. The wire electrical discharge machining process was examined and premises for developing a device for wire electrical discharge machining were formulated. These premises are used in order to develop an ideas diagram able to offer suggestions for the structure of the device. Distinct components necessary in the device structure were identified and taken into consideration, and three distinct versions of the device were defined.
Specifics of Surface Micro-Geometry Modification under the Action of Temperature and Electric Field of Electrode Spots
Authors: Topala Pavel , Guzgan Dorin , Rusnac Vladislav , Ojegov Alexandr , Besliu Vitalie
Published: November 2015

The paper presents the results of experimental research on the possibilities of micro-geometry modification of conductible and semiconductor surfaces, that gives them new functional properties. It emphasizes that surface micro-geometry modification occurs in practically all cases of the action by concentrated sources of energy, but a prescribed geometry can be reached only under strict conditions. The process of this geometry formation is a function of the physical and mechanical properties and the chemical composition of the processed material, the gradient of applied energy, the intensity of electric field applied in the interstice between the workpiece and the tool-electrode, the connection mode of the workpiece (as anode or as cathode) in the discharge circuit of the current impulse generator, etc. It highlights the fact that on the processed surface can be formed spherical shaped craters, round asperities or Taylor cone shaped asperities. Depending on the shape and the size of asperities, the active surface area, and, respectfully, the emission and absorption properties of elementary particles and light radiation are modified.
Investigation on CO and Microparticles Concentrations Produced in MAG-M Welding Process
Authors: Mihailescu Danuţ , Gheonea Marius Corneliu , Scutelnicu Elena
Published: November 2015

It is well known that CO and microparticles generated during GMAW welding processes can affect the welder's health and the environment quality and should be avoided. The main goal of the research was to quantitatively assess the concentrations of CO and microparticules resulting through melted wire - shielding gas - welding pool interaction, specific to fusion welding process, in particular MAG-M (Metal Active Gas with Corgon shielding gas)) process. The concentrations of microparticles and emission of CO developed by several combinations of filler metal and shielding gas, such as ordinary solid wire, basic flux-cored wire, rutile flux-cored wire, metal powder cored wire, low fume metal powder cored wire and Corgon 18, as shielding gas mixture, have been monitored and investigated in detail. The experimental data, achieved for different wire feed speed values, were collected by using special devices as Multilyzer NG and MicroDust Pro and further processed, plotted and comparatively analysed. The analysis revealed that the low fume rutile flux-cored wire significantly developed lower concentrations of microparticles and CO, in comparison with the other types of wires used in MAG-M welding process, and a better protection of the environment would be achieved. Important conclusions related to the influence of the wire type on the concentrations of CO and microparticles produced during MAG-M welding process have been drawn and some recommendations useful for the producers of welded structures are provided at the end of the paper.
Testing of Flame Sprayed ZrO2 Matrix Coatings Containing CaO
Authors: Górka Jacek , Czupryński Artur
Published: November 2015

Presented in this article are the properties of flame sprayed ceramic coatings using oxide ceramic materials consisting of a powdered zirconium oxide (ZrO2) matrix with 30% calcium oxide (CaO) applied to unalloyed S235JR grade structural steel. A primer consisting of a metallic Ni-Al-Mo based powder has been applied to plates with dimensions of 5x200x300 mm and front surfaces of ø 40x50 mm cylinders. Flame spraying of primer coating was conducted using a RotoTec 80 torch, and an external surface was coated with a CastoDyn DS 8000 torch. Evaluation of the coating properties was conducted using metallographic testing, phase composition research, measurement of microhardness, abrasive wear resistance (acc. to ASTM G65 standard) and erosion wear resistance (acc. to ASTM G76-95 standard).
The Influence of Quenching Temperature on the Structure of a Dual-Phase Steel with 0.094% C and 0.53% Mn
Authors: Dulucheanu Constantin , Bancescu Nicolai , Severin Traian
Published: November 2015

In this article, the authors have analysed the influence of quenching temperature (TQ) on the microstructure of a dual-phase steel with a low carbon and manganese content (0,094 % C and 0,53 % Mn). The ferrite-martensite structures, typical of the dual-phase steels, has been obtained by intercritical quenching that consisted of heating at temperatures (TQ) ranging between 750 °C and 830 °C, maintaining for 30 minutes and cooling in water. After carrying out intercritical heat treatments, samples have been subjected to metallographic analysis through which the volume fraction of martensite (VM), the volume fraction of ferrite (VF), the carbon content of the martensite (CM), the morphology and distribution of these phases have been determined, and then, the influence of quenching temperature (TQ) has been established.
A Study on Uncertainties in Estimations of Thermal Conductivity of Alumina Nanofluids
Authors: Moldoveanu Madalina Georgiana , Minea Alina Adriana
Published: November 2015

An innovative way of improving the thermal conductivities of fluids is to suspend small solid particles in the fluids. Various types of powders such as metallic, non-metallic and polymeric particles can be added into fluids to form slurries. The thermal conductivities of fluids with suspended particles are expected to be higher than that of common fluids. Application of nanoparticles provides an effective way of improving heat transfer characteristics of fluids. By suspending nanophase particles in heating or cooling fluids, the heat transfer performance of the fluid can be significantly improved. Moreover, the thermal conductivity of nanofluid is strongly dependent on the nanoparticle volume fraction. So far it has been an unsolved problem to develop a sophisticated theory to predict thermal conductivity of nanofluids, although there are some semi empirical correlations to calculate the apparent conductivity of two-phase mixture. In this article few correlations were considered and differences were noted between different theories. In conclusion, a lot of uncertainties in determining thermal conductivity were noticed.
Particularities of Modelling the Mechanical Properties of Woven Composite Fabrics
Authors: Axinte Andrei , Bejan Liliana , Ţăranu Nicolae , Roșca Victoria
Published: November 2015

The mechanical properties of composite fabrics rely on a fabric made by a textile weaving process. In order to use their special ability of being drapeable, instead of just plain weave fabrics, satin or twill reinforcement can be selected. Although some other advantages of the resulting composite, such as good impact resistance or damage tolerance are similar to all woven reinforcement composites, the superior drapeability of satin is a major reason to favour this type of textile reinforcement. This paper is focused on the modelling procedures of stiffness characteristics, specific to satin reinforced laminated composites, using a semi-discrete approach. This method is a compromise between the continuous and pure discrete approaches and is associated with a mesoscopic analysis of the repetitive unit cell (RUC). The elastic properties of the textile reinforced epoxy composite, namely longitudinal modulus and transverse modulus, in case of carbon and fibre glass based 5-harness satin reinforcement, are determined. The differences between the two resulting composite materials and the influence of the various geometric and material parameters involved are studied.
Quantification of Fe-Base Alloy Degradation after Immersion Test
Authors: Săndulache Florina , Stanciu Sergiu , Cimpoesu Ramona , Ratoi Mihaela , Cimpoesu Nicanor
Published: November 2015

A new FeMnSi metallic alloy is proposed as biodegradable material with applications in medical field. The corrosion behavior in simulated body fluids is evaluated after immersion for 14 days. The metallic biodegradable material surface was analyzed with a SEM (2 and 3D)+EDAX equipment. The effects of the solution on the metallic surface present an area with pitting corrosions, marks around 10 µm in depth, and a different one with new chemical compounds form from biological solution with good stability on the surface. Even if is a new biodegradable material based on iron simmilar results about the surface behavior were obtain by other researchers on different FeMnSi chemical compositions.
Rotating Cam and Knife Edge Follower Mechanism Optimisation from Cam Curvature Constraints
Authors: Alaci Stelian , Ciornei Florina , Filote Constantin
Published: November 2015

The work presents an optimisation method for the rotating cam and knife edge follower mechanism using optimisation restraints required to the cam curvature radius when the follower motion law is provided. Imposing a constraint to the cam curvature radius implies a connection between the constructive mechanism parameters. The optimisation condition is plotted in the plane of constructive parameters and a closed curve corresponds to the case of a law of motion with continuous acceleration. If the “characteristic point” is placed outside this region, automatically conducts to fulfilled condition, for any mechanism’s position. For an analytical study, in the present work, the restraint of strictly positive cam curvature radius was imposed.
Programmes for a NC Command Rehabilitation Equipment Designed for Knee and Hip Affections Recovery
Authors: Petre Ioana Mădălina , Deaconescu Andrea
Published: November 2015

The aim of the article is to present an experimental research on the behavior of a pneumatic muscle actuated rehabilitation device for hip/knee affections, developed in a laboratory from Transylvania University of Brașov. The equipment has been tested and studied its response to some rehabilitation programs implemented: one for hip joint recovery and other for knee joint recovery. For the research was used WINPISA software with the two programs created by the researchers using NC commands. The knee rehabilitation program consists of slider displacement corresponding to a rotating angle of the knee of 75 degrees with a short temporization and the hip joint rehabilitation program consists of slider displacement corresponding to a rotating angle of the hip of 40 degrees. The results of experiments present the displacement of the slider which effectuates the rehabilitation moves, the velocity and acceleration in a proposed time.
Research on the Growth Sustainability Active Organs of Agricultural Machinery
Authors: Lungu Sergiu , Mitsi Sevasti , Ion Antonescu , Paraschiv Dragos , Rotariu Constatin , Bădănac Ana , Popa Sorin , Munteanu Camelia Elena
Published: November 2015

One way to increase the durability of the machine is active surface coatings using new technological processes such as thermal spray coatings, especially the plasma jet. Was made by coating nickel plating process of the plasma jet knife blade for removal of a group from the grower. In order to emphasize increasing the reliability of these knives by coating with nickel, they were mounted on a cultivator with a lot of knives witness, uncovered, and have been used extensively. Data on wear two groups of knives, coated with nickel and witness uncovered were recorded by photometric methods were processed and plotted statisitic. There was a significant decrease of 66.79% in average wear on the knife blades coated with nickel compared to the control, uncoated.
Modified Mohr-Coulomb Theory for Triaxial State of Stress
Authors: Barsanescu Paul Doru , Comanici Ana Maria , Andrusca Liviu , Savin Adriana
Published: November 2015

The Mohr-Coulomb failure theory presents the major drawback that can be applied only for plane state of stress. In this paper, we propose a modification of the Mohr-Coulomb theory that might eliminate this disadvantage. It is proposed to replace the three Mohr's circles for spatial state of stress with one “virtual circle” with diameter σ1-σ3±2ρ, concentric with the circle that has the diameter σ1-σ3. The triaxial state of stress and biaxial state of stress are considered to be equivalent dangerous.
Some Considerations on Vibration Diagnose of Miniature Ball Bearings
Authors: Tărăboanţă Iulian Paul , Paleu Viorel , Bujoreanu Carmen , Benchea Marcelin , Olaru Dumitru
Published: November 2015

Vibration based fault detection and diagnose analysis is a well established field in machine or monitoring supervision. The vibration diagnose is also suited for the miniature ball bearings monitoring. The typical balls size starts at 3 mm with the bearing outer diameter of maximum 20 mm. Ball bearings of this size are ideal for precision mechanisms, they are able to carry light loads and they are perfect for handheld medical equipment and tools which must be very small but also very precise and durable. The paper presents experiments carried out on a fully instrumented universal CETR micro-tribometer at room temperature. The tested miniature ball bearing, lightly loaded and operating at low speeds, is subjected to dry and lubrication conditions with two different oil viscosities. A comparative study is realized concerning the vibration diagnose potential using the FFT analysis of the bearing acquired signals. Statistical analysis of the vibration signals is a key point in the detection of the overall vibration level of bearings lubricated with oils of different viscosities.
Control of a Pneumatic Muscle Actuated Rehabilitation System of the Lower Limb Bearing Joints
Authors: Deaconescu Tudor , Deaconescu Andrea
Published: November 2015

The specific objectives of rehabilitation medicine are maintaining and recovering human body functions, as well as preventing dysfunctionalities by means of kinetic and orthotic techniques and a variety of equipment for support and adaptation. The latter are medical systems facilitating the exercise of muscles at constant or variable speeds according to professional recommendations. The paper presents and discusses the control of rehabilitation equipment designed for the passive mobilisation exercises of joints. The novelty of such equipment resides in its actuation by pneumatic muscles, as well as in its control by means of an SPC 200 controller and WinPISA software. The paper presents a number of examples of rehabilitation programmes and the corresponding motion graphs of the rehabilitation equipment sliding block.
Research Regarding Improvement of Torsional Stiffness for Planetary Speed Reducers Used in the Actuation of Industrial Robots
Authors: Butunoi Paul Alin , Stan Gheorghe , Ungureanu Ana Lăcrămioara
Published: November 2015

Planetary speed reducers are used in the actuation of the revolute kinematic joints thanks to their specific advantages. However, in order to achieve a good positioning accuracy for the kinematic chains, these must have reduced backlash and high torsional stiffness. Therefore the deformations of the elements composing the mechanical structure under the action of gearing forces should be as low as possible, thus leading to backlash reduction. This also becomes important since the presence of backlash in the structure of the planetary speed reducer affects the stability of the overall kinematic chain. In this paper, a novel computation method for bearing deflections is proposed, starting from the kinematic diagram of the planetary speed reducer. Having known the kinematic diagram, it becomes possible to compute the gearing forces, keeping in mind the non-uniform power distribution on the planetary gears. The bearing reactions were computed in two cases: when the planetary gears are free to spin on the planetary carrier and when the planetary gears are fixed on the planet carrier, being supported at the extremities. Based on the computed values for bearing reactions, the corresponding deflections are determined. Once the values of the bearing reactions and deflections had been determined, the load-deflection and stiffness-deflection diagrams were elaborated for ball and roller bearings, allowing the determination of the bearing type that ensures low deflections and high stiffness. Based on the results, some recommendations are made, allowing the reduction of bearing deflections, and increasing the torsional stiffness.
Layered Structures Analysis, with High Entropy Alloys, for Ballistic Protection
Authors: Cherecheş Tudor , Lixandru Paul , Geantă Victor , Voiculescu Ionelia , Dragnea Daniel , Ştefănoiu Radu
Published: November 2015

In this paper the authors present some of the results of research on the behavior of high entropy alloys used in ballistic protection structures. Bullet impact testing methodology and results on layered Ballistic Packages that incorporate high entropy alloys (HEA) are presented. The paper details the technological processes used to improve the mechanical characteristics of Ballistic Packages. The optimization of the high entropy alloy based layered ballistic composite structures is also investigated. Testing methodology of ballistic boxes, the special heat treatment processes, the homogenization and the artificial aging of high entropy alloys, designed and applied during scientific research; represent the novelties of the article. Ballistic Packages are layered structures which include combinations of the following materials: HEA, armored steel, ceramic plates and laminated polyamide fibers arranged in a predetermined order depending on the constructive version. Ballistic Boxes behavior was investigated by ballistic experimental methods and numerical simulation methods. For the numerical simulation a FEM with an explicit numerical code was used. The numerical and test results are consistent in underling the ballistic protection effectiveness of the investigated configuration.