Journal of Mechanical Engineering 56 (2010) 5

SV-JME-5-2010 in digital form »

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Characterisation of High-Carbon Steel Surface Welded Layer

 

Corresponding author - Olivera Popović

Authors - Radica Prokić-Cvetković - Aleksandar Sedmak - Vencislav Grabulov - Zijah Burzić - Marko Rakin

Abstract

In this paper microstructural and mechanical properties of high-carbon steel surface welded layer, obtained with self-shielded flux cored wire, are presented in the case of a standard rails and crossings. The testing results of tensile characteristics, hardness, toughness via instrumented Charpy pendulum, microstructural analysis and fatigue crack growth resistance of all characteristical zones are analysed in details, especially from the point of view of interaction between microstructure and properties.
Obtained results indicate superior properties of repaired welded layers, due to their similarity to the new generation of bainitic steel, i.e., due to change of microstructure from original pearlitic structure to final bainitic structure. Finally, fatigue crack growth parameters have shown that deposite layer has higher resistance to the crack growth, improving overall reliability of rails and crossings.

Keywords - surface welding, toughness, fatigue crack growth parameters, bainitic microstructure

Paper's information

Strojniški vestnik - Journal of Mechanical Engineering 56(2010)5 
UDC 621.791.05

 Characterisation of High-Carbon Steel Surface Welded Layer (pdf)

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Optimum Design of a Hybrid-driven Mechanical Press Based on Inverse Kinematics

Corresponding author - Hui Li

Avtorji - Lihui Fu -Yuping Zhang

Abstract

A novel hybrid-driven mechanical press for deep drawing is presented. The main feature of hybrid-driven linkage is to combine the motion of a large constant velocity motor with a small servomotor via a two degree of freedom mechanism. The former provides the main power and motion required, while the latter acts as a motion modulation device. Therefore, the hybrid-driven linkage can provide for programmable motion output. In this paper, a mechanical press driven by hybrid mechanism is developed that considers the displacement and velocity requirement of the drawing process. Inverse kinematic analysis and dimension synthesis optimization of this hybrid-driven mechanism is presented, which points out a new way for press research and provides a new method for press application in flexible manufacture.

Keywords - hybrid-driven mechanism, press, deep drawing, optimum design, servomotor

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)5
UDC

 Optimum Design of a Hybrid-driven Mechanical Press Based on Inverse Kinematics (pdf)

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Application of Non-Discrete Boundaries with Friction to Smoothed Particle Hydrodynamics

Corresponding author - Gregor Petkovšek

Authors - Elvira Džebo - Matjaž Četina - Dušan Žagar

Abstract

Smoothed particle hydrodynamics (SPH) is a meshless particle method for simulation of fluid flows. It is especially suitable for simulating flows with rapid changes. Treating the solid boundaries, however, is not as straightforward as with finite element or finite volume based methods. This paper describes a non-discrete boundary with friction approach to model particle-boundary interaction. This approach is mathematically consistent with the solution for the particle-particle interaction, and it provides a continuous solution along the boundary. The proposed model was verified against the experiments of Martin & Moyce [1] and numerical simulations by other authors. The results showed at least as good overall agreement as the simulations of other models, while local behaviour at the boundaries was better.

Keywords - hydrodynamic simulation, meshless particle method, boundary treatment, fluid column collapse

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)5
UDC 532.5:519.876.5

 Application of Non-Discrete Boundaries with Friction to Smoothed Particle Hydrodynamics (pdf)

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Experimental Analysis of the Deviation from Circularity of Bored Hole Based on the Taguchi Method

Corresponding author - Ihsan Korkut
Authors - Yilmaz Kucuk

Abstract

In this study, the effects of cutting parameters, boring tool material and the overhang ratio of boring tool (tool clamping length) on the deviation from circularity of bored hole were examined experimentally. The optimal cutting condition can be estimated by the analysis of the signal to noise (S/N) ratio in Taguchi method. The individual contributions of each factor on the deviation from circularity were calculated by using the Analysis of Variance (ANOVA). Therefore, at the determined condition, it could be observed that whether if a factor is significant or not. Also it was observed that the values of deviation from circularity increased significantly with increasing the effective tool length at the lower depth of cut values. Besides, the circularity could be improved with increasing the depth of cut values for the same tool clamping lengths.

Keywords - boring, machining, experimentation, optimization, Taguchi, analyze

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)5
UDC 621.95

 Experimental Analysis of the Deviation from Circularity of Bored Hole Based on the Taguchi Method (pdf)

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A Multi-Objective optimization of a robotic arm for service tasks

Corresponding author - Cristina Castejón

Authors - Giuseppe Carbone – J.C García Prad - M. Ceccarelli

Abstract

In this paper, main characteristics and peculiarities of service tasks are investigated in order to propose design criteria in the form of computationally efficient objective functions. Then, these design criteria can be implemented in a multi-objective optimization algorithm by using ever commercial packages in order to obtain optimal design solutions for service robots. The proposed procedure has been applied to a robotic arm for service tasks that is composed of two modules having altogether four degrees of freedom (dofs). The main module with two dofs is called as SIDEMAR (Spanish acronym of Mechatronic Design of an Integrated System for Service Robots). It has been designed and built at Carlos III University of Madrid as a module for service robot applications. Results of the above-mentioned case of study are reported to show both the soundness and engineering feasibility of the proposed multi-objective optimal design procedure.

Keywords - Robotics, Robot Design, Service Robots, Optimal Design

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)5
UDC

 A Multi-Objective optimization of a robotic arm for service tasks (pdf)

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Solving JSSP by Introducing Hamilton Similarity and Time Dependent Fitness Scaling

Corresponding author - Arijan Abrashi

Authors - Nedjeljko Štefanić - Dragutin Lisjak

Abstract

In this paper we proposed and tested a niching genetic algorithm (GA), which for comparison of individuals in the population uses so-called Hamilton similarity. The advantage of the Hamilton similarity lies in the fact that there is no need for context sensitive information in order to successfully compare two population members. Furthermore, the algorithm was tested on the famous Job Shop Scheduling Problem (JSSP) - benchmark mt10, and statistical results of the test were given. Significantly smaller standard deviation of the proposed GA compared to Simple GA clearly demonstrates its superiority.
In addition to the Hamilton similarity, time dependent fitness scaling was proposed which in conjunction with niching significantly reduces the probability of the algorithm to get stuck in one of the less desirable local optimum. Finally, suggestions for future research are given.

Keywords - genetic algorithm, niching, Hamilton similarity, time dependent fitness scaling, Job shop scheduling problem (JSSP)

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)5
UDC

 Solving JSSP by Introducing Hamilton Similarity and Time Dependent Fitness Scaling (pdf)

 

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Novel Technique for Spatial Objects Shaping With High-Pressure Abrasive Water Jet

Corresponding author - Przemyslaw Borkowski

Abstract
Novel method for the 3D shaping of different materials using a high-pressure abrasive water jet is presented in the paper. For steering movement process of the jet a principle similar to raster image way of record and readout was used. However, respective colors of pixel of such a bitmap are connected with adequate jet traverse speed that causes erosion of material with adequate depth. Thanks to that innovation, one can observe spatial imaging of the object. Theoretical basis as well as spatial model of material shaping and experimental stand including steering program are presented in. There are also presented methodic and some experimental erosion results as well as practical examples of object’s bas-relief made of metal.

Keywords - high-pressure abrasive water jet, material shaping

Paper's information
Strojniški vestnik - Journal of Mechanical Engineering 56(2010)5
UDC 621.7.04:621.527.4

 Novel Technique for Spatial Objects Shaping With High-Pressure Abrasive Water Jet (pdf)

 

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