Abstract: Virtual prototyping becomes more and more a less-expensive alternative of physical mockups. Its applicability to product certification procedures is already included in several standards where it is possible to replace completely physical prototyping and testing. A sample is given based on the standard for assessment of mechanical behavior of railway applications – wheel sets and bogies – EN 13979-1:2003+A1:2009. This study includes developed assessment approach for wheel mechanical strength check using engineering analyses, based on virtual prototyping technology. The approach contains 6 steps that allow user to determine required by the standard dynamic stress maximal values and to compare them against permissible ranges stated in the standard. Developed approach is demonstrated by an example of monoblock wheel for train vehicle up to 50t load capacity. This example shows an effective way to reduce expenses and obtain a cost-effective solution as well as to shorten time to reach market. Additional advantage is design evaluation at early stage of product life cycle and possibility to explore structural behavior in detail as to improve product performance. Virtual prototyping application combines overall product performance optimization, time and expenses reduction and detailed diagnosis of ongoing physical phenomena.

Key words: virtual prototyping, engineering analyses, train wheel, FEA.

pp. 105-110 View full text

OPTIMIZATION OF GEOMETRIC PARAMETERS OF HARD METAL MICRO

DRILS TO INCREASE TOOL LIFE AND PERFORMANCE OF DRILLING

PACKAGE OF PRINTED CIRCUIT BOARDS

Raul TURMANIDZE^1,*, Vasili BACHANADZE², Giorgi POPXADZE³

¹⁾ Doctor of science, Prof., Head of the Department, Production Technologies of

Mechanical Engineering department, Georgian Technical University, Tbilisi, Georgia

²⁾ Senior laboratory, Production Technologies of Mechanical Engineering Department, Georgian Technical University, Tbilisi, Georgia

³⁾ Undergraduate Student, Faculty of Transportation and Mechanical Engineering, Georgian Technical University, Tbilisi, Georgia

Abstract: In the presented work, there are investigated the changes of power characteristics of deep drilling package of printed circuit board’s hard-alloy micro drills depending on the drilling depth, cutting data and geometry of the drill. In particular are studied the nature of changes in axial efforts and torque depending on the drilling depth drill with different inclinations of the spiral grooves using specially designed highly sensitive devices, enabling direct measurement method. On the basis of the analysis of results of research are made the changes in geometry of the existing standard drills. New construction of micro drills vari-angle spiral grooves in such a way that the angle is the maximum value at the top of the drill and uniformly decreases towards the end of the working parts are suggested. The drills are manufactured with different inclinations of the spiral grooves. On the basis of experiments of them chosen more for its close standing power rates to the standard drill bit and its comparative test with a standard drill bit, bringing them up to the breakage, thanks to which the proven advantages of drills new design. Taking into account the results of the experiments, there are suggested drill elongated structures to improve performance by increasing the processing drilling depth and accordingly the number of plates in the package of printed circuit boards.

Key words: drill, gradient of spiral groove, variable angle, device.

pp. 111-116 View full text

REMOTE CONTROL OF HYDROSTATIC DRIVE MECHANISMS

FOR HOISTING MACHINERY AND LOGISTICS CENTERS

Otto GRIGOROV¹, Vsevolod STRYZHAK², Daria ZIUBANOVA³

¹⁾ Prof., D.Sc. in engineering, National Technical University “Kharkiv Polytechnic Institute”, Kharkiv, Ukraine

²⁾ Senior Lecturer, National Technical University “Kharkiv Polytechnic Institute”, Kharkiv, Ukraine

³⁾ Ph.D. Student, National Technical University “Kharkiv Polytechnic Institute”, Kharkiv, Ukraine

Abstract: The analysis of the crane or loader travel mechanism construction with hydrostatic drive and low-moment hydraulic motor has been performed. It has been proposed that the electric circuit of pump performance remote control system that meets the requirements applicable to the crane drives control system. The zero-setter design has been developed for hydraulic drive emergency braking in case of an emergency, while the bridge runover on the obstacle when travel limit switches of the traveling mechanism triggered , and also the electric drive motor of the pump and electric control scheme of pump productivity loses power. The hydraulic circuit of the lifting machines mechanism is presented and its operating principle is described. Implementation and testing of remote control system elements are implemented on the travel mechanism experimental stand of the crane with a lifting capacity of 32/5 t that is described in the article.The stand design allows to provide long-term trials in a wide range of static and dynamic loads, to realize implement typical operation cycles and to record the nature of dynamic loads and energy consumption. In consequence of the research it was proved that hydrostatic drive with low-moment hydraulic drive and described remote control system has deep adjustable speed for a given program, softens dynamic load transients, and saves a significant amount of power during acceleration and braking.

Кey words: hydrostatic drive, travel mechanism, control system, low-moment hydraulic motor, hydraulic motor, servomotor.

pp. 117-122 View full text

INTEGRATION OF VIRTUAL ROBOTS WITH PHYSICAL ROBOTS BASED ON WIRELESS COMMUNICATIONS

Aurel FRATU^1,*

¹⁾ Prof., PhD, Dept. of Automatics and Technology of Information, “Transilvania” University of Brasov, Brasov, Romania

Abstract: In this paper, we propose the idea of integration of virtual robots prototypes with physical robots, based on wireless communications. The goal of this paper is to discuss how the virtual prototyping can be effectively employed for design challenges dealing with non-material concepts, in form of virtual prototypes, that permits to examine on a computer monitor, the behavior of the physical robots using her virtual prototype to predictive programming idea. Virtual prototypes as non-material systems can communicate wirelessly with physical robots by transferring the virtual path of virtual robot prototypes in domains of the work space of the physical robots. In this paper we discuss the requirements and opportunities of such an approach.

Key words: virtual prototyping, virtual robot, wireless communication, wireless robots networks, robot programming.

pp. 123-130 View full text

COMPARATIVE ANALYSIS OF HARDNESS IN DIFFERENT ZONES OF WELD

Nicolae GRIGORE^*

PhD. Student, University “Politehnica” of Bucharest, Department of Materials Technology and Welding, Bucharest, Romania

Abstract: This paper studies the HV 10 Vickers hardness values measured on the end zones (beginning and end) of the samples taken for approval of welding technologies to analyze the situation less common welding technology without end plates. These values are then compared with those determined by measurements made in areas of welds means to assess the degree of deviation from the recommended values for steel grade analyzed. It was chosen for homologating of a welding process a steel sheet of thickness 20 mm of P355NL1 quality welded by the processes 141 + 111 + 121. The work presents the macroscopic and microscopic analysis of samples and preheats temperature calculation, calculation and estimation of carbon equivalent maximum hardness in the heat affected zone when welding steel P355NL1. In these areas of the beginning and end of the seam, there is a situation similar to welding the weld below 100 mm in length, where the thermal field propagates in welding non-steady state compared to the middle portion of long welded row, where the heat propagates quasi-stationary regime.

Keywords: weld, hardness HV 10, homologation, HAZ, WIG welding.

pp. 131-140 View full text

WORKFLOW FOR ADDITIVE MANUFACTURING OF AN INDIVIDUALIZED

SURGICAL TEMPLATE

Diana POPESCU^1,*, Dan LĂPTOIU², Anton HADĂR³, Cătălin ILIE⁴, Cristian PÂRVU⁵

¹⁾ Assoc. Prof., PhD, Machine and Manufacturing Systems Department, University “Politehnica” of Bucharest, Romania

²⁾ M.D., PhD, Colentina Clinical Hospital, Orthopedics II Department, Bucharest, Romania

³⁾ Prof., PhD, Department of Strength of Materials, University “Politehnica” of Bucharest, Romania

⁵⁾ Eng., Head of Research Projects Department, OSF Global Services, Romania

⁶⁾ Eng., Project Manager, OSF Global Services, Romania

Abstract: Individualized surgical templates are becoming increasingly used in the medicinal field due to their advantages, ensuring better orientation during intervention, decrease of the surgery time and costs, risks of infections and X-ray exposure during surgery. Moreover, their use enrolls in the modern approach of personalized medicine, which envisions tailoring interventions and instruments according to patient’ characteristics and needs. This article presents the workflow for design and manufacturing orthopedics guides using additive technology. A customized osteotomy template for hand is presented as case study, exemplifying the integration between different applications (for medical modeling, .stl files correction, 3D CAD guide modeling, virtual model viewer and annotation, etc.) and serving to the deployment of an intelligent online platform which can support guides’ design and manufacturing process automation. Moreover, this platform contributes to a better communication between surgeon and engineer, thus helping bridging the gap between two fields which have specific professional languages, evaluation criteria, etc.

Key words: design, additive manufacturing, computer tomography, individualized template, osteotomy.

pp. 141-146 View full text

MATERIALS SELECTION FOR AN ENGINEERING APPLICATION USING MULTIPLE-CRITERIA DECISION ANALYSIS

Cătălin GHEORGHIȚĂ^1,*, Vlad GHEORGHIȚĂ²

¹⁾ PhD, Lecturer, University "Politehnica"of Bucharest Romania, Department of Manufacturing Technology, Bucharest, Romania,

²⁾ PhD Student,^.University "Politehnica" of Bucharest Romania, Department of Manufacturing Technology, Bucharest, Romania.

Abstract: The process of choosing materials for one part is always a difficult task, due to the large variety of materials and manufacturing processes. The complex list of requests defining the appropriate material leads to a multicriteria problem. The selection methods must have materials databases and resources for comparing objectively specific materials according to a set of requests. Systematic methods for material selection were developed and implemented in selection programs. The interaction between function, material, shape and process is an important issue in the material selection process. All materials and processes are candidates, requiring a procedure which allows access to data. At the beginning of the design process, the goal of the selection softwares is to establish the best materials. The material for components of machine tools requires special attention for the coefficient of expansion, vibration absorption and strength. Decisions for a given problem are made by using methods of decision making to eliminate unsuitable alternatives and to select the most suitable alternative. A decision matrix method is a formalized procedure by which materials are classified considering the selection decision. In this paper a method is used to identify the best solution for conventional and alternative materials used in machine tool structures.

Key-words: material selection, machine tool, multiple criteria decision, subjective weight, Topsis method.

pp. 147-152 View full text

BUSINESS PARTNERS EVALUATION & SELECTION AT THE SMES

– A ROMANIAN CASE STUDY

Dan Alexandru MITREA¹, Sebastian Marius ROSU², Ionel-Bujorel PAVALOIU³, George DRĂGOI^4,*

¹⁾ PhD Student, Faculty of Engineering in Foreign Languages, University POLITEHNICA of Bucharest, Romania

²⁾ PhD, Special Telecommunications Service, Bucharest, Romania

³⁾ Lecturer, Faculty of Engineering in Foreign Languages, University "Politehnica" of Bucharest, Romania

⁴⁾ Prof., Faculty of Engineering in Foreign Languages, University "Politehnica" of Bucharest, Romania

Abstract: At the SMEs level, the partner evaluation and selection is an activity aimed to build a business partnership that will lead both to increased competitiveness and adaptability to market demands. In recent years, the Romanian SME investments needed to implement a knowledge management system closely related in terms of ICT facilities and existing software, personnel qualification, objectives and the chosen technology solution implementation. The knowledge-based system for the partner evaluation and selection presented in this paper was implemented at the Department of Engineering and Foreign Languages and the UPB-PREMINV&CTTM research centers from University "Politehnica" of Bucharest, in an university – SMEs partnership.

Key words: business partnership, knowledge-based system, partner evaluation, partner selection, SME..

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